SECTION B3400: PAVEMENT LAYERS OF GRAVEL MATERIAL
B3401
SCOPE
Add the following:
“This section also covers the construction of pavement drainage layers.
The scope includes the work and constraints as described in Part C4: Site Information.”
B3402
MATERIALS
(a)
General
Add the following at the end of the second paragraph:
“For chemically stabilised layers the material shall conform to the requirements in table B3402/5.”
Add the following after the second paragraph:
“Distinction shall be made between crushed and natural G4, G5 and G6 materials. Where the
crushing and/or screening of these materials has been specified, the combined grading shall conform
to the grading limits specified for G4 class material in table B3402/1. Material used to construct all
stabilised subbase layers shall be of crushed G5 quality and the combined grading shall conform to
the grading limits specified for G4 class material in table B3402/1.
The same shall apply for all materials obtained from commercial sources.”
Add the following:
“Natural gravel material may also be obtained from commercial sources as provided for in the
schedule of quantities and where such material is to be used in chemically stabilised pavement layers
it shall be capable of achieving the requirements stated in table B3402/5 for C3 and C4 with not more
than 3% cement.
When materials from different sources are mixed together in a lot the uniformity of the mixed material
shall be determined from the CBR values of at least six samples taken randomly, by expressing the
calculated standard deviation value of the set of CBR values as a percentage of the calculated mean
value of the same set of results. The variation value so determined shall not be greater than 30% for
the G7 material in the selected subgrade layer, and not greater than 25% for the G5 material in the to
be stabilised subbase layer.”
Replace the grading section in Table 3402/1 with:
Nominal
aperture
size of
sieve (mm)
Grading
53
50
37,5
28
20
14
5
2
0,425
0,075
Percentage passing through sieve by
mass
Crushed material
Uncrushed
Nominal max size
material
37,5 mm
28 mm
100
95 - 100
100
85 – 100
86 - 95
73 - 86
87 - 96
61 - 91
61 - 76
73 – 86
37 - 54
43 - 61
31 - 66
23 – 40
27 – 45
20 – 50
11 – 24
13 – 27
10 – 30
4 - 12
5 - 12
5 - 15
The
percentage
by mass
passing
the
2,00mm
sieve shall
not be less
than 20%
not more
than 70%
Note:
Refer to standard COLTO table for COLTO grading if required
C3-92
Replace table 3402/5 with:
“Table B3402/5
Requirements for Chemically Stabilised Layers
Classification
C1
C2
Material before
At least G2
At least G4
treatment
quality
quality
PI after treatment
UCS (MPa) *(2)
ITS (kPa) *(3)
WDD (% loss)
Non-plastic
6 min.
5 max.
Non-plastic
4 min.
10 max.
C3
At least G5
quality, (but with
G4 grading)
6 max. *(1)
1,5 min
250 min.
20 max.
C4
At least G6
quality
6 max. *(1)
0,75 min.
200 min.
30 max.
Note:
* (1) For materials derived from the basic crystalline rock group, the Plasticity Index after stabilisation
shall be non-plastic.
* (2) Unconfined Compressive Strength @ 100% Mod. AASHTO density at 7 days *
(3) Indirect tensile Strength @ 100% Mod. AASHTO density at 7 days
* (4) Wet/Dry Durability according to Method B 8110”
Add the following after the last paragraph:
“With the in-situ reconstruction of the pavement layers, the existing pavement layers may be broken
up in part or completely and mixed together with additional imported material.
The existing pavement layers and imported material does however contain isolated hard boulders with
sizes varying up to the layer thicknesses of the existing pavement layers and more. The Contractor
shall do the necessary investigation prior to in-situ reconstruction of any pavement layer in order to
verify that his choice of equipment can cope with the existing pavement layer types and conditions
without the risk of damage to his construction equipment. The cost of this investigation shall be
deemed to be included in the tendered rates of sections 3300 and 3400.
No claim for additional payment for damage to equipment as a result of construction equipment
incapable of coping with the existing pavement layer types and conditions shall be considered.”
(b)
Compaction requirements
Amend the compaction requirements as follows:
“The minimum in-situ dry density of sand and gravel material on this project shall be as specified
hereinafter for the respective layers in terms of a percentage of modified AASHTO density.
Selected layer:
Lower Selected layer (G9)
Granular upper Selected layer (G7)
(Not sand)
Subbase (Crushed G5):
93% (100% for sand: see B3402(e) and Table B3402/7)
95%
97% for material not chemically stabilized
97% for chemically stabilized (C3 / C4) material
Gravel Shoulders (G5)
& Wearing course (Type 2)
97%
Drainage layer
95%”
The minimum densities specified shall be attained throughout the full depth of the layer including the
upper 50 mm. For layers constructed in thicknesses of 200 mm and thicker the density of the upper
and lower half of the layer shall be measured and evaluated separately.”
C3-93
Add the following clauses:
“(d)
Drainage material
Material for a drainage layer shall comply with the following requirements:
The Plasticity Index shall not exceed 6.
The gradation of the material in the completed drainage layer, measured after compaction shall
comply with the limits stated in table B3402/6.
Table B3402/6
GRADATION OF DRAINAGE MATERIAL
(e)
Sieve Size (mm)
Percentage by mass passing
53,0
37,5
28,0
14,0
5,00
2,00
0,425
0,075
100
74 - 100
57 - 98
41 - 69
25 - 37
15 - 20
4-9
0-4
Defining sand and compaction requirements
Material within the limits as described in table B3402/7 below will be classified as sand.
Table B3402/7
DEFINING SAND
PROPERTY
Grading percentage passing:
5,00 mm, (minimum)
0,425 mm, (minimum)
0,075 mm, (maximum)
Plasticity Index
LIMIT
96
50
20
Non-plastic
“Notwithstanding the above criteria, the compactibility of a material shall be assessed by means of
trials and if it is found that it compacts readily to a density of 100% of modified AASHTO and is nonplastic, it shall henceforth be classified as sand for the purposes of the density and CBR at 100%
modified AASHTO.”
B3403
CONSTRUCTION
Requirements applying prior to the construction of the layer
Delete the third paragraph which starts with “Where the in situ material .......”.
Add the following:
“The contractor shall note the requirements of clause B3307(d)”
(b)
Placing and compaction
Insert the following paragraph after the 1st paragraph:
“All in-situ density determinations shall be measured using two individual nuclear density gauges that
have been calibrated/validated according to the guidelines described in the manuals for each type of
nuclear gauge. The reading taken by each nuclear gauge shall be calculated to obtain a density and a
moisture content. Both density results shall then be average to obtain a single result. This result will
then represent the density achieved of the spot being tested as the accepted value.
C3-94
The minimum densities specified shall be attained throughout the full depth of the layer including the
upper 50 mm. For layers constructed in thicknesses of 200 mm and thicker the density of the upper
and lower half of the layer shall be measured and evaluated separately.”
(ii)
Shoulders
Add the following:
"Where the existing unsurfaced shoulder has to be temporarily surfaced to accommodate traffic it shall
be constructed to the width shown on the drawings or directed by the engineer.
If material is to be added to the base layer of the shoulder in order that the final compacted inner edge
may be level with the adjacent roadway with a cross-fall of 3%, it shall be done with G5 quality gravel
material.
Having flattened and spread any imported material, the base layer shall be ripped or scarified over the
required width to a depth of 150 mm, watered, mixed, shaped and compacted to 95% of modified
AASHTO density. If so ordered by the engineer, the shoulder shall be stabilised with the addition of
cement as specified in section 3500.
The contractor shall take care to ensure that despite the restricted working width, the material is well
mixed with a uniform moisture content and that a neat and well compacted joint is formed between the
shoulder and the adjacent pavement and shall grade the shoulder such that with the surfacing to
follow, surface water will drain without ponding on the roadway.”
(e)
Classification of layers for payment purposes
Replace the first paragraph with the following:
“Payment for pavement layers constructed from gravel material, shall distinguish between layers
constructed with material from cuts, or from existing pavement layers, or from commercial sources, or
in situ reprocessed layers with or without the use of additional material.”
Add the following subclauses:
“ (f)
Utilisation of existing pavement materials
When the road to be constructed overlaps the existing road prism, the materials from the existing
pavement layers including the surfacing, shall be utilised as specified or as instructed by the engineer,
and if not to be spoiled, shall be used either in fill or in selected subgrade layers of the new road.
In the case of half-width construction the contractor shall take care and use suitable techniques for
cutting the existing surfacing in a neat line along the inner edge of the working width. Excessive over
break of the surfacing extending into the roadway of adjacent traffic shall be reinstated at the
contractor's own cost to the satisfaction of the engineer.
(g)
Stormwater drainage
The contractor shall, at no additional payment, apply sound constructional principles to protect the
works and keep pavements dry as specified in clause 1217. In the case of partial-width construction
where on account of the box construction, accumulation or ponding of stormwater may occur in the
low spots, special measures will be required to provide temporary drainage. The contractor shall allow
for all such special measures in the tendered rates and no additional payment shall be made on
account of delays or remedial work having to be done where layer material has become too wet under
circumstances which, in the opinion of the engineer, is due to the neglect of the contractor to take the
necessary precautions.”
C3-95
B3405
CONSTRUCTION TOLERANCES
(a)
Level
Replace the table in the sub-sub-clause with the following:
Selected layers
Sub-base layers
Base layers
Shoulders
“H90
Hmax
25 mm
15 mm
12 mm
33
20
15
25
mm
mm
mm
mm"
Add the following:
“Level control for the various pavement layers shall be done at least at the following intervals in the
longitudinal direction:
Layer
Selected layer, shoulders and wearing course
Subbase and Base
(b)
Interval
20 m
10 m
Layer thicknesses
Replace the table in the sub-sub-clause with the following:
Selected layers
Sub-base layers
Base layers
Shoulders
(f)
“D90
Dmax
Dave
25 mm
18 mm
15 mm
35
24
22
30
8
5
5
0
mm
mm
mm
mm
mm
mm
mm
mm"
Surface regularity
Replace the subclause with the following:
“For new base layers and rehabilitation of existing base layers where the layer or part thereof (in
depth) is required to be reworked or recycled over a length of 600 m or more and over the full width of
a traffic lane or shoulder wider than 2.0 m (to be surfaced) the roughness of the base layer will be
determined by using a inertial laser profilometer capable of producing a class 1 vertical measurement
resolution, and a class 3 longitudinal sampling distance as defined in ASTM standard (E950-09). If the
inertial laser profilometer is unavailable the roughness of the base layer can be determined by using a
ARRB Walking Profiler or Face Dipstick® Profiler. However, these latter instruments are not suitable
for mass measurements. Shoulders less than 2.0 m wide (to be surfaced), will be assessed according
to measurements obtained from the adjacent lane.
The inertial laser profilometer, ARRB Walking Profiler or Face Dipstick® Profiler shall be used to record
the longitudinal profile in both wheel tracks of each traffic lane or shoulder wider than 2.0 m, as
determent according to the final line markings that will be applied on road surface after completion of
construction. For Inertial laser profilometer three repeated runs will be required, for the ARRB Walking
®
Profiler or Face Dipstick Profiler only single measurement will be required per wheel track. The two
wheel tracks shall be 1,75 m apart. Should the two tracks not be measured simultaneously during the
same pass, then procedures shall be implemented to ensure that the longitudinal profile data recorded
for the two wheel tracks are at the same longitudinal location on the road.
The measured longitudinal profiles will then be processed using the Quarter-Car simulation model with
parameter values as defined in ASTM standard (E1170-97) for Ride Meter-Vehicle Mounted. The
simulated suspension mentioned will then be linearly accumulated and divided by the length to yield
100 m IRI (International Roughness Index) values in units of mm/m or m/km for each wheel track. The
last 50 metres and the joining first 50 metres of adjacent sections will be evaluated as a 100 m section
in the direction of vehicle travel. For inertial laser profilometer measurements the left and the right
C3-96
100 m IRI values from the three runs for each measured lane will then be averaged to produce the
average IRI as follows:
Run1 IRI 100m Ave = (100m IRI Left wheel track + 100m IRI Right Wheel track) / 2
Run2 IRI 100m Ave = (100m IRI Left wheel track + 100m IRI Right Wheel track) / 2
Run3 IRI 100m Ave = (100m IRI Left wheel track + 100m IRI Right Wheel track) / 2
Average IRI 100m = (Run1 IRI 100m Ave + Run2 IRI 100m Ave + Run3 IRI 100m Ave) / 3
For the ARRB Walking Profiler or Face Dipstick Profiler measurements the Average IRI will be
calculated as follows:
Average IRI 100m = (100m IRI Left wheel track + 100m IRI Right Wheel track) / 2
The Average IRI 100m values is then evaluated and judged according to table B3405/1 to determine
whether the 100 m section needs corrective work or payment adjustments.
Table B3405/1
PAYMENT ADJUSTMENT FOR BASE LAYER
Average IRI 100 m (m/km)
New Pavement Construction
<1.30
1.31 to 1.40
1.41 to 1.50
1.61 to 1.70
1.71 to 1.80
1.81 to 1.90
1.91 to 2.00
2.01 to 2.10
2.11 to 2.20
2.21 to 2.30
2.31 to 2.40
2.41 to 2.50
2.51 to 2.60
2.61 to 2.70
2.71 to 2.80
2.81 to 2.90
2.91 to 3.00
>3.01
1.050
1.050
1.025
1.010
1.000
0,990
0,975
0,955
0,930
0,900
0.865
Reject
Reject
Reject
Reject
Reject
Reject
Reject
Any adjustment to the payment for the base will be made by multiplying the full payment value for
each 100 m section, for payment items B36.01, by the payment adjustment factor derived from table
B3405/1. The payment adjustment shall apply to the total base layer width placed over the 100 m
section in question.
Surfaced shoulders less than 2 m wide will be assumed to have the same roughness measurements
as the adjacent lane and the quantity of material in the shoulder shall be added to the quantity of
material of the adjacent lane for determination of the payment adjustment factor.
C3-97
On sections where the Average IRI 100 m is worse than the cut-off value listed in table B3405/1 the
section is rejected and corrective work will be necessary.
Any corrective work required shall be made by the removal of the total base layer width placed over
the 100 m section in question, followed by reinstatement. Surfaced shoulders less than 2.0 m wide
will be treated similar to the adjacent slow lane. Corrective work shall not commence until the
engineer has approved the contractor’s method statement. If the contractor proposes any other
corrective procedure he shall apply to the engineer for the employer’s approval of his proposal.
Corrective work shall be done at the contractor’s expense and shall be completed prior to determining
pavement thickness. After completion of the corrective work, the 100 m sections shall be re-evaluated
according to the specifications.
The longitudinal profile and the 100 m International Roughness Index (IRI) values shall be determined
using an inertial laser profilometer or an ARRB Walking Profiler or Face Dipstick® Profiler furnished
and operated by the contractor or on his behalf in the presence of the engineer. Prior to using an
inertial laser profilometer it shall have successfully completed a validation trial against the Instrument
®
of Reference (Face Dipstick ) used by the employer.
As an absolute minimum the longitudinal profile shall be measured as soon as a 2000 m section of
lane or shoulder is completed. Where shorter than 2000 m sections of a layer is required to be
constructed the section as a whole will be measured as soon as it is completed. The contractor will be
paid for these measurements under payment item B81.05. No additional payment will be made to the
contractor for additional measurement and analysis of profiles if ordered for his own assessment
purposes, or if additional surveys are required as a result of any remedial/corrective work identified
and subsequently completed.
For new base layers and rehabilitation of existing base layers where the layer or part thereof (in depth)
is required to be reworked or recycled over a length of less than 600 m and over the full width of a
traffic lane or shoulder the roughness of the layer will be determined by using a rolling straight edge as
described in subclause 8111(c), the number of surface irregularities shall not exceed those given
below:
(i)
the average number of irregularities per 100 m equal to or exceeding 5 mm when taken in the
wheel paths over 300 – 600 m lengths: 3
(ii)
the number of irregularities equal to or exceeding 5mm when taken in the wheel paths over 100
m lengths:
4
The maximum value of any individual irregularity measured with the rolling straight-edge or a 3 m
straight-edge shall not exceed 10 mm.
The measurements with a rolling straight edge or 3 m straight-edge shall be done in each wheel path
of each lane or shoulder over the full length of the section.
Where a 3 m straight-edge is used it shall be placed in such a way that for a measured line each
measurement shall overlap by at least 500 mm with the previous measurement.”
B3406
QUALITY OF MATERIALS AND WORKMANSHIP
Replace the second paragraph with the following:
“Test results and measurements will be assessed in accordance with the provisions of Section 8200.”
B3407
MEASUREMENT AND PAYMENT
Add the following at the beginning of this clause:
”Rates tendered under section 3400 shall cover all additional costs involved in initially placing and
compacting the pavement layers in areas larger than theoretically required (in order to achieve
compaction and level control) and later cutting back into the compacted layer when the rest of the road
C3-98
is constructed and no additional payment will be made for this activity. The quantities of the subbase
layer for payment shall be calculated from the authorized dimensions of the completed layer as shown
on the drawings or prescribed by the Engineer.”
Replace the item description of item 34.01 with the following:
“Item
Unit
B34.01 Processing of gravel pavement layers”
Add the following subitem:
“(i)
Drainage layer compacted to 95% of modified AASHTO density (state
layer thickness) ........................................................................................... cubic metre (m3)”
Add the following to the first paragraph:
“For half-width construction the measured quantities shall not include for having to cut back into
previously constructed layers.”
Delete the second paragraph (payment paragraph) of this item and substitute with the following:
“The tendered rates shall include full compensation for mixing, watering, placing and compacting the
material supplied under item B34.03, the protection and maintenance of the layer, the conducting of
control tests and the trimming and removal of surplus material, all as specified.
In addition the tendered rate for subitem (g): gravel shoulders, shall, when combined with item B34.03,
include full compensation for reworking the existing shoulders as specified in subclause B3403(b)(ii). ”
Replace the description of item 34.02 with the following:
“Item
Unit
B34.02 Extra over item B34.03(a) for excavation of material in:”
Add the following to the first paragraph:
“Measurement shall be as for item 33.03.”
Replace item 34.03 with the following:
“Item
Unit
B34.03 Supply of material for pavement layers
(a)
Gravel taken from cut or borrow including free-haul up to 1,0 km .................. cubic metre (m3)
(b)
Non-cemented material reworked in situ ....................................................... cubic metre (m3)
(c)
Non-cemented material taken from pavement layers, including freehaul up to 1,0 km.......................................................................................... cubic metre (m3)
(d)
Commercial sources (including unlimited free-haul)
(i)
(ii)
(iii)
(iv)
(v)
(vi)
(vii)
G9 quality material ...................................................................................... cubic metre (m³)
G7 quality sand ............................................................................................ cubic metre (m³)
G7 quality gravel (not sand).......................................................................... cubic metre (m³)
G5 quality material ....................................................................................... cubic metre (m³)
G5 quality (with a G4 grading) crushed material (37.5 mm nominal
size) (not Laterite, not bituminous)................................................................ cubic metre (m³)
Crushed stone drainage layer material ......................................................... cubic metre (m³)
Wearing course material (Type 2) ................................................................. cubic metre (m³)
(e)
Milled bituminous material in stockpile .......................................................... cubic metre (m³)
C3-99
In general the unit of measurement shall be the cubic metre of compacted pavement layer, and the
quantity shall be calculated from the authorised dimensions of the completed layer unless otherwise
specified hereinafter. For half-width construction the measured quantities shall not include for having
to cut back into previously constructed layers.
For subitem (a) the tendered rate shall include full compensation for procuring, as if from soft
excavation or pits, transporting the material for a distance of 1,0 km, for off-loading and spreading,
breaking down, and for the removal, disposal and transporting for a distance of 1,0 km, of up to 5% by
volume of oversize material, all as specified.
For subitem (b) the tendered rate shall include full compensation for ripping and breaking up noncemented existing pavement material intended to be reworked in situ and for mixing and redistributing
the material transversely to obtain an even mix of uniform thickness over the width of the layer, all as
specified. It shall also include for longitudinal redistribution where this can be done by grader.
The ripping and breaking-down of the existing surfacing, where applicable, shall be measured and
paid for separately under item B38.16.
For subitem (c) the tendered rate for non-cemented material supplied from excavation in existing
pavements shall include full compensation for the excavation of pavement materials, including any
previously broken-down surfacing, in any layer thickness to the depth ordered by the engineer, for
breaking down, loading, transporting for an unlimited free-haul distance, off-loading and spreading of
the material, all as specified. It shall also include full compensation for controlling the depth of
excavation as specified in subclause B3805(a).
For subitem (d) the tendered rates shall include full compensation for procuring and furnishing the
material from a commercial source, for transporting the material for an unlimited free-haul distance,
off-loading and spreading, all as specified.
For subitem (e) the tendered rates shall include full compensation for loading the material from
stockpile, for transporting the material for a distance of 1,0 km, off-loading and spreading, all as
specified.
General:
(1)
The tendered rates for the respective subitems when combined with that of item B34.01,
shall include full compensation for all the work involved in pavement layers constructed from
materials taken from various and any combination of sources as specified. The addition of a
soil binder or the mixing of materials from two or more different sources in a new layer shall
comply with the requirements of clause 3504 and provided the addition and mixing of
materials from different sources has been instructed by the engineer, additional payment
under item B35.03 shall be made.
(2)
The measured quantity of material to be added to a layer to make up a shortfall in the
available volume of existing in situ pavement material shall be computed by subtracting the
quantity of material determined for subitem (b) from the total quantity for the layer as
calculated from the authorised dimensions of the completed layer. The in situ volume of
pavement materials shall therefore be assumed to be equal to its compacted volume.
(3)
Where materials supplied to a particular layer section are to be measured and paid for under
two or more of the relevant subitems and cannot readily be measured separately in the
compacted layer, the individual compacted quantities may be calculated from the ratio of
material imported as measured loose in the hauling vehicles.
(4)
For subitem (c), and in the event of it having to be stockpiled temporary, on the instruction of
the engineer, the material so stockpiled will be paid for at 50% of the tendered rate and the
balance will be paid when it has been finally placed and measured in the intended layer.
The quantity to be paid for in stockpile shall be calculated from the volume measured loose
in the hauling vehicles and converted with a bulking factor of 1,5. If any material is left over
in a stockpile on completion of the project, no further payment will be made for it. If the
C3-100
engineer decides that the stockpile area has to be cleared and the remaining material moved
elsewhere or to spoil, such work will be paid for on a daywork basis.”
Delete items 34.04 and 34.06 in total.
Replace item 34.05 with the following:
“Item
Unit
B34.05 Extra over item B34.01 for processing gravel pavement material
3
mixed with bituminous surfacing material ................................................ cubic metre (m )
The unit of measurement shall be the cubic metre of gravel pavement layer constructed with
recovered pavement material mixed with existing bituminous surfacing material.
The tendered rate shall be extra over the rates tendered for item B34.01 and shall include full
compensation for all additional costs and incidentals for placing and compacting material mixed with
more than 10% by volume of bituminous surfacing material.
This item is not applicable to the C3/C4 stabilised subbase layers.”
Note that items 34.09 will not apply to this contract.”
C3-101
SECTION B3500: STABILIZATION
B3501
SCOPE
Add the following as a 3rd paragraph:
“The use of recyclers for cold in situ recycling purposes is also covered in this section, which includes
cement, lime, emulsion and foam stabilisation of base and subbase layers consisting of gravel and/or
crushed stone material as described in sections 3400 and 3600.”
B3502
MATERIALS
(a)
Chemical stabilizing agents
Delete sub-clauses (ii) Ordinary Portland cement and (iii) Portland blast-furnace cement and replace
with the following:
“Cement shall comply with the relevant requirements of SANS 50197-1:2000. The use of strength
classes greater than 32,5 shall not be permitted.
The stabilizing agent for this contract shall be CEM II/A-L 32.5 or CEM II 32.5 A-S or composite CEM
II/B-M (L-S) 32.5. The preferred stabilising agent will be based on performance tests results obtained
on insitu materials by site laboratory trials.”
B3503
CHEMICAL STABILIZATION
(a)
Preparing the layer
Insert the following before the first paragraph:
“Moisture content tests shall not be undertaken more than one day in advance of in situ stabilization
operations. Care shall be taken to ensure that samples are representative of the in situ material.
Checks shall be conducted when wet weather occurs between initial testing and work commencing on
any section.”
Add the following:
“The material shall then be spreaded in a uniform layer over the full half width under construction
before additional granular material is added, if required. After the layer has been cut to level, the
surface of the layer to be stabilized shall be watered and rolled to obtain a smooth compacted surface
without loose or coarse patches in order to ensure a uniform application of stabilizing agent or agents.
Payment for preparing the layer surface to these standards shall be deemed to be included in the
tendered rates of sections 3400 and 3500.”
(b)
Applying the stabilizing agent
Add the following to the first paragraph:
“Application of the stabilizing agent using a bulk supply truck will not be permitted.”
Replace the second sentence of the second paragraph with the following:
“Spreading shall only commence when the engineer is satisfied that the correct quantity of stabilizing
agent has been placed on the layer and has given permission that the stabilizing agent may be spread
uniformly over the entire surface to be treated.”
Add the following:
"The minimum rate of application shall be a total of 2,0% by mass of the specified stabilizing agents.
The Engineer may order a variation in the rate of application. The spreading of stabilizing agent/s shall
be done by placing bags along the road and spreading by hand using rubber squeegees to obtain a
uniform layer of stabilizing agent/s. Bags which have become damaged or wet shall not be used and
C3-102
such bags shall be replaced at the Contractor’s cost. No additional payment other than the scheduled
payment items shall be considered if more than one type of stabilizing agent is used for the
stabilization of a layer.”
(d)
Mixing in the stabilizing agent
Add the following:
”Where chemically stabilized pavement layers are constructed, no stabilizing agent may be spread or
mixed beyond the specified width. The Contractor shall not mix material for stabilization on adjacent
bituminous surfaces.
Where existing and new works are joined (longitudinal joints and others), the material shall be
satisfactorily mixed and compacted without any permeable or loose patches.”
(f)
Compaction
Add the following at the end:
“The entire layer, regardless of its thickness, shall be processed within the time limitations stipulated in
sub-clause B3503(i).”
The minimum densities specified shall be attained throughout the full depth of the layer including the
upper 50 mm. For layers constructed in thicknesses of 200 mm and thicker the density of the upper
and lower half of the layer shall be measured and evaluated separately.”
(h)
Curing the stabilized work
Replace the first paragraph with the following:
"The stabilized layer shall be protected against rapid drying out by being kept continuously wet or
damp by watering at frequent intervals until one of the methods of protection listed below is put into
effect. Stabilized layers which are not kept continuously wet or damp but is subjected to consecutive
wet-dry cycles, may be rejected by the Engineer should he consider the layer to have been adversely
affected. Method (iii) and (iv) shall not be applicable."
For method (i) amend the second sentence to read as follows:
“This method shall be applied for an initial period of at least 48 hours, but thereafter one of methods (ii)
or (v) shall be applied.”
For method (ii) add “after the initial 48 hour period” after “layer” in the second line.
Add the following to method (ii):
“The covering material shall be placed by end-tipping, spread, and not compacted until the underlying
layer has cured for at least 7 days.”
Add the following to paragraph:
“Method (iii) and (iv) shall not be applicable.”
Add the following:
“The contractor shall take note of this clause and in particular the requirement that notwithstanding the
method of curing used, the stabilized layer shall be kept continuously wet or damp for seven days.”
C3-103
Amend the final paragraph to read:
"No additional payment will be made for curing as described above."
(i)
Construction limitations
Replace the fourth paragraph starting with “No stabilization ...” with the following:
“No stabilization shall be done during windy conditions, wet weather or with falling air temperatures
(7°C and dropping), or during rising air temperatures (when the air temperature is below 5°C).
The surface temperature of a compacted stabilized layer shall not be allowed to fall below 1°C during
the first three (3) days after stabilization. The contractor shall be responsible for taking the necessary
precautions to prevent the layer from freezing.
All stabilized layers damaged by rain, frost or by the formation of ice in the layer shall be removed and
replaced by the contractor at his own expense.
The contractor shall make allowance for these requirements in his construction programme.”
Add the following:
“Under no circumstance shall traffic be allowed to travel on layers of cement stabilised material for a
period of at least 7 days.
Moisture content tests shall not be undertaken more than one day in advance of in-situ stabilisation
operations. Care shall be taken to ensure that samples are representative of the in-situ material.
Checks shall be conducted when wet weather occurs between initial testing and work commencing on
any section.”
In table 3503/1, delete “8 hours” for Ordinary Portland cements and cement blends and replace with “6
hours”.
B3506
TOLERANCES
(b)
Uniformity of mix (chemical stabilisation)
For this project method (ii) shall apply.
B3509
QUALITY OF MATERIALS AND WORKMANSHIP
Add the following after the second paragraph:
“The test results and measurements will be judged in accordance with the provisions of Section 8200.
Add the following paragraphs:
“The engineer shall be notified in good time to enable him to conduct tests himself.
Sample preparation and testing for cement stabilization content shall be done by means of the Rapid
Cure Method as described in clause B8110.
The stabilized material sampled from the layer for the compaction of modified AASHTO briquettes,
shall be prepared according to SANS 3001; GR54; i.e. discard material coarser than a 37,5 mm test
sieve, and compacted according to SANS 3001; GR31.
Any delamination of the completed layer (biscuiting), identified by the hollow sound caused when a
chain is dragged over the stabilized layer, shall be removed and repaired prior to the construction of
subsequent layers. The repair method shall be approved by the engineer. No payment will be made
for repairs.”
C3-104
B3510
MEASUREMENT AND PAYMENT
Replace the first paragraph with the following:
“For this project only the areas as defined under clause B3407 shall be deemed to be restricted areas.
Item
Unit
B35.01 Chemical stabilization (layer thickness indicated) extra over
unstabilized compacted layers (layer to be stabilized indicated) ........................... cubic metre (m)
In the fifth line of the second paragraph, add “for at least 48 hours” after “sections”.
Item
Unit
B35.02 Chemical stabilizing agent
Replace the full stop at the end of the third paragraph with the following:
“and layer dimensions. ”
Item
Unit
B35.03 Mechanical modification (extra over untreated layer):
Add the following to the payment clause:
“The procurement and furnishing of the material to be added or mixed from different sources shall be
measured and paid for under item B34.03 or B33.02 as the case may be.”
C3-105
SECTION B3600: CRUSHED-STONE BASE
B3602
MATERIALS
(a)
Requirements for crushed aggregate
After the first sentence delete the remainder of the paragraph and replace with the following:
“The aggregate shall not contain more than 0,1% by mass of unwanted material such as wood, coal or
similar organic material.
Aggregates containing mica, such as granite, gneiss, mica schist, pegmatite, sandstone shall not
contain more than 2% by mass of free mica, especially muscovite, when assessed by visually
separating the particles, or more than 4% by volume when assessed by means of microscopic slides.
Aggregate containing easily detectable quantities (more than 1%) of olivine, serpentine and sulphide
minerals such as pyrites and marcasite, must be considered with caution, and may warrant additional
evaluation to the satisfaction of the engineer. Argillaceous rocks may only be used if specified in the
project specifications, or with the engineer’s written approval.
Soft or weathered particles shall be controlled by the Durability Mill Index values specified in B3602(e)
Durability.
Provision has been made in clause B8108(b)(iii), calculation, for the determination and calculation of
the apparent density for aggregates with a total water absorption greater than 1,5%, when total water
absorption is determined according to TMH1 methods B14 and B15.”
(c)
Grading requirements
Replace entire clause with the following:
“The target grading, after compaction, shall be as near as possible to the mean of the specified
grading envelope listed in table B3602/1 and shall be continuous with no marked gaps or excessive
quantities of any particular size. The mean grading of each lot (minimum of 4 but preferably 6 test
points per lot) shall conform to the approved target grading plus or minus the tolerances specified in
table B3602/4. However, no target grading plus tolerance can be set such that the original grading
envelope in table B3602/1 is exceeded. ”
Table 3602/1
In table 3602/1 delete “85% of bulk relative density” and replace with “88% of Apparent Relative
Density".
Replace the grading section in table 3602/1 with:
Percentage passing through sieve by mass
Nominal aperture size
of sieve (mm)
GRADING
37,5
28
20
14
5
2
0,425
0,075
G1
37.5mm
100
Nominal max size
G2
G3
37.5mm
37,5 mm
28 mm
100
100
86 - 95
86 - 95
86 - 95
73 - 86
61 - 76
37 - 54
23 – 40
11 – 24
6 - 10
73 - 86
61 - 76
37 - 54
23 – 40
11 – 24
6 - 10
73 - 86
61 - 76
37 - 54
23 – 40
11 – 24
6 - 10
87 - 96
73 – 86
43 - 61
27 – 45
13 – 27
5 - 12
C3-106
Note:
Refer to standard COLTO table for COLTO grading if required
Replace table 3602/4 with:
Table B3602/4
Sieve size (mm)
Permissible deviations by mean
Permissible deviations by
values (% by mass)
individual values (% by mass)
Nominal maximum size (mm)
37,5
26,5
37,5
28
±5
±5
±5
±5
±7
±7
±5
±5
±7
±7
±5
±5
±7
±7
±4
±4
±5
±5
±3
±3
±5
±5
±2
±2
±3
±3
28
20
14
5
2
0,425
0,075
Note:
Refer to standard COLTO table for COLTO grading if required
Add the following sub-clause:
“(e)
Durability
The durability property of aggregates derived from the basic crystalline group shall be assessed by
means of the Ethylene Glycol Durability Index. When tested in accordance with the method
prescribed in B8105(g) the durability index shall not exceed four. In addition, the 10% FACT value
obtained after soaking in ethylene glycol for four days shall not be less than 50% of that obtained on
the unsoaked sample. Where any values are obtained that fall outside the above requirements, a
detailed assessment of the quarry shall be undertaken together with a specialist mineralogical
evaluation of both the coarse as well as fine fractions in order to assess the long-term durability
properties of the material.
For basic crystalline rocks, arenaceous rocks, argillaceous rocks and diamictites the durability mill
index (DMI) shall be less than 125. For all other rock types the durability mill index (DMI) shall not be
more than 420, subject to the % passing the 0,425 mm sieve not increasing by more than 8
percentage points during the durability mill test.”
B3604
CONSTRUCTION
(b)
Compaction
Replace that last sentence of the first paragraph with:
“The density of the layer shall be tested at each third of the layer thickness.”
Add the following:
“All insitu density determinations shall be measured using two individual nuclear density gauges that
have been calibrated/validated according to the guidelines described in the manuals for each type of
nuclear gauge. The reading taken by each nuclear gauge shall be calculated to obtain a density and a
moisture content. Both density results shall then be averaged to obtain a single result. This result will
then represent the density achieved of the spot being tested as the accepted value.”
The minimum densities specified shall be attained throughout the full depth of the layer including the
upper 50 mm.”
C3-107
(c)
Surfacing preparation of the base
Replace the final paragraph in subsubclause 3604(c)(i) with:
“Slushing of the base, is compulsory and shall be carried out within 48 hours after completion of the
compaction. Even if the specified density is achieved without slushing or before completion of the
slushing process, the full slushing process must still be completed.”
Delete subsubclause (ii) Multi-stage process (water or slurry rolling).
B3605
PROTECTION AND MAINTENANCE
Add the following to the end of the second sentence:
“as determined according to TMH 1 method A7.”
B3607
QUALITY AND WORKMANSHIP
Delete “or 8300” in the second paragraph.
Add the following at the end of the first paragraph:
“All crushed-stone base material shall be subjected to the tests and their frequencies specified in
Table 3602/5. The material may only be placed on the road when all of the specified tests have been
completed and have passed”.
TABLE 3602/5: TEST FREQUENCIES OF BASE
Test Description
Frequency
(test / m 3 of base material)
10% Fines Aggregate Crushing Values
5 000
(i)
Ethylene glycol durability testing
5 000
(ii)
Atterberg Limits:
(iii)
PI –0,425
1 000
PI –0,075
2 000
Soluble salts
Grading
(iii)+(iv) Durability Mill Index
(i)
(ii)
(iii)
10 000
10 000
5 000
Test method B8116 durability shall not exceed 5.
PI -0,425 = Plasticity Index determination on - 0,425 mm material.
PI -0,075 = Plasticity Index determination on - 0,075 mm material.
Durability mill index shall be less than 125.
Replace the last paragraph with the following:
“Test results and measurements shall be assessed in accordance with the provisions of
Section 8200 (Ls = 88,0% or 89,0% as ordered).”
B3608
MEASUREMENT AND PAYMENT
Add the following at the beginning of this clause:
C3-108
”Rates tendered under Section 3600 shall cover all additional costs involved in initially placing and
compacting the base in areas larger than theoretically required (in order to achieve compaction and
level control) and later cutting back into the compacted layer when the rest of the road is constructed
and no additional payment will be made for this activity. The quantities of the base layer for payment
shall be calculated from the authorised dimensions of the completed layer as shown on the drawings
or prescribed by the Engineer.”
Delete the first paragraph and replace it with the following:
“Note: No additional or extra over payment shall be made for work in restricted or confined areas.”
Item
B36.01
Unit
Crushed-stone base
In the description of subitem (a) replace "88% of apparent relative density" with "89% of apparent
relative density".
In the description of subitem (c) replace "85% of bulk relative density" with "88% of bulk relative
density".
C3-109
SECTION B3800: BREAKING UP EXISTING PAVEMENT LAYERS
B3801
SCOPE
Add the following:
“The scope includes the work and constraints as described in Part C4: Site Information.”
B3804
PLANT AND EQUIPMENT
(a)
Milling equipment
Add the following:
“No payment shall be made for moving the milling machine onto or within the site.”
(b)
General
Add the following:
“Compressed air for cleaning the milled surface shall be delivered by a mobile compressor capable of
producing at least 3 m3/minute compressed air at 750 kPa, equipped with the necessary filters to
ensure clean air. The compressor shall be free of oil and diesel leaks.”
B3805
CONSTRUCTION
(a)
General
Amend the first paragraph to read as follows:
“Where the engineer instructs that all or a part of the existing surfacing material is to be reprocessed
together with the underlying layer either in place or elsewhere in fill or new pavement layers, the
surfacing shall be properly broken down and mixed thoroughly with the underlying material to the
depth instructed by the engineer. Fragments of the bituminous material shall be broken down to sizes
not exceeding 37,5 mm.”
Add the following to the second paragraph:
“The contractor shall use methods and procedures which will result in the surfacing being removed
with the minimum amount of base material lost. Bituminous material so removed shall be classified as
bituminous material excavation as specified in subclause 3803(a).”
Amend the fourth paragraph to read as follows:
“The existing pavement material shall be broken down to the depth specified or ordered by the
engineer and removed, or reprocessed in place, whichever may be required. The underlying layers
may not be damaged, and material from one layer may not be mixed with that from another layer
unless so instructed by the engineer. Where such unauthorised mixing occurs or where the material is
contaminated in any other way by the actions of the contractor, he shall remove such material and
replace it with other approved material, all at his own cost.”
Add the following:
“For material classified as non-cemented material, the contractor's method of excavating the
pavement material and his control over the depth of excavation shall be such that when instructed to
remove a particular layer as defined by the quality of the material, the material is not contaminated as
specified herein above. Similarly, when the depth of excavation is defined to be to the top of a specific
layer in the new pavement, then any over or under excavation resulting in a shortfall or surplus of
material when such a layer is subsequently processed in situ, will be made good at the contractor's
own cost.
C3-110
The work is proposed to be executed in sections as described in Part A of the specifications and which
may necessitate the de-establishment and re-establishment of certain plant items. Payment for the
moving of plant onto or from site, or from one location to another on site, shall only be made as may
explicitly be provided for in the schedule of quantities and the contractor shall provide for all additional
expenditures in this regard in his tendered rates. ”
(b)
(iv)
Milling
Milling in restricted areas
Delete this paragraph. No separate payment will be made for having to mill in narrow widths.
(vi)
General
Add the following:
“The exposed floor of the excavation shall be lightly sprayed with water to identify cracks. The
engineer shall be given the opportunity to inspect the milled surface for cracks and loose patches and
any cracks or loose patches shall be repaired in accordance with the relevant sections of the
specification.
The floor of the milled excavation shall, before the application of the tack coat, be cleaned of all loose
material by brooming, blowing with compressed air or vacuuming or any other method that will
produce an exposed surface that is closely-knit, firm and stable, free of nests of segregated materials,
laminations or corrugations.
Where milling is to be done at existing structures, care shall be exercised to avoid damage to concrete
elements, expansion joints, nosings to expansion joints, manholes, catch pits etc. Damage caused to
any element forming part of the permanent works shall be repaired at the contractor’s cost.
Milled excavations shall not be left open to traffic unless longitudinal and transverse joints have been
treated. Where the difference in level between the floor of the milled excavation and the existing road
surface exceeds 25 mm, joints shall be treated as follows:
Transverse steps shall be tapered off at a slope of 1 vertical to 20 horizontal (1:20) and longitudinal
joints exposed to traffic shall be tapered to a slope of 1 vertical to 5 horizontal (1:5). An alternative
method using a compacted asphalt wedge of the same dimensions is acceptable.”
(c)
Treatment of pavement excavation floor
Replace the paragraph with the following:
“After removal of the bituminous surfacing layer, the floor of the milled area shall be cleared in the
conventional manner of all loose material. In the case where a skin of bituminous material has
remained and which is not well bonded to the underlying base layer, it shall be carefully scraped off by
hand and removed.
If so ordered it shall thereafter be cleaned further using compressed air to remove any remaining loose
fragments and dust so that the surface may be inspected by the engineer for cracks and other defects.
When using compressed air passing vehicles shall be protected from flying particles which may cause
damage by strictly controlling the compressed air nozzle direction, or when this is in the opinion of the
engineer, not sufficient, by providing a suitable mobile screen to contain any flying particles.”
C3-111
B3807
MEASUREMENT AND PAYMENT
(a)
General
(v)
Measurement for excavating existing pavement material and underlying fill
Add the following:
“Where deemed more appropriate, the quantity will be computed by the method of average end areas
from levelled cross-sections taken before and after the excavation.”
Replace paragraph (c) with the following:
“(c)
Items 38.05 and 38.06 will not apply to this project and payment for working in restricted
areas shall be allowed for in the tendered rates.”
Item
Unit
B38.02 Milling out existing bituminous material with an average milling
depth: ........................................................................................................ cubic metre (m³)
Insert as a new fourth paragraph the following:
“The rates shall also include for transverse saw-cutting at the start and end of sections prior to the
commencement of the milling operations.”
Add the following at the end of this clause:
“Note:
Where material under this section requires haulage in excess of 1 km, item B16.02 shall be
included in this section of the schedule of quantities to make provision for overhaul to
stockpile except where the material is specified for immediate re-use in which case overhaul
shall be paid under the relevant construction payment section(s).”
Item
B38.08
Unit
Sawing or cutting asphalt or cemented pavement layers:
Amend subitem (a) to read as follows:
“(a)
(i)
(ii)
(iii)
Sawing bituminous surfacing to an average depth:
Not exceeding 30 mm..............................................................................................metre (m)
Exceeding 30 mm but not exceeding 60 mm............................................................metre (m)
Exceeding 60 mm.................................................................................................. metre (m)”
Replace the second payment paragraph with:
“Payment will distinguish between the various depths of sawing, irrespective of the number of separate
cuts which may be required to saw the bituminous layer.”
Item
Unit
B38.14 Providing the milling machine on site
Replace the first paragraph with the following:
“No payment for this item shall be made under this contract. All costs related to the provision of a
milling machine on site shall be deemed to be included in the other pay items in this section.”
C3-112
Item
Unit
B38.15 Moving the milling machine on the site
Replace the first paragraph with the following:
“No payment for this item shall be made under this contract. All costs related to the moving of the
milling machine on site shall be deemed to be included in the other pay items in this section.”
Add the following item:
“Item
Unit
B38.16 Breaking-down existing surfacing intended for re-use, with an
average thickness of: (state thickness)..................................................... square metre (m2)
The unit of measurement shall be the square metre of existing surfacing broken down on the
instruction of the engineer in order for it to be reprocessed and re-used together with the under lying
layer.
The tendered rates shall include full compensation for ripping and breaking down to the maximum
aggregate size specified, for removing by hand or other means lumps of bituminous material that
cannot be broken down and disposing thereof, and for mixing of the broken-down surfacing with the
underlying layer(s) and/or material added to it so as to obtain a uniform mixture containing not more
than 30% bituminous material. ”
C3-113
SECTION B3900: PATCHING AND REPAIRING EDGE BREAKS
B3901
SCOPE
Add the following to the first sentence:
“This section also covers the repair of potholes which are generally defined to be patching of a local
failure with a surface area less than 2 m².”
B3904 PATCHING
(c)
Excavating pavement material
Add the following after the first paragraph:“Excavated material to be spoiled must be removed and dumped on a suitable site on the same day it
is excavated.”
Replace the last paragraph with the following:
“For this contract patching shall refer to surfacing repair and base repair. For surfacing repair the
depth of excavation shall be nominally 40 mm. For base repair the depth of excavation shall be as
directed by the engineer up to the full thickness of the existing asphalt layer which is nominally 100
mm.
After completion of the initial excavation to the depth ordered, the engineer shall be afforded the
opportunity to examine it to determine whether the excavation depth shall be increased. When no
further layer materials are to be removed the floor of the excavation shall be cleaned of all loose and
uncompacted material.”
(d)
Backfilling excavations
Add the following as new paragraph one for subparagraph (i):
“The backfilling of excavations must be done in layers. Every layer must be compacted before the
next layer is placed.
The following layer thickness limits shall be applied:-
Gravel
Crushed stone
Asphalt base
Asphalt wearing course
Minimum
Maximum
75 mm
75 mm
50 mm
30 mm
75 mm
75 mm
75 mm
60 mm
Base patching shall be effected with a continuously graded asphalt base mix as specified in section
4200 and the project drawings.
Where asphalt material is used for patching, special cognisance must be taken of the requirements of
section 4200 as it pertains to the material that will be used for patching.
Where instructed by the engineer, after completion of the trimming and finishing of the patch, its
circumference up to 100 mm beyond the edges, shall be sealed by applying a diluted bitumen
emulsion (e.g. Colseal) or an approved equivalent to seal the joints. Where needed, an approved
crack sealant is to be applied along the joints between the patch and the existing road pavement. The
cost of sealing the patch shall be deemed to be included in pay item 42.20.”
Replace subparagraph (ii) with the following:
“The contractor shall place and spread the material with mechanical equipment or by hand in layer
thicknesses matching the capability of the compaction equipment that can be used, “building up” until
the full depth is obtained. To achieve a level patch that gives a smooth ride the base shall be
C3-114
screeded off using a board or rails or a different method approved by the engineer. Once the
backfilling has been done to the level of the adjacent base layer, the final compaction should be done
with a heavy vibratory and/or pneumatic roller. As soon as it is feasible the area around the patch shall
be washed off to remove all surplus slush and other contaminants which will affect the subsequent
reinstatement of the asphalt wearing course
Before placing the surfacing, a tack coat shall only be applied where directed by the engineer.
Application of prime or tack coat shall be paid under payment item 42.15. Any consolidation of the
patch under traffic shall be made good by the contractor at his own expense. Where the engineer is
satisfied with the structural capability of the patch, the depression may be corrected by replacing the
asphalt surfacing.”
(e)
Restrictions
Replace the first sentence with the following :
“All excavations for localised isolated patching shall be backfilled on the same day. Where a number
of patches and/or other repairs are required, subject to the approval of the engineer, a half width
length of the road not greater than 500 m may be closed to traffic.”
Add the following new subclauses:
“(f)
Spreading and compaction equipment to be used with patching
The compaction equipment for patching areas (surfacing repairs) of more than 2,0 m² (where the width
of the patch is equal to or exceeds 1,0 m) shall comply with the same standards as that for asphalt
bases and surfacing, as described in section 4200. In this regard special emphasis is placed on the
use of the prescribed spreading equipment when placing the asphalt mixture. This requirement is
necessary to ensure that the requirements for construction tolerances and finish requirements are as
set out in section 4200.
(g)
Potholes
A pothole shall be defined as a failure of the existing pavement layers where the surfacing and/or base
materials no longer exist over a relative small area (less than 2,0 m2). Pothole repair shall consist of
trimming away any ravelled edges and loose material to the full depth of the pothole and the backfilling
thereof with asphalt as follows:
(i)
Excavation and preparation
The existing material shall be removed in a neat rectangle to sound base, with a minimum dimension
of 200 mm x 200 mm and a minimum depth of 60 mm.
Prior to backfilling the areas with asphalt the excavation shall be cleaned of all fine material, and lightly
watered and tacked with an invert emulsion complying with the requirements of SABS 1260 and shall
be applied at a rate of 0,7 litre/m².
(ii)
Backfilling
The backfilling of potholes shall be done with asphalt which shall be obtained from commercial
sources. The asphalt supplied from commercial sources shall be as detailed in section 4200, table
4202/7 for medium continuously graded.
The medium grade continuously graded asphalt shall be placed and well compacted in layers not
exceeding 60 mm after compaction. The contractor shall use suitable compaction equipment and
shall ensure that adequate compaction is applied for the mix used to produce a dense asphalt layer
which will not deform under traffic.
(iii)
Trimming and finishing
The edges of the reinstated pothole shall not be above the existing surface by more than 3 mm.
Nowhere shall the edges be below the existing surface. The surface of the repaired area shall be a
continuation of the existing road cross-fall.
C3-115
Surplus material resulting from the repairs shall be suitably disposed of and the drainage systems
cleared of any spoil.
(iv)
Sealing
Immediately on completion of the trimming and finishing of the reinstated pothole, its total area and up
to 100 mm beyond the edges, shall be sealed by applying a diluted bitumen emulsion (e.g. Colseal) or
an approved equivalent to render the repaired area impermeable. The cost of sealing the patch shall
be deemed to be included in pay item B42.21.”
B3907
MEASUREMENT AND PAYMENT
Add the following payment item:
“Item
Unit
B39.06 Repairing potholes in the existing surfacing with a bituminous
mixture ........................................................................................................ cubic metre (m³)
The unit of measurement for repairing potholes shall be the cubic metre measured to the nearest
0,001 cubic metre of bituminous mixture placed in accordance with the specifications.
The tendered rate shall include full compensation for all excavation and spoiling of the excavated
material. The tendered rate shall also include full compensation for all transport, handling, labour,
plant, supply and mixing of all materials, preparation of the area to be repaired, the placing and
compaction of the bituminous mixture and all incidentals necessary for completing the work.”
Add the following clause:
“B3908 CONSTRUCTION TOLERANCES, FINISH REQUIREMENTS AND RESTRICTIONS
The final riding surface on any particular point on patches or between the patch and existing surface
shall not deviate more than 5 mm from the bottom of a 3 m long straight edge.”
C3-116
COLTO SERIES 4000:
ASPHALT PAVEMENTS AND SEALS
SECTION B4100: PRIME COAT
B4102
MATERIALS
(a)
Priming material
Add “(such as MSP 1)” to the definition of invert bitumen emulsion
(b)
Aggregate for blinding
Add the following sentence:
“Blinding of the primed surface with aggregate shall only be permitted to facilitate vehicular access to
adjoining properties”
B4104
WEATHER AND OTHER LIMITATIONS
Replace paragraph (g) with the following:
“(g)
When at any position within the layer the moisture content of a granular base layer is more
than 50% of the optimum moisture content determined according to TMH 1, Method A7. In the event
of rain after priming, the base shall be allowed to dry out to meet the above moisture content
requirement prior to surfacing.”
Add the following paragraph:
“(h)
When the moisture content of a granular base layer during the periods May to August is more
than 2%.
B4106
APPLICATION OF THE PRIME COAT
Replace paragraph (c) with the following:
“The type of prime and application rate best suited for the base shall be determined during
construction. The contractor shall provide about 20ℓ of each prime and apply it at different application
rates with a brush on the base. The engineer will then instruct the type of prime and application rate to
be used. No payment shall be made for tests to determine the type of prime.
Unless directed otherwise by the engineer or indicated on the drawings, the edges of the primed
surface shall be 150 mm wider than the edges of the surfacing.”
Add the following to subclause (e):
“Areas showing a deficiency in prime shall be made good, and areas with excessive prime shall be
blinded before opening to traffic, all at the contractor’s cost. However, blinding material ordered by the
engineer for primed areas where prime has been applied at the specified rate of application, shall be
paid for under payment item B41.02.”
Add the following sub-clause:
“(j)
Application in areas treated by reworking and construction of a new base shall be primed
using a mechanical distributor complying with sub-clause 4103(a). The edges of the previously
constructed or existing surfacing shall be adequately protected by approved means to ensure that an
overlap of prime not exceeding 50 mm is sprayed onto the previously constructed or existing
surfacing.”
C3-117
B4108
TOLERANCES
Replace the first paragraph with the following:
“The actual spray rates measured at spraying temperature shall not deviate by more than 8.0% from
that ordered by the engineer. The engineer may, at his discretion, conditionally accept application
rates falling outside this tolerance at reduced payment in accordance with table B4108/1.
Table B4108/1
PAYMENT REDUCTION FACTORS FOR CONDITIONALLY ACCEPTED PRIME COAT
Deviation specified spray rate at spraying
temperature. (%)
Payment reduction factor of tendered rate.
±8,0
±9,0
±10,0
±11,0
±12,0
±13,0
1.00
0.97
0.95
0.90
0.85
0.80
Any deviation outside these limits shall not be paid for, however, the engineer shall have the right to
instruct the contractor to make up any deficiency, or blind excessive prime without additional payment.
Where so instructed, the material for blinding shall consist of approved, but shall consist of screened 5
mm nominal single size aggregate. The use of crusher dust for blinding shall not be permitted. If
under-spraying occurs, and it is accepted by the engineer, only the actual quantities applied shall be
paid for.”
B4109
TESTING
Add the following:
“No payment will be made if this condition is not adhered to. The contractor shall provide, at his cost,
representative samples of every batch of prime delivered onto site.”
B4110
MEASUREMENT AND PAYMENT
Item
Unit
B41.01 Prime coat
Replace the description of subitem (e) with the following:
“(e)
Invert bitumen emulsion (MSP 1) .................................................................................... litre”
Add the following subitem:
“(f)
Emulsion based prime i.e. Colprime E ............................................................................. litre”
Add the following at the end of the payment paragraph:
“The prime coat may have to be applied in restricted areas. The tendered rate shall apply for all
applications of the prime coat irrespective of the size of the area where it has to be applied. Making
good of deficiency in prime, and blinding of excessive prime shall be for the cost of the contractor.”
Item
Unit
B41.02 Aggregate for blinding ............................................................................. square metre (m²)
Add the following to the payment paragraph:
“Blinding of areas with excessive prime as a result of an application rate deviating from the specified
application rate, shall not be measured for payment.”
C3-118
SECTION B4200: ASPHALT BASE AND SURFACING
B4201
SCOPE
Add the following to sub item (a):
“(viii)
Continuously graded asphalt surfacing with modified binder
Add the following sub item:
(d)
The work as described in Part C4: Site Information”
B4202
MATERIALS
(a)
Bituminous binders
(i)
Conventional binders
Add the following:
“The binders to be used shall be as follows:
(a)
(b)
Continuously graded surfacing -: 50/70 penetration grade bitumen
Continuously graded base: 50/70 penetration grade bitumen”.
(iii)
Homogeneous modified binders
Replace the last sentence with:
“The modified binder to be used on this project shall be A-E2.
The homogeneous modified binder shall be manufactured according to the guidelines contained in
“Technical Guideline: The use of Modified Bituminous Binders in Road Construction (TG 1-2007):
Asphalt Academy”. The base bitumen shall conform to SANS 4001-BT1:2012, or a blend of SANS
4001-BT1:2012 grades. The type as well as percentage of modifier is not prescribed, however the
contractor shall indicate in the Pricing Schedule what polymer he shall be using. The properties of the
homogeneous modified binder shall comply with the relevant requirements for binder class A-E2 as
listed in table B4202/12.”
Table B4202/12
PROPERTIES OF POLYMER-MODIFIED BINDER FOR HOT-MIX ASPHALT
Binder Class
Property
1
Softening Point
Dynamic Vicosity@165°C
Unit
Test Method
°C
MB-17
A-E1
A-E2
A-P1
55-65
65-85
63-73
Pa.s
MB-18
≤0.6
Force Ductility @ 5°C
N
EN 13703
Report*
Elastic Recovery @ 15°C
%
MB-4
>50
>60
>30
Storage Stab @ 160°C)
°C
MB-6
≤5
≤5
≤5
Flash Point
°C
ASTM: D93
≥230
≥230
≥230
MPa
AASHTO:TP1
Report
Report
Report
Creep Stiffness
≤0.6
3
Properties after ageing (RTFOT)
Report*
≤0.55
3
Report*
3
MB-3
Diff in Softening Point
°C
MB-17
-2 to +8
-2 to +8
-2 to +8
Elastic Recovery @ 15°C
%
MB-4
>40
>50
Report*2
Mass change
%
MB-3
≤1.0
≤1.0
≤1.0
Pa.s
MB-18
Report*2
Report*2
Report*2
Dynamic Viscosity @
165°C
C3-119
* Notes:
1.
The prescribed test method is based on not using stirrers although it has been reported that the
use of stirrers has shown no difference in test results. For referencing purposes no stirrers
should be used.
2.
No limits are given and the values should be recorded for reporting purposes only as they may
be used in future specifications.
3.
No values given but the test can be used to rank various binders according to their low
temperature cohesion properties
(b)
Aggregates
Add the following paragraph to the introductory description:
“Asphalt mixes shall be manufactured using different individual single size coarse aggregates fractions
and crushed fine aggregates blended to conform to the specified grading requirements. The use of
natural sands shall only be permitted if approved by the engineer and shall be limited to a maximum of
5% for continuously graded mixes. All aggregate in excess of 4,75 mm shall consist of individual
nominal single sized aggregate. For stone mastic asphalt mixes all aggregate fractions in excess of
2,36 mm shall consist of individual single size fractions. The Contractor shall note that commercial
suppliers may not be able to supply all the required single size aggregates, in which instance
arrangements will have to be made for additional on-site screening. No additional payment shall be
made for screening aggregate. The use of run of crusher type materials shall not be permitted.”
(v)
Absorption
Add the following sentence:
“In addition, the total binder absorption of the combined coarse and fine aggregate blend shall not
exceed 0,5%.”
(viii)
Grading
Delete the second paragraph commencing with "The target grading…" and add the following
paragraphs
“The grading limits for the combined aggregate grading for the asphalt base shall be as specified in
table 4202/6: Continuously graded 26,5m maximum.
The grading limits for the combined aggregate grading for the asphalt surfacing shall be as specified in
table 4202/7: Continuously graded medium grade.”
Add the following:
“The engineer may request a reconsideration of a blend to achieve any grading within the given
envelope to improve certain properties.”
(x)
Rolled-in chippings
Replace Table 4202/11 with:
Table B4202/11
Sieve size (mm)
20,0
14,0
10,0
7,1
0,425
Chip size - Percentage passing by mass
20 mm
14 mm
100
0 – 20
100
0–5
0 – 20
0–1
0–5
0,5 max
0,5 max
Note:
Refer to standard COLTO table for COLTO grading if required
C3-120
Add the following new sub-items:
“(xi)
Moisture content
The moisture content of aggregates, sampled from the cold feed belt, shall not exceed the following
limits at the time that it is introduced into the mix:
Coarse aggregate
Fine aggregate
(xii)
2%
4%
Deleterious materials
The presence of deleterious material in both coarse and fine aggregates to be used in the asphalt
mixes shall be determined from the following tests:
SABS Method 1243: 1994: Deleterious clay content of the fines in aggregate (methylene blue
adsorption test). The methylene blue value of the materials shall not exceed a maximum of 5 %.”
(c)
Fillers
Delete the second last sentence of the first paragraph and replace with:
“Not more than 2% by mass of active filler be used in the mixes.”
Add the following after the last paragraph:
“For tender purposes the active filler shall be hydrated lime”
(h)
General
Add the following after the second paragraph:
“Sufficient aggregate for a minimum of 3 days production shall be separately stockpiled and tested for
conformance and uniformity prior to use. The test results shall be presented to the engineer”
Add the following:
“The contractor shall inform the engineer at least three (3) weeks before any shortage of bitumen
develops, of the circumstances surrounding the impending shortage. He shall indicate the expected
tonnage to be imported, shall demonstrate that every local source and facility has been or will be
exhausted and shall obtain the engineer’s written permission to import standard penetration grade
bitumen.
A pay item (B42.23) has been provided for in the schedule of quantities for the additional cost of
importation of bitumen on the written instruction of the engineer to cover shortfalls of SABS standard
penetration grade bitumen arising at the local refinery, local sources and facilities during this contract.”
B4203
COMPOSITION OF ASPHALT BASE AND SURFACING MIXTURES
In the first paragraph, third last line, after “or active filler content” add:
“or aggregate content”
Replace the fifth paragraph with the following:
“The design of the asphalt mixes shall be in accordance with “Interim Guidelines For The Design Of
Hot-Mix Asphalt In South Africa (June 2001)”, and appropriate research results. The mix properties
and requirements shall be as specified in the project specifications”
The relevant asphalt mixes for the base and surfacing layers shall comply with the requirements in
table B4203/1.
C3-121
In the fifth paragraph, delete “guidelines of TRH 8” and replace with “Interim Guidelines for the Design
of Hot-Mix Asphalt in South Africa and the design criteria specified in B4203”.
In the last sentence of fifth paragraph replace “table 4203/1” with “table B4203/1”
Add the following:
“The design of the asphalt surfacing mix shall be in accordance with the design criteria at 100%
Marshall density (2 x 75 blows)
Additional joint permeability criteria will also apply. Mix design proposals and parameters shall be
finalised between the contractor and the engineer before commencement of paving work.”
Replace Table 4202/6 with:
Table B4202/6
Sieve size (mm)
Maximum nominal size (mm)
Continuously
Semi-gap
graded
37,5
28
37,5
28
Percentage passing sieve by mass
100
100
87 – 100
100
86 – 95
100
77 – 96
93 – 100
73 – 86
87 - 96
83 – 94
61 – 76
73 - 85
61 – 81
73 – 88
52 - 68
64 - 79
62 – 77
46 – 61
51 – 65
37 – 54
43 – 61
39 – 51
39 – 51
23 - 40
28 - 44
35 - 46
35 – 46
17 - 32
20 - 35
32 – 42
32 – 42
15 – 30
22 – 35
22 – 35
9 – 21
11 – 24
10 – 20
10 – 20
6 – 17
8 – 19
4 - 10
4 – 10
4 - 12
5 - 12
93,5%
95%
94,5%
37,5
28
20
14
10
7,1
5
2
1
0,600
0,300
0,150
0,075
Aggregate
Nominal Mix
Bitumen (grade
Proportions by Mass
according to project
5,5%
when Bitumen is
specifications)
Used
Active filler*
1,0%
* Active filler for tender purposes to be hydrated lime.
Notes: 1.
2.
4%
4,5%
1,0%
1,0%
For recycled asphalt the nominal mix ratios of recovered asphalt, new aggregate,
new bituminous binders, and active mineral filler to be used for tender purposes, shall
be as specified in the project specifications.
Refer to standard COLTO table for COLTO grading if required
C3-122
Table B4202/7
Fine
100
85 – 100
56 – 77
33 – 48
25 - 40
18 – 32
11 – 23
7 – 16
4 - 10
100
66 – 89
42 – 59
31 - 51
24 – 40
16 – 28
10 – 20
4 - 12
28
20
14
10
5
2
1
0,600
0,300
0,150
0,075
AGGREGATE
93,5%
93,5%
93,0%
BITUMEN (GRADE
ACCORDING TO
PROJECT
SPECIFICATIONS)
5,5%
5,5%
6,0%
ACTIVE FILLER
1,0%
1,0%
1,0%
PERCENTAGE
THROUGH SIEVE BY
MASS
NOMINAL PROPORTIONS BY
MASS
Continuously graded
Medium
Coarse
100
88 – 100
73 – 86
64 – 77
44 – 62
27 – 45
21 - 35
16 – 28
12 – 20
8 – 15
4 - 10
Note:
Refer to standard COLTO table for COLTO grading if required
Replace Table 4203/1 with:
Table B4203/1
ASPHALT MIX REQUIREMENTS: BASE AND SURFACING
Property
Marshall Stability (kn)
Marshall Flow (mm)
Stability /Flow (kN/mm)
VMA (%)
VFB (%)
Air voids (%)
Indirect tensile strength @ 25°C (kPa)
Dynamic Creep Modules @ 40°C (MPa)
Modified Lottmann @ 7% voids (TSR)
2
Air permeability @ 7% voids (cm )
Binder film thickness (microns)
Filler bitumen ratio
Immersion index (%)
Marvil penetration on joints (litre/h)
Continuously
graded base mixes
8 – 18
2–6
>2,5
> 14
65 – 75
4–6
> 1000
> 20
> 0,7
–8
< 1 x 10
5,5 – 8,0
1 – 1,5
-
Continuously
graded surfacing
mixes
8 – 18
2–6
> 2,5
> 15
65 – 75
4–6
> 1000
> 20
> 0, 8
–8
< 1 x 10
5,5 – 8,0
1 – 1,5
<3
Add the following:
“The contractor shall within 14 days of handing over of site, provide the engineer with his proposed
asphalt mix designs as well as samples of the materials he intends to use in the asphalt, to ensure the
timely approval of the asphalt mixtures.”
C3-123
B4204
PLANT AND EQUIPMENT
(b)
Mixing plant
(i)
Conventional binder
Add the following after the third paragraph:
“The manufacturer’s rated capacity of the mixing plant shall be adequate to meet production
requirements for the work. The rate of production shall not exceed manufacturer’s rated capacity of
the plant.”
(c)
(i)
Spreading equipment
Paver
Add the following
“Asphalt base with a surface area of > 5 m² and equal or wider than 1.0 m shall be placed by means of
a paving machine.
Each paver must be capable to be operated at forward speeds consistent with satisfactory placement
and compaction of the relevant mixture. The paver must also be capable of screeding a smooth
asphalt finish of uniform texture."
(d)
(i)
Rollers
General requirements
Add the following:
“No vibratory compaction may be used on bridge decks and within 5 m of any designated water main
or high voltage cable.”
(f)
Vehicles
Replace the second paragraph with the following:
“To minimize temperature loss all vehicles used for transporting asphalt to the site shall be fitted with
thermal asphalt covers (canvas covers not acceptable) irrespective of the prevailing climatic conditions
or distance of transport.”
Add the following
“Plant and vehicles used at the laying site shall be free from oil, fuel, and hydraulic fluid leaks. Any
item of plant or vehicle showing signs of these leaks shall immediately be removed from the site.”
Add the following subclause:
“(h)
Transfer of mix to paver
Asphalt shall be transferred from the haul trucks to the paver by means of a materials storage and
transfer vehicle (“shuttle buggy”) and no material shall be transferred directly from the haul vehicle into
the paver.
The material storage and transfer vehicle must be able to store and transfer hot-mixed asphalt
material from a truck to a paver to ensure continuous paving. It must contain an anti-segregation
auger which remixes materials just before they are delivered to the asphalt paver.”
B4205
GENERAL LIMITATIONS AND REQUIREMENTS AND THE STOCKPILING OF MIXED
MATERIAL
(b)
Moisture
Add the following at the end of the second last paragraph after “engineer”
“even if the underlying layer has been previously primed.”
C3-124
Amend the last paragraph as follows:
Insert “and/or primed base” after “surfacing” in the third line of the first sentence.
Replace the last sentence with “In such case the base shall be allowed to dry out to meet the above
moisture content requirement prior to placing the surface layer.”
(c)
Surface Requirements
(iii)
Tack Coat
Add the following after the third paragraph:
“A tack coat consisting of 60% stable grade emulsion shall be applied to the exposed edges of the
bituminous layers in milled-out excavations prior to placing abutting layers. The tack coat shall be
applied by brush at a nominal application rate of 2,0 ℓ/m².”
Add the following paragraph:
“Hand spraying shall only be permitted on areas approved by the engineer. The binder distributor
shall be capable to apply the binder evenly over the full area. The equipment shall comply with clause
4103. Tack coat shall be applied to all transverse and longitudinal joints by hand utilizing a paint
brush.”
B4206
PRODUCING AND TRANSPORTING THE MIXTURE
(a)
Mixing and storage temperatures of binder
Add the following at the end of the paragraph:
“The temperature-time limits for hot polymer modified binders as provided in table B4203/1a are for
tender purposes only. The selected supplier of the homogeneous modified binder shall provide
information with respect the type of modifier used and storage and handling characteristics of the
product, to the contractor prior to commencement of the works. The selected supplier shall also
advise on the applicability of table B4203/1a to his product.
Table B4203/1a
TYPICAL TEMPERATURE / TIME LIMITS FOR HOT POLYMER MODIFIED BINDERS
Binder class
Short term handling
Max.
Max.
Temp.
Holding
o
( C)
Time (h)
S-E1 and S-E2
180
24
A-E1, A-E2, A-P1
180
24
Storage
Max.
Max.
Temp. Holding
(ºC)
Time
(h)
150
240
140
240
Spraying / Asphalt mixing
Max.
Min.
Max.
Temp.
Temp. Holding
(ºC)
(ºC)
time (h)
200
185
8
170
160
36
To prevent the development of any "hot spots" within the product, or possible separation, a
circulation/stirring system shall be in place, even for periods of short-term storage. Many long chain
polymers have low shear stability and can be degraded by the action of a high shear rate pump such
as a close tolerance gear pump. Due to the cost of these premium products, storage tanks shall be
fitted with slow stirrers or augers, which, while assisting in keeping modified blend homogeneous, also
ensures no localized build-up of heat in the vicinity of the flue pipes.
The SBS binder shall be handled according to the TG1of November 2007 guidelines and shall also
include the following:
(1)
(2)
Storage tanks on site must be able to maintain a constant temperature between 160 °C and
170 °C. A constant recording device must be installed to monitor the storage temperatures.
The testing frequency on modified binders will be according to TG1 Guidelines November
2007 Table 19 as published by the Asphalt Academy. ”
C3-125
(b)
Production of the mixture
(ii)
Using drum-type mixer plants
Add the following:
“Pre-blending of aggregate fractions shall not be permitted and the contractor shall ensure that
sufficient cold-feed bins are installed to accommodate each individual aggregate fraction, including the
filler.”
(c)
Transporting the mixture
Delete the second sentence in this paragraph.
Add the following paragraph:
“Special precautions shall be taken by the contractor to ensure that the temperature of the total mass
of asphalt does not decrease by more than 10 º C from point of despatch to the point where it is to be
paved.
The contractor shall ensure that trucks used to haul asphalt are not overloaded and the legal axle
loads are not exceeded. Before any asphalt can be transported, the contractor must provide the
engineer with the certified carrying capacity of each truck intended for the purpose of transporting the
mix. The contractor shall provide the engineer with a weighbridge ticket before discharging into the
paver hopper.
ANY truck that is overloaded shall not be allowed to discharge its load and shall return to the
depot/batching plant for adjustment of the load. ”
Add the following subclause:
“(f)
Approval of asphalt mixture
Before any asphalt is placed on the road, the engineer shall approve the mix design. The approval
process shall be as follows:
The contractor shall prepare and submit a laboratory design mix with test results at four different
bitumen contents. The design mix shall be submitted on the prescribed form D3 of TMH 10:
“Instruction for the Completion of As-Built Materials Data Sheets” with all the necessary test results
completed. In addition, the proposed asphalt mixture shall be subjected to gyratory testing. All the
expenses in preparing and submitting the laboratory design mix shall be to the contractor’s cost.
The proposed design, as well as samples of all aggregate and bitumen intended for use, shall be
submitted with the laboratory design mix to enable the engineer to carry out check design testing as
necessary. The above design and aggregate shall be submitted to the engineer at least six weeks
before it is intended to commence with any asphalt production. The contractor shall check his mix
design proposal thoroughly before submitting it to the engineer. The engineer may request tests to be
repeated at the expense of the contractor if the results do not make sense and this will delay the
approval process. The engineer shall not be liable for this delay.
After approval is obtained for the laboratory design mix, a plant mix at varying binder contents of
approximately 5 to 10 tons each shall be produced. The purpose of the plant mix is for the contractor
to prove that the laboratory design mix can be produced successfully. The engineer shall conduct the
necessary testing on the plant mix. The plant mix shall not be placed on the road. During the
production of the plant mix, the engineer shall be afforded the opportunity to inspect the asphalt plant.
After the plant mix is approved, permission shall be given for laying a trial section at varying binder
contents in accordance with the requirements of section 4211 of the specifications. The engineer may
require that the mix be further assessed by means of CSIR Wheel Tracking or MMLS testing, the cost
of which will be borne by the employer. Mass production of asphalt shall only commence after
approval of the trial section, which should be given within a maximum of ten days.
C3-126
The engineer may instruct the contractor at any time to halt his paving process and to review the
whole or part of the above process should a change of aggregate properties occur, the specified
asphalt requirements not being met and/or a consistent asphalt mixture not be produced.”
B4207
SPREADING THE MIXTURE
Add the following to clause sub-clause (a):
“For base repairs, the existing base shall be excavated to a depth as instructed by the engineer (but
not exceeding 150 mm) with the side of the excavation stepped back by 100 mm from the milled edge
of the asphalt surfacing. Where instructed, asphalt base is to be placed in layers of at least 50 mm
thick but not exceeding 75 mm thickness.”
B4208
JOINTS
Add the following to the first paragraph:
“Saw-cutting of the longitudinal joints on newly placed asphalt will not be allowed and hence the
wheel-cutting shall be done as soon as possible after completion of compaction. In the case of a joint
between adjacent phases the removal of the material that has been cut loose may be delayed to
protect the edge from damage. If, in the opinion of the engineer, the edges are nevertheless
damaged, the affected area shall be cut back further. When, on account of the age of the asphalt, this
cannot be done effectively with a cutting wheel, paving breakers shall be used in an expert manner.”
Add the following to the fourth paragraph:
“The cut edges of all asphalt joints, longitudinal and transverse, shall receive a tack coat before the
adjacent asphalt is placed against it.”
Replace the fifth paragraph with the following:
“The density of asphalt at the joint locations and the assessment thereof shall be as specified in clause
B4210 and the water permeability of the surfacing layer shall be assessed as specified in clause
B4213(g). In order to meet the permeability requirement at the joints, all joints in the surfacing layer
shall be treated along a strip with width 200 mm either side of the joint, with an approved diluted
bitumen emulsion (e.g. Colseal).
Transverse joints shall be cut back in a neat straight line to approximately nought comma three metre
(0,3 m) to the full depth and over the full paved width of the layer. The cut line shall be determined
with a straight edge to eliminate the tapering asphalt layer thickness at the end. Longitudinal joints
may be cut back up to 1,5 times the nominal layer thickness without the wastage being deemed
excessive.
All joints shall be marked out with chalk lines prior to cutting.
There shall be no deduction in payment for the asphalt removed and spoiled when forming transverse
joints and for cutting longitudinal joints unless the engineer considers the wastage to be excessive,
and his decision shall be final. Asphalt removed and spoiled at unplanned transverse joints or from
trimming the outside edge of the completed asphalt wearing course along the shoulder, shall be
regarded as excessive wastage.”
Add the following to this clause:
“Temporary transverse joints shall be rolled smooth to the engineer’s satisfaction.
There shall be a perfectly smooth joint between existing and new surfacing.
Where the engineer so directs, an asphalt fillet shall be placed along the edge of the completed
asphalt course. Unless otherwise directed, the fillet shall be 150 mm wide. Separate payment will be
made for the placing and subsequent removal of the fillet.
C3-127
The contractor, having due regard for his responsibilities in terms of clause 17.2 of the conditions of
contract, shall form, protect and treat temporarily exposed longitudinal joints in a manner which will
minimise traffic risks. The minimum requirement shall be that the edges be rolled-over prior to
opening to traffic and that they subsequently be cut back before continuing with the adjacent asphalt
layer.
Unless explicitly otherwise stated the cost of all joint construction activities (temporary and
permanently, transverse and longitudinal joints) is to be included into the relevant asphalt layer rates.
Where the difference in level between the new work and the existing road surface exceeds 25 mm,
joints shall be treated as follows:
Transverse steps at the end of a day’s work shall be tapered off at a slope of 1 vertical to 20 horizontal
(1:20) to tie in with the existing surface. The tapered section shall be removed before surfacing is
recommenced and a joint formed in accordance with clause 4208 of the specification.
Longitudinal joints exposed to traffic shall be provided with a taper of compacted asphalt material over
the full length of the exposed joint. The width of the taper shall be at least 5 times the difference in
level between the old and new work.
All costs involved in the provision and removal of these temporary ramps shall be deemed to have
been included in the rates tendered for the relevant asphalt payitem.”
B4209
PRE-COATED CHIPPINGS FOR ASPHALT SURFACING
Replace the first sentence of the fifth paragraph with the following:
“The pre-coated chippings used shall be 14 mm size aggregate.”
In the last sentence of the fifth paragraph, delete “between 0,6 and 1,0 mm” and replace with:
“minimum 0,8 mm”.
B4210
COMPACTION
Add the following to the sixth paragraph:
“ The asphalt base shall have a maximum density of 96,5%, and the asphalt surfacing a maximum of
96%, of the theoretical maximum (Rice’s) density of the material.
In addition hereto the compaction within the zone up to 200 mm away from the joint plane shall be
done in a manner to ensure densities not less than the minimum specified - less 2% (including all hot
and cold joints). Joint densities shall be determined from cores taken not closer than 70 mm to the
joint plane and not further away than 200 mm and they shall be assessed by treating the cores from
each of the 200 mm zones as separate lots for acceptance and payment purposes.”
Replace subclause (e) with the following:
“In restricted areas, or on bridge decks, where the specified rollers cannot be used, compaction shall
be carried out with hand operated mechanical compaction equipment, approved smaller vibratory
rollers or static rollers (bridge decks). The revised compaction procedure shall be predetermined and
approved during the laying of trial sections and, if required, a relaxed density specification shall be
applicable as determined by the engineer.”
Add the following:
"Rolling must continue until all roller marks have been eliminated and the specified minimum density
has been obtained, but not after the mat has cooled to 90º C or below. Vehicular traffic shall not be
allowed on the newly compacted surface before the mat has cooled to 50°C or lower.”
C3-128
B4211
LAYING OF TRIAL SECTION
Replace the first paragraph with the following:
"Before the contractor commences with the construction of any asphalt surfacing, he shall
2
2
demonstrate, by laying a trial section of between 300 m and 600 m in an area as ordered, his ability
to reproduce in practice a mix, the properties of which conform with that of the recommended mix
design, and that the equipment and processes that he proposes to use, will enable him to construct
the particular asphalt course in accordance with the specified requirements.”
Replace the fifth paragraph with the following:
“Only when such a trial section has been satisfactorily laid, finished and tested, and complies with all
the specified requirements, will the contractor be allowed to commence with construction of the
permanent work.”
Add the following to the end of the first paragraph:
“As the purpose is not to calibrate any equipment, etc., the contractor shall calibrate the equipment
and refine the mix design at his own cost.”
B4213
CONSTRUCTION TOLERANCES AND FINISH REQUIREMENTS
(a)
Construction tolerances
(iii)
Thickness
Add the following tolerance:
“Davg+
(v)
surfacing = 3 mm”
Surface regularity
Insert the following before the first paragraph:
“For the lanes and surfaced shoulders wider than 2.0 m of the through road as well as interchange
ramps and cross roads the roughness of the surfacing will be determined by using an inertial laser
profilometer capable of producing a class 1 vertical measurement resolution, and a class 3 longitudinal
sampling distance as defined in ASTM standard (E950-09). Surface shoulders less than 2.0 m wide,
will be assessed according to measurements obtained from the adjacent slow lane.
The inertial laser profilometer shall be used to record the longitudinal profile in both wheel tracks of
each traffic lane or shoulder wider than 2.0 m, as determent according to the final line markings that
will be applied after construction. Should the two tracks not be measured simultaneously during the
same pass, then procedures shall be implemented to ensure that the longitudinal profile data recorded
for the two wheel tracks are at the same longitudinal location on the road.
The measured longitudinal profiles will then be processed using the Quarter-Car simulation model with
parameter values as defined in ASTM standard (E1170-97) for Ride Meter-Vehicle Mounted. The
simulated suspension mentioned will then be linearly accumulated and divided by the length to yield
100 m IRI (International Roughness Index) values in units of mm/m or m/km for each wheel track. The
last 50 metres, and the joining first 50 metres of adjacent sections will be evaluated as a 100 m
section in the direction of vehicle travel. For each measured lane the left and the right 100m IRI values
from the three runs will then be average to produce the Average IRI as follows:
Run1 IRI 100m Ave = (100 m IRI Left wheel track + 100 m IRI Right Wheel track) / 2
Run2 IRI 100m Ave = (100 m IRI Left wheel track + 100 m IRI Right Wheel track) / 2
Run3 IRI 100m Ave = (100 m IRI
Left wheel track
+ 100 m IRI Right Wheel track) / 2
Average IRI 100m = (Run1 IRI 100 m Ave + Run2 IRI 100 m Ave + Run3 IRI 100 m Ave ) / 3
The Average IRI100m values is then evaluated and judged according to table B4213/2 to determine
whether the 100m section needs corrective work or payment adjustments.
C3-129
For the asphalt base the values in payment bracket 6 in table B4213/2 shall be applied as the
payment adjustment factors for the asphalt base on the contract or section.
For the asphalt surfacing, the applicable payment bracket in table B4213/2 for the measured lanes
and shoulders will be determined as follows:
1.
Calculate the applicable Target IRI100m Ave for full payment as follows,
Target IRI100m Ave = greater of 1.05 or [IRIb Ave * {1-(NAT/100)}[
Where:
IRIb Ave = Average IRI100m before the construction of the asphalt surfacing as determined from:
i
ii
The Average IRI100m as calculated from measurements performed for the UTFC
section to be milled and replaced, prior to commencement of the milling, or
The Average IRI100m as calculated from the measurements performed as part of the
assessment of the new constructed base (refer B3405(f) for granular base and
B4213(a) for asphalt base).
NAT = Total New Asphalt Surface Thickness as specified (measured in mm) applied over a section as
part of this contract. For example, should 40mm AC be applied followed by 18mm UTFC, then
NAT = 58mm.
2.
Using the Target IRI100m Ave calculated under 1 above, find the matching Target IRI100m Ave
range in the first column of table B4213/2 into which the value fits. Then read horizontally to
the relevant Full Payment Bracket column in which the unit value (1.000) appears. The values
in this column shall then be applied as the payment adjustment factors for the contract or
section. For example should the Target IRI100m Ave be 1.33, then the Full Payment Bracket will
be No 4.
Should the Total New Asphalt Thickness (NAT) as specified vary over the contract length,
then a Payment Bracket will need to be calculated for each of these uniform NAT sections.
Any adjustment in the payment for asphalt base or asphalt surfacing will be made by multiplying the
full payment value for each 100 m section, for payment items 42.01, B42.02, 42.09 and B42.11 by the
payment adjustment factor derived from table B4213/2. The payment adjustment shall apply to the
total asphalt layer width placed during a single pass by the paver over the 100m sections in question.
Surfaced shoulders less than 2 m wide will be assumed to have the same roughness measurements
as the adjacent lane and the quantity of material in the shoulder shall be added to the quantity of
material of the adjacent lane for determination of the payment adjustment factor.
On sections where the Average IRI100m is worse than the cut-off value listed in table B4213/2 the
section is rejected and corrective work will be necessary.
Any corrective work required shall be made by the removal, through milling of the total asphalt layer
width placed during a single pass of the paver over the 100 m section in question, followed by
reinstatement. The contractor shall submit his method statement for any corrective work to the
engineer for approval, prior to commencing with any corrective work. Corrective work shall be done at
the contractor’s expense and shall be completed prior to determining pavement thickness. After
completion of the corrective work, the 100 m sections shall be re-evaluated according to the
abovementioned procedure.
The longitudinal profile and the 100 m International Roughness Index (IRI) values shall be determined
using a profilometer furnished and operated by the contractor or on his behalf in the presence of the
engineer. Prior to using the inertial laser profilometer it shall have successfully completed a validation
trial against the Instrument of Reference (Face Dipstick®)used by the Employer.
C3-130
As an absolute minimum, measurements shall be provided to the engineer after 10%, 50% and 100%
of the surfacing area of the project has been completed. The contractor will be paid for these
measurements under payment item B81.03(c). No additional payment will be made to the contractor
for additional measurement and analysis of profiles.
On all road sections and in areas where the use of a profilometer is not possible, the rolling straightedge specification as indicated below shall apply.”
(c)
Gradings
Replace Table 4213/1 with:
Table B4213/1
AGGREGATE GRADING TOLERANCES
Size of aggregate passing Sieve size
(mm)
28
20
14
10
7,1
5
2
1
0,600
0,300
0,150
0,075
Permissible deviation from target
grading (%)
±5
±5
±5
±5
±5
±4
±4
±4
±4
±3
±2
± 1*
* When statistical methods are applied the permissible deviation for the 0,075 fraction is ± 2%.
C3-131
Table B4213/2
PAYMENT ADJUSTMENT FACTORS FOR ASPHALT BASES AND ASPHALT SURFACINGS
PAYMENT ADJUSTMENT FACTORS
Target IRI100m
Ave (m/km)
Full Payment
Bracket 1
Full Payment
Bracket 2
Full Payment
Bracket 3
Full Payment
Bracket 4
Full Payment
Bracket 5
Full Payment
Bracket 6
Full Payment
Bracket 7
Full Payment
Bracket 8
< 0.80
1.050
1.050
1.050
1.050
1.050
1.050
1.050
1.050
0.81 to 0.90
1.025
1.050
1.050
1.050
1.050
1.050
1.050
1.050
0.91 to 1.00
1.010
1.025
1.050
1.050
1.050
1.050
1.050
1.050
1.01 to 1.10
1.000
1.010
1.025
1.050
1.050
1.050
1.050
1.050
1.11 to 1.20
0,990
1.000
1.010
1.025
1.050
1.050
1.050
1.050
1.21 to 1.30
0,975
0,990
1.000
1.010
1.025
1.050
1.050
1.050
1.31 to 1.40
0,955
0,975
0,990
1.000
1.010
1.025
1.050
1.050
1.41 to 1.50
0,930
0,955
0,975
0,990
1.000
1.010
1.025
1.050
1.51 to 1.60
0,900
0,930
0,955
0,975
0,990
1.000
1.010
1.025
1.61 to 1.70
0.865
0,900
0,930
0,955
0,975
0,990
1.000
1.010
1.71 to 1.80
Reject
0.865
0,900
0,930
0,955
0,975
0,990
1.000
1.81 to 1.90
1.91 to 2.00
Reject
Reject
Reject
Reject
0.865
Reject
0,900
0.865
0,930
0,900
0,955
0,930
0,975
0,955
0,990
0,975
2.01 to 2.10
Reject
Reject
Reject
Reject
0.865
0,900
0,930
0,955
2.11 to 2.20
Reject
Reject
Reject
Reject
Reject
0.865
0,900
0,930
2.21 to 2.30
Reject
Reject
Reject
Reject
Reject
Reject
0.865
0,900
2.31 to 2.40
Reject
Reject
Reject
Reject
Reject
Reject
Reject
0.865
>2.41
Reject
Reject
Reject
Reject
Reject
Reject
Reject
Reject
C3-132
(e)
Voids
Add the following:
“The void content shall not deviate from the approved production mix void content by more than 1%."
Add the following subclause:
“(g)
Permeability
The water permeability of the continuously graded asphalt base and surfacing layer shall be tested
using the falling head (MARVIL) apparatus as described in clause 8109(d). The engineer shall
determine the number and location of test points and no single result shall exceed a value of 3 litres
per hour. In the case of all joints the permeability of the surfacing layer up to 200 mm either side of
the joint, shall not exceed 1 litre per hour. Refer to clause B4208 for the specified standard treatment
of joints prior to testing for permeability.
Areas of asphalt surfacing which meets all the stated specifications except for the permeability
requirement, shall be demarcated and treated (retreated in the case of joints) with an approved water
proofing agent e.g. a diluted emulsion (Colseal), at the contractor’s cost and re-tested for
conformance. All permeability testing which prove non-conformance shall be for the contractor’s
account as per clause B1143.
The water proofing agent shall be suitably diluted with water and applied by roller in a manner which
facilitate penetration and sealing of the layer without undue enrichment of the surface or alteration of
the surface texture.”
B4214
QUALITY OF MATERIAL AND WORKMANSHIP
(b)
Coring of asphalt layers
Add the following:
“A suitable coring machine shall be available on a daily basis when asphalt paving is taking place.
Cores shall only be drilled, when the road temperature is 20°C or less. Core holes shall be filled with
hot mix asphalt and compacted, all within 24 hours of the core being drilled. Coring shall be carried
out within 48 hours after the paving has been completed and supplied to the engineer. The test
results of cores shall be submitted to the engineer within 24 hours after coring.
Cores may only be drilled when the road temperature is 20ºC or less. Core holes must be dried out,
tacked and backfilled as soon as possible with hot mix asphalt. Coring shall be carried out within 48
hours after the paving has been completed. The process control core test results and material testing
results shall be submitted to the engineer not later than 24 hours after coring and sampling
respectively”
(c)
Routine inspection and tests
Add the following paragraphs:
“The contractor shall keep accurate records of:
(i)
(ii)
(iii)
The position where every truckload of asphalt is paved (chainage, lane, time and date).
The temperatures of the asphalt in the trucks both at the mixing plant and at the paving
equipment immediately prior to discharging the load.
The truck and load number from which control samples are taken. All samples taken shall be
appropriately numbered.
Quality Control Scheme 1 given in Section 8200 will apply to the asphalt paved on this contract.”
Add the following subclause:
“(d)
Special tests
n-Heptane-Xylene Equivalent (Spot test) (AASHTO-T102)
C3-133
If the engineer suspects that bitumen or asphalt has been overheated, he may order that the bitumen,
or the bitumen recovered from the asphalt, be subjected to the Spot Test. Recovery of binder for use
in the Spot Test shall be carried out according to an approved method.
Any bitumen having an n-Heptane-Xylene equivalent in excess of 36, or in excess of the
manufacturers test result on the dispatched stock, shall be considered to have been overheated and
shall be deemed to be rejected unless proven otherwise. ”
B4215
MEASUREMENT AND PAYMENT
Replace the first paragraph with the following:
“No additional or extra over payment shall be made for work in restricted or confined areas.”.
Item
Unit
B42.02 Asphalt surfacing
Add the following to the first payment paragraph:
“The tendered rates shall also include for all joint construction activities as specified including the
backfilling of cores holes, sealing of all joints with an approved diluted bitumen emulsion, and for
having to cut back into existing surfacing as specified on the drawings.”
Amend the following payment item:
“Item
Unit
B42.08 100 mm cores in asphalt paving ................................................................... number (No)”
Amend the 1st sentence by adding the following after the word “drilled….”.
“irrespective of depth of core.”
Add to the second paragraph”
“The tendered rate shall also include full compensation for the traffic accommodation required to drill
and recover the cores.”
Item
Unit
B42.11 Asphalt constructed for rehabilitation purposes in accordance
with the provisions of subsubclause B4213(f)(ii) and B4213(f)(iii) ......................... ton (t)
Insert the following paragraphs after the 1st paragraph:
“The unit of measurement for subitem (a) shall be the ton of asphalt base placed in compacted layer
thickness not exceeding 60 mm, and measured according to certified weighbridge tickets issued in
respect of the mixture used.
The unit of measure for subitem (b) shall be the ton of asphalt overlay placed to the nominal thickness
specified if placed in terms of B4213(f)(iii) and placed to the specified level if placed ito B4213(f)(ii),
and measured according to certified weighbridge tickets issued in respect of the mixture used.
No payment shall be made for excess width and wastage of asphalt, and the mass of such excess or
wasted material shall be deducted from the recorded delivery for payment purposes. For layers
constructed in terms of clause B4213(f)(iii) no payment shall be made for asphalt in excess of the
mean spread rate(s), which shall be determined as follows:
S
=
S
=
1000 m2/ton where,
AXB
2
Mean spread rate in m /ton
A
=
Average bulk relative density achieved on the road in ton/m3
C3-134
B
=
(specified asphalt thickness in mm) + 5mm”
Add the following to the 3rd paragraph:
“The tendered rate shall also include full compensation for joint forming, temporary ramping of
construction joints between paving operations when new work is opened to traffic (including ramping
material), breaking up and disposal of temporary ramps and waste material, weighing the material on
the specified weighbridge and cleaning the surface.”
Add the following payment item:
“Item
Unit
B42.14 Extra over item 42.04 for applying tack coat by hand .................................................. litre
The unit of measurement shall be litre of 30% stable-grade emulsion applied by hand.
The tendered rate shall include full compensation for additional costs for applying the tack coat by
hand.”
Add the following payment items:
“Item
Unit
B42.21 Aggregate variations ................................................................................................. ton (t)
The unit of measurement in respect of increases or decreases in the aggregate content from that
specified in the nominal mix shall be the ton.
Payment for variations shall be made as specified for clause 1213.
Item
Unit
B42.22 Apply diluted bitumen emulsion (e.g. Colseal) to joints on
circumference of patches .............................................................................................. litre
The unit of measurement shall be the undiluted litre of emulsion applied to the joints at the instruction
of the engineer.
The tendered rate shall include full compensation to procure and apply the emulsion as specified and
instructed.
Item
Unit
B42.23 Extra over items 42.01, B42.02, 42.09, 42.10 and B42.11 for the
transportation cost of bitumen binder supplied by a refinery
outside the Western Cape Province ....................................................................... ton (ton)
Where bitumen that meets the requirements of the specification is not available from a refinery in the
Western Cape Province the engineer may agree that material be imported from other sources.
The unit of measurement shall be the ton of net cold bituminous binder and shall be calculated from
the average binder content of the asphalt placed for a day’s work or the actual volume of prime, tack
and binder sprayed.
The tendered rate shall include full compensation for the additional cost of transporting bituminous
binder which meets all the requirements of the specification from a refinery outside the Western Cape
Province. Any difference in the “ex refinery” price of bitumen shall be compensated for by means of
the special material adjustment formula.”
C3-135
SECTION B4300: SEALS: MATERIALS AND GENERAL REQUIREMENTS
B4301
SCOPE
Add the following paragraph:
“The contractor shall take and submit samples of materials and/or mixtures to the engineer who must
approve designs before construction work can commence.”
B4302
MATERIALS
Add the following to the first paragraph:
“Any tests referred to in the publication “Technical Guideline: TG1 The Use of Modified Bituminous
Binders in Road Construction (TG 1-November-2007): Asphalt Academy”, shall supersede those
specified in the COLTO Standard Specifications for Road and Bridge Works for State Road Authorities
(1998 edition). This document is available from the Asphalt Academy.”
a)
Bituminous binders
(ii)
Non-homogeneous (heterogeneous) modified binders (summer grade)
(4)
Diluent
Add the following sentence:
“The addition of a diluent or cutter to the blend shall not be permitted unless approved by the
engineer.”
(iv)
Homogenous cold applied modified binders
Replace the entire sub-sub-clause with the following:
“(1)
Base bitumen
The cationic emulsion shall be manufactured from bitumen complying with the requirements of SANS
4001-BT1:2012.
(2)
Polymer
The contractor shall indicate, in the relative payitem in the Pricing Schedule, the type of polymer to be
used in the blend.
(3)
Polymer modified emulsion blend
All blending shall be done at the factory. The modified binder for this project shall be Binder Class SCE2 (65-68)(t) and SC-E2 (70-73)(t), where “(t)” indicates that no fluxing agent or cutter is allowed in the
binder. The binder shall comply with the requirements in table B4302/5.
The recovered binder residue shall be obtained using either the rotary vacuum evaporation or simple
evaporation method. If there is any discrepancy in the test results then the results on recovered binder
obtained from the rotary vacuum evaporation method shall be binding.
The use of a volatile solvent flux added to the bitumen shall not be permitted unless approved by the
engineer.”
C3-136
TABLE B4302/5: PROPERTIES OF POLYMER MODIFIED EMULSIONS FOR
SURFACE SEALS
Property
Modified Binder Content
Saybolt Furol Viscosity @ 50°C
Residue
on 710µm sieve
4
sieving
150µm sieve
(/100ml)
Particle charge
Sedimentation after 60 rotations
Modified Binder Class
Unit
Test Method
(%)
MB-22
65-68
70-73
65-68
70-73
Second
MB-21
51-200
51-400
51-200
51-400
g
MB-23
SC-E1
SC-E2
≤0,1
≤0,1
≤0,5
≤0,5
-
MB-24
Positive
Positive
°C
SANS 309
Nil
Nil
1
Properties of recovered binder residue (MB-20)
Softening Point
2
°C
MB-17
≥48
Elastic recovery @ 15°C
%
MB-4
≥50
Force Ductility @ 5°C
N
EN 13703
Report
≥55
≥55
3
Report
3
Notes:
1.
2.
3.
4.
(v)
Either the rotary vacuum or the simple evaporation method can be used. For on site testing the simple
method is more practical and is thus recommended. The simple method retains a very small portion of the
fluxing oils whereas these are removed in the rotary vacuum method. The latter method renders a better
indication of the binder properties after in-service curing.
The prescribed test method is based on not using stirrers although it has been reported that the use of
stirrers has shown no difference in test results. For refereeing purposes no stirrers should be used.
No values given but the test can be used to rank various binders according to their low temperatures
cohesion properties. The properties listed as “Report” will only be determined on instruction of the
engineer. The contractor will not be liable for the cost of such testing.
Pour the emulsion through the larger sieve to remove the skin and larger particles before passing the
emulsion through the finer sieve.
Homogeneous hot applied polymer modified binders (summer grades)
Replace the entire sub-sub-clause with the following:
“(1)
Base bitumen
The base bitumen or blends thereof, shall comply with the requirements of SANS 4001-BT1:2012 . In
addition, the chemical composition of the bitumen shall be such as to permit blending with the
proposed polymer to form a stable product.
(2)
Polymer
The type and percentage of polymer to be blended with the bitumen is not prescribed, however the
contractor shall indicate, in the relevant payitem in the Pricing Schedule, the type of polymer to be
utilized.
(3)
Polymer modified blend
The polymer modified bitumen shall be blended at the factory.
The polymer modified bitumen to be used on this project shall be Binder Class S-E2 and shall comply
with the requirements of table B4302/7.
The binder for the day’s production shall be tested on site to determine the softening point before any
seal work is commenced with. No claim for delays due to this requirement shall be considered. As a
control, a hand held spindle viscometer shall be used to monitor the viscosity of the binder at the spray
temperature.”
C3-137
TABLE B4302/7
APPLICATIONS
PROPERTIES OF POLYMER MODIFIED BINDERS FOR HOT SEALING
Property
1
Softening Point
Dynamic Viscosity @165°C
Force Ductility @ 5°C
Binder Class
S-E1
S-E2
Unit
Test Method
°C
MB-17
50-60
Pa.s
MB-18
≤0,55
N
EN 13703
Report
3
60-80
≤0,60
2
Report2
Elastic Recovery @ 15°C
%
MB-4
>50
>70
Flash Point
°C
ASTM:D93
≥230
≥230
Stability (R&B diff. @ 160°C)
°C
MB-6
≤5
≤5
Difference in Softening Point
°C
MB-17
-2 to +8
-2 to +8
Elastic Recovery @ 15°C
%
MB-4
>40
>50
Mass Change
%
MB-3
≤1.0
≤1.0
Properties after ageing (RTFOT)
Notes:
1.
2.
3.
The prescribed test method is based on not using stirrers although it has been reported that the use of
stirrers has shown no difference in test results. For refereeing purposes no stirrers should be used.
No values provided but the test can be used to rank various binders according to their low temperature
cohesion properties
The softening point values obtained for bitumen modified with SBS will tend to fluctuate over time and on
reheating.
* Note: The properties listed as “Report” will only be determined on instruction by the engineer. The contractor will
not be liable for the cost of any such testing.
b)
Aggregates
(i)
Aggregates for seals
Add the following at the end of the sentence:
“and durability.”
(1)
Grading
Add the following:
“Only grade 1 aggregate shall be used for the construction of seals on this project.”
(3)
Shape
Add Table B4302/13 and the following paragraph:
“Ninety five (95%) percent of the particles shall have at least three fractured faces. The Average Least
Dimension (ALD) of the relevant nominal aggregate sizes shall comply with the requirements of Table
B4302/13.”
TABLE B4302/13: MINIMUM ALD REQUIREMENTS
Nominal Aggregate Size (mm)
20
14
10
7
Minimum ALD (mm)
12,0
8,0
5,5
4,0
C3-138
Replace Table 4302/8 with:
TABLE B4302/8
Percentage by mass passing
Sieve size
(mm)
Grade
Nominal size (mm)
28
20
14
10
37,5
100
28
85 – 100
100
20
0 – 30
85 – 100
100
14
0-5
0 – 30
85 – 100
10
1&2
0-5
0 – 30
#
##
7
0–5
7
2
100
85 – 100
0 – 30
#
##
5
5
0–5
100
85 – 100
0 – 30
#
3,35
100
85 - 100
100
0 – 30
##
2,0
0–5
3
0-5
0 – 100
Gradings shall comply with the requirements for Grades 1 and 2 with the
following exceptions: # 0 – 50, ## 0 – 10
Fines
content:
passing
0,425 mm
sieve
1
0,5
0,5
0,5
0,5
0,5
1,0
15
2
1,5
1,5
1,5
1,5
1,5
2,5
15
3
N/A
N/A
2,0
2,0
3,0
3,5
15
Dust
content:
passing
0,075 mm
sieve
1
N/A
N/A
N/A
N/A
N/A
N/A
2,0
2
0,5
0,5
0,5
0,5
1,0
1,0
2,0
3
N/A
N/A
1,5
1,5
1,5
1,5
2,0
Note:
Refer to standard COLTO table for COLTO grading if required
Replace Table 4302/9 with:
TABLE B4302/9
Sieve sizes (mm)
5
0,425
0,075
Percentage passing by mass
95 minimum
50 minimum
20 maximum
Plasticity index = Non-plastic
Note:
Refer to standard COLTO table for COLTO grading if required
Replace Table 4302/10 with:
TABLE B4302/10
Nominal size of
aggregate (mm)
20
14
10
7
Maximum flakiness index (%)
Grade 1
Grade 2
25
30
25
30
30
35
30
35
Note:
Refer to standard COLTO table for COLTO grading if required
C3-139
Replace Table 4302/11 with:
TABLE B4302/11
Sieve size (mm)
Fine grade
14
10
7
5
2
1
0,600
0,300
0,150
0,075
100
84 – 99
60 - 90
42 – 72
23 – 48
10 – 27
4 - 12
Percentage passing sieve by mass
Fine slurry
Coarse slurry
Medium grade Coarse grade
Type 1
Type 2
100
100
86 – 100
100
100
87 – 100
71 – 91
84 – 100
72 – 91
72 – 91
62 – 82
51 - 90
40 – 64
40 - 63
36 – 56
33 – 68
25 - 46
22 – 41
22 - 41
22 – 50
19 – 34
15 – 30
15 – 30
15 – 37
12 – 35
10 – 20
10 – 20
7 – 20
7 – 18
6 – 15
6 – 15
4 - 12
2-8
4 - 10
4 - 10
Note:
Refer to standard COLTO table for COLTO grading if required
Delete Table 4302/12 without replacement
Add the following sub-sub-clause:
“(4)
Durability
Aggregate used in seals and asphalt shall show a durability index of less than 4 as determined by the
test method specified in Clause B8105 paragraph (g)."
(ii)
Aggregate for slurry seals
In the first paragraph, add the following after the first sentence:
“The engineer may order the addition of an approved natural sand or additional cement to improve
either the permeability or workability of the slurry.”
Add the following sub-sub-clause:
“(iii)
Aggregate for blinding
The aggregate used for blinding the single seal shall consist of 2,00mm to 5mm crushed aggregate or
river sand. The aggregate shall be clean, hard and free from clay, silt or other deleterious matter."
d)
Hydrophilic aggregates
(i)
Precoating of aggregate for stockpiling or for immediate use:
In the second paragraph, delete “12 litre” in the second sentence, and add the following sentence:
“Precoating fluid shall be manufactured from petroleum based products. The use of tar based
precoating fluids will not be permitted. For tender purposes the nominal quantity of precoating fluid for
the relevant nominal aggregate sizes is specified in table B4302/14.”
C3-140
TABLE B4302/14: NOMINAL APPLICATION RATES FOR PRECOATING FLUID
Nominal aggregate size (mm)
Nominal precoating application rate (ℓ/m³)
20
12
14
16
10
19
7
22
Add the following sub-clauses:
“e)
Water for diluting emulsions
Water used for the dilution of emulsions on site shall be suitable potable water, and each source of
water used shall be tested for compatibility with the emulsion before it is added to the bulk emulsion.
f)
Testing of polymer modified bitumen/emulsion
Testing shall be in accordance with the methods described in “Technical Guideline: The use of
Modified Bituminous Binder in Road Construction (TG 1-November-2007): Asphalt Academy”.
During spraying of each batch, the contractor shall draw off at least three test samples of the modified
bitumen/emulsion product and submit them to the engineer for acceptance testing purposes. The
supplier shall submit all his tests results to the engineer for correlation purposes, failing which the
engineer’s results shall be binding in terms of acceptance or rejection of the product.”
B4303
PLANT AND EQUIPMENT
b)
Binder distributor
Add the following:
"Prior to the commencement of any work, a calibration certificate, not older than 12 months, for the
binder distributor shall be presented to the engineer for approval.
The binder distributor shall be capable of spraying the binder at the specified application rates and to
the satisfaction of the engineer. The pump of the distributor shall be capable of delivering the binder at
the spray bar nozzles at the correct pressure to obtain the specified application rates, irrespective of
the viscosity properties of the prescribed binder. The spray bar of the distributor shall be fitted with
fishplates at the outside edge of the bar to prevent over spraying onto gravel shoulders or staining of
concrete elements on the edge of the surfacing of the road
In addition, the transverse distribution of the spray bar shall be field-verified by means of SANS 3001BT24: Civil engineering test methods Part BT24: Measurement of transverse distribution (‘Bucket test’)
for a binder distributor. The maximum permissible tolerance permitted between the troughs (excluding
the outer 300mm) is dependent on the viscosity of the binder type being applied and shall be as
follows:

Emulsions, cutback and penetration grade bitumens - 5%
Homogeneous modified bitumens - 7%


Non- homogeneous binders (bitumen rubber) - 10%
The spray bar shall be of such design as to allow for any adjustments to be made in order to meet the
above tolerances. This procedure shall be carried out each time the distributor is first established on
site and once a week thereafter or when a problem with transverse distribution is suspected. The
binder distributor shall thus have a set of troughs available in order to allow the execution of the test.
For limited quantities of spray-work, the engineer may accept the results of a recently completed
distribution test that has been recorded and approved by an independent supervisor on the
distributor's test log book.
The binder distributor shall be fitted with a suitable valve or other access gate for taking of samples of
the binder for testing purposes.”
C3-141
c)
Chip spreaders
Add the following at the end of the first paragraph:
“The chip spreader shall be capable of delivering a proper and uniform transverse distribution of chips
across the conveyor belts. The chip distribution shall be tested by means of canvas patches, each
1,0m by 1,0m and placed side by side. The mass of chips spread onto each individual canvas patch
shall not deviate by more than 10% from the calculated average spread per canvas patch.”
Add the following to the last paragraph:
"A non-self-propelled chip spreader may only be used in the event of a breakdown of the selfpropelled chip spreader during a pull, and shall be limited to the completion of that pull. No further
application of binder shall be permitted until such time as the self-propelled chip spreader is repaired
or replaced.”
B4304
a)
GENERAL LIMITATIONS AND REQUIREMENTS
Weather limitations
Add the following:
“Seal work using bitumen rubber or hot applied polymer modified binder shall not be permitted during
the months of May to August (inclusive). Winter grade binders shall not be used in any seal work and
the contractor’s program shall reflect this limitation.”
b)
Moisture content
Replace “reseal” with “seal” in the second line of the second sentence.
Insert “and/or primed base” after “surfacing” in the third line of the second sentence.
Replace the last sentence with “In such case the base shall be allowed to dry out to meet the above
moisture content requirement prior to placing the seal layer.”
(i)
General
Add the following:
“Seal work shall not be permitted on granular base layers if the moisture content in the upper 50mm
exceeds 50% of the optimum moisture content, determined in accordance with TMH1 Method A7. This
limitation shall apply even if the layer has been previously primed.
Sealing work shall not commence until the engineer has approved all other works ordered on that
section of road.”
e)
Demarcation of the working areas
(i)
New work
Add the following:
“Before the tack coat and first application of aggregate may be applied, the centreline of the road shall
be demarcated by means of a clearly visible weatherable fibre rope, pegged down with nails driven
into the existing surface at intervals of 15m on straight sections and 3m apart on curves. The
demarcating rope shall be removed prior to the application of the tack coat and aggregate on the
adjacent lane.’
C3-142
B4305
HEATING AND STORAGE OF BITUMINOUS BINDERS
d)
Homogeneous cold applied modified binders
Add the following:
“The requirements for short term handling, storage and application of these binders shall comply with
the requirements listed in table B4305/5:”
TABLE B4305/5: TEMPERATURE/TIME LIMITS POLYMER MODIFIED EMULSIONS
Short term handling
Binder Class
Storage
Max Temp
(°C)
Max Time
(hrs)
Max Temp
(°C)
Max Time
(hrs)
Max
Temp
(°C)
70
24
Ambient
240+
80
Spraying
Min
Temp
(°C)
Max
Time
(hrs)
50
2
1
SC-E1
1
SC-E2
CC-E1
Ambient
240+
Ambient
240+
Ambient
240+
Notes:
1.
This applies to modified emulsions with a binder content of approximately 70% m/m. For emulsions with a
binder content of approximately 65% m/m the maximum short term handling and maximum spraying
temperature limit shall be reduced by 10°C.
e)
Homogeneous hot-applied binders (summer grade)
In the second paragraph, replace table 4305/3 with “table B4305/3”:
TABLE B4305/3: TEMPERATURE/TIME LIMITS FOR HOT POLYMER MODIFIED BINDERS
Binder Class
Short term
handling
Max
Max
Holding
Temp
Time
(°C)
(hrs)
180
24
180
24
180
24
180
24
180
24
180
24
180
24
160
24
Storage
Max
Temp
(°C)
Max
Holding
1
Time
(hrs)
240
240
240
240
240
240
240
240
2
Spraying/Asphalt
Mixing/Application
Max
Temp
(°C)
Min
Temp
(°C)
Max
Holding
Time
(hrs)
8
12
12
8
12
12
24
8
S-E1 (SBR)
150
210
190
S-E1 (SBS)
150
185
175
S-E2
150
185
175
A-E1 (SBR)
150
190
175
A-E1 (SBS)
150
180
170
A-E2
150
180
170
A-P1
150
170
150
C-E1
140
180
160
Notes:
1.
If the recommended maximum holding time has been exceeded then resample and test the binder to
ensure compliance with the specification.
2.
In the event of non-polymer modified binders being used, refer to the supplier for guidelines on handling
and application temperatures.
B4306
STOCKPILING OF AGGREGATE
a)
General
Add the following:
"The contractor shall heed the environmental requirements of Part C of this volume in the preparation,
operation and closure of stockpile sites. The positions for stockpiling of aggregate and the proposed
operation methods shall be approved by the engineer before delivery of the aggregate can
commence.
After application of the seal all loose stones swept off the road surface are to be heaped either in the
drain or gravel shoulder, whichever is applicable, and removed in one operation. No sweepings are to
C3-143
be left on site for more than 24 hours. No sweepings are to be heaped or stored on the vegetated
areas of the road reserve. No loose stone is to be spoiled in the road reserve.”
B4307
CONSTRUCTION OF SEAL
b)
Single and double aggregate seals
(i)
Application of tack coat and aggregate
Replace the last sentence of the fourth paragraph with the following:
"The contractor shall so place the strips when constructing the seal that the joint between two adjacent
aggregate applications shall be located along the centreline and at 3,7m from the centreline."
Add the following to the fourth paragraph:
“Joints shall be straight and aggregate shall be broomed back in a neat straight line before the next
spray. String lines shall be used to demarcate joint edges. All stone-loss and "tram-lining/roping" shall
be made good by the contractor at no additional cost.”
(ii)
Initial rolling of aggregate
Replace the second sentence with the following:
"In the case of modified emulsions, initial rolling by means of self-propelled 5-ton flat steel wheel
rollers shall only be permitted if crushing of aggregate does not occur. Pneumatic-tyred rolling shall be
delayed until the emulsion has been allowed to break sufficiently to firmly secure the aggregate.
Rolling shall be postponed if there is any pick-up of aggregate on the tyres of the pneumatic type
roller."
(iii)
Broom drag and final rolling of aggregate
Add the following after the first paragraph:
“The contractor shall provide a back-chipping team, together with a pneumatic-tyred roller, of sufficient
capacity to ensure that back-chipping and rolling of aggregate shall be completed within thirty minutes
after initial application of the aggregate.”
Replace third paragraph with the following:
"After completing the spreading of the aggregate, final rolling shall consist of a minimum of four
passes utilizing a 15-ton to 20-ton pneumatic-tyred roller, followed by one or two passes of a 6-8 ton
flat steel wheel roller."
iv)
Joints between binder sprays
Add the following at the end of the paragraph:
"The protective sheets shall be made of reinforced building paper."
(v)
Protection of kerbs, channels etc.
Add the following:
"Where bitumen binder is to be sprayed directly adjacent to existing concrete kerbs, channels, side
drains, concrete edge beams and bridge balustrades, or over bridge joints, such concrete elements
shall be covered with an approved reinforced building paper.”
Add the following sub-sub-clause:
C3-144
“(vi)
Trial section
Before the contractor commences with the construction of any seal work he shall demonstrate that the
equipment and processes he proposes to use will enable him to construct the seal in accordance with
the specified requirements.
At the commencement of the surfacing operation, a 200m half-width section shall be considered as a
trial. After completion of each phase of the seal on this 200m section, the engineer will review and
then approve/reject the work method. If approval is granted for a specific operation i.e. application of
tack coat, aggregate, fog or slurry, the contractor may proceed with that approved operation.
Should the contractor at any stage fail to deliver an acceptable product he shall rectify the problems at
his own cost and demonstrate with a further trial section that he can carry out the operation
successfully. No specific payment shall be made for conducting these trials and the cost thereof shall
be deemed to be included in the tendered rates of sections 4400, 4500 and 4600.”
B4308
RATES OF APPLICATION
In the first sentence of the first paragraph, delete the following after "conventional":
"or homogeneous modified"
Add the following at the beginning of the second sentence:
"Homogeneous and"
In the second paragraph, replace 4314 with:
"B4314"
Add the following at the end of the second paragraph:
“In the case of single seals the engineer may, at his discretion, permit the application of a diluted
emulsion fog spray in instances where application rates are below the minimum allowable tolerances.
In such instances no additional payment over and above the unit rate tendered for the accepted seal,
plus or minus any variation from the nominal, will be made. In the case of sand seals or graded seals
the engineer may accept, at his discretion, an application of binder sprayed above the allowable
tolerance subject to the contractor, at his own cost, applying and rolling any additional sand/aggregate
necessary as a result of such over application.”
B4314
TOLERANCES AND FINISH REQUIREMENTS
c)
The rate of application
Replace the first paragraph with the following:
"The maximum permissible variation from the rates of application of aggregate or slurry, as ordered by
the engineer, shall be plus or minus 5%.
For binders, the maximum permissible variation from that specified shall be 5% for conventional
bitumen and all emulsions (measured net cold), and 5% for hot applied modified binders (measured at
spray temperature). Provided he is satisfied that the seal will perform satisfactorily, the engineer may,
at his discretion, conditionally accept out of tolerance variations at the reduced rates of payment listed
in Table B4314/1 below. However, variations in total binder application rates in excess of those tabled
shall be deemed rejected. Rejected sprays will not be considered for payment unless corrected to the
satisfaction of the engineer.
A lot for acceptance control purposes shall be at least 2000 litres. Lots smaller than 2000 litres shall
be combined with succeeding lots until a combined lot not less than 2000 litres is obtained. “
C3-145
TABLE B4314/1: PAYMENT REDUCTION
BINDER APPLICATION RATES
FACTORS
FOR
CONDITIONALLY
ACCEPTED
Conventional bitumen and emulsion.
Deviation from specified spray rate
Net cold bitumen. (%)
Hot applied homogeneous and nonhomogeneous modified bitumen.
Deviation from specified rate. At spray
temperature. (%)
±5,0
±5,0
100%
±6,0
±7,0
±6,0
±7,0
97,5%
95%
±8.0
±8,0
90%
±9,0
±9,0
85%
±10.0
±10,0
80%
% Payment of tendered rate
for seal
Add the following at the end of the last paragraph:
"The completed surfacing shall be of uniform texture without gaps or patches and shall be free from
longitudinal and transverse corrugations and any loose aggregate or binder spillage.
The edges of the completed bituminous surfacing shall be true to line."
d)
Conditional acceptance
Delete the entire sub-clause
C3-146
SECTION B4600: BITUMINOUS SINGLE SEAL WITH SLURRY (CAPE SEAL)
B4602
GRADES OF BINDER TO BE USED
a)
Tack coat
(iii)
Homogeneous modified binders
Delete “(1) 5% latex cationic emulsion” and replace with:
“Binder Class SC-E2 (65-68)(t) or (70-73)(t) where “(t)” indicates that the binder being applied shall
contains no diluents (cutters).”
(b)
Second application of binder
The second application of bituminous binder, as directed by the engineer shall consist of the following:
(1)
35% polymer modified spray-grade emulsion of Class SC-E2 (1 part 70% emulsion mixed
with 1 part of water).”
B4603
CONSTRUCTION BEFORE SLURRY APPLICATION
a)
Application of tack coat and aggregate
Add after the first paragraph:
“The Engineers may instruct the pre-coating of the 20mm aggregate of the first layer with a bituminous
3
based pre-coating fluid, at 12ℓ/m as specified in sub-clause 4302(d).
A second application of 35% cationic bitumen emulsion shall be applied to the surface of the 20mm
aggregate.
The aggregate to be used with the tack coat shall conform to the grading requirements for a 20mm
nominal size Grade 1 surfacing aggregate.”
b)
Initial rolling
Replace “sub-sub-clause 4307(b)(ii)” with:
“Sub-sub-clause B4307(b)(ii)”
c)
Broom drag and final rolling of aggregate
Replace “sub-sub-clause 4307(b)(iii)” with:
“Sub-sub-clause B4307(b)(iii)”
B4604
SLURRY
c)
Composition of slurry
Add the following:
“The aggregate used for slurry shall comply with the requirements of Table 4302/11. The first slurry
shall be a fine slurry "coarse” to “medium grade" and the second slurry shall be fine slurry "medium
grade". For tender purposes the mix proportions of the slurry shall be based on mass.”
After the second paragraph add the following:
C3-147
"The slurry consistency when measured in accordance with ASTM D3910 Section 6.1 shall be
between 30mm and 40mm."
e)
Application of slurry
In the first sentence of the third paragraph insert the words "one or" before "two layers".
Replace the fifth and sixth paragraphs with:
"The measurement of slurry application rate shall be the dry mass of aggregate in kg/m² applied per
m² of surfacing and the total nominal rate of application shall be 13 kg/m2 if only the 1st slurry layer is
applied, and 15 kg/m2 in total if the 1st and 2nd slurry layers are applied. Payment for slurry
application variations shall be based only on the actual total rate of slurry application of the completed
Cape Seal.”
Add the following after the eighth paragraph (now the seventh paragraph):
"Both the first and second layer of slurry shall be spread to the full final width of the primed surface."
Change the eighth line of the tenth paragraph as follows:
“… pneumatic-tyred roller. However, each layer of slurry shall be ….”
B4605
MEASUREMENT AND PAYMENT
Item
Unit
B46.01 Bituminous seal with 20mm aggregate and slurry
In the heading to this item add the words:
"(excluding 2nd application of binder)."
Delete the unit and add the following subitems:
"(a)
Single 20mm seal with first (coarse to medium grade) slurry layer
with a tack coat comprising
(i)
70% polymer modified cationic spray-grade emulsion of
2
Class SC-E2……………………………………………………………………….square metre (m )
(b)
Extra over (a) for 2nd (fine) slurry layer ................................................... square metre (m2)"
In the measurement paragraph delete the word "complete", and after the word "slurry" insert;
"(excluding 2nd application of binder)".
Add the following at the end of the payment clause for this item:
"The cost of providing the slurry seal over the final primed width shall be included in the rate for
providing the seal with slurry over the bituminous surfaced width."
Item
Unit
B46.03 Bituminous binder variations
Amend (l) to read:
"(l)
Polymer modified spray grade emulsion of SC-E2 (70-73) ........................................ litre (ℓ)"
C3-148
Add the following items:
“Item
Unit
B46.09 Extra over items B46.01(a) and (b) and 46.06 for the addition
of natural sand from commercial sources to the aggregate of the slurry…………………….. ton (t)
The unit of measurement shall be the ton of natural sand from commercial sources added to the slurry
aggregate calculated from the proportion of natural sand ordered by the engineer and the actual
measured application of the slurry.
The tendered rate shall include full compensation for all additional cost for procuring and furnishing the
sand from commercial sources, transporting the sand over an unlimited free-haul distance, and the
mixing of the sand into the slurry aggregate.
Item
Unit
B46.11 Second application of binder consisting of 35% spray
grade cationic emulsion……………………………………………………………………………….. litre (ℓ)
The unit of measurement shall be the litre of emulsion sprayed as specified and measured of the
application temperature.
The tendered rate shall include full compensation for procuring and furnishing the binder and applying
the second application of binder as specified."
Item
Unit
B46.12 Extra over items B46.01 and B46.11for the transportation cost of
bitumen binder supplied by a refinery outside the Western Cape
Province................................................................................................................... ton (ton)
Where bitumen that meets the requirements of the specification is not available from a refinery in the
Western Cape Province the engineer may agree that material be imported from other sources.
The unit of measurement shall be the ton of net cold bituminous binder and shall be calculated from
the average binder content of the asphalt placed for a day’s work or the actual volume of prime, tack
and binder sprayed.
The tendered rate shall include full compensation for the additional cost of transporting bituminous
binder which meets all the requirements of the specification from a refinery outside the Western Cape
Province. Any difference in the “ex refinery” price of bitumen shall be compensated for by means of
the special material adjustment formula.”
C3-149
COLTO SERIES 5000:
ANCILLARY ROADWORKS
SECTION B5100: PITCHING, STONEWORK AND PROTECTION AGAINST EROSION
B5102
MATERIALS
(a)
Stone
Replace the 2nd paragraph with the following:
“Unless suitable stone can be located on site, the stone for pitching shall come from commercial
sources but, from whatever source, its use shall be subject to the prior approval of the engineer.”
(c)
(ii)
Sand
Sand for bedding
Replace this sub-sub-clause with the following:
“Sand for bedding used for paving blocks shall not contain any deleterious impurities and shall comply
with the requirements given in table B5102/1.
Table B5102/1
Sieve size (mm)
10
5
2
1
0,600
0,300
0,150
0,075
Percentage passing
100
95 – 100
73 – 86
43 - 78
25 – 60
10 - 30
5 – 15
5 - 10
Note:
Refer to standard COLTO table for COLTO grading if required
B5106
SEGMENTAL BLOCK PAVING
(d)
Edge beams
Add the following paragraph:
“Where concrete edge beams are constructed the relevant specifications under section 2300 shall
apply."
C3-150
SECTION B5400: GUARDRAILS
B5402
MATERIALS
(a)
Guardrails
At the end of the 1st sentence delete the full stop and add “or SANS 51317 and carry the SABS mark.”
(b)
(ii)
Guardrail posts
Steel posts
Replace the paragraph with the following:
“Where offered or instructed to be used, steel posts shall be part of an approved guardrail system as
tested and complying with SANS 51317, and galvanized in compliance with the requirements of SABS
763 for type A1 articles, shall be used.
Where guardrails are placed on concrete retaining walls or concrete structures, the steel posts shall be
of the type and size shown on the drawings or described in the project specifications.”
B5403
CONSTRUCTION
(a)
Erection
Replace the 7th paragraph with the following:
“Steel posts placed on concrete retaining walls or concrete structures shall be erected and fixed as
shown on the drawings. For all other applications, wooden posts shall be erected and fixed in
compliance with the approved guardrail system as tested and approved in terms of SANS 51317.”
B5405
REMOVING, RENOVATING AND RE-ERECTING GUARDRAILS
(a)
Removing the guardrails
In the 3rd line of the 1st paragraph, after “150mm layers,” delete the full stop and add “of suitable
material (not less than G7 quality material).”
B5406
MEASUREMENT AND PAYMENT
Replace item 54.01 with the following:
“Item
Unit
B54.01 Guardrails on 3.81 m spaced posts
(a)
Complete galvanised system on:
(i)
Timber posts .......................................................................................................... metre (m)
(b)
Extra over 54.01(a) for the following:
(i)
Type A - Bridge terminal flared end treatment with combination of
single and double guardrail sections ................................................................... number (No)
Type B - Bridge terminal flared end treatment with double guardrail
sections.............................................................................................................. number (No)
Type E1 - Bridge terminal end treatment with combination of single
and double rail section ....................................................................................... number (No)
Type F1 - Bridge terminal end treatment with double guardrail
sections.............................................................................................................. number (No)
Bridge connect treatments with double guardrail sections ................................... number (No)
End wing ............................................................................................................ number (No)
Guardrail adapters.............................................................................................. number (No)
(ii)
(iii)
(iv)
(v)
(vi)
(vii)
C3-151
(viii)
(ix)
(x)
Bullnoses WCG detail......................................................................................... number (No)
Type G – WCG detail end treatment approach end ............................................. number (No)
Type G – WCG detail end treatment departure end ............................................ number (No)
The unit of measurement for (a) shall be the metre of guardrail as erected, (including length of end
treatments and curved guardrails).
The unit of measurement for (b)(i) to (b)(x) shall be the number of end treatments, connect treatments,
adaptors and steel posts of each type installed.
The tendered rates shall include full compensation for furnishing all materials and labour for erecting
and galvanizing the guardrails, complete with posts, spacer blocks, bolts, nuts, washers and
reinforcing plates, and excavating holes in all classes of material, concrete, backfilling and removing
any surplus material. It shall also include full compensation for incidentals in respect of supplying and
erecting curved guardrails, end treatments, connect treatments, adaptors and turned down sections.
Reflective plates and drilling and blasting will be paid for separately under items 54.06 and 54.12
respectively.”
Replace item 54.02 with the following:
“Item
Unit
B54.02 Guardrails on 4.0 m spaced posts
(a)
Complete galvanised system on:
(i)
Steel posts ............................................................................................................. metre (m)
(b)
Extra over 54.02(a) for the following
(i)
Type A - Bridge terminal flared end treatment with combination of
single and double guardrail sections ................................................................... number (No)
Type B - Bridge terminal flared end treatment with double guardrail
sections.............................................................................................................. number (No)
Type E1 - Bridge terminal end treatment with combination of single
and double rail section........................................................................................ number (No)
Type F1 - Bridge terminal end treatment with double guardrail
sections.............................................................................................................. number (No)
Bridge connect treatments with double guardrail sections ................................... number (No)
End wing ............................................................................................................ number (No)
Guardrail adapters.............................................................................................. number (No)
(ii)
(iii)
(iv)
(v)
(vi)
(vii)
The unit of measurement for (a) shall be the metre of guardrail system (complying with SANS 51317)
as erected (including length of end treatments and curved guardrails).
The unit of measurement for (b)(i) to (b)(vii) shall be the number of end treatments, connect treatments
and adaptors of each type installed.
The tendered rates shall include full compensation for furnishing all materials and labour for erecting
and galvanizing the guardrails, complete with posts, spacer blocks, bolts, nuts, washers and
reinforcing plates, and excavating holes in all classes of material, concrete, backfilling and removing
any surplus material. It shall also include full compensation for incidentals in respect of supplying and
erecting curved guardrails, end treatments, connect treatments, adaptors and turned down sections.
Reflective plates and drilling and blasting will be paid for separately under items 54.06 and 54.12
respectively.”
C3-152
Delete items 54.03, 54.04 and 54.05 without replacement
Item
Unit
B54.07 Removing existing guardrails ............................................................................. metre (m)
Add the following:
“The tendered rate shall also include for the backfill of the holes with suitable G7 quality material.”
Add the following payitems:
“Item
Unit
B54.14 Nailing of gang nail plates on top of timber guardrail posts ........................ number (No)
The unit of measurement shall be the number of gang-nail plates supplied and fixed as specified.
The tendered rate shall include full compensation for supplying all materials and labour and for fixing
to the top of the sealed guardrail post.
Item
Unit
B54.15 Proprietary H4B containment level with a working width of 2.5 m
guardrail system complying with SANS51317 ................................................... metre (m)
The unit of measurement shall be the metre of guardrail erected including end treatments.
The tendered rate shall include full compensation for furnishing all materials and labour, and erecting,
painting and galvanising the guardrail, complete with posts, spacer blocks, bolts, nuts, washers and
reinforcing plates, and excavating the holes in all classes of material and backfilling the post holes,
including concrete backfill, and removing any surplus excavated material.”
C3-153
SECTION B5500: FENCING
B5501
SCOPE
Add the following:
“This section also covers the repairing of existing fences that form part of the permanent work and/or
routine maintenance”
B5502
MATERIALS
Add the following new sub-clauses:
(k)
Type 2 Fence - Pedestrian fence welded mesh
Pedestrian fence welded mesh shall be constructed using 2.5mm diameter wire that is fully hot dip
galvanized and of the quality as shown in drawing J01802-01-10-905. Aperture sizes shall be 100mm
by 50mm centre to centre.
(l)
Type 3 Fence – Anti – dazzle screen welded mesh
Anti – dazzle screen welded mesh shall be a mesh with aperture size of 100mm by 20mm and of 4mm
diameter wires and shall be in accordance with drawing J01802-01-10-906. All wire shall be fully hot
dip galvanized.
B5503
TYPES OF FENCING
st
In the 1 paragraph add the following subclauses:
“(f)
B5508
Anti – dazzle screen”
ERECTING DIAMOND MESH OR WIRE NETTING
Change the heading to “B5508
NETTING”
ERECTING DIAMOND MESH, WELDED MESH OR WIRE
In the 2nd line of the 1st paragraph, after “wire netting” add “, welded mesh”
B5514 MEASUREMENT AND PAYMENT
Item
Unit
B55.02 Supply and erect new fencing material for new fences and
supplementing material in existing fences which are being
repaired
Add the following item under the subsubitem (ii) Inclined of subitem (i) Straining posts, stays and
anchors:
Add the following items:
(j)
Type 2 Fence (Pedestrian) - Pedestrian fence welded mesh 1.8m in
height (aperture size 100mm x 50mm x 2.5mm dia). Fully
galvanized…………………… ................................................ ……………… square metre (m2)
C3-154
B55.03 New gates
Add the following items:
“(a)
Type 1 Fence (Stockproof) - Double leaf 7.2m wide stock proof fence
gate, manufactured from 42.9mm ɸ X2.6mm mild steel tubing
complete with hinges, washers, bolts and locking chain. Fully hot
galvanized. ………… ...................................................................................... ….number (No)
“(b)
Type 1 Fence (Stockproof) - Single leaf 3.6m wide stock proof fence
gate, manufactured from 42.9mm ɸ X2.6mm mild steel tubing
complete with hinges, washers, bolts and locking chain. Fully hot
galvanized. ………… ...................................................................................... ….number (No)
(c)
Type 2 Fence (Pedestrian) - Double leaf 5m wide pedestrian fence
gate, manufactured from 42mm ɸ X 2mm mild steel tubing frame
21.4mm ɸ X 2mm mild steel tubing bracing complete with hinges,
washers, bolts and locking chain. Fully hot dip galvanized. …………… .... ……….number (No)
B55.04 Moving existing fences and gates
Add the following item under subitem (a) Fences:
“
(v)
Moving private property fences and walls. … ............................................ ….provisional sum”
B55.05 Dismantling existing fences
Add the following item under subitem (a) Fences:
“(v)
Vibacrete walls. ………………………………. ................................................. .kilometre (km)”
Add the following items:
“Item
Unit
B55.10 Repairing existing fences ............................................................................ kilometre (km)
The unit of measurement for repairing existing fences shall be the kilometre of existing fence repaired
on the instruction of the engineer.
The tendered rate shall include full compensation for untying the existing fence (where necessary) and
reinstating it, tying of droppers and repairing and re-aligning of standards to the satisfaction of the
engineer as well as for coiling and stacking material unsuitable for re-use. Fencing material replaced
shall be paid for under items 55.02 and 55.03.
If the existing fence is damaged by the contractor’s construction activities, the contractor shall repair
the fence at his own cost.”
B55.11 Type 3 Fence (Anti – Dazzle Screen) – Anti – dazzle screen
complete as per drawing J01802-01-10-906. All steel fully hot dip
galvanized............................................................................................................. metre (m)
The unit shall be the metre of anti – dazzle screen installed measured from centre of post to centre of
post complete as per drawing J01802-01-10-906.
The tendered rate for each metre of anti – dazzle screen shall include full compensation for providing
all materials, including all concrete, bolts, washers and nuts, back plates, anti – dazzle mesh, posts,
connection plates, excavation or drilling of holes, erecting all posts, fixing all mesh, incidentals and the
complete putting up of the fence as specified and shown on the drawing.”
C3-155
SECTION B5600: ROAD SIGNS
B5601
SCOPE
Replace “South African Road Traffic Signs Manual” in the second paragraph with:
“SADC Road Traffic Signs Manual”
B5603
MANUFACTURING OF ROAD SIGN BOARDS AND SUPPORTS
(a)
Road signboards
Add the following:
“The contractor shall make every effort to ensure that signboards are correct in all respect and before
dispatching the boards from the manufacturer’s factory shall provide the engineer with a 100 mm x
150 mm colour photograph of each sign face for approval of the correctness of the legend. Such
approval will not imply final acceptance of the board. If the contractor is in any doubt as to the
correctness of the sign detail, the sign designer shall be contacted for verification.”
(ii)
Steel profile road signboards
Add the following:
“Chromadek section shall be assembled in accordance with the details on drawings.
Where the letter or legends cross the horizontal joints of the sign panels, the letter shall be cut on the
joint and both ends folded around the radius.
Retro-reflective material to adjoining Chromadek panels on a sign shall be practical visual match of the
specified colour.”
B5604
ROAD SIGN FACES AND PAINTING
Add the following subclause:
“(e)
Application of retro-reflective material
All sign faces shall be faced with retro-reflective material. Painted front sign faces shall not be used.
Where applied to Chromadek sections, retro-reflective material shall be applied as specified for
aluminium section in clause 5603(d) of the standard specification, and of clause B5603(a)(ii) of this
project specification.”
B5605
STORAGE AND HANDLING
Add the following:
“The following shall not be allowed on the sign face:




Drilling of holes, except for the fastening of overlays
Application of any form of adhesive
Cleaning with any chemicals that are not specifically approved by the manufacturer of the retroreflective material.
Covering the sign face with an impermeable material that does not allow free circulation of air.”
B5606
ERECTING ROAD SIGNS
(b)
Excavation and backfilling
Add the following:
“Where posts are to be backfilled with concrete or soilcrete the lower 50 mm of the post shall protrude
into the in-situ material if it is of a free draining nature, alternatively, a 50 mm thick layer of imported
free draining material shall be placed around the foot of the post before placing the concrete or
soilcrete.”
C3-156
(c)
Erection
Add the following:
“After erection the signboard shall be thoroughly cleaned with a cleaning agent approved by the retroreflective material’s manufacturer.
All vegetation obstructing the new or replaced sign board shall be removed and disposed of as
instructed by the engineer.”
B5608
DISMANTLING, STORING AND RE-ERECTING EXISTING ROAD SIGNS
Add the following:
“Existing road signs that are being replaced by new signs shall be dismantled and disposed of by the
Contractor. Where possible the dismantling of the signs shall not be before the replacement sign is
erected and displayed. Where dismantling of the sign is required before erection of the replacement
sign, the dismantling shall not take place until immediately before work is to commence on the
replacement, and the replacement shall be completed and the new sign displayed as soon as possible
thereafter (within 72 hours).
Dismantling shall include sign panels and ground mounted sign supports.
Ground mounted sign supports shall be cut off just below ground level. Material excavated for removal
of buried poles shall be replaced, and any depression made good using excess material from
excavation for new signs.
Payment items are provided in the Pricing Schedule. Payment will differentiate between different
types of sign panels.”
B5609
MEASUREMENT AND PAYMENT
Item
Unit
B56.01 Road sign boards with painted or coloured semi-matt
background. Symbols, lettering, and borders in semi-matt black
or in Class I retroreflective material, where the sign board is
constructed from:
Amend the last two lines of the second paragraph to read:
“completion, delivery, installation of the road sign board complete as specified, and the removal and
disposal of all vegetation obstructing the motorists’ view of the new or replaced sign board.”
Item
Unit
B56.02 Extra over item B56.01 for using:
(a)
Background of retro-reflective material:
Add the following subitem:
“
(iv)
(b)
Diamond grade: Class IV .......................................................................... square metre (m²)”
Lettering, symbols, numbers, arrows, emblems and border of retro-reflective material:
Add the following subitem:
“(iii)
Diamond grade: Class IV .......................................................................... square metre (m²)”
C3-157
Add the following payment items:
“Item
Unit
B56.10 Danger plates at culverts/structures (800 mm x 200 mm) .............................. number (No)
The unit of measurement shall be the number of danger plates provided and erected in accordance
with the drawings.
The tendered rate shall include full compensation for all labour and material, painting, posts,
excavation, backfilling with soil etc., as may be necessary for completing the work in accordance with
the details shown on the drawings.
C3-158
SECTION B5700: ROAD MARKINGS
B5701
SCOPE
Replace “South African Road Traffic Signs Manual” in the second paragraph with:
“SADC Road Traffic Signs Manual”
Replace the words “ordinary road marking paint” with “solvent borne road marking paint”.
Replace “BS 3262” with “EN 1436”.
Replace “Hot melt plastic road marking” with “thermoplastic road marking”.
B5702
MATERIALS
Insert the following before subclause (a) Paint:
“The selection of the appropriate road marking paint and materials for permanent road markings to
ensure conformance with the requirements of this specification rests with the contractor. Such paint
and material shall have technical characteristics (brightness, luminance, skid resistance, durability)
equal to or greater than road marking paint and materials specified in subclauses 5702(a), (b) and
B5702(c).
Where plastic road-marking material (hot-melt plastic (also known as thermoplastic) and twocomponent (also known as cold plastic)) is used, the contractor shall obtain an approved guarantee
from the manufacturer that the paint complies with the specification. This shall be submitted to the
engineer on request.”
(a)
(i)
Paint
Road marking paint
Replace the subclause with the following:
“Road marking paint shall be Type 1 as specified in SANS 731-1. Only paint, manufactured in a
SANS approved and accredited facility shall be accepted. The no-pick-up time of road-marking paint
shall comply with the Class 1 requirement in accordance with SANS 731-1.
The paint shall be delivered at the site in sealed containers marked in accordance with SANS 731-1.
The viscosity of the paint shall be such that it can be applied without being thinned down.”
Replace subclause (iii) with the following:
“(iii)
Thermoplastic road marking material
Thermoplastic road marking material shall comply with the requirements of EN 1436, and
EN 1423: 1998 for drop-on glass beads for road marking and anti-skid aggregates and mixtures
thereof. Blending of thermoplastic road marking material and glass beads shall comply with EN 1424:
1998.
The binder shall be an elasticized synthetic resin and the material shall be reflectorized by mixing in
25% by mass Class A glass beads in accordance with EN 1424: 1998. An additional topping of glass
beads shall be applied to the hot surface of the material for instant retro-reflectivity.
The white road marking material shall contain 6% by mass minimum titanium dioxide content and shall
have a skid resistance of 45 S.R.T. – units or higher. SABS Method 1248: 1995 shall be used for
determination of traffic wear index; indication of durability.
C3-159
The following minimum lumination values are required for the completed product:
250 mcd/m2.lux & 120 mcd/m2.lux for white & yellow lines respectively, at 30 days after
application.
200 mcd/m2.lux & 100 mcd/m2.lux for white & yellow lines respectively, at 6 months after
application.
Determination of coefficient of retro-reflected luminance by means of portable retro-reflectometer shall
be carried out using SANS 6261: 2008. Application of the permanent roadmarking will thus have to be
performed within the first 6 months of the 12 month defects liability period to allow for the second
measurement to fall within the contract dates. Should the application of the permanent road-marking
fall outside the first half of the defects liability period for whatever reason, the settlement of the
retention money will be delayed until the second measurement of luminance can be performed at the
stipulated time and the required adjustment can be made to the tendered rate (if required).
Two-component cold plastic road marking material shall be used for symbols, arrows and letters (hand
painted markings) unless otherwise instructed by the engineer.”
Add the following subclauses:
“(v)
Cold plastic road marking material
Cold plastic road marking material shall be used for symbols, arrows and letters (hand painted
markings) and shall consist of a solvent-free reactive acrylic resin, stuffing, beads and pigment to
which a hardener shall be added. Application is carried out using a trowel. Material applied by paint
brush shall not be used.
Cold plastic road marking material shall be reflectorized by mixing in 25% by mass (or 400 g/m2)
Class A glass beads in accordance with EN 1424: 1998. An additional topping of glass beads is
applied to the wet surface of the material after application and will comply with EN 1423: 1997.
(vi)
Epoxy Primer applied to Kerb Markings
The primer to be applied to the kerbs shall be SigmaCover 280 manufactured by Sigma Coatings or
similar approved.”
(b)
Roadstuds
Replace the second sentence with the following:
“All square roadstuds shall have a footprint of 100 mm x 100 mm and a height of at least 20 mm.
Round roadstuds shall be 100 mm in diameter and not less than 20 mm in height.”
Add the following subclause:
“(c)
Retro-reflective beads
Retro-reflective glass beads shall be applied to the wet paint, thermoplastic and cold plastic.
The beads shall comply with Class A beads in accordance with EN 1424: 1998, with the following
requirements or as approved by the engineer:
colour :
roundness
size range of
refractive index
specific gravity
granulometry
crystal clear
: > 80%
: 14 – 200 US Mesh (75 – 1400 Microns)
: > 1.5
: ± 2.5
:
C3-160
SIEVE
1700
1400
1180
850
600
425
355
212
PAN
CUMULATIVE RETAINED MASS
MINIMUM
0
0
5
40
70
80
90
95
100
MAXIMUM
2
10
30
80
100
100
100
100
100
The beads shall be delivered to the site in sealed bags, marked with the name of the manufacturer,
the batch number and an inspection seal of SANS, confirming that the beads form part of a lot tested
by SANS and comply with the requirements of EN 1424: 1998. Alternatively, the contractor shall at all
times have a SANS certificate on the site, identifying the batches to which the inspection seals apply
and certifying that they have been tested by SANS, and comply with the requirement of EN 1424:
1998.”
B5704
MECHANICAL EQUIPMENT FOR PAINTING
Add the following sentence at the end of the first paragraph:
”The road-marking machine shall be fitted with a device to guide the operator to the centre of the line
to be painted. This device shall be used at all times of operation.”
B5705
SURFACE PREPARATION
Add the following at the end of the second paragraph:
“The onus is on the contractor to ensure that the surface on which the road markings are to be applied
is sufficiently clean and dry to ensure that the quality of the road markings will not be adversely
affected. The contractor is also responsible for protecting road studs from being painted over, and the
subsequent cleaning thereof if such over-painting did occur.”
Add the following new paragraph after the fourth paragraph:
“Where permanent road markings are specified on kerbs or on concreted surfaces, as instructed by
the Engineer, the surface shall first be cleaned in order to remove any dust and traces of mould
release oils. The surface is to be prepared to a wood floated (etched) finish by applying light
sandblasting or by any other approved means. An approved epoxy primer shall then be applied to the
concrete surface to ensure good adhesion of the paint with the concrete surface. The epoxy primer
shall be compatible with road marking paint. Once the primer has dried, the specified road marking
colour paint shall be applied as a top coat at the specified application rate.”
B5707
APPLYING THE PAINT
Insert the following before the first paragraph:
“The contractor’s establishment on site and general obligation shall be deemed to fully include the
establishment of the road-marking team, irrespective of the number of times the road-marking team is
required to be on site or is required to move within the site.
Provision is also made under item 57.07 for de-establishment and re-establishment in the contract or
maintenance period if such action is required by delays not attributable to the contractor and/or
ordered by the engineer.”
Replace the sixth paragraph with the following:
“Solvent borne road marking paint shall be applied at a nominal rate of 0, 42 ℓ/m2 or as directed by the
2
engineer. Thermoplastic road marking shall be applied at a nominal rate of 2,5 kg/m to achieve a
minimum thickness of 1,25 mm to 1,5 mm or as directed by the engineer. The two-component road
marking material shall be applied by hand by means of a trowel. The desired symbol or line shall be
marked with a tape or a template on the road surface. Thereafter apply the required volume of
C3-161
material and spread uniformly over the entire area. When dry/set, remove the tape or template. A
spreading rate of 4,5 kg/m2 is estimated to achieve a 2,0 mm material thickness.
In order to ensure proper coverage on all types of surfaces the engineer may order an increase in the
above nominal application rates. Payment for these variations in application rates shall be made
under item 57.04.
A daily log-sheet, provided by the employer, shall be completed and signed by the contractor and the
engineer’s representative, recording the quantities of paint and glass beads used on that day and shall
be available for inspection at all times. The completed and signed log-sheet for the period covered by
a payment certificate shall be attached to the payment certificate.”
Replace the last paragraph with the following:
“Solvent-based road marking as specified by the engineer shall be carried out within 14 days of
opening the road full width to traffic after the completion of the surfacing.
If in the in the opinion of the engineer, conditions are unsafe, the centre-line shall be painted
immediately after 2,0 km of continuous road has received a new asphalt layer, or 4,0 km of continuous
road has received a new seal surfacing.”
B5708
APPLYING THE RETRO-REFLECTIVE BEADS
In the first paragraph, replace the nominal application rate of 0,8 kg/litre with “400 g/m2”.
Replace the second paragraph with the following:
“The thermoplastic road marking material and two-component road marking material shall contain
insitu glass beads of minimum content of 25% in order to obtain night visibility (reflectivity). The
contractor shall immediately apply additional glass beads at 400 g/m2 to obtain immediate reflectivity.
The beads shall be sprayed onto the road marking layer by means of a pressure sprayer. Where
letter, symbol, traverse line and island road marking is undertaken by hand, the glass beads may be
applied by hand if approved by the engineer. Prior to any hand application work, the contractor shall
first request approval from the engineer.”
Add the following:
“Beads shall be applied in accordance with EN 1424.”
B5710
TOLERANCES
Add the following paragraphs to subclause (c) Alignment of markings:
”When an unbroken line and a broken line are painted alongside each other, the beginning and the
end of the unbroken line shall coincide with the beginning of one broken line and the end of another
broken line. When existing lines are repainted, the new markings shall not deviate more than 100 mm
in the longitudinal direction or 10 mm in the transverse direction from the existing marking.
The alignment of the road studs shall not deviate from the true alignment by more than 10 mm and
shall be positioned so that the reflective faces are within 5 of a right angle to the centre line of the
road.”
Add the following subclause:
“(e)
(1)
Testing
Plant
Before painting any permanent road markings, the contractor shall satisfy himself and the engineer, by
painting test lines on a section of pavement other than the section required to be marked:
(i)
(ii)
that the painting machine is in good working order and properly adjusted;
that the operator is fully experienced; and
C3-162
(iii)
that the machine sprays at the specified rate of paint application.
The contractor shall bear the cost of all materials and workmanship required for the above plant tests.
In addition, the contractor shall conduct random paint thickness tests and dip/spread tests as required
by the engineer.”
B5711
GENERAL
Insert the following into the last sentence of the last paragraph between “black paint” and “or chemical
paint remover”:
“, bituminous emulsion, slurry”
Add the following to the last paragraph:
“Where black paint is used, it shall be matt.”
Add the following paragraph:
”The contractor shall provide temporary traffic control facilities in accordance with section 1500 to
ensure traffic safety where work is being executed.
Property and/or road signs damaged by the contractor, his personnel, his agents or subcontractors
shall be repaired or restored to their condition prior to the damage at his own cost.”
B5712
FAULTY WORKMANSHIP OR MATERIAL
Add the following paragraphs to this item:
“The durability of the roadstuds supplied and the installation thereof shall be guaranteed for 12 months
after installation. Defective or lost roadstuds shall be replaced by the contractor at his own cost.
Excluded from this guarantee is damage or faults originating from vandalism or extreme mechanical
damage.
The contractor shall rectify in an acceptable manner and at his own costs; all markings that do not
comply with the specified requirements.
While work is in progress, tests shall be carried out on materials and/or the quality of work to ensure
compliance with the specified requirements. The sampling methods are specified in SANS 731-1.
The sampling methods described in TMH5 shall be followed where applicable.”
B5713
PROTECTION
Add the following paragraph
”Traffic cones shall not be smaller than 750 mm in height and shall be placed on the road not further
than 48 m apart. Cones shall not be removed before the paint on the road has hardened to such an
extent that it will not be damaged by traffic and the adhesive of the road studs has hardened to such
an extent that the studs will not turn or become loose. All marks on the road caused by traffic driving
over wet paint shall be removed by the contractor at his own cost.”
Add the following clause:
“B5715 REMOVAL OF EXISTING ROAD STUDS
The existing road studs shall be removed from the road surface prior to milling.”
C3-163
B5714
MEASUREMENT AND PAYMENT
Item
Unit
B57.01 Road-marking paint
“(g)
Kerb markings (any colour)......................................................................... square metre (m²)
Add the following to this pay item:
“The colour to be applied shall be as per the details given in the Southern African Development
Community Road Traffic Signs Manual (SADC RTSM), Volume 1, Chapter 7.
The unit of measurement for applying the road marking paint to concrete kerb surfaces shall be the
actual area painted. The undercoat and top coat shall not be measured separately but as a single
layer.
The tendered rate per square metre shall include full compensation for procuring and furnishing all
labour, materials and equipment including all costs associated with cleaning and preparing the surface
to receive both the undercoat and topcoat paint applications. The tendered rate shall also include for
applying the undercoat and topcoat layers (as per the manufacturers specifications).”
Amend the heading for item B57.03 as follows:
“B57.03 Thermoplastic road-marking paint
(a)
(b)
White lines (broken or unbroken) (width of line indicated) .................................kilometre (km)
Yellow lines (broken or unbroken) (width of line indicated) .............................. kilometre (km)”
Add the following after the third paragraph:
“Full payment of the tendered rate will be applicable upon completion of the application of the roadmarking paint. However, should the coefficient of retro-reflected luminance fall below the required
minimum levels as specified in clause B5702 above, payment will be reduced on the following sliding
scale :
White lines:
Below 250 mcd/m2.lux at 30 days : minus 10 % of the tendered rate
Below 200 down to 180 mcd/m2.lux at 6 months : minus 10% of the reduced rate
Below 180 down to 160 mcd/m2.lux at 6 months : minus 20% of the reduced rate
Below 160 down to 140 mcd/m2.lux at 6 months : minus 30% of the reduced rate
Yellow lines:
Below 120 down at 30 days: minus 20 % of the tendered rate
Below 100 down to 80 mcd/m2.lux at 6 months: minus 20% of the reduced rate
The reduction in the tendered rate applicable for failing to meet the specified minimum luminance level
at the 30 days and 6 months measurement dates shall be applied accumulative in the certificate
immediately following the date of measurement.”
Amend item B57.05 as follows:
“Item
Unit
B57.05 Roadstuds installation and maintenance (type stated) ................................. number (No)”
Add the following after the first sentence of the second paragraph:
“No additional payment will be made should temporary or permanent road studs be replaced if lost or
broken during the construction period or during the Defects Notification Period.”
C3-164
Item
B57.08
Unit
Removal of existing, temporary or permanent road markings by:
Add the following subitem:
“(c)
Black Stamark removable roadmarking tape............................................. square meter (m²)”
Add the following items:
“Item
Unit
B57.10 Cold plastic road marking material
(a)
White lettering and symbols....................................................................... square metre (m2)
(b)
Yellow lettering and symbols ..................................................................... square metre (m2)
(c)
Transverse lines, painted island and arrestor bed markings (any
colour) ....................................................................................................... square metre (m2)
The unit of measurement for applying the roadmarking material for the lettering, symbols, transverse
lines, islands and arrestor bed markings shall be the square metre, and the quantity to be paid for shall
be the actual surface area of the lettering, symbols, transverse lines, islands and arrestor bed
markings, completed in accordance with the instructions of the engineer.
The tendered rate per square metre for applying the road marking material shall include full
compensation for procuring and furnishing all material, including the retro-reflective beads and all
necessary equipment, and for applying, protecting and maintenance as specified, including the setting
out of lettering, symbols, transverse lines, islands and arrestor bed markings.
Item
Unit
B57.11 Re-establishing the painting unit on instruction of the engineer
during the construction period ...................................................................... number (No)
The unit of measurement shall be the number of times the painting unit is re-established on site on
instruction of the engineer.
The contractor’s establishment on site and general obligation shall be deemed to fully include the
establishment of the road-marking team, irrespective of the number of times the road-marking team is
required to be on site or is required to move within the site.
Provision is made under payment item 57.07 for de-establishment and re-establishment in the contract
or maintenance period if such action is required by delays not attributable to the contractor and/or
ordered by the engineer.
The tendered rate shall include full compensation for re-establishing the complete painting unit on the
site and the subsequent removal of all special equipment, personnel, etc., for painting the road-traffic
markings during the construction period.
Item
Unit
B57.12 Retro-reflective removable road marking tape
(a)
(b)
White lines (broken or unbroken) (width of line indicated) ................................ kilometre (km)
Yellow line (broken or unbroken) (width of line indicated) ..................................kilometre (km)
The unit of measurement for applying the temporary road making tape shall be a km of each specified
width of line and the quantity paid shall be the actual length of line applied in accordance with the
instructions of the engineer, excluding the length of gaps in broken lines.
The tendered rate per km shall include full compensation for procuring and furnishing all material and
the necessary equipment, and for applying, protecting and maintenance as specified but excluding
setting out and pre-marking the lines.”
C3-165
SECTION B5800: LANDSCAPING AND PLANTING PLANTS
B5801
SCOPE AND DEFINITION
Delete this paragraph and replace with
“This section includes all areas affected by construction activities. It includes landscaping, grassing,
rehabilitation, erosion protections and planting trees and shrubs.
(b)
Definition
WEEDS
Delete the following:
“(as listed in bulletin 413 issued by the Department of Agriculture, Directorate of Agricultural
Information)”
and replace it with:
“(as listed in the Conservation of Agricultural Resources Act)”
B5802
MATERIALS
(c)
Grass seeds
Add the following:
“The grass seed mixture and soil additives shall be as follows:
(i)
Seed mixtures
Locally harvested seed mix of suitable indigenous plants for areas under consideration
(5 kg/ha). Refer to EMPr Rehabilitation Plan in Part C3 Section C.
(ii)
Mulch
Straw mulch (250 kg/ha)
(iii)
Fertiliser
Organic fertiliser weed free (250 kg/ha)
(iv)
Soil binder
Earthbound (250 kg/ha)
(e)
Grass sods
Delete “until they are placed” and add “once placed for planting”.
(i)
Nursery-grown sods
Add the following:
“The sods shall be free of weeds, weed seeds, insects and fungal diseases.”
(ii)
Veld sods
Add the following:
“The sods shall be free of weeds, weed seeds, insects and fungal diseases.”
(f)
Anti-erosion compounds
Add the following to the end of the paragraph:
“Straw bales harrowed into the sand fill slopes is also recognized as a supplementary measure for
stabilising the slopes and suppressing dust.”
C3-166
(g)
Topsoil
Add the following at the end of the first paragraph:
“The contractor shall be responsible for the control of any germination of weed seeds within topsoil
used on site.”
Add the following at the end of the second paragraph:
“Areas such as stockpiles, borrow pits and spoil sites shall be stripped of all topsoil before work may
commence within the area. Should a larger site for any of the above be required during construction,
the contractor shall refer to the DEO for best practice methods on ensuring the preservation of the
additional stripped topsoil.”
Add the following paragraph:
“The topsoil shall be kept free of all foreign material generated during construction. This shall include
all stone and bituminous products. Topsoiling shall not be accepted should it contain any of the above
material.”
B5804
PREPARING THE AREAS FOR PLANTS
(b)
Areas which do not require topsoil
Replace “50 mm” with “20 mm“ and “150 mm” with “20 mm”
Add the following:
“In areas with large natural rock, i.e. not blasted or excavated rock, these rocks may be placed so as
to look like a natural part of the landscape”
Add the following sub-clause:
“(g)
Removal of undesirable vegetation
During the course of the contract the engineer may instruct the contractor to physically remove
undesirable vegetation from within the road reserve. Such an operation will take place before the
flowering stage of the undesirable vegetation upon written instruction from the engineer, but shall not
relieve the contractor of his obligation towards weeding sodded, grassed areas as described under
5806(a) and any area directly affected by any construction activity. Should the contractor fail to
respond to the written instruction from the engineer for the removal of the aforementioned undesirable
vegetation before flowering, the contractor shall be held contractually responsible for any growth or
seeding of said vegetation for a period of not less than twenty four (24) months in the affected area.”
B5805
GRASSING
(a)
Planting grass cuttings
2nd paragraph – remove “be covered with 30 mm of approved soil”. Replace with:
“have the root system of the grass cuttings thoroughly planted within the topsoil layer to ensure good
growth. No part of the grass root system shall be left protruding from the topsoil”.
Remove “and, when sufficiently dry, shall be rolled with a light agricultural roller”
(b)
Sodding
Add the following:
“Grass sods obtained from a commercial grass farm shall be used for the following:
A 1m wide strip shall be placed next to the road edge where no gravel shoulder exists.
A 0,5 m wide strip shall be placed adjacent to all concrete-lined drains. Full sodding must be used for
grass-lined drains. This sodding shall extend over the entire drainage channel, including the tops of
the sides. The use of grass sods will commence from the point of acceptance of water, up to the safe
discharge of water. No area shall be left without grass sods within the drainage channel should it
provide a risk of erosion.
C3-167
A minimum of a 1 m wide strip shall be placed over the shoulder breakpoint for all fill slopes.
Full sodding to be used for all slopes steeper than 1:2. Any slope that exceeds 3 m in width shall be
sodded, the type of which shall be determined by the slope.”
(f)
Sowing by hand
Delete the following:
“If approved by the engineer,”
Replace the second sentence with:
“The top 20 mm of prepared topsoil shall be raked away in sections, the seed shall then be spread
uniformly within the prepared area. The top 20 mm topsoil shall then be raked over the seedbed,
ensuring an even thickness. This method is to be systematic, and where applicable, follow the
contours of any slopes.”
Add the following:
“The thickness of the topsoil layer shall be as specified by the engineer. The preparation of the soil of
the soil for areas to be grassed is to include scarifying just before sowing the grass seed. Should
erosion of any kind (by animal, wind or rain) have occurred before the contractor applies the grass
seed, the slope shall be re-instated, at the contractor’s cost, to its original, erosion free state before
seeding.
The types and mixtures of seeds to be used shall be as specified in the project specifications. The
contractor shall be solely responsible for establishing an acceptable grass cover, and any approval by
the engineer of seed mixtures intended for use by the contractor shall not relieve him of his
responsibility”.
B5807
TREES AND SHRUBS
(a)
Positions of trees and shrubs
Add the following:
“(x)
B5808
No median shall be planted with shrubs, should the median width be less than 10 m wide.”
GENERAL
Add the following subclauses:
“(f)
Weeding
The contractor shall maintain all areas affected by construction activities free of all undesirable plant
species. They shall be removed before the flowering stage of each species. Should the contractor fail
to remove the alien plant species before flowering he shall be held responsible for alien plant removal
within the affected area, for an additional period of one year, over and above the contractual one year
defects liability period.
The method for the removal of undesirable plant species shall be either by hand, which shall include
the removal of the complete root system, or by chemical means, through the use of a registered
selective herbicide. A registered, licensed pest control operator, licensed for the industrial application
of herbicides, shall only administer the application of the herbicide.
(g)
Establishment of vegetation within areas disturbed by construction activities
The engineer shall assess any area within the construction boundaries that has been disturbed by
construction activities, but which is not scheduled for formal re-vegetation within the contract. The
assessment shall include whether re-vegetation is required. These disturbed areas, none the less
remain the contractor’s responsibility for the removal of alien vegetation (see 5807(e)).”
C3-168
B5809
MEASUREMENT AND PAYMENT
Item
Unit
B58.03 Preparing the areas for grassing
(e)
Providing and applying chemical fertilisers and/or soil-improvement material
Add the following subitem:
(vii)
gypsum ........................................................................................................................ ton (t)
Amend subitem (f) to read as follows:
“(f)
Stockpiling topsoil where the following applies:
(i)
(ii)
(f)
topsoil stored at a stockpile site agreed with by the engineer (free haul
1.0 km)........................................................................................................ cubic metre (m3)
topsoil pushed or bladed into heaps next to area from which it was
taken ......................................................................................................... cubic metre (m3)”
Stockpiling the topsoil
Delete the 2nd paragraph and replace with the following:
“The volume of topsoil removed shall be measured in cut, calculated from the difference in crosssections of the natural ground level before the commencement of clearing to cross-sections taken after
the removal of the topsoil.
The contractor shall constantly liaise and agree with the engineer as to the depth of topsoil to be
removed. Where, in the opinion of the engineer, material that would normally be classed as topsoil
has also been excavated, the excavation shall be backfilled and compacted with selected material at
the contractor’ expense. Should material that is deemed by the engineer not to be topsoil, be
removed and stockpiled together with material classed as topsoil, the contractor shall be responsible
for the removal of this unsuitable soil from the stockpile and the replacement of the quantity of topsoil
contaminated by the unsuitable material at his cost. The quantity of topsoil to be replaced shall be
determined by the engineer.
The rates tendered shall include for the excavation of the topsoil and where required, the loading and
hauling thereof to temporary stockpile, placing in stockpile, maintaining of the stockpile until re-use of
the material as well as any payment to private owners for the use of the stockpile area. The rates
tendered shall also include for all supervision required to ensure that only topsoil is removed.”
Item
Unit
B58.04 Grassing
Amend sub item (f) as follows:
“(f)
2
Straw stabilisation ...................................................................................... square metre (m )
The unit of measure shall be the square metre of sand fill slope that is straw stabilised at a rate of one
2
bale per 10 m and harrowed into the top 100 mm of the top material. This item is not intended as
payment for any measures for which the contractor is liable for as mentioned under clause 5808(c),
but rather intended for the use at the engineer discretion where an accommodation of traffic safety risk
exists due to unavoidable dust generation.”
Add the following to the end of the first paragraph of the item 58.10 Extra work for landscaping:
“The provisional sum shall also allow for the provision and planting of new trees, the establishment of
landscaped beds and the appointment of a landscaping or horticultural specialist for the sole use of
the engineer.”
C3-169
SECTION B5900: FINISHING THE ROAD AND ROAD RESERVE AND TREATING OLD ROADS
B5901
SCOPE
In the first line of the second paragraph, insert the following after ‘this section’
“…distinguishes between new construction and renewal construction. When construction is new, as in
the case of new alignments for example, then this section”
B5902
FINISHING THE ROAD AND ROAD RESERVE
Retain the existing paragraphs as subclause: “(a) New construction”
Replace the sixth paragraph with:
“All materials resulting from the finishing operations shall be disposed of at approved spoil sites.”
Add the following clause:
“(b)
Renewal construction
After completing construction work within the site, the contractor shall ensure that all construction
generated or related material that may have been swept, windrowed, stockpiled, stored or spread
beyond the road surface is removed. This shall be done before any other rehabilitation work is
undertaken, including shaping, top soiling and grassing. Should, during the removal of construction
generated or related material, existing vegetation or topsoil be disturbed or destroyed, the contractor
shall, at his own cost, re-instate the road reserve to its original state. This shall include ripping, should
the construction material have compacted the existing surface.
Culvert in lets and outlets, culvert barrels, and open drains shall be cleared of debris, soil, silt and
other material generated from the construction activities.
The surfacing shall be cleared of all dirt, mud and foreign objects. Dragging, pushing or scraping
material across the finished surfacing shall not be permitted.
All junctions, intersections, islands, kerbing and other elements making up the completed works shall
be neatly finished off.
The contractor shall ensure that all undesirable plants have been removed from the road reserve and
borrow pit areas.
All materials resulting from the finishing operations shall be disposed of at approved spoil sites.”
C3-170
COLTO SERIES 6000:
STRUCTURES
SECTION B6100: FOUNDATIONS FOR STRUCTURES
B6103
GENERAL
(a)
Subsurface Data
Add the following:
“It is expressly understood that, while all subsurface information is given in good faith, the correctness
of the information furnished is not guaranteed. Where the actual foundation conditions encountered
are considerably at variance with conditions visualised and described in the contract documents and
those terms for which the rate or price provided for in the contract is rendered unreasonable or
inapplicable, such other rate or price consistent with the rates set out in the contract shall be fixed as
set out in clause 13 of the FIDIC Conditions of Contract subject always to a founding depth variation
not exceeding 2.5 m in any foundation component (except piling depth) of the permanent structure
not, by itself, being held to constitute cause for variation for the contract rates or prices.
If required and instructed by the engineer, additional foundation investigations shall be conducted by
an appointed sub-contractor.”
Add the following sub-item
(j)
Plum Concrete
Plum concrete shall consist of mass concrete and plums. Mass concrete shall comply with the
requirement of Section 6400. The water cement ratio shall be adjustable, within approved limits, to
maintain the appropriate viscosity of concrete to fill all the interstices between plums. The stone size to
be used for plums shall be between 200 and 300 mm. The stone shall be veld or quarry stones of such
quality that they will not disintegrate on exposure to water or weathering with a minimum crushing
strength of 20MPa. The stones shall be free from soil, shale or organic material. Neither the breadth
nor thickness of a single stone shall be less than one-third its length. The proportion of plums shall not
exceed 60% of total volume of plum concrete. Not more than 10% of the total volume of plums shall
consist of stones with a size of less than 0.5 times the specified size. Not more than 10% of the total
volume of plums shall consist of stones with a size of more than 2 times the specified size.
B6104
ACCESS AND DRAINAGE
(c)
Drainage
Add the following:
“Where dewatering and keeping dry of excavations has not been billed separately as per item 61.03
“Access and Drainage”, it shall be deemed to be included in the rates tendered and paid for under
excavation and backfill.”
B6105
EXCAVATION
(a)
General
Add the following:
“Excavation required for diverting, channelling or widening streams within 5.0 m of concrete structures
shall be measured and paid for under item 61.02. Excavations beyond the 5.0 m limit shall be
measured and paid for under the appropriate items in Sections 2100 and 3300.
Excavation in the vicinity of existing structures shall be performed with due care and diligence. The
contractor shall take special care not to disturb the founding material of the existing foundations.
The contractor shall provide complete details of the proposed shoring system or temporary earth
retaining system including a design by a registered professional engineer for any location where the
appropriate system is required and shall submit these to the engineer for his approval at least 30 days
C3-171
before commencement of the excavation or fill. Any additional costs shall be included in the
appropriate payment items under B61.51.”
(c)
Excavation
Add the following paragraphs:
“Where excavation is in soft material, the final 0.75 m and in the case of hard material, the final 0.25 m
of material shall be removed using suitable hand tools such as pick and shovel or pneumatic tools.
Where the excavation forms part of an existing fill, the excavated material shall be measured under
the appropriate mass earthwork items in Section 3300 up to the natural ground level. A typical
example would be where large portions or the whole of the fill at bridge abutments are removed.”
During construction of river bridges the contractor will only be permitted to construct, subject to the
approval of the Directorate of Water Affairs, low level causeways to access the rivers that cause
negligible backing up; and cofferdams around the piers and abutments for the construction of the
foundations using material excavated in the road prism consisting of natural alluvial deposits of sand
boulders, etc. These obstructions must be removed at the end of the contract and the river and banks
restored to their original condition.
(g)
The safety of excavations
Add the following paragraph:
“The design for shoring, signing of the drawings and inspection prior to construction of the permanent
works of excavations to ensure it is safe shall be undertaken by the contractor’s competent person,
who shall be a professional engineer with the relevant experience. The contractor shall ensure that all
temporary works undertaken shall comply with the relevant sections of the Occupational Health and
Safety Act and the Construction Regulations”.
B6106
FOUNDING
Add the following clause at the end of the last paragraph:
“Where foundation slabs or pile caps are cast directly against the face of the excavations, the volume
of concrete measured for payment shall be the total volume of concrete placed or the volume based
on the plan dimensions detailed on the drawings plus a 100 mm allowance for overbreak on each
applicable side whichever is the lesser. No formwork to the footing shall be measured when the
concrete is cast against the face of the excavations”.
B6109
FOUNDATION FILL
Add the following after the 4th paragraph:
“Foundation fill consisting of plum concrete shall be constructed in uniform layers not exceeding
600mm above adjoining work. The plums shall be laid in layers using concrete as mortar and flowable
concrete to fill all the interstices. Plums shall extend beyond each layer to prevent slip planes between
layers. Plum concrete shall be maintained wet for at least 7 days.”

In the 5th paragraph, 7th line delete “60” substitute “45”.

Add the following after the 6th paragraph:
“Concrete blinding shall extend 100 mm all round beyond the horizontal dimensions of all formed
footings to facilitate placing of the formwork, unless otherwise directed by the engineer.
In the case of structures where excessive ground water is encountered, the blinding layer may extend
over the full plan area of the base of the excavation and beyond the edge of the foundation where
required. Payment shall be made for the quantity of concrete calculated as the product of the
specified thickness of blinding layer and the actual area of blinding placed subject to a maximum
distance of 500 mm beyond the edge of the foundation.”
C3-172
B6113
FOUNDATION PILING
(p)
Determining pile lengths
Add the following:
“It is required that the top section of each pile has a minimum length of 2,5 m below the pile cap before
the coupler or such greater length as specified by the engineer. The contractor shall submit to the
engineer for approval the minimum length he proposes to use.”
(u)
(i)
Load test
General
Insert the following as a first paragraph at the beginning of this clause:
“The engineer may require that a trial pile(s) be installed and load tested prior to the commencement
of the piling works proper. The engineer may require that the installation of such trial pile(s) be
measured and paid for separately, thus not forming part of the working piles installed later on.“
Insert the word “working“ between the words “selected“ and “piles” in the first sentence of the next
paragraph.
(x)
Nuclear integrity testing
Delete this subclause and replace it with the following:
“(x)
(i)
Pile integrity testing (PIT)
Calibration piles
Before piling on any site is commenced with, the contractor shall (per pile construction site) construct a
5.0 m long calibration pile of the same pile type, same method of construction as the piles in the bridge
or structure or wall, same diameter, and same concrete mix and reinforcing. The location of this
calibration pile (at any particular site) will be selected in agreement with the engineer.
(ii)
Provisions with regard to pile cap construction
Results from integrity tests on the piles for each pile cap must be evaluated and submitted to the
engineer for approval, before any work on the pile cap itself may commence. Tests on the calibration
pile must be done at the same time or before tests on the first working pile are undertaken.
(iii)
Pile integrity test method
The purpose of integrity testing is to prove that the construction techniques employed to create a
bored or augured pile is satisfactory in terms of quality assurance with respect to aspects such as
necking of concrete in the pile shafts, checking concrete cover to reinforcement, checking for
honeycombing or grout loss, segregation of aggregate inclusion and for large cracks or voids.
(1)
Cross-Hole Sonic Logging (CSL) and optional Base Integrity Test
(aa)
Overview
This method is used to verify the integrity of the pile shaft particularly in the case of larger diameter
piles.
By sending ultrasonic pulses through concrete from one probe to another (probes located in parallel
tubes), the CSL procedure inspects the drilled shaft structural integrity and extent and location of
defects, if any. At the receiver probe, pulse arrival-time and signal strength are both affected by the
concrete. For equidistant tubes, uniform concrete yields consistent arrival times with reasonable pulse
wave speed and signal strengths.
Non-uniformities such as contamination, soft concrete,
honeycombing, voids, or inclusion exhibit delayed arrival times with reduced signal strength.
An optional Base Integrity Test (in order to establish the quality of the pile base/end bearing contact
via the CSL tubes) specification is included at the end of this section.
C3-173
(bb)
Personnel Requirements
The CSL consultant shall have a registered professional engineer supervising the testing and
interpretation of results. The CSL consultant shall be an independent testing agency with at least 3
years’ experience in CSL testing. The consultant’s qualifications and the specifications for the
equipment used shall be submitted to the engineer for approval prior to beginning bored or augured
pile shaft installation.
(cc)
Equipment requirements
A Cross Hole Analyser (CHA) that meets the following minimum requirements:
(1)
Computer based CSL data acquisition system for display of signals during data
acquisition, with a minimum 12 bit A/D converter with a sampling frequency of at least
500 000Hz, and recording of all pulse signals for full analysis and individual
inspection.
Note: Converting signals with low noise using high A/D resolution and sampling rates is
important to obtain quality data and allow proper full data interpretation.
(dd)
(2)
Ultrasonic transmitter and receiver probes capable of producing records at a minimum
frequency of 50 000Hz with good signal amplitude and energy through good quality
concrete. The probes shall be less than 28mm in diameter and shall freely descend
through the full depth of properly installed access tubes in the drilled shafts.
(3)
Two depth sensors to independently determine transmitter and receiver probe depths.
(4)
Triggering of the recording system time base with transmitted ultrasonic pulse.
Access tube preparation
The access tubes in each drilled shaft are indicated on the drawings. Every drilled shaft shall be
equipped with access tubes to permit inspection by CSL. All permanent drilled shafts are to be tested
by CSL. 50 mm (minimum) nominal diameter 3mm wall thickness mild steel tubes are specified for
access for the probes in each drilled shaft. Typically 3 to 4 tubes are used, although up to 6 may be
used in larger piles. Round tubes with regular internal diameter free of defects and obstructions,
including any tubes joints, to permit the free, unobstructed passage of the probes shall be used.
Tubes shall be watertight and free from corrosion with clean internal and external faces to ensure a
good bond between the concrete and tubes. Tubes may be extended with mechanical couplings.
Duct tape or other wrapping materials to seal the joints and butt welding of joints are prohibited.
Tubes shall be installed by the contractor such that the CSL probes will pass through the entire length
of the tube without binding. Ensure that the access tubes are plumb and verify that unobstructed
passage of the probes is achievable before the CSL consultant arrives.
Note: If an existing pile does not contain access tubes, access holes can be installed by coring a
borehole in the concrete. Locate cored holes about 150 mm inside the reinforcement cage. Log core
holes and include descriptions of any inclusions or voids. For pile drilled shafts with access tubes that
do not allow the probe to pass through the entire length of the tube due to poor workmanship,
replacement access holes may be provided by core drilling.
Fit the tubes with watertight shoe in the bottom and a removable cap on the top. Secure the tubes at
regular intervals not to exceed 1,0 m to the interior of the reinforcement cage. Install the tubes
uniformly and equidistantly around the circumference such that each tube is spaced parallel for the full
length and at the maximum distance possible from each adjacent tube. Tubes should be spaced as
far as possible from the main axial reinforcing steel. Extend the tubes to within 300 mm of the bottom
of the pile, and at least 1,0 m above the drilled shaft tops, and at least 0,6 m, but no more than 1,5 m
above the ground surface. Do not damage the tubes during installation of the reinforcement cage.
Note: Do not allow the tube to rest on the bottom of the drilled shaft excavation.
After placement of the reinforcement cage, fill the access tubes with clean fresh water as soon as
possible but within at the latest one hour of concrete placement. Cap the tube tops to prevent debris
C3-174
from entering the access tubes. Do not apply excessive torque, hammering or other stresses that
could break the bond between the tube and concrete when removing caps from the tubes.
Note: The tubes should preferably be filled with water prior to concrete placement, but MUST be filled
with water within at most 4 hours after placing concrete to prevent debonding of the access tubes due
to differential temperatures.
(ee)
Test sequence
Test the drilled shaft no sooner than 3 calendar days after placement of all concrete in any drilled
shaft, but within 10 days after placement and prior to loading for test drilled shafts, or within 45 days
after placement on production drilled shafts.
Note: CSL testing can be performed any time after concrete installation, although 2 days is usually the
minimum acceptable wait. Because the concrete strength and quality generally increases as the
concrete cures, longer wait times are usually desirable, particularly if minimum pulse wave speeds are
specified or to reduce result variability between drilled shafts or even as a function of depth in a single
drilled shaft. However, if PVC tubes are used, long wait times increase the tube debonding, which is
detrimental to the test. Production of drilled shaft installation and subsequent construction influence
the dates of CSL testing.
After all CSL testing has been completed, and after acceptance of the drilled shaft by the engineer, the
contractor shall remove the water in the tubes, place grout tubes extending to the bottom of the access
tube, and fill all access tubes in the drilled shafts with grout.
(ff)
Test procedures
Prior to CSL testing, the contractor shall provide the engineer and CSL consultant with a record of all
drilled shaft lengths with elevations of the top and bottom, and installation dates of all drilled shafts.
The access tubes shall be clearly labelled for identification by the CSL consultant.
The CSL testing shall be performed with the transmitter and receiver probes in the same horizontal
plane in parallel tubes unless test results indicate potential defects, in which case the questionable
zone may be further evaluated with angled tests (source and receiver vertically offset in the tubes).
Using the labelling established for the tubes, perform CSL testing between all adjacent perimeter
access tube pairs and across at least two major diagonals within the drilled shafts with more than four
tubes, additional logs in other diagonal tube pairs may be required to estimate the extent of the defect.
Lower the probes from the top, effectively measuring the access tube lengths. Pull the probes
simultaneously, taking CSL measurements at intervals of 50 mm or less from the bottom to the top of
the drilled shaft. Defects indicated by late pulse arrival times and significantly lower amplitude/energy
signals shall be immediately reported to the engineer. Additional tests such as the offset elevation
CSL testing may be required by the engineer to further evaluate the extent of such defects. If
debonding between the access tube and the concrete is indicated by the CSL results, an alternative
test method will be required to determine the integrity of the concrete in the debonded region.
Note: In case defects are detected, additional tests or analysis options may include CSL tomography,
Gamma-gamma nuclear density logging, sonic echo or impact response tests, high strain dynamic pile
testing, static load testing, or concrete coring. If the drilled shaft is cored, an accurate log of the cores
that include depth and core recovery shall be kept, and core and coring logs shall be properly
identified and given to the engineer.
(gg)
Results
Present the results of the CSL in a written report within five (5) working days of completion of testing.
The report shall include presentation of CSL logs for all tested tube pairs including:
(1)
Presentation of the traditional signal peak diagram as a function of time plotted versus
depth.
(2)
Computed initial pulse arrival time or pulse wave speed versus depth.
C3-175
(3)
Computed relative pulse energy or amplitude versus depth.
A CSL log shall be presented for each tube pair. Defect zones, if any, shall be indicated on the logs
and their extent and location discussed in the report text. Defect zones are normally (see Note below
also) defined by an increase in arrival time of more than 20% relative to the arrival time in a nearby
zone of good concrete, indicating a slower pulse velocity.
Note: Because the tubes might not be perfectly straight or even parallel, a fixed absolute limit of a
wave speed value cannot be used for evaluation. It should also be noted that if the referenced good
concrete exceeds the specifications, then a concrete with a local 20% wave speed reduction might still
exceed the specifications.
The log for each tube pair shall be clearly identified and oriented relative to the structure. The
engineer shall have five (5) working days to evaluate the results and determine whether the drilled
shaft construction is acceptable or not. The contractor shall not perform any load testing or other
construction associated with these drilled shafts until after acceptance by the engineer. If the drilled
shaft is accepted by the engineer, the contractor may then proceed with construction. If the engineer
determines the drilled shaft is not acceptable, the drilled shaft must be cored, repaired or replaced by
the contractor at the contractor’s expense and with no increase in contract time.
(hh)
Base integrity test
In order to establish the quality of the pile/base rock contact, a base integrity test shall be performed.
This shall be accomplished in the following manner:
(1)
The 85 mm diameter tubes for the “Cross Hole Sonic Logging” shall be installed to
within 300 mm of the base pile of the pile. The base of the tubes shall be sealed
square with a water tight seal.
(2)
NX (55 mm) diameter cores shall be drilled within 85 mm diameter tubes, through the
remaining 300 mm of pile concrete and for a distance of 1200 mm into the rock at the
toe of the pile. The core shall be carefully retrieved with drill string lengths and
datums noted. This core shall be marked and carefully placed inside a plastic sheath
such that the actual condition of the interface between pile and rock is not disturbed.
The core shall be temporarily stored in a core box for later inspection.
At the completion of the test, and when instructed by the engineer, the complete assembly to the top
of the pile shall be filled with non-shrink grout of at least 30 MPa strength. The hole shall be filled from
the bottom up.
The basis of payment shall be in accordance with payitems 61.37, 61.38 and 61.39.
B6115
MEASUREMENT AND PAYMENT
Delete payitem 61.01 and replace it with the following:
“Item
Unit
B61.01 Additional founding investigation
(a)
Provisional sum allowed for additional founding ............................................. provisional sum
(b)
Handling cost and profit in respect of subitem B61.01 (a)................................ percentage (%)
The provisional sum allowed under subitem (a) shall be expended to cover the actual costs of the
appointed sub-contractor for the additional founding investigation.
The tendered percentage of subitem (b) is a percentage of the amount actually spent under the
subitem (a) and shall include full compensation for all charges and incidental costs of the contractor,
profit and overheads in connection therewith”.
C3-176
Item
61.08
Unit
Foundation fill consisting of:
Add the following subitem:
3
(f)
Plum concrete (class indicated) ................................................................... cubic meter (m )
Delete payitem 61.50 and replace it with the following items for Pile Integrity Testing (PIT):“Item
Unit
B61.50 Pile Integrity Testing on bored/augured piles
(a)
Constructing 4.0 m long reinforced concrete/grout calibration bored
piles of (indicate diameter(s)) inclusive of the required number of 85
mm diameter mild steel tubes ............................................................................ number (No)
(b)
Providing and installing 85 mm diameter mild steel tubes used for
“Cross Hole Sonic Logging” in all designated piles (per pile
construction site) .................................................................................................... metre (m)
(d)
Cross-Hole Sonic Logging tests and interpreted results (per pile
diameter and per pile construction site) ....................................................... metre of pile (m)
The unit of measurement shall be the number of cores logged. The tendered rate shall include full
compensation for the log of the core data by a qualified person, who shall be approved by the
engineer. The core logging shall be done in general accordance with the “Guidelines for soil and rock
logging” compiled by the Geotechnology Workshop and published by SAICE in 1990.
Grouting up all CSL tubes after successful testing ....................................... cubic metre (m3)
(f)
The unit of measurement shall be the volume of grout used to fill all the tubes used for sonic testing
and the cores.
The tendered rate shall include full compensation for the grout, equipment and all labour used to fill
the tubes and cores. The grout shall have a compressive strength of at least 30 MPa.
The unit of measurement for subitem (a) shall be the number of 4.0 m long calibration reinforced
concrete bored piles provided complete with the required number (and length) of 85 mm mild steel
tubes to facilitate CSL testing and constructed similarly to the proposed working piles.
The unit of measurement for subitem (b) for the 85 mm nominal diameter mild steel tubes shall be the
metre of approved 3 mm thick tubes provided and installed into all designated piles of various
diameters in accordance with the specification.
The unit of measurement for subitem (d), i.e. the CSL tests, shall be the metre of pile shaft fully tested
(for all designated piles) using the Cross-Hole Sonic Logging method, and shall include full
compensation for establishment and removal of all specialised equipment and expert personnel as
well as for all materials, for the preparation and conducting and supervising the tests as well as full
compensation for the proper evaluation and reporting of the results as well as the interpreted
findings/conclusions/recommendations to the engineer by the CSL consultant”.
Add the following items:
Item
Unit
B61.51 Lateral support to:
(a)
Excavation or fill at Location 1:
(i)
(ii)
2
0 to 5m depth ............................................................................................. square meter (m )
5 to 10m depth .......................................................................................... square meter (m2)
C3-177
(b)
Excavation or fill at other locations
The unit of measurement shall be the square meter of lateral support at a specific location over the
successive depth ranges. The depth ranges shall be measured down from the level where shoring is
required at each location and agreed with the Engineer.
The rate shall include full compensation for design, supply, fabrication, installation, removal (if
required), and for all labour, materials, equipment, plant and incidentals to provide the complete lateral
support to the excavated or filled faces. The rate shall also include the inspections, supervision by the
safety officer and for the maintenance of the lateral support. The lateral support shall remain in
position for as long as required and only removed with the approval of the Engineer.”
C3-178
SECTION B6200:
B6204
DESIGN
(a)
General
FALSEWORK, FORMWORK AND CONCRETE FINISH
Add the following:
“The contractor shall submit to the engineer at least 4 weeks before the structure is scheduled for
construction a detailed analysis showing the effect of the stresses that will be induced by the
contractor’s chosen method of construction. The cost of any additional prestressing, reinforcing steel,
concrete, etc, required as a result of the contractor’s chosen method of construction shall be to the
contractor’s account. No construction shall commence until the engineer has given his written
approval.”
(b)
Falsework
“Unless instructed otherwise by the engineer, the contractor shall submit his design criteria and
detailed drawings of the staging to the formwork. The design, signing of the drawings and inspection
of the falsework prior to construction of the permanent works shall be undertaken by the contractor’s
competent person, who shall be a registered professional engineer with the relevant experience.”
B6205
CONSTRUCTION
(b)
Formwork
(i)
General
Add the following:
“Formwork to faces of structures with a gradient equal to or greater than ten vertical to one horizontal
shall be classified as vertical formwork.
Formwork to faces of structures with a gradient less than ten vertical to one horizontal, or equal to or
greater than one vertical to ten horizontals, shall be classified as inclined formwork.
Formwork to faces of structures with a gradient of less than one vertical to ten horizontal shall be
classified as horizontal formwork.”
(ii)
Formwork to exposed surfaces
Add the following:
“The formwork at construction joints shall have moulding strips 25 mm x 25 mm neatly butted and set
at the position of the construction joint”.
B6207
FORMED SURFACES: CLASSES OF FINISH
(d)
Class F3 surface finish
Replace the second paragraph with the following:
“The use of steel forms shall be permitted to form surfaces for which Class F3 surface finish has been
specified, provided that only undamaged forms shall be used for such work and that the forms shall be
subject to the approval of the engineer. Formwork comprising of steel faced panels shall have
minimum face plate thickness of 5mm. Particular careful attention is required for preparation and
execution of steel plate to form fillet roundings and aesthetic details.”
Add the following subclause:
“(g)
Making good tie holes
All openings resulting from the use of ties shall be made good in an approved manner such that the
colour matches that of the adjoining concrete, there is no shrinkage or slumping and the finished
surface is flush with the adjoining concrete. All formwork tie holes shall be repaired to full depth of tie
C3-179
hole, including the complete removal of all embedded plastic components. Removal of plastic form tie
linings shall be conducted by drilling 3mm oversize holes, to suitably roughen the concrete surface to
assist with bonding of cementitious repair materials used to fill the remaining void. The procedure shall
be proven by the contractor submitting a sample completed hole for approval which shall then be
regarded as the minimum acceptable standard for all other holes.
(h)
Formed surface finish
This surface finish shall be the specified indentations formed in the concrete surface as shown. The
surface shall first be given a class U2 surface finish and after the concrete has hardened sufficiently, it
shall be shaped and finished as specified without torn and unduly loosened coarse aggregate. "
B6210
MEASUREMENT AND PAYMENT
Item
Unit
B62.04 Inclined Formwork to provide (class of finish indicated as F1, F2,
F3 or board) surface finish to (description of member to which
applicable)
Delete the entire note at the end of this item.
C3-180
SECTION B6300:
B6306
STEEL REINFORCEMENT FOR STRUCTURES
PLACING AND FIXING
Replace the second and third paragraphs with the following:
“The concrete cover for all structural concrete shall be within the acceptance ranges shown in table
B6404/6. Prior to fixing the steel, samples of the proposed cover and spacer blocks shall be submitted
to the engineer along with a written statement for in situ manufacture, if applicable, for approval.
Overlap of steel reinforcement bars shall be such that the cover to the lapped bars remains constant at
the specified cover.”
B6307
COVER AND SUPPORT
Amend the second paragraph as follows:
Replace the second sentence, commencing with ”Where no cover is indicated…shown in table
6306/1” with the sentence “Where no cover is indicated, the contractor shall inform the engineer who
shall after consultation with the design engineer indicate the required cover in writing and the as-built
drawings shall indicate such cover”.
Add the following to the end of the fifth paragraph:
“Proprietary micro-concrete cover- and spacer-blocks of reputable high-quality are preferred for this
contract. Plastic- (or equal) -type positioners shall not be permitted.
Non-proprietary concrete cover block and spacer blocks shall be made using the same cement and
aggregate type as the main concrete with the same water/ cement ratio so that differences in
shrinkage, thermal movements and strain are minimised. Cover- and spacer-blocks shall be water
cured by submersion for a minimum of 7 days and thereafter kept submerged in water until
immediately before fixing onto reinforcing steel. Where concrete cover- and spacer-blocks,
subsequent to fixing, have visually dried out they shall be remoistened by an appropriate method so
that they are damp before the placing of concrete.
Where fixing wire is inserted into cover- and spacer-blocks, it shall be galvanised Class A wire in
accordance with SANS 675. Cover and spacer blocks manufactured from other materials e.g. plastic
or wood, shall not be permitted. All cover blocks regardless of the type of material manufactured from,
shall not be visible on exposed concrete surfaces
Delete Table 6306/1 in its entirety.
Add the following paragraph:
“Where the concrete cover specified has not been achieved after cover tests have been carried out in
accordance with clause B8106(j), reduced payment as determined under clause B8212 shall be
applied to all the relevant payitems under section 6300.”
C3-181
B6310
MEASUREMENT AND PAYMENT
Item
Unit
B63.01 Steel reinforcement for: ...................................................................... ton (t) / kilogram (kg)
Add the following paragraph:
“Where hot-dip galvanized steel reinforcement is indicated, the steel reinforcement shall be paid under
Item 63.01. The additional costs associated with the hot-dip galvanizing shall be included in the extra
over payment item B63.04.
Add the following items:
“Item
Unit
B63.04 Extra over item B63.01 for hot-dip galvanizing
steel reinforcement ............................................................................. ton (t) / kilogram (kg)
The unit of measurement shall be the kilogram of hot-dip galvanized steel reinforcement. The tendered
rate shall include only the costs associated with the hot-dip galvanizing to the required specifications.
C3-182
SECTION B6400:
B6401
CONCRETE FOR STRUCTURES
SCOPE
Add the following paragraph:
“The contractor shall take and submit samples of materials and/or mixtures to the engineer who must
approve mix designs before construction work can commence.”
B6402
MATERIALS
(a)
Cement
Replace the colon at the end of the first paragraph with a comma, and add the following:
“taking into account the adoption of the new SANS 50197-1: 2013 code for common cements: (refer to
Concrete Institute website (www.theconcreteinstitute.org.za). All common cements shall hold
certification in the form of a valid Letter of Authority (LoA) issued as certified approval pursuant to
Compulsory Specification for cement as published by Government Notice R544 (Government Gazette
No. 30023) of 6 July 2007 and shall be included in the latest version of the National Regulator for
Compulsory Specifications’ cement database (www.ncrs.org.za).
In order to promote resource sustainability principles, common cements shall have a maximum
average emission value of 950 kg CO2e per ton.”
Add the following paragraphs:
“The type of cement to be used in any concrete element shall take into account the environmental
conditions and durability requirements at the location of the site of the works, and shall be as
approved by the engineer.
With the exception of the standard SANS approved cement blends supplied by the primary cement
producers, the blending of proprietary cements and supplementary cementitious materials (extenders)
shall not be permitted unless specifically approved by the engineer on the basis of an acceptable
quality assurance procedure. The quality assurance procedure shall ensure that the ternary blending
of common cements containing a proportion of supplementary cementitious materials shall not be
further extended with supplementary cementitious materials of a different generic type or nature.
supplementary cementitious materials accepted for use as cement extenders shall include: Slag,
conforming to SANS 1491-1; Fly ash, conforming to SANS 1491-2; Silica fume, conforming to SANS
1491-3 and Supplementary Cementitious Materials, conforming to SANS 1491-4.
Wherever durability (W-class) concrete is specified, the cementitious binder system shall comprise of
the following permitted blends:





(b)
75% CEM II A-L 52,5N (PPC W.Cape OPC) and 25% fly ash, or
50% CEM II A-L 52,5N (PPC W.Cape OPC) and 50% Ground Granulated Corex Slag, or
81% CEM III A-S 42.5N (PPC W.Cape Surebuild) and 19% Ground Granulated Corex
Slag, or
70% CEM I 42.5 N (or greater strength class supplied by a SANS 50197 approved cement
manufacturer) and 30% fly ash.
50% CEM I 42.5 N (or greater strength class supplied by a SANS 50197 approved cement
manufacturer) and 50% Ground Granulated Corex Slag.”
Aggregates
Delete the remainder of the sentence after “exceed” in subclause (i)(1)and replace with the following:
“150% of that of the reference norite aggregate or any of the other three reference aggregates”
Delete the remainder of the sentence after “exceed” in subclause (i)(2) and replace with the following:
“200% and of the coarse aggregate 175% of that of the reference norite aggregate or any of the other
three reference aggregates”
C3-183
Delete the remainder of the sentence after “exceed” in the first paragraph of subclause (i)(3) and
replace with the following:
“235% of that of the reference norite aggregate or any of the other three reference aggregates”
Delete the entire last paragraph of subsubsubclause (i)(3) commencing with “The drying shrinkage of
concrete…”
Add the following subsubclause:
“(vi)
The maximum chloride ion content of fine aggregate shall be 0,03% by mass of aggregate as
specified by SANS 1083:2002. Where concrete is situated in a chloride environment the value shall
be reduced from 0,03% to 0,01%.”
(d)
Water
Add the following:
“Water utilised to mix concrete shall comply with SANS 51008. Water for concrete other than
prestressed concrete, shall not contain chlorides, calculated as sodium chloride, in excess of three
thousand parts per million (3000ppm) nor sulphates, calculated as sodium sulphate, in excess of two
thousand parts per million (2000ppm).
Water for curing concrete shall not contain impurities in sufficient amount to cause discolouration of
the concrete or produce etching of the surface.
No sea-water or water containing salts shall be used.
No water shall be added on site to ready mix concrete prior to placing to improve workability. All
concrete delivered to site shall be checked for workability using the slump cone test and slump
measured outside of the limit set from the design mix shall be rejected.
The maximum permitted mix water content per cubic meter of concrete shall be 190 litres.”
(e)
Admixtures
Replace the following subclauses:
“(i)
All admixtures shall be used in liquid form and shall be batched in solution in the mixing water
by mechanical batcher capable of dispensing the admixture in quantities accurate to within 2% by
mass of the desired quantity.
(ii)
All admixtures shall comply with the requirements of ASTM C494, EN 934-2, or AASHTO
M194 and shall be of an approved brand and type suited to the cementitious binder system.”
Add the following subclauses:
“(v)
Admixtures, which have a retarding effect on the rate of hydration of the cement, may not be
used when the concrete temperature is below 20°C.
(vi)
A retarding admixture shall be used if the temperatures of concrete mixes using cements of
strength class 42.5 or higher is between 20 to 30°C or where the ambient temperature is between 20
to 30°C.”
Add the following:
“Note: Only admixtures of the type that do not increase the water content of the mix will be considered
by the engineer. In addition, no admixtures shall be added on site to ready mix concrete prior to
placing to improve workability.”
C3-184
B6403
STORING THE MATERIALS
(a)
Cement
Insert the following paragraph after the third paragraph:
“Where hot weather concreting conditions exist, the bulk cement silos shall be painted white with high
solar reflectance paint to reduce any temperature rise in the stored cement. Furthermore, the sides
and tops of silos shall be insulated with 4 mm Alucushion double sided aluminium foil insulation which
shall be wrapped around silos, and kept in position with galvanized steel hoop straps. Alucushion
insulation material shall overlap by at least 100 mm at joints.”
(b)
Aggregates
Insert the following paragraph after the first paragraph:
“Where hot weather concreting conditions exist, the both the coarse- and fine-aggregate stockpiles
shall be the aggregate shall at all times be stored in a cool environment and be shaded from the sun
by means of 80% shade netting. When the ambient temperature reaches and exceeds 30°C, only the
coarse aggregate shall be sprayed with water to assist cooling. Water shall be delivered by means of
an approved water droplet sprayer system.
The Contractor shall ensure adequate drainage of the coarse aggregate stockpile area.”
Insert the following subclause:
“(e)
Water
“Where hot weather concreting conditions exist, the sides and tops of water tanks for mixing water,
including pipework leading to and from tanks, shall be insulated with 4 mm Alucushion double sided
aluminium foil insulation which shall be wrapped around silos, and kept in position with galvanized
steel hoop straps. Alucushion shall overlap by at least 100 mm at joints. The burying of pipework at
sufficient depth below ground will be permitted only if it can be demonstrated that temperature of
mixing water remains below 20 ̊C when added to the concrete mix.”
B6404
CONCRETE QUALITY
(a)
General
Insert the following paragraph after the second paragraph:
“When structural concrete prefixed ‘W’ is shown on the drawings, it shall, in addition to the strength
requirement, comply with the durability requirements specified in subclause 6404(h), ‘W’ class
concrete shall not apply to minor structural elements such as side drains and catch pits except in very
severe environmental conditions of exposure. Requirements for concrete quality (including any
durability requirements) for concrete pavements are found in Section 7100 of the specifications.”
(b)
Strength concrete
Replace the sixth paragraph with the following:
“Where concrete is designated by the prefix “W”, e.g. class W30/20, such designations shall denote
concrete achieving the durability criteria specified in the relevant tables under subclause B6404(h).”
Add the following subclauses:
“(h)
(i)
Concrete durability
General
Concrete designated by the prefix ‘W’ shall, in addition to the requirements of subclause 6404(b)
comply with the durability parameters described below. Durability is influenced by the materials used
in the concrete, their mix proportions, transporting, placing, compacting and, in particular, curing of the
finished cover concrete (concrete layer between the outermost layer of steel reinforcement and the
exposed outer surface of the concrete element). The tests required to prove durability performance of
the placed concrete are given under sub-clause B8106(i).
C3-185
It is the engineer’s responsibility to approve the component materials and their mix properties,
however it is the contractor’s responsibility to utilise acceptable component material and to achieve
mix properties complying to the specifications. It is the contractor’s responsibility to design and blend
materials to produce concrete of the specified quality
(ii)
Durability parameters
Water sorptivity:
Sorptivity is sensitive to surface effects and may be used to assess the
effectiveness of initial curing.
Oxygen permeability:
Permeability is sensitive to changes in the coarse pore fraction and thus
a means of assessing compaction of concrete. It is used to quantify the
microstructure of the concrete and sensitive to macro-defects such as
voids and cracking.
Chloride conductivity:
Chloride conductivity provides a method of characterisation of concretes
in the marine environment and is used to assess the chloride resistance
of concrete.
Cover concrete/covercrete: Cover concrete (covercrete) is the outer concrete layer that protects
reinforcing steel. Concrete cover is a requirement for all concrete whether
specified as durability concrete (Class “W”) or strength class (normal)
reinforced concrete.
Individual Cover Depth Individual cover depth measurement determined
Measurement (CDM): by an electromagnetic cover meter, complying with BS 1881, Part 204.
Individual mean cover:
The arithmetic mean of at least 24 individual CDM’s per 600mm by
600mm grid (or 0.36m² area) determined using the grid or block method
on a clearly identified area.
Overall Cover:
The arithmetic mean cover determined for the total scan area per
element or structure.
Scan Area:
Total areas of approximately 1m², represented by at least 3 individual
mean cover randomly distributed over the entire element or structure.
The total scan area per structure shall represent at least 2% of total
surface area (formed and unformed, internal and external surfaces) for
that structure.
Individual bar reading:
A minimum of 3 linear CDM’s, spaced at 100mm intervals, representing a
single bar of reinforcement.
Capped CDM:
The value applied to all CDM’s in excess of the maximum allowed CDM,
determined by the engineer (e.g. 40mm (specified cover) + 25mm (upper
limit) = 65mm) or
Capped Value:
A value in mm, assigned to a cover reading where the raw reading
exceeds the specified cover plus a value (mm) specified by the engineer
(eg. the greater of 25mm or 2,0*bar diameter).
Quick/Linear Scan:
This method shall not be used for this contract unless the normalisation
procedure is strictly followed and approved in writing by the Engineer. For
evaluation of cover depth measurements taken perpendicular to closest
rebar in a line covering required area to be scanned. Each scan area to
exceed 0,36m2).
C3-186
Image/Block/Grid Scan:
Provides an overview of rebar layout. Measurements taken over a square
meter clearly indicating position of first and second layer of rebar. Each
scan area to exceed 0,36m2).
Cover:
Cover is a dimensional indicator of covercrete depth and it varies
according to the requirements of the different environmental exposure
classes.
Notes:
1.
Water sorptivity and Oxygen Permeability tests are required to assess carbonation resistance
2.
Water sorptivity, permeability and chloride conductivity tests are required to assess chloride
resistance
When tested in accordance with the test protocols described in B8106 for each potential durability
parameter, the concrete shall meet the limits listed in tables B6404/4 and B6404/6.
(iii)
Cement content
In order to meet the durability criteria, the proportions of cementitious binder used shall be determined
to suit the fine and coarse aggregate and cement type used in order to achieve the durability limits
specified in tables B6404/4 and B6404/6 under the Acceptance Category of “Concrete made, cured
and tested in the laboratory.”
In order to avoid the possibility of Alkali Silica Reaction (ASR), the following shall be taken into
account when designing the mixes:
(1)
Where aggregates are tested in accordance with ASTM C227-03 and the expansion at 14
days determined as equal to or more than 0.20% and are categorised as ‘rapidly expansive’, the
3
maximum permitted equivalent sodium monoxide (Na2Oeq) of the concrete mixture shall be 2,1kg/m
of concrete.
(2)
Where aggregates are tested in accordance with ASTM C227-03 and expansion at 14 days
determined as equal to or more than 0,10% but less than 0,20% and are categorised as ‘slowly
expansive’, the maximum permitted equivalent sodium monoxide (Na2Oeq) of the concrete mixture
shall be 2,8 kg/m3 of concrete.
(3)
Where aggregates are tested in accordance with ASTM C227-03 and expansion at 14 days
determined as less than 0,10% and are categorised as ‘innocuous’, the maximum permitted equivalent
3
sodium monoxide (Na2Oeq) of the concrete mixture shall be 4,0 kg/m of concrete.
(4)
The contractor shall prior to the use of cement provide test certificates from an approved
laboratory confirming the equivalent sodium monoxide (Na2Oeq) content of the batch of cement
proposed for use.
(5)
Special literature should be consulted e.g. Fulton’s Concrete Technology.
For tendering purposes a cementitious binder content of 400 kg/m3 shall be used in order to meet the
durability criteria. If the actual cementitious contents fall below 400 kg/m3, the mix will not be subject
to the reduction mentioned under clause B1213(b) and shall be to the contractors benefit providing all
durability requirements are met.
Notwithstanding what is indicated above, should the contractor wish to increase cementitious content
above limits stated for reasons not related to durability, such as the need for early strengths, then the
additional costs shall be borne by the contractor.
(iv)
Environmental classes of exposure
For this project, the environmental classes for carbonation and chloride exposure for the different
structural elements are as shown below in table B6404/3.
C3-187
Table B6404/3
ENVIRONMENTAL CLASSES OF EXPOSURE FOR ELEMENTS OF STRUCTURE
Element
Carbonation Environment (OPI)
Foundations
XC2
Substructures
XC3
Superstructures
XC4
(v)
Acceptance ranges
Table B6404/4
DURABILITY PARAMETERS ACCEPTANCE RANGES
Test No./ Description/ Unit
Acceptance Category
Concrete made, cured and tested
in the laboratory using Trial Panels
Full acceptance of in situ using Test
Panels
Conditional acceptance of in situ
concrete based on results of Test Panels
Rejection based on results of Test Panels
Notes:
1.
2.
3.
Oxygen Permeability
(log scale)
SuperSubstructures
structure
Water
Sorptivity
(mm/ h)
Parapets
<10.0
>9.60
>9.30
>9.10
N/A
<10.0
>9.60
>9.30
>9.10
N/A
9.20 - 9.60
9.29 - 9.00
9.09 - 9.0
N/A
<9.20
<9.00
<9.00
N/A
Not applicable
2
Not applicable
2
Foundation
s
A value has been given, but the value to be adopted shall be based on the results from design mixes.
Although no value has been given due to ongoing research, values above 12 are regarded as poor
quality concrete.
For purposes of interpretation, substructure is deemed to be all supporting elements below the deck
(superstructure), including buried lengths of columns, etc, but excluding foundation elements like bases
and spread footings.
Table B6404/6
DURABILITY PARAMETERS ACCEPTANCE RANGES: Cover for all concrete types
Acceptance Range
Test No.
B8106(g)
(iv)
(vi)
Description
of Test
Concrete
cover to
reinforcement (mm)
Specified
Cover
(mm)
40 to 75
Overall
cover
Min
Individu
al bar
85% of
specified
cover
75% of
specified
cover
Max
Overall cover
Individual bar
Specified cover +
15mm or where
member depth is
less than 300mm
the limit accepted in
writing by Design
Engineer.
Specified cover +
25mm or where
member depth is
less than 300mm
the limit accepted in
writing by Design
Engineer.
Site testing
To ensure that the concrete has been placed, compacted and cured correctly, a number of tests shall
be carried out on the concrete by an approved laboratory.
(vii)
Non-compliance with specified criteria
The contractor should also note that there is specific provision made for curing of concrete under
payment item B64.07 of the project specification. The amount priced under this item will be subject to
reduced payments should the durability tests indicated under B8106(h) fail to meet the required
targets. Similarly, failure to achieve the required durability test results will be sufficient cause to apply
partial payment factors for all the payitems of the elements of the structure under sections 6300 and
6400 of the standard and project specifications or in some cases the removal of the rejected concrete.
C3-188
(i)
(i)
Mix design approval procedures
General
The compressive strength achieved on ‘W’ class concrete shall generally exceed the characteristic
strength class structurally required. The contractor shall note that the process of finalising ‘W’ class
mix designs could take up to two months. In order to expedite the process, the contractor must submit
samples of aggregate and cement to an approved laboratory within seven days of the commencement
date. Should ‘W’ class concrete be required before the mix design is finalised, the engineer will
approve a preliminary mix design in consultation with the contractor.
(ii)
Laboratory designs and site tests based on trial panels
Good mix design practice is essential and the following criteria shall be taken into consideration when
pricing and determination of the mix design:
(1)
Selection of sands and aggregates to achieve a good grading is important if the desirable
concrete density and durability have to be achieved.
(2)
The selection and use of the correct cement grade and type for the environmental conditions
(and not based solely on costs) is fundamental
(3)
Water: cement ratios are critical, dictating both the structural strength and the durability
requirements
Mix proportions for the concrete to be used on site need to be determined by an approved laboratory,
cylindrical specimens, 70 ± 2 mm in diameter shall be made or cored from a trial panel during the
laboratory trial mix for performance of tests B8106(g)(i), (ii) (if required).
Note that concrete cubes are not cored for durability testing during design trial mix stage or during the
construction stage.
Testing for approval purposes shall be carried out by an accredited laboratory approved by the
engineer, the costs of which are deemed to be included in the contractor’s rates for structural
concrete. Concrete as designed shall satisfy the limits set out in table B6404/4 under the heading
“Concrete made, cured and tested in the laboratory, using Trial Panels”. It is therefore a requirement
that the trial panels be cast on the site and the cores extracted and tested in the laboratory as part of
the mix design approval process. Where the site is remote from the laboratory, the trial panels may be
cast at the laboratory in accordance with the requirements of subclause B8106(g).
It will be necessary for the contractor to establish a target mean strength with a margin above the
minimum requirement so that small fluctuations due to material changes or workmanship can be
accommodated. In general, mean target strength = characteristic strength + 1,645xSn.
Once the mix is approved, the target mean compressive strength for quality control purposes for
durability class concrete shall be the mean compressive strength obtained from the mix that satisfies
the durability requirements.”
B6405
MEASURING THE MATERIALS
Add the following sub-clause:
“(d)
Admixture
All admixtures shall be dosed at an accuracy of 2% by mass. The dosing unit shall be checked daily
for accuracy using a nominal dispensing volume, typically 2 litres, as recommended by the dosing unit
manufacturer/supplier. At least once a week, the dosing unit shall be checked for accuracy using a
3
typical dispensing volume suited to the concrete mixing procedures employed on site, typically for 6m
concrete batch mixed by a standard ready mix truck.”
C3-189
B6407
PLACING AND COMPACTION
Add the following:
“(b)
Placing
Casting of the in situ parapets or placing of precast parapets shall only commence after removal of the
deck staging, and in addition, in the case of prestressed decks, the stressing must be complete.
Where specified on the drawings the top of the parapets after placing shall follow the pre-camber
levels specified on the drawings to allow for future creep effects. This is of particular importance on
the edges of very long skew decks and prestressed simply supported decks. The levels of the top rail
of each panel of the balustrades/parapets shall be confirmed in writing by the design engineer
Subject to the approval of method statements for particular concrete pour operations, the maximum
height concrete will be permitted to free-fall shall be limited to 3.0m. Preventative measures to avoid
segregation shall be employed whenever deemed necessary, particularly for concrete pours
exceeding 2.4m high.”
B6408
CONSTRUCTION JOINTS
(a)
General
Add the following:
“No construction joints other than those indicated on the drawings will be permitted without the written
approval of the engineer. In all cases the proposed method of forming the joint shall be discussed and
agreed with the engineer and approved as a particular method statement.”
B6409
CURING AND PROTECTION
Delete the content of subclause 6409(c) and replace with the following:
“Covering it with mats, made from moisture retaining material, and waterproof or plastic sheeting firmly
anchored and sealed at the edges and joints. The moisture retaining material must be kept wet for the
duration of the curing period.”
Add the following to the end of subclause 6409(f):
“Where a curing compound is used, it shall consist of an approved water based low viscosity clear wax
emulsion applied in accordance with the manufacturer’s instructions.”
Add the following paragraphs to the end of this subclause:
“Where curing by retention of formwork is used as the only method of curing the concrete, it must be
left in place for the minimum period specified in table 6206/1 but in no instance shall it be less than 7
days.
The materials used for formwork shall take into account properties such as thermal insulation and
moisture absorption when assessing the suitability of the material, to the approval of the engineer.
If impermeable curing membranes are to be used as a curing method, they shall be installed at the
same time as formwork is removed and no portion of a concrete surface may be left unprotected for a
period in excess of 2 hours. If the surface is an unformed finish e.g. top of deck slab, then the surface
must be protected immediately by appropriate methods approved by the engineer after it is finished,
without damage to that surface, since it is vulnerable to plastic shrinkage cracking due to high rates of
evaporation while the concrete is still in a plastic state. Plastic shrinkage and settlement shall not be
permitted on any of the structural elements since it compromises the durability of the concrete. In
order to prevent early settlement and shrinkage of the concrete, the concrete placed shall be revibrated after initial compaction while the concrete is still in a plastic state. Any remedial measures
shall be as approved in writing by the engineer. On bridge decks, the top surface shall be cured using
the method described in clause 6409(c) or 6409(d.)
For all concrete, curing shall be excluded from the make-up of rates for measurement under items
B64.01 and B64.02 and will be paid for separately under pay item B64.07. Where the application of a
C3-190
curing compound is used, the type and nominal application rate thereof shall be as specified in the
schedule of quantities or to the manufacturer’s nominal specified rates.
For parapets, retain formwork in place for 72 hours to avoid cracking”
B6410
ADVERSE WEATHER
Add the following subclause:
“(d)
Temperature and hydration of concrete
Site batched concrete: The temperature of concrete delivered to site shall be within the range 10°C to
30°C. Concrete which has a temperature outside of this range shall not be placed in the structure.
Ready mix concrete: In the case of ready mix concrete the temperature limits at point of delivery shall
be as specified in SANS 878 2004 unless the engineer has specified other limits due to specific design
requirements. If slump loss occurs at concrete temperatures of over 30°C and or more than two hours
after mixing has elapsed, the concrete shall be rejected. Also if after addition of recovery packs the
concrete begins to stiffen again such as to place in doubt that full compaction and finishing can be
achieved, the concrete shall be rejected.
Care must also be taken not to cast concrete onto hot steel shutters as this might induce cracking.
Where thinner concrete elements are to be cast in steel shutters, such as parapets, the contractor
shall make the necessary arrangement to shield the shutters from direct sunlight during the full casting
and curing period(s).
The rate of hydration of the cement in the concrete shall be such that the concrete can be placed and
properly compacted within 2 hours after the addition of water to the mix ingredients. The initial set of
the concrete shall not be unduly delayed due to inappropriateness of admixtures or cement type,
which could promote bleeding.”
B6413
PRECAST CONCRETE
Add the following final paragraph:
"Precast concrete units shall comply with the requirements of the latest SANS 986:2006 specification.
Prior to the manufacture of any units the manufacturer shall submit his quality plan to be approved by
the engineer. The quality plan must incorporate all requirements and frequency for durability index
testing i.e. sorptivity, oxygen permeability, chloride conductivity (if required) and cover testing. As part
of the quality plan submitted for approval, copies of calibration certificates of both gauges used for
proof loads and cover meters used at the factory shall be supplied to the engineer. The originals of
these certificates shall at all stages also be available for inspection at the factory premises. The
manufacturer shall check each precast unit for cover compliance, and random checking of units shall
not be permitted. The engineer's representative may visit the factory at any stage to ascertain
adherence to the quality plan including test results from the durability index testing as well as to check
covers before delivery to site. Any substandard cover shall result in the applicable structural element
or part thereof being rejected. Should the manufacturer not be adhering to their quality plan the
engineer may exercise the right to reject the use of products from the manufacturer concerned. The
employer shall also be informed in all such cases.
For durability requirements due to the reduced cover provided for precast culverts, all such durability
testing shall be done in accordance with clause B6404(h). "
B6414
QUALITY OF MATERIALS AND WORKMANSHIP
(a)
Criteria for compliance with the requirements
Add the following paragraphs after the first paragraph:
“The cores shall be taken from the trial panels cast using the design mixes made in the laboratory.
Where the site is remote from the laboratory, the trial panels may be cast at the laboratory in
accordance with the requirements of sub-clause B8106(g).
C3-191
In the event that for ‘W’ classed concrete strength requirements the actual achieved average cube
strengths of an element are less than 85% of the target mean strength needed to meet durability
requirements or less than 100% of the target mean strength to meet strength requirements, it may
result in the durability parameters not meeting the prescribed targets and the engineer will instruct the
taking of cores from the test panel and structure for additional testing. The cost of these in situ tests
shall be borne by the contractor.
The approved quality control criteria for process control testing for durability concrete shall be coring
and testing of test panels. The frequency of manufacture and coring of test panels shall be as ordered
by the engineer and indicated in tables B8106/1 and B8106/2.
Tests B8106(g)(i), (ii) and (iii) (when required), shall be conducted on cores extracted from the test
panels when the concrete reaches the age of at least 28 days. To allow for variability in the material
potential, the type of chloride conductivity values shall be limited to 110% of the values indicated in
table B6404/5. Test no. B8106(g)(iv) shall be conducted to confirm that the specified depth of
concrete cover has been achieved. The frequency of these tests shall be as described under item
B8106(g). The test results shall be accepted or rejected on the criteria set out in table B6404/4 and
B6404/5 based on the following categories:
(i)
Full acceptance
Concrete shall be accepted unconditionally and full payment shall be made.
(ii)
Conditional acceptance
Concrete may be accepted, based on the cube strength and durability index results with a warning
that construction methods be examined to improve the durability criteria. A reduced payment shall be
applied to all the relevant payitems of the specific element under B6300 where the cover requirements
are not achieved and B6400 where the oxygen permeability and strength requirements are not
achieved for the non-conforming element or concrete pour as set out in tables B8212/1 and B8212/2.
The decision to accept the substandard concrete at reduced payment shall rest solely with the
employer.
Should the test result(s) indicate conditional acceptance of the element tested, the contractor shall
have the option of carrying out additional tests (on 4 extracted cores) on that element of the structure,
at his own expense to confirm or disapprove the original test result(s). These cores shall be extracted
within 56 days from the date of the element being cast.
Should the additional test confirm the original test result, then the original test result shall serve to
determine payment in accordance with tables B8212/1 and B8212/2.
Should the additional test show that the structure meets the targets, the penalty shall be halved.”
(iii)
Rejection
The concrete shall be removed and replaced with fresh concrete at the expense of the contractor, as
directed by the engineer.
B6416
MEASUREMENT AND PAYMENT
Add the following at the beginning of clause 6416:
"Note that items B64.01, B64.02 and B64.07 below are only applicable to durability concrete prefixed
‘W’."
Item
Unit
B64.01 Cast in situ concrete
Amend the descriptions of subitems 64.01(a) and (b) to read as:
"(a)
Durability concrete (Class W) ..................................................................... cubic metre (m3)
C3-192
(i)
(ii)
Indicate part of structure and strength e.g. Piers (W30/20))
Etc for other parts of structure
3
(b)
Normal concrete ......................................................................................... cubic metre (m )
(i)
(ii)
Indicate part of structure and strength e.g. Blinding (15/20)
Etc for other parts of structure
In the case of cast in situ concrete, delete “curing and protecting the concrete,” in the sixth line of the
description of the tendered rate for item 64.01.
Add the following after the second paragraph in the rate make-up:
“The contractor shall note that the strengths indicated above are to meet structural requirements only.
In order for the durability criteria to be achieved, it may result in higher strengths being required.
Target mean strengths to be achieved for durability purposes may therefore be higher than those
shown above, as discussed under subclauses B6406(b) and B6404(h)(ii). All durability testing costs
required for process control testing shall be included in the rate make-up for durability class concrete.”
Item
Unit
B64.02 Manufacturing precast concrete members (description of member
with reference to drawing) ................................................................................ number (No)
In the case of precast concrete, delete “curing and" in the second line of the description of the
tendered rate for item 64.02.
Item
Unit
B64.06 Demolishing existing concrete
Amend the payment paragraph as follows:
“The tendered rate shall include full compensation for all labour, plant (including access and craneage)
and equipment (including concrete cutters) required to demolish the existing concrete (irrespective of
strength) and the disposal of the product of the demolishing to a borrow pit within a free-haul distance
of 15 km. The tendered rate shall also include full compensation for any necessary measures to
ensure no debris falls into rivers or surfaces where damage is possible and for any debris that has
fallen into rivers to be recovered.
Payment shall distinguish between plain and reinforced concrete. For the purposes of this item,
reinforced concrete is defined as concrete containing at least 0,2% of steel reinforcement measured
by volume.”
Add the following payment items:
“Item
Unit
B64.07 Curing of concrete:
(a)
(Indicate structural element and surface to be cured) (Tenderer to
2
specify method of curing) .......................................................................... square metre (m )
(b)
Etc. for various elements (Tenderer to specify method of curing) .............. square metre (m2)
The unit of measurement shall be the square metre of completed concrete element cured using an
approved method as described in clause B6409 of these project specifications.
The tendered rates shall include full compensation for providing the curing agent and applying it to the
fresh concrete surface by means of an approved pressure distributor (or other approved methods of
application) in accordance with the manufacturer’s specified nominal rates of application. Wet fine
mist spray curing is also permitted providing it is done for 7 days. Payment will also be made under
this item if this is the preferred method to be used. Should no curing method be specified at time of
C3-193
tender then it will be assumed wet fine mist spray curing is to be done. Partial payment shall be
applied in the event that the engineer allows conditional acceptance.
Item
Unit
B64.08 Hot weather concreting ....................................................................................... lump sum
The tendered lump sum shall include full compensation for all measures specified in clause B6410(d)
required to ensure that the temperature of the concrete placed will not exceed the temperature
specified under clause B6410(f) of these specifications.
Payment will be made pro-rata to the quantity of all structural concrete, which is placed on the
contract. Payment will only be made if all the necessary measures required to ensure that the
concrete is placed at the temperature specified are implemented”.
C3-194
SECTION B6500: PRESTRESSING OF STRUCTURES
B6505
TECHNICAL DATA
(h)
Bursting reinforcement
Add the following paragraph:
“The contractor shall design the bursting reinforcement for his proposed prestressing system and
submit drawings to the engineer for approval in accordance with clause 6507. The price for the steel
and fixing shall be included in the rate tendered for stressing.”
B6510
POST-TENSIONING
(b)
Fabrication
Add the following after the sixth paragraph:
“Vent pipes shall also be installed at all low points of the prestressing ducts to facilitate grouting.”
(d)
Concrete strength
Add the following after the first paragraph:
“Notwithstanding the concrete strength provisions above, permanent prestressing cables shall not be
stressed within 7 days after completion of the last concrete pour unless the method and sequence of
construction is based on a method of assessing the in situ concrete strength, such as match casting,
which demonstrates that adequate strength has been attained. The proposed method shall be
described in a method statement which shall be submitted to the engineer for approval at least 28
days before construction of that part of the works commences. When determining concrete strengths
at which stressing operations can safely commence, due regard shall be taken of the tensile strength
in addition to compressive strength, to prevent undesirable cracking in tendon anchorage zones. In
this regard, tests shall be carried out to determine the rate of gain of both tensile and compressive
strengths before the above method statement is submitted to the engineer for approval”.
B6512
MEASUREMENT AND PAYMENT
Item
Unit
B65.01 Prestressing tendons:
(a)
Longitudinal tendons ................................................................. meganewton-metre (MN-m)
Add the following to the paragraph describing the unit of measurement:
“The cross-sectional area of the tendon used in the calculations shall be the area of the minimum
number of strands necessary to develop the jacking force.”
C3-195
SECTION B6600: NO-FINES CONCRETE, JOINTS, BEARINGS, PARAPETS AND DRAINAGE
FOR STRUCTURES
B6603
JOINTS IN STRUCTURE
(a)
Materials
(i)
General
Add the following after the last paragraph:
“It is a firm requirement that all contracts have full Agrément certification for bridge deck joints, with the
target date for new applications for Agrément assessment one year from receipt and acceptance by
Agrément South Africa of each application. Proof of original acceptance of application by Agrément is
required in such a case.
(1)
current Agrément assessments: 1 September 2010.
(2)
new applications for Agrément assessment one year from receipt and acceptance by
Agrément South Africa of each application. Proof of original acceptance of application by
Agrément is required in such a case.”
(ii)
Joint filler
Add the following after the last paragraph:
“ The specifications for generic products used on this project are shown below in table B6603/1
Table B6603/1
GENERIC PRODUCT SPECIFICATIONS
Description on drawing
Specification
20 mm thick polyethylene joint former
Closed cell, cross-linked expanded Polyethylene joint
former with thickness of 20 mm.
10 mm thick polyethylene joint former
Closed cell, cross-linked expanded Polyethylene joint
former with thickness of 10 mm.
Synthetic-fibre filter fabric
Non-woven synthetic fibre fabric impregnated and
coated with a neutral compound based on saturated
petroleum hydrocarbons and inert silaceous fillers, with
a nominal thickness of 1.15mm and mass per unit area
of 1.44 kg/m2.
“
(iii)
Sealants
Add the following after the last paragraph:
“The specifications for generic products used on this project are shown below in table B6603/2
Table B6603/2
GENERIC PRODUCT SPECIFICATIONS
Description on drawing
Specification
Silicone sealant
One component, gun grade, low modulus, neutral cure
silicone sealant that complies with ASTM D5893, does
not require a primer and has resistance against
temporary fuel spillage.
Composite asphalt and polypropylene
Composite membrane incorporating rubberised asphalt
mesh membrane
and polypropylene reinforcing mesh, 2.0 mm thick, with
self-adhering properties and inclusive of substrate
primer, for use under hot asphalt wearing course or in
direct contact with road fill material.
C3-196
(g)
Installing the expansion joints
Delete the first paragraph and replace with the following:
“All deck expansion joints shall be installed by approved specialist subcontractors only. Installed deck
expansion joints shall have the following guarantees:
Proprietary joints
Asphalt plug type joints
Concrete nosings (replacement)
Joint sealant
- 15 years
- 10 years
- 10 years
- 5 years
All deck expansion joints will only be considered for use on this contract if the manufacturer has
obtained Agrément certification. New applications for Agrément assessment takes up to one year
from receipt to acceptance by Agrément South Africa.”
B6604
BEARINGS FOR STRUCTURES
(a)
Materials
Add the following after paragraph (a)(ii):
“ The specifications for generic products used on this project are shown below in table B6604/1
Table B6604/1
GENERIC PRODUCT SPECIFICATIONS
Description on drawing
3 Ply asphaltic waterproof membrane
(e)
(v)
Specification
Asphaltic waterproofing membrane with a fibre felt
carrier with nominal thickness of 2.0 mm and nominal
2
mass per unit area 2.20 kg/m .
Proprietary Bearings
Construction
Delete the final three (3) paragraphs of subclause (e)(v)(7) and replace with the following:
“Applying two coats of epoxy MIO paint, with each coat a minimum of 75 micrometers of dry-film
thickness and of a dark grey colour.
Applying a semi-gloss, acrylic polyurethane (2 pack) finish with a minimum of 50 micrometers of dryfilm thickness and of light grey colour.
Surfaces in contact with concrete shall be sprayed with zinc, but not painted, so that it complies with
the requirements of SABS 1391 part 1 for type Zn 150 surfacing.”
B6606
DRAINAGE FOR STRUCTURES
Add the following after paragraph (d):
C3-197
“ The specifications for generic products used on this project are shown below in table B6606/1
Table B6606/1
GENERIC PRODUCT SPECIFICATIONS
Description on drawing
Specification
200 mm wide composite band drain
Pre-manufactured composite band drain for vertical and
strips
near-vertical inclined surfaces comprising a heavy duty,
extruded HDPE geospacer, wrapped in needle-punched,
non-woven, continuous filament, polyester geotextile of
minimum tensile strength of 11 kN/m in the machine
diection with nominal band width of 200 mm.
100 mm diameter drainage pipe
HDPE drainage pipe with typically 70% open area with
nominal 100 mm diameter and nominal 4 mm wall
thickness.
65 mm diameter drainage pipe
HDPE drainage pipe with typically 70% open area with
nominal 65 mm diameter and nominal 3 mm wall thickness.
Polyester geotextile
Needle-punched, non-woven, continuous filament,
polyester geotextile with typical tensile strength of 22 and
19 kN/m in the machine and transverse direction
respectively, determined in accordance with SANS 10221.
“
B6608 MEASUREMENT AND PAYMENT
Item
Unit
B66.05 Expansion Joints
(a)
(Description of joint measured in metre) ............................................................ metre (m)
Add the following to the measurement clause of subitem (a):
“The tendered rate for a complete buried type joint shall include the G1/G2 material, Asphalt base,
tack coat and fibreglass pavement reinforcement as specified on the drawings.”
(b)
(Description of joint measured per number) ................................................. number (No)
Add the following to the measurement clause of subitem (b):
“The joint measured shall be the complete joint shown on the drawings including termination details
and recesses at balustrades and cover plates and fixings.”
Add the following to the end of the second paragraph:
“The tendered rate for subitems (a) and (b) shall also include for water test required to prove the joint.
The water shall be ponded and maintained to a minimum depth of 150 mm above the top of the joint
for a period of one hour each. Testing should follow the installation of the various sections of joints to
take advantage of the existing traffic accommodation and each test shall cover the length of each joint
installed (generally half width of bridge)”.
Item
Unit
B66.06 Filled Joints ......................................................................................................... metre (m)
Add the following to the end of the second paragraph:
“The tendered rate for subitems (a) and (b) shall also include for water test required to prove the joint.
The water shall be ponded and maintained to a minimum depth of 150 mm above the top of the joint
for a period of one hour each. Testing should follow the installation of the various sections of joints to
take advantage of the existing traffic accommodation and each test shall cover the length of each joint
installed (generally half width of bridge)”.
C3-198
Item
Unit
B66.15 Concrete parapets ............................................................................................... metre (m)
Add the following to this clause:
“The tendered rate shall include for sealing of joints between balustrade units as shown on the
drawings.
Add the following payment items:
“Item
Unit
B66.28 Drainage strips (Type and position) .................................................................... metre (m)
The unit of measurement shall be the linear metre of drainage strips as shown on the drawing.
The tendered rate shall include full compensation for all material, labour, and equipment to supply and
install the strips as shown.
Item
Unit
B66.29 Perforated drainage pipes – 100mm diameter drainage pipe
wrapped in polyester geotextile ....................................................................................... metre (m)
The unit of measurement shall be the linear metre of perforated drainage pipes placed behind the
earth faces as shown on the drawing.
The tendered rate shall include full compensation for all material, labour, and equipment to supply and
install the perforated pipes as shown including the 200mm wide by 75mm thick concrete screed class
15/20 under the core.
Item
Unit
B66.30 Joint protection plates ........................................................................................ metre (m)
The unit of measurement shall be the linear metre of specified width installed. The tendered rate shall
include full compensation for supplying all materials, including fastening or adhesives, for galvanizing
and installation, including all labour and equipment, and for any wasted material.
Item
Unit
B66.31 Additional water tests for joints ordered by the engineer ............................ number (No)
The unit of measurement shall be the number of additional water tests for proving the expansion joints,
as ordered by the engineer. The test shall be executed by ponding water to a minimum depth of 150
mm deep above the top of the joint for a period of one hour each. Testing should follow the
installation of the various sections of joints to take advantage of the existing traffic accommodation and
each test shall cover the length of each joint installed (generally half width of bridge).
The tendered rate shall include full compensation for providing the pond of water and maintaining its
minimum depth of 150mm for the full one hour period, and clearing away the ponding materials on
completion.
Item
Unit
B66.32 Service ducts (type, size and location indicated) .............................................. meter (m)
The unit of measurement shall be the linear metre of specified type and size installed. The tendered
rate shall include full compensation for supplying all materials, including fastening, installation and all
labour and equipment, and for any wasted material”
C3-199
COLTO SERIES 7000:
SECTION B7200:
SUNDRY STRUCTURES
REINFORCED EARTH
Delete the entire Section 7200 Reinforced Earth, and replace with the following:
“SECTION B7200: MECHANICALLY STABILISED EARTH WALLS (MSEW)
B7201
SCOPE
This section covers the construction of (vertical) MSEW structures. In broad terms this consists of a fill
material with horizontal layers of reinforcing elements which may take the form of sheets, grids,
meshes, strips, bars, rods etc. The reinforcing elements, which are either metallic or polymeric, are
capable of sustaining tensile loads and the effects of deformation developed in the fill, with a positive
connection to the clad face.
The outer, clad face of the fill shall, for this project, be vertical and consist of concrete panels with a
high aesthetic finish.
All cladding, soil reinforcement and fastener materials shall be sourced from a single MSEW supplier
who will be responsible for the internal stability of the structure. The MSEW supplier shall have
suitable professional indemnity insurance cover. The engineer assumes overall responsibility for the
structure regarding foundation analysis and design criteria.
B7202
MATERIALS
(a)
General
All materials used in constructing the MSEW, shall be subject to the approval of the engineer. When
requested by the engineer, the contractor shall submit test certificates from an approved independent
testing authority to show that the respective materials comply with the specified requirements, or
where applicable the certificates from the patent holders or licensees certifying that the manufactured
items comply in all respects with the relevant product specifications.
(b)
Concrete panels
Concrete panels shall be manufactured from materials which comply with the relevant requirements of
sections 6200, 6300 and 6400.
(c)
Concrete bases and foundations for earth retaining systems
All materials for concrete bases and foundations for earth retaining systems shall comply with the
relevant requirements of sections 6200, 6300 and 6400.
(d)
Metallic soil reinforcements
Metallic soil reinforcement shall be made from materials having a certain resistance to corrosion when
buried and may take the form of sheets, grids, meshes, strips, bars, rods, ladders etc. and shall
comply with section 6.2.2, Table 6 and Table 7 of the latest edition of SANS 207:2006
Galvanizing shall comply with the requirements of SANS 121 for bars and SANS 675 for wire up to
5mm.
(e)
Fasteners between the facing and reinforcing elements
The fasteners between the facing and the reinforcing elements shall comply with section 6.4 of the
latest edition of SANS 207:2006. The facing shall have a positive connection to the reinforcing
elements.
(f)
Polymeric soil reinforcements and joints
Polymeric soil reinforcements and joints shall comply with section 6.2.3 and section 6.2.4 of the latest
edition of SANS 207:2006.
C3-200
(g)
Accessory proprietary products
Any accessory proprietary products, elements or fittings necessary for the construction of the MSEW
structure shall comply with the appropriate, accepted standards or specifications.
(h)
Fill Materials
All material which is used as fill behind MSEW cladding panels shall comply with the grading and
chemical requirements specified below in addition to all the requirements of series 3000.
(i)
Grading
The material which is used as fill in reinforced earth structures shall fall within the unshaded section of
graph 7202/1 and shall also comply with the requirements of table 7202/1.
Table 7202/1
MATERIAL SUITABLE FOR USE IN MSEW STRUCTURES
Percentage passing
through an 80 µm sieve
Percentage
finer than 20
µm
Plasticity Index
-
-
< 10%
-
< 12%
Type
Granular
12 to 35%
> 10%
PI < 30
> 35%
Intermediate
< 40%
Table 7202/2
MATERIAL SUITABLE FOR USE IN MSEW STRUCTURES
Pebbles
Coarse
Sand
Gravel
100
Fine
Sand
Silt
Clay
90
80
70
60
50
40
GRANULAR
SUITABLE
40
INTERMEDIATE
CONDITIONALLY
SUITABLE
30
20
10
10
(j)
0,2 µm
0,5 µm
1 µm
2 µm
5 µm
10 µm
20 µm
50 µm
0,1
0,2
0,5
1
2
5
10
20
50
100
200
250
500
1000
0
Chemical and electro-chemical properties
Except in the case of structures which will come into contact with salt water, in which case the
requirements will be set out in the project specifications, fill material shall comply with the following
chemical requirements:
Resistivity (Ohm.mm)
pH
Chlorides (ppm)
Class A
>- 10 000
5 to 10
<200
Class B
>- 30 000
5 to 10
<100
C3-201
Sulphates (ppm)
<1000
<500
Sulphides (ppm)
<300
<100
The resistivity shall be determined in accordance with the method prescribed by the patentee.
Class B requirements shall apply.
Intermediate materials may be utilised on sections of the walls shallower than 5 m, and only if the
plasticity index is less than 20.
A copy of all the results of the tests conducted on the material by the contractor or his supplier shall be
submitted to the engineer.
Material which does not comply with these specifications shall not be used without the written
permission of the engineer.
B7203
MANUFACTURING AND HANDLING THE CLADDING PANELS
(a)
Concrete panels
Concrete panels shall be manufactured in accordance with the dimensions and details shown on the
drawings, and, where necessary, these details shall be adapted to suit joining onto existing structures,
inclined foundations, varying heights or similar conditions.
The concrete panels shall be manufactured in accordance with the provisions of sections 6200, 6300
and 6400, and shall have an off-shutter class F2 surface finish. Concrete panels shall be between
140 mm and 180 mm thick. Selected panels shall have a protruding patterned effect.
The date of manufacture and the classification of every panel shall be clearly marked on the back of
such panel.
The concrete panels may be removed from the mould once the concrete has attained a cube
compressive strength of 7 MPa.
The concrete panels shall not be stacked more than five panels high during storage. The bottom
concrete panels shall be supported off the ground by means of timber blocking, and adjacent concrete
panels shall be separated by timber blocks packed between the tie strips to prevent any forces from
being transmitted onto the tie strips.
(b)
Accessories
Any accessory proprietary products, elements or fittings shall be manufactured in accordance with the
dimensions and details shown on the drawings. The accessories shall be handled in accordance with
the supplier’s recommendations.
B7204
CONSTRUCTION
(a)
Excavations
All excavations for the bases of the earth retaining systems shall be done in accordance with the
provisions of section 6100. The contractor shall not commence with the construction of the bases
before the excavations have been properly cleaned by the contractor and inspected and approved by
the engineer.
(b)
Foundation
The foundation plane for the MSEW structure shall be graded for a width equal to the length of soil
reinforcement and to the heights shown on the drawings, and compacted to a minimum of 93%
modified AASHTO density in accordance with the requirements of clause 3305. All foundation soils
found to be unsuitable shall be removed and replaced with compacted, approved granular material.
Measurement and payment for this work will be paid for under the relevant items of section 3300.
C3-202
A concrete footing, conforming to the correct line and level, shall be provided in accordance with the
details shown on the drawings, or as may be directed by the engineer.
(c)
Construction of MSEW
The construction of the MSEW structure shall conform to the procedures specified by the wall system
supplier. Concrete panels may be installed once the concrete reaches the cube compressive strength
of 18 MPa.
The bottom row of cladding panels shall be carefully aligned on the foundation footing in accordance
with the details provided. These panels shall be properly braced to prevent movement during the
placing of the first layers of fill. Each cladding panel shall be individually checked after having been
placed to confirm that the panel is correctly aligned to line, levels and inclinations shown on drawings
within the stipulated tolerance.
The fill material behind the cladding panels shall be placed and compacted in accordance with the
provisions of section 3200 and 3300 of the specifications to at least 93% modified AASHTO density,
except that the layer thickness may vary slightly to suit the position of the soil reinforcement. The fill
should be deposited, spread, levelled and compacted in horizontal layers of appropriate thickness.
The deposition and compaction should be carried out so that all layers of soil reinforcing elements are
fixed at the specified levels on top of compacted fill.
The fill should be placed such that it slopes away from the face at 2% to ensure that rainwater is kept
away from the face of the MSEW structure during construction.
The deposition, spreading, levelling and compaction of the fill should be carried out generally in a
direction parallel to the facing and should be executed in stages to alternate with the placing and fixing
of the reinforcing elements and facing. Fill shall not be placed right up to the cladding panels before
the underlying reinforcing has been covered, for sufficient length from the centre of the fill, with
compacted earth so as to anchor the reinforcement adequately to keep the cladding panel in position.
The filling shall be made from the end of the reinforcement to the cladding panels.
Care should be taken to ensure that the reinforcing elements are not damaged or displaced beyond
the specified tolerance during the process of filling and compacting. Filling should be arranged so that
no machines or vehicles run on the reinforcing elements. All vehicles and construction equipment
weighing more than 1500 kg should be kept at least 2 m away from the cladding. Suitable compaction
equipment weighing less than 1500 kg can be used within 2 m of the cladding
B7205
PATENT RIGHTS AND DESIGN
The license holder shall be responsible for the design by a professionally registered engineer (ECSA),
manufacture and supply of the cladding panels, reinforcing elements and accessories and for
providing technical assistance during construction.
The contractor shall negotiate direct with the patent holders or licensees in connection with royalties
payable for the use of the patented systems. The contractor shall arrange for technical assistance by
the patent holders or licensees before and during construction.
The patent holders or licensees shall design each wall, and full details shall be submitted to the
engineer for scrutiny and approval not later than (20) days prior to the commencement of construction
of any part of the wall(s). No construction work shall be carried out in accordance with any drawings if
the official approval of the licence holder has not been clearly indicated on it.
B7206
QUALITY ASSURANCE
(a)
General
The quality of the various materials covered in this section of the specifications must be monitored and
the results recorded to ensure that they comply with the requirements of the general or project
specifications. Series 8000 of the specifications provide tests and quality control procedures that
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cover a variety of materials and finishes. The standards given on the wall system supplier’s drawings
need to be checked for compliance.
(b)
Cladding panels
The quality of the various cladding panels covered in this section of the specifications must be
monitored to ensure that they comply with the requirements of this specification. All results should be
recorded for quality assurance purposes.
(c)
Materials and components not covered in the specifications
For testing procedures not covered by this specification reference shall be made to section 6.5 of the
latest edition of SANS 207:2006.
B7207
MEASUREMENT AND PAYMENT
The tendered rates shall also include for all incidentals necessary to carry out the works, specifically,
labour, transport, equipment, tools, all measures necessary for the safety of workers on the walls and
supervision.
Item
Unit
B72.01 Cladding panels and reinforcement elements
2
(a)
Concrete panels (F2 surface finish) ............................................................ square metre (m )
(b)
Special panels
(i)
(ii)
(iii)
Corner panels ........................................................................................... square metre (m2)
Patterned recessed panels ....................................................................... square metre (m2)
Steel mesh panels lined with geotextile ..................................................... square metre (m2)
The unit of measurement shall be the square metre of each type of cladding panel supplied. The
quantity shall be calculated on the basis of the specified dimensions on the surface which will be
visible in the completed structure. The front surface of the panel only shall be measured in respect of
special panels (e.g. corner elements)
This item shall also specifically include the supply of the required reinforcement elements behind the
wall according to the MSEW and patent holders design.
The tendered rates shall include full compensation for the labour, the supplying of all materials,
including tie strips, dowels and tubes, bolts and nuts, lifting devices and the necessary jointing
material, for manufacturing, storing, loading, transporting and off-loading and all appurtenant work
which may be necessary for providing the cladding panels on the site, also for all royalties, design
costs and technical assistance.
Item
Unit
B72.02 MSEW structures..................................................................................... square metre (m2)
The unit of measurement shall be the square metre of the front vertical face of the earth retaining
system placed in position as shown on the drawings. The front vertical face shall be measured from
the top of the base including embedment to the top of the earth retaining systems and include the
surface area of nominal panel joint openings and wall penetrations such as pipes and other utilities.
The tendered rate shall also include full compensation for procuring, furnishing, transporting, handling
and placing all materials including the reinforcement elements (strip, grids, etc.) and any additional
costs required for placing the panels and reinforcement elements into position complete as specified.
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Item
Unit
B72.03 Excavation for concrete bases for earth retaining systems
(a)
In soft material ............................................................................................ cubic metre (m³)
Measurement and payment for excavation shall be as specified for item 61.02 except that no
additional excavation shall be measured where formwork is required.
Item
Unit
B72.04 Concrete bases for earth retaining systems (Class 25 MPa/19) .............. cubic metre (m³)
The unit of measurement shall be the cubic metre of concrete cast in the concrete bases for earth
retaining systems, calculated in accordance with the net approved dimensions of the concrete bases.
The tendered rate shall include full compensation for supplying and placing the concrete and
constructing the concrete bases, including any formwork which may be necessary, and for all steel
reinforcement, complete.
Item
Unit
B72.05 Infill concrete and finishing on top of the wall (Class 30 MPa/19) ............ cubic metre (m³)
The unit of measurement shall be the cubic metre of infill concrete placed on top of the wall.
The tendered rate shall include full compensation for all labour, material, formwork and construction
equipment necessary for placing infill concrete and for finishing off the top of the wall.
Item
Unit
B72.06 Borrow to fill G6 material from approved commercial source ............... cubic metre (m3)
The unit of measure shall be the cubic metre of granular G6 fill material according to the relevant
provisions of section 3400 measured in the compacted fill, calculated from the authorised dimensions.
The tendered rate shall include full compensation for procuring from an approved commercial source,
furnishing and placing the material, for transporting of the material, for preparing, processing, shaping
and compacting the materials to the densities or in the manner specified.
Item
Unit
B72.07 Extra over items B72.06, 33.01(a)(i) and 33.01(a)(ii) for backfill
behind MSEW compacted in layers of 150mm to min. 93% MOD
3
AASHTO density at optimum moisture content ...................................... cubic meter (m )
The unit of measure shall be the cubic metre of fill placed between the geotextile or strip reinforcement
in accordance with approved dimensions of the MSEW fills bounded by reinforcing elements.
The tendered rate shall include full compensation for the additional costs of constructing the fills
containing geotextile or strip reinforcement, and for any adjustments to normal backfilling methods as
may be necessary for placing the backfill material as specified, including the trimming of layer planes
for providing intimate contact with reinforcement elements.
Item
Unit
B72.08 Filter Fabric (State Grade) ...................................................................... square metre (m2)
The unit of measurement shall be the square metre area covered with filter fabric placed in position as
indicated.
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The tendered rate shall include full compensation for the supply of the filter fabric, for cutting, waste,
placing, jointing, overlapping and securing the fabric in position as per the MSEW design
requirements.
Note: Pay item 64.02 shall apply to the manufacture of prefabricated concrete coping and pay item
64.03 to its transport and erection. These pay items shall be listed under section 7200 in the schedule
of quantities. ”
SECTION B7800:
B7801
SHOTCRETING SPECIFICATION
SCOPE
This specification covers the supply and application of shotcrete to cut and soil nail faces and other
areas as directed by the engineer. It shall include the supply and installation/application of the
shotcrete and the mesh.
B7802
SHOTCRETE AND MESH
(a)
Aggregate
The aggregates employed shall be of such quality as to meet the strength requirements specified and
shall comply with the requirements of Section 6400 of the Standard Specifications.
Fine aggregate shall be stored in such a manner that the moisture content is kept constant at all times.
The moisture content should not exceed 5% by weight when a dry mix process for shotcrete
application is to be used. The aggregate particles shall be spherical or cubical in shape. Natural river
aggregates are ideal. Where crushed aggregates are used the crushing process shall be aimed at
producing aggregate of the specified size from the outset. Aggregates which are screened off during
the manufacture of larger sizes generally contain an excess of flaky and elongated particles and are
not acceptable for shotcrete unless otherwise approved by the engineer.
(b)
Cement
Cement should be either Cem 1 (42.5) or Cem 2 (42.5) complying with Section 6400 of the Standard
Specification.
(c)
Additives
Proposed additives shall be submitted to the engineer for approval prior to the commencement of
work. The use of additives containing chloride will not be permitted. Additives shall have no
deleterious effects on the steel reinforcement or the shotcrete. Once an additive has been approved,
its use shall not be discontinued nor the agreed quantities per batch varied, nor another additive
substituted without the prior consent of the engineer. Where different additives are included in the
same batch, they shall be chemically compatible. Additives shall be metered into the batch in such a
way that uniform dispersal throughout the mix is achieved.
The engineer may require the contractor to apply test sections of shotcrete to prove the adequacy of
the proposed additives prior be starting on the specified work. Test sections shall be at contractor’s
cost.
(d)
Mesh
All steel employed shall conform to Section 6300 of the standard specification. The mesh to be used
in the shotcrete on plane surfaces shall be welded steel mesh R395.
(e)
Mix design
The contractor shall submit details of the mix proportions he proposes to adopt 14 days prior to
commencing the work. The contractor shall demonstrate to the engineer the suitability of the mix
proportions, the competence of each operator and method of application by shotcreting test sections
prior to commencing work. Such test sections shall not be carried out on a cut face requiring being
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shotcreted. Only when the mix suitability, the competence of each operator and method of application
have been demonstrated to the satisfaction of the engineer shall the contractor be permitted to
commence production.
(f)
Mixing and batching
All constituents shall be thoroughly mixed before they are discharged into the shotcrete pump. All
constituents for each batch shall be accurately measured each time a fresh batch is prepared. Weight
batching is preferred but volume batching will be permitted if accurately made gauge boxes of an
approved design are employed, all subject to the engineers discretion. Where volume batching is
permitted, the bulking factor of the sand shall be determined and taken into account. Cement shall be
measured by weight. Prepared batches shall be discharged through the nozzle within 30 minutes of
mixing.
(g)
Strength requirement
The required minimum cube strength of test specimens shall be 5; 8 and 30 MPa at 8 hours; 24 hours
and 28 days respectively. Test cubes are to be made by blowing shotcrete into prepared cube moulds
using the same technique as for application of shotcrete onto the rock face (i.e. the cube mould shall
be placed on its side and shotcrete shot into it horizontally). The cube mould itself shall be protected
by means of a suitable template. A set of three test cubes shall be required to be made for every 100
m² of shotcrete applied or as directed by the engineer and at the cost of the contractor.
(h)
Thickness required and measurement
The nominal thickness required is 25; 150 and/or 175 mm. The thickness shall be determined by
means of random test holes drilled by the contractor at positions indicated by the engineer. At least
one thickness measurement shall be taken every 10 m². The basis of acceptance shall be that in any
area of 100 m², the arithmetic mean thickness at all the points checked shall be equal to or greater
than the specified thickness. In addition, at no point checked should the thickness be less than 80%
of the specified thicknesses. Where the thickness is not acceptable, the engineer may order an
additional layer of shotcrete to be applied. All test holes shall be filled with mortar after the engineer
has approved the thickness of the shotcrete.
(i)
Sequence of applying shotcrete
All soil or rock to be covered with shotcrete shall be cleaned thoroughly with compressed air as
ordered by the engineer, to remove all loose pieces of rock and soil. Where soft material is to be
covered, only obviously loose material shall be removed and boulders shall be thoroughly cleaned with
compressed air. Shotcrete shall be applied as an initial layer of approximately 20 to 50 mm thick
(depending on specified thickness). The steel mesh shall then be fixed over this initial layer and the
shotcrete completed to the final specified thickness.
(j)
Method of fixing mesh reinforcement
The reinforcing mesh shall be securely fixed over the initial shotcrete layer by fastening to the dowels
as shown in Drawing J02173-01-11-3104 with wire ties or other approved fixings. The mesh shall be
fixed so that it lies snugly against the initial shotcrete layer and will not vibrate during application of the
second layer of shotcrete. Where sudden concave or convex surfaces preclude this, the mesh may be
cut so that smaller pieces of mesh can be formed into the curved surfaces. All sheets of mesh shall
overlap at junctions by at least 150mm. No additional payment shall be made for overlaps.
(k)
Application of shotcrete
Equipment used for the application of shotcrete shall be of approved manufacture and in good
condition. The operating crew shall be skilled in the use of this equipment. Care shall be taken to
ensure that the strands of mesh reinforcement are completely covered with the second layer of
shotcrete and that voids are not formed between shotcrete layers. The operations shall be carried out
in such a manner that rebound material falls clear of future working areas, wherever possible. At all
times the engineer may suspend shotcreting operations if in his opinion either the equipment used
becomes defective and results in a deterioration in the quality of the resulting shotcrete work, the
operator applying the shotcrete is incompetent or if adverse weather conditions preclude the
application of good shotcrete.
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(l)
Rebound material
Rebound material shall not be re-used. Rebound material shall be removed from all future working
areas and may not be covered up by subsequent applications of shotcrete. Rebound material shall
also be cleaned from the surface of any finished work.
(m)
Weep holes
Weep holes comprising of 75mm nominal diameter PVC piping, as shown in Drawings J02137-01-113103 and J02137-01-11-3104, shall be installed at those positions indicated or as requested by the
Engineer. The pipe shall protrude with sufficient length to allow for the cladding to be constructed in
front of the shotcrete without requiring a joint in the pipe, and have its inner end wrapped with a single
layer of geofabric. Weep holes shall be positioned in the no fines layer wrapped in geotextile, as
shown in Drawing J02137-01-11-31003, prior to shotcreting with the geofabric end The outer ends of
the tubes shall be adequately protected against shotcrete.
(n)
Detail of edge of shotcrete
Detail of the finishing off of shotcrete at the brow of cuttings is illustrated in Drawing 2 which shall be
provided by the client.
Where boulders or outcrop occur on the brow of the cut, no cut off is required and the shotcrete shall
be neatly stopped on top of the rock. As an alternative, the contractor may submit details for approval
of other proposed methods to terminate the shotcrete at the edge and the top of the cutting so as to
prevent surface water from undermining the shotcrete.
(o)
Curing
The finished shotcrete shall be adequately cured by an approved curing compound applied within half
an hour of application of the shotcrete. Where the shotcrete is applied in two layers hanging hessian
over the face and keeping the hessian wet for a period of 24 hours shall cure the first layer.
(p)
Blasting restriction
In order to reduce damage to the shotcrete no blasting shall be carried out within 50 m of a shotcreted
section within 72 hours of application of the shotcrete.
(q)
Procedure in event of failure of shotcrete
In the event that test samples do not achieve the specified minimum strength, the engineer may order
the contractor to carry out additional tests to determine new mix proportions.
If the engineer considers that the low strengths of the applied shotcrete may reduce the safety of the
Works and persons he may order that the following action be taken:
Either
(i)
Remove the defective shotcrete in strips or panels in such a way that the safety of the Works
and persons is not endangered and replace with shotcrete that is acceptable. This may also require
replacement of the mesh; or
(ii)
Apply an additional layer of shotcrete not exceeding the specified thickness originally required.
In neither case will payment be made for the defective shotcrete already applied, nor for the work
involved in removing the defective shotcrete from the areas where it has been applied, nor for any
mesh that must be replaced, nor for any costs involved in removing the resultant rubble and spoiling it
in an approved site.
Any additional laps required for mesh that must be replaced shall be to the Contractor's cost. Payment
shall only be made for placed and accepted shotcrete.
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B7803
MEASUREMENT AND PAYMENT
Measurement and payment for the mesh shall be based on the square metre of rock slope covered
with mesh measured on the plane of the slope. No extra payment shall be made for overlap of the
mesh.
Item
Unit
B78.01 Establishment on site ......................................................................................... lump sum
The unit of measurement shall be a lump sum and shall be payable in two instalments as follows:
(i)
50% of the tendered sum in the payment certificate following establishment of the necessary
equipment (to the engineer's satisfaction) on site.
(ii)
50% of the tendered sum after the work has been accepted and the installation team has left
the site.
The tendered rate shall include full compensation for the establishment and subsequent removal from
site of all the equipment, transport, plant, scaffolding, materials and personnel necessary to carry out
the specified work.
Item
Unit
B78.02 Supply and Installation of Reinforcing
(a)
Welded steel fabric Mesh Ref. 395. ................................................................... kilogram (kg)
The unit of measurement shall be the square metre of mesh actually incorporated into the shotcrete.
Overlaps shall not be measured.
The tendered rate shall include full compensation for the supply and installation, including all
equipment, plant, materials, labour and incidentals necessary to carry out the specified work and
including specifically, the supply and installation of pins, wire ties, gun nails and any other approved
fastenings for the completion of the work to the satisfaction of the Engineer.
Item
Unit
B78.03 Shotcrete of specified thickness applied in one, two or more
layers as necessary
(i)
(ii)
(iii)
30Mpa 25mm thick (unreinforced) flash coat ............................................. square metre (m²)
30Mpa 150mm thick final coat retained faces less than 3m high ................ square metre (m²)
30Mpa 175mm thick final coat retained faces 3m to 4.5m high................... square metre (m²)
The unit of measurement shall be the square metre of face measured in the plane of the cutting face,
which is protected by shotcrete of the specified thickness, installed to the satisfaction of the engineer.
No separate allowance shall be made for an uneven surface when measuring the area over which
shotcrete has been applied. The tendered rate shall include for everything necessary to carry out the
specified work to the satisfaction of the engineer and shall include the following:
(1)
Supplying all materials, including additives (if any), mixing and applying shotcrete including
test sections as ordered by the engineer, either to prove the adequacy of the additives or the
shotcrete methods and materials, mix design and the competence of operators.
(2)
Cleaning down the cutting face with air as ordered, and the removal of all resulting soil and
rock debris from the site to an approved spoil site, including all loading and transport
(3)
Applying the shotcrete in one, two or more layers as directed by the engineer.
(4)
Checking the thickness in the manner specified.
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(5)
Cleaning off all rebound and excess material and the disposal of thereof at an approved spoil
site.
(6)
Making, curing and testing test specimens as specified.
The tendered rate shall include any extra over payment for the instalment of the weep holes through
the shotcrete as shown in Drawings J02137-01-11-3103 and J02137-01-11-3104. The payment of the
piping for the weep holes will be done under Item 12/66.19, the no fines concrete under Item 12/66.01
and the geotextile fabric under Item 12/66.21.
No separate or additional payment shall be made for shotcrete applied to a thickness greater than
specified and required, nor shall any additional payment be made for shotcrete whether applied in one
or more layers.
Item
Unit
B78.04 Finishing off of shotcrete along brow of cut face .............................................. metre (m)
The unit of measurement shall be the linear metre of the top of cut face where the shotcrete is finished
off in the manner as detailed on the drawings or any other equivalent method, all to the satisfaction of
the engineer.
The tendered rate shall include full compensation for excavation and spoiling of material from cut off
trenches, bending of mesh/netting, application of shotcrete irrespective of the volume involved as well
as all equipment, labour, transport and other incidentals necessary to complete the specified work.
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