Specification Part 3 - Road & Bridge Works - Urban Administration ...

Minimum Stability (kN at 22. 2.2 for paving 2.2 for maintenance
2°C) Emulsion (kN at 25"C)
3.3 for paving
Cutback
Percent maximum stability 50 25
loss on soaking
Minimum flow (mm) 2 2
Compaction level (number of 50 75
blows)
Per cent air voids 3-5 3-5
Per cent voids in mineral See table 500-38
aggregate (VMA)
Percent minimum coating6 50 -
Notes:
1 Using "Marshall Method for emulsified asphalt -aggregate cold mixture design". Appendix K,
MS -14.
2 Using "Marshall method for cut -back asphalt -aggregate cold mixture design". Appendix H. MS-
14.
3 With vacuum saturation Mid immersion.
4 Hour days soak at 25°C.
5 Refers to total voids in the mix occupied by air and water.
6 Coating Test, Appendix 1;, MS-14.
TABLE 500-38.
MINIMUM PER CENT VOIDS IN MINERAL AGGREGATE (VMA)
Nominal Maximum
Minimum VMA (per cent)
Particle Size
IS Sieve (mm)
9.5 16.0
12.5 15.0
19.0 14.0
25.0 13.0
37.5 12.0
ingredients satisfy the physical and strength requirements of these Specifications.
(7)Approval of the job mix formula shall be based on independent testing by the Engineer in
charge for which samples selected jointly with the Engineer in charge of all ingredients of the mix
shall be furnished by the Contractor as required by the former.
(8)The approved job mix formula shall remain effective unless and until modified by the Engineer
in charge.
(9)Should a change in the source of materials be proposed, a new job mix formula shall be
established and approved by the Engineer in charge before actually using the materials.
519.2.2.4. Permissible variation from the job mix formula:
(i)It shall be the responsibility of the Contractor to produce a uniform mix conforming to the
approved job mix formula, subject to the permissible variations of the individual percentages of
the various ingredients in the actual mix from the job mix formula to be used, within the limits as
specified in Table 500-39.
(ii)These variations are intended to apply to individual specimens taken for quality control tests in
accordance with Section 900.
519.2.3. Construction operations
519.2.3.1. Weather and seasonal limitations: Construction with cold mix must not be
undertaken when ambient temperatures below 10°C are expected, during rain, in standing water,
or generally when poor weather is predicted. Bitumen emulsions and cutbacks depend on the