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

(iii)The surface of the mastic asphalt, tested with a straight edge 3.0m long, placed parallel to the
centre line of the carriageway, shall have no depression greater than 7mm.
(iv)The same limit shall also apply to the transverse profile when tested with a camber template.
515.7. Arrangements for Traffic
During the period of construction, arrangements for traffic shall be made by as per direction of
Engineer in charge.
515.8. Measurement for Payment
Mastic asphalt shall be measured as finished work in square meters at a specified thickness, or
by weight in tonnes as stated in the Contract.
515.9. Rate
The contract unit rate for mastic asphalt shall be payment in full for carrying out the required
operations including full compensation for all components listed under Clause 501.8.8.2. (i) to (ix).
516. SLURRY SEAL
516.1. General
(i)Slurry seals are mixtures of fine aggregate, Portland cement filler, bitumen emulsion and
additional water.
(ii)When freshly mixed, they have a thick consistency and can be spread to a thickness of 1.5 - 5
mm.
(iii)They may be used to seal cracks, arrest fretting and fill voids and minor depressions, to
provide a more even riding surface or a base for further treatment; they may also be used on top
of a single coat surface dressing.
516.2. Materials
The materials for slurry seal immediately prior to mixing shall conform to the following
requirements:
516.2.1. Emulsified bitumen:
(i)The emulsified bitumen shall be a cationic rapid setting type as approved by the Engineer in
charge, conforming to the requirements of IS: 8887. Where special mobile mixing machines are
available, Class A4* rapid setting or Class K3* road emulsions to BS 434: Part 1 should be used
to obtain very early resistance to traffic and rain. Generally, emulsion for slurry seal should be
capable of producing slurry that will develop early resistance to traffic and rain and is sufficiently
stable to permit mixing with the specified aggregate, without breaking during the mixing and
laying processes.
(ii)If approved by the Engineer in charge, a slow setting emulsion may be used. (iii)Guidance on
selection of an appropriate grade of emulsion is given in the Manual for Construction and
Supervision of Bituminous Works.
516.2.2. Water:
(i)Water shall be of such quality that the bitumen will not separate from the emulsion before the
slurry seal is in place.
(ii)The pH of the water must lie in the range 4 to 7, and if the total dissolved solids in the water
amount to more than 500ppm, the Engineer in charge may reject it, or order the Contractor to
conduct a trial emulsion mix to demonstrate that it does not cause early separation.
516.2.3. Aggregate:
(i)The aggregate shall be crushed rock, or slag and may be blended, if required, with clean,
sharp, naturally occurring sand free from soft pieces and organic and other deleterious
substances to produce a grading as given in Table 500-33.
(ii)The aggregates shall meet the requirements of the film stripping test (IS: 6241), and a suitable
amount and type of anti -stripping agent added, as may be needed (details given in Appendix 5).
516.2.4. Additives: