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

505.3.2 Equipment : A mechanical broom, compressor, self propelled or trailed bitumen
heater/distributor, mechanical aggregates spreader and 8 to 10 tonnes smooth steel wheel roller
or vibrating roller are required for the preparation of penetration macadam.
505.3.3 Preparation of the base: same as per clause 504.3.2 and 504.3.3.
505.3.4. Spreading coarse aggregates:
(i)The coarse aggregate shall be dry and clean and free from dust, and shall be spread uniformly
and evenly at the rate specified in Table 500-6.
(ii)It shall be spread by a self- propelled or tipper tail mounted aggregate spreader capable of
spreading aggregate uniformly at the specified rates over the required widths.
(iii)The surface of the layer shall be carefully checked with camber templates to ensure correct
line and level and cross fall.
(iv)The spreading shall be carried out such that the rolling and penetrating operations can be
completed on the same day.
(v)Segregated aggregates or aggregates contaminated with foreign material shall be removed
and replaced.
505.3.5. Compaction: After the spreading of coarse aggregates, dry rolling shall be carried out
with an 8 — 10 tonne smooth steel wheel roller. The requirements given in Clause 501.6 and
501.7 shall apply. After initial dry rolling, the surface shall be checked with a crown template and
a 3 meter straight-edge. The surface shall not vary more than 10 mm from die template or
straight-edge. All surface irregularities exceeding the above limit shall be corrected by removing
or adding aggregates as required. The rolling shall continue until the compacted coarse
aggregate has a firm surface true to the cross section shown on the plans and has a texture that
will allow free and uniform penetration of the bituminous material.
505.3.6. Application of bituminous material: After the coarse aggregate has been rolled and
checked, the bituminous binder shall be applied, at the rate given in Table 500-6, in accordance
with Clause SOI, and at a temperature directed by the Engineer in charge. At the time of applying
the binder, the aggregates shall be surface dry for the full depth of the layer.
505.3.7. Application of key aggregates: The key aggregate shall be clean dry and free from
dust. Immediately after the first application of bitumen, the key aggregates shall be spread
uniformly over the surface by means of an approved mechanical spreader or by approved manual
methods at the rate specified in Table 500-6. Where directed by the Engineer in charge, the
surface shall be swept and the quantity of key aggregate adjusted to ensure uniform application,
with all the surface voids in the coarse aggregate being filled without excess. The entire surface
shall then be rolled with a 8 - 10 tonnes smooth steel wheel roller (or vibrating roller operating in
non -vibratory mode) in accordance with the procedure specified in Clause 505.3.5.
505.4. Surface Finish and Quality Control
The surface finish of the completed construction shall conform to the requirements of Clause 902.
For control of the quality of materials supplied and the works carried out the relevant provisions of
Section 900 shall apply.
505.5. Surfacing
The Penetration Macadam shall be provided with a surfacing (binder/ wearing course) within a
maximum of forty-eight hours. If there is to be any delay, the penetration macadam shall be
covered by a seal coat before opening to traffic. The seal coat in such cases shall be considered
incidental to the work and shall not be paid for separately.
505.6. Arrangements for Traffic
During the period of construction, arrangements for traffic shall be made as directed by the
Engineer in charge.