Quality Assurance Handbook for Rural Roads Volume-I - pmgsy
Quality Assurance Handbook for Rural Roads Volume-I - pmgsy
Quality Assurance Handbook for Rural Roads Volume-I - pmgsy
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3. Section-500<br />
(iii) In the final layer, the mix should be spread slightly proud of the surface so that after rolling,<br />
the surface shall be flush with the adjoining surface.<br />
(iv) Where required, a Seal Coat should be applied as per the specified procedure. The surface<br />
levels should be checked using a 3 m straight edge.<br />
(b) Crack Sealing<br />
(i) The fine cracks (less than 3 mm in width) should be sealed by Fog Spray, which is a very<br />
light application of low viscosity Slow Setting Emulsion. Prior to this treatment, it is important<br />
that the surface is thoroughly cleaned, preferably with compressed air. The Fog Spray should<br />
be applied at a rate of 0.5-1.0 litre/m 2 of the specified emulsion, using 0.5-1.0 litre/m 2 of the<br />
specified emulsion, using an approved hand-held ‘sprayer. For sites in sub-zero<br />
temperatures, Medium Curing Cutback as per IS 217can be used.<br />
(ii) The wide cracks (more than 3 mm in width) should be filled with crusher dust or other<br />
approved fine material passing 4.75 mm sieve to a level about 5 mm below the road surface<br />
level. After sweeping the surface clear of dust, Slow Setting emulsion should be poured<br />
into the cracks, minimizing any spillage. If spillage does occur, crusher dust should be applied<br />
to blot up the spillage. Isolated areas, with wide cracks, shall be cut and patched as per<br />
Section 501.<br />
4. Profile Corrective Course<br />
(i) Where specified, a profile corrective course should be provided.<br />
(ii) After preparing the surface as explained above, the profile corrective course with the specified<br />
material should be laid and compacted to the requirements of the particular specification.<br />
(iii) A tack coat as per Sub-section 503 should be applied over a primed granular surface or an<br />
existing bituminous surface prior to laying the bituminous profile corrective course.<br />
(iv) Short sags or depressions in the surface should be corrected by laying profile corrective<br />
course in the <strong>for</strong>m of flat wedges (layers).<br />
The thickness of layer at any point should not be more than 100 mm.<br />
Where the profile corrective course is laid in more than one layer, successive layers should<br />
completely extend over and fully cover the underlying layer.<br />
B. <strong>Quality</strong> Control Requirements<br />
1. Material<br />
(i) Crusher stone dust <strong>for</strong> crack filling should be a fine-grained material, passing 4.75 mm sieve.<br />
(ii) The bituminous mixture to be used <strong>for</strong> patching should be either a hot mix or cold mix in<br />
accordance with appropriate specifications.<br />
(iii) The material <strong>for</strong> profile corrective course should meet relevant specifications.<br />
(iv) The binder <strong>for</strong> prime coat and crack filling should be a Slow Setting bituminous emulsion<br />
(SS-1 grade) as per IS:8887. For sub-zero temperatures, however, a Medium Curing (MC)<br />
Cutback con<strong>for</strong>ming to IS:217 can be used. Prime coat should be applied as per Sub-section<br />
502.<br />
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