Quality Assurance Handbook for Rural Roads Volume-I - pmgsy

C. Do’s and Don’ts
Do’s Don’ts
1. Ensure that aggregates for premix carpet and seal
coat conform to the prescribed physical and grading
requirements and are clean and dry.
2. Exercise strict control over mixing and laying
temperature as per specifications using appropriate
thermometers.
3. Rolling operations should be completed before the
temperature of the mix falls below 100oC.
508.2 PREMIX CARPET USING BITUMEN EMULSION
A. Methodology
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Quality Assurance Handbook for Rural Roads
1. Do not allow manual mixing.
2. Do not undertake the work in foggy, rainy or windy
weather or when the atmospheric temperature in the
shade is less than 10oC or when the surface is wet.
3. Do not allow the premix material to adhere to the roller
wheels. Do not use excess water for the purpose. Light
sprinkling should do.
4. Do not allow the roller to stand on newly laid material.
5. Do not allow any traffic without laying seal coat over
the premix carpet.
1. Prepare the base on which premix carpet is to be laid to the specified lines, grade and cross section
2. Apply a tack coat over an existing prepared black top surface.
3. The quantities of material required for 20 mm thick premix carpet should be as indicated below
(i) Aggregate as per Table 508.1.1 of Sub-section 508.1
(ii) Binder : Cationic Bitumen Emulsion
(a) For 0.18 m3 of 13.2 mm nominal size stone at 78 kg 14.0 kg
cationic bitumen emulsion per m3
(b) For 0.09 m3 of 11.2 mm nominal size stone at 84 kg 7.5 kg
cationic bitumen emulsion per m3
Total 21.5 kg
4. Premix bitumen emulsion and aggregates in a suitable mixture such as cold mixing plant as per
IS:5435 (revised) or concrete mixture
5. Spread the premix to the desired thickness, grade, cross fall within 10 minutes of applying the
tack coat and ensure that all levelling, raking is completed within 20 minutes of the mixing.
6. Roll the surface as per Para 6 & 7 of the methodology described in Sub-section 508.1
7. Provide a seal coat as specified in the contract within 4-6 hours after laying the premix carpet.
Follow Sub-section 510 for the work on seal coat.
8. Preferably, the road should be opened to traffic after 24 hours of laying the seal coat. In single lane
roads traffic may ordinarily be allowed after 6-8 hours with the care that the speed is rigorously
restricted to not more than 16 km/h.