Quality Assurance Handbook for Rural Roads Volume-I - pmgsy

3. Section-400
TABLE 402.2: GRADING AND PLASTICITY INDEX REQUIREMENTS FOR SURFACE COURSE
(ii) Wet Aggregate Impact Value (IS:5640) shall not exceed 40 and 30 when used in base and 30
when used in surfacing.
(iii) Flakiness Index (IS:2386 Part I) shall not exceed 25 percent when used in base and 20 when
used in surfacing.
(iv) In high rainfall areas (annual rainfall of 1500 mm or above), coastal areas and where local
soils are salt infested, if the water absorption value of the coarse aggregate is greater than 2
percent, the Soundness test shall be carried out on the material delivered to the site as per
IS:2386 (Part 5).
(a) Loss with Sodium Sulphate, 5 cycles : 12 per cent maximum
(b) Loss with Magnesium Sulphate, 5 cycles : 18 per cent maximum
(v) If crushed slag is used, Clause 405.2.5 of MORD specifications shall apply.
(vi) If crushed gravel/shingle is used, not less than 90 per cent by weight of the gravel/shingle
pieces retained on 4.75 mm sieve shall have at least two fractured faces.
(vii) The needed gradation shall be obtained by crushing, screening and blending processes as
necessary.
(viii) Fine aggregate material passing 4.75 mm sieve shall consist of natural or crushed sand and
fine mineral particles.
2. Horizontal Alignment
The edges of the Base shall be correct within a tolerance limit of (±) 30 mm in plain and rolling
terrain and (±) 50 mm for hilly areas. The edges of the carriageway with Gravel/Soil-Aggregate
Surfacing shall be correct within (±) 20 mm in plain and rolling terrain and (±) 30 mm in hilly
terrain.
3. Surface Levels
IS Sieve Designation Per cent by Weight Passing IS Sieve
26.5 mm 100
19 mm 97–100
4.75 mm 41–71
425 µ 12-28
75 µ 9–16
Plasticity Index 4–10
The tolerance in surface level for Gravel/Soil-Aggregate Base and Surface will be restricted to (±)
10 mm. A grid of 10 m by 2.5 m may be formed to check the surface level.
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