Quality Assurance Handbook for Rural Roads Volume-I - pmgsy

3. Section-500
TABLE 506.1 RATE OF APPLICATION OF AGGREGATE PER 10 SQM AREA
Description Thickness of Modified Penetration Macadam layer
75 mm 50 mm
On Bituminous On WBM On WBM On Bituminous
surface(cum) surface(cum) 100 surface(cum) surface(cum)
40 mm size hand
broken metal
0.90 0.90 0.6 0.6
12 mm size stone chips 0.18 0.18 0.12 0.12
TABLE 506.2 RATE OF APPLICATION OF BITUMEN PER 10 SQM AREA
Description Thickness of Modified Penetration Macadam layer
75 mm 50 mm
On Bituminous On WBM On WBM On Bituminous
surface(kg) surface(kg) 100 surface(kg) surface(kg)
Bitumen for grouting 20 20 17.50 17.50
Tack Coat As per Sub-section 503
4. Spread coarse aggregate of 40 mm size metal uniformly at the rate of 0.9 cum for 75 mm thickness
(0.6 cum for 50 mm thickness) per 10 sqm area to proper camber/ super-elevation Remedy all
high spots and depressions by removing or adding aggregates.
5. Commence rolling with 80-100 kN rollers (three-wheel or tandem type), beginning from the edge
and progressing towards the centre longitudinally. On superelevated portions, rolling should
progress from lower to upper edge parallel to centre line of pavement.
6. Correct any irregularities noticed after the roller has passed over the whole area once by loosening
the surface and removing or adding the coarse aggregates followed by rolling. Continue rolling
till the entire surface has been rolled to desired compaction such that there is no crushing of
aggregates and all roller marks have been eliminated. Each pass of roller should overlap not less
than one-third of the track made in the preceding pass.
7. Heat bitumen (paving grade S-35 to S-90) to a temperature of 160 0 C to 180 0 C and spray uniformly
on aggregate layer at the rate of 20 kg per 10 m 2 for 75 mm thick layer and 17.5 kg per 10 m 2 for 50
mm thick layer.
8. Immediately after application of bitumen, spread 12 mm size key aggregates at a uniform rate of
0.18 cum for 75 mm thickness (0.12 cum for 50 mm thickness) per 10 m 2 so as to cover the surface
completely and roll. Rolling should continue until the key aggregates are firmly embedded in
position and stop moving under roller.
9. Provide a wearing course over the modified penetration macadam immediately within 2 days. If
there is to be any delay in laying of wearing course, a seal coat would be required before it is
opened to traffic.
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