Quality Assurance Handbook for Rural Roads Volume-I - pmgsy

C. Do’s and Don’ts
1. Back fill properly, surface trenches and soft spots in
the sub-grade and compact the same. Remove all
organic and extraneous material from sub grade.
2. Saw cutting of joints should be done when concrete
is neither too soft nor too hard.
3. Ensure that side forms are sufficiently robust and
rigid to support the weight and pressure caused by
paving equipment.
4. Do make provisions to maintain sufficient supply of
tarpaulin or other water proof cloth during
placement of concrete when rain is expected.
5 The Coarse aggregate shall be free from dirt, flint,
chalecedony or other silica.
6. Use fine aggregate free from soft particles of clay,
shale, loam cemented particles, mica and other
foreign matter.
7. Ensure sufficiency and accuracy of material, plant
and equipment and methods of construction by
laying a trial length of at least 30 m.
8. Measure workability of the concrete at the time of
placing with slump cone Test.
9. Provide proper construction joint if concreting is
suspended for more than 30 minutes. Use bulk head
to retain the concrete.
1502: ROLLER COMPACTED CONCRETE PAVEMENT
A. Methodology
Do’s Don’ts
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Quality Assurance Handbook for Rural Roads
1. Do not lay sub-base on a sub grade softened by rain
2. Do not expose concrete slab for a period of more than
half an hour for saw cutting of joints.
3. Do not provide any vertical step between the adjacent
side forms greater than 3 mm
4. Do not carry out concreting work when concrete
emperature is more than 300C or less than 50C at the
point of placing and ambient temperature is greater
than 350C 5. Do not use disintegrated, soft, flaky, elongated, highly
angular or splintery coarse aggregate.
6. Do not vibrate concrete excessively to prevent flow of
mortar to the top.
7. Do not allow normal working until the trial length has
been approved.
8. Do not walk on freshly laid concrete to place covering
for curing.
9. Do not allow any traffic, including construction
vehicles on the finished surface of concrete pavement
till the joints are permanently sealed.
1. Lay a trial length of minimum 30 m length as detailed in sub-section 1501 A (i) To (iii). Roll the
trial length as per rolling sequence in Table No. 1502.1. If waves appear on top of the rolled
surface in front of roller during construction of trial length, the moisture content shall be varied
and strength redetermined. Determine natural moisture content on day to day basis, before
production of the mix.
TABLE 1502.1: ROLLING SEQUENCE FOR ROLLER COMPACTED CONCRETE PAVEMENT
Sl. Type of Roller No. of Static No. of vibrating Remarks
No. passes passes
1 Double drum tandem 2 Nil Breakdown rolling
roller Nil 4-6 Vibratory rolling with amplitude
0.8-0.4 mm
1-2 Nil Smoothening
or
2 Single front drum steel 1 Nil Breakdown rolling
roller with rear tyres of Nil 4-5 Vibratory rolling with amplitude
rubber descending
1-2 Nil from 0.8 to 0.4mm Smoothening