Quality Assurance Handbook for Rural Roads Volume-I - pmgsy

B. Quality Control Requirements
1. Materials
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Quality Assurance Handbook for Rural Roads
(a) Flyash should conform to the requirements given in Tables 409.1 and 409.2. The chemical
requirements specified in Table 409.1 may be ascertained from the source of supply.
TABLE 409.1 : CHEMICAL REQUIREMENTS FOR FLYASH AS A POZZOLANA
Characteristics Requirements for Flyash
AnthraciticFlyash LigniticFlyash Methodof Test
1. SiO 2 +Al 2 O 3 +Fe 2 O 3 in per cent by mass, Min 70 50 IS:1727
2. SiO 2 in per cent by mass, Min 35 25 IS:1727
3. MgO in per cent by mass, Max 5.0 5.0 IS:1727
4. SO 3 in per cent by mass, Max 2.75 3.5 IS:1727
5. Available alkalies as Na 2 O in per cent by mass, Max 1.5 1.5 IS:4032
6. Total chlorides in per cent by mass, Max 0.05 0.05 IS:1727
7. Loss in ignition in per cent by mass, Max 5.0 5.0 IS:1727
(b) Lime should have a purity of not less than 70% by weight of CaO when tested as per IS:1514.
Quick lime which has been pre-slaked at site should be used within 7 days. Slaked lime
supplied in airtight bags should not be stored for more than 3 months.
(c) Soil should have a PI between 4 and 20; soil with PI more than 20 may be used provided
strength requirements are satisfied.
(d) Water should be free from injurious salts, organic matter and other deleterious matter. Potable
water is satisfactory.
2. Horizontal Alignment
The edges of the lime-flyash stabilized soil sub-base should be correct within a tolerance limit of
(±) 30 mm in plain and rolling terrain and (±) 50 mm in hilly terrain.
3. Surface Levels
TABLE 409.2 : PHYSICAL REQUIREMENTS FOR FLYASH AS A POZZOLANA
Characteristics Requirement
1. Fineness–specific surface in m2 /kg by Blaine’s permeability test, Min 250
2. Particles retained on 75 micron IS Sieve, Max 40
3. Lime reactivity in N/mm 2 , Min 3.5
4. Soundness by autoclave test-expansion of specimen in per cent, Max 0.8
5. Soundness by Lechatelier method–expansion in mm, Max 10
The tolerance in surface levels for lime-flyash stabilized soil subbase will be (+) 10 mm and (–) 20
mm. A grid of 10 m x 2.5 m may be formed to check the surface level.