STANDARD CODES FOR CONCRETE ADMIXTURES
Standard Codes for concrete admixtures:
Admixtures used should conform to the following relevant standard codes.
In reinforced concrete, the chloride ion of any admixture used should not exceed 2% by weight of the admixture as determined in accordance with IS:6925 and the total chloride ion in all admixtures used in concrete mi shall not exceed 0.83% by weight of cement. The addition of calcium chloride to concrete containing embedded metal will not be permitted under any circumstance.
Accelerating concrete Admixtures conforming to IS:9103 & 2645 should be used. It is in liquid state with a specific gravity of 1.3 and complying with ASTM C-494 type E. It accelerates the setting and hardening of the concrete mix thereby achieving high early ago strength. Accelerating concrete admixture should be compatible with all types of cement.
Retarding concrete Admixtures conforming to IS:9103. It is in liquid state with a specific gravity of 1.22 and complying with ASTM C-494 type B&D, CRD-C87 type B & D, BS:5075part 1. It should be added to the concrete mix during the mixing process along with water and aggregates. No extension of normal mixing time is necessary. It will delay the initial and final setting time and helps to spread the heat of hydration over a longer period of time. It gives a highly workable concrete with a low W/C ratio. It must be compatible with all types of cement depending on requirement.
Air-entraining Admixtures conforming to IS:9103.
Water-reducing admixtures conforming to IS:9103.
Integral waterproofing admixtures conforming to IS:2645. It is used as an excellent cement admixture in all types of concrete/ plaster mortars, pointing mortars, masonry works, guniting works and pressure grouting works. It improves resistance of the surface to weathering and chemical attacks. It should not be toxic so as to use for waterproofing in water tanks, reservoirs, tanks, etc.
