<p>Supply and use of retarding chemical admixture in concrete, complying ASTM C-494 Type-B of approved brand/origin/manufacturer and supplied by only manufacturer's authorised dealer with certificate of origin. The admixture for retarding setting time of concrete, there by reducing shrinkage in concrete specially for concrete laid in thick layers and intended delayed construction for improved construction joints, re-concreting etc.[PWD 07.19.2]</p>