supply of op wks stores:- ( a ) supply of cement opc 43 grade ( isi mark ) conforming to is 8112 ( 2013 ) , in bags of 50 kg each. make: acc ( associated cement co. ltd ) / ambuja cement / lafarge cement / ultra tech cement / birla corp ltd / binani cement / dalmia cement / jk cement ( jammu & kashmir ) ( is-8112: 2013 ) ( b ) natural sand conforming to is 383-1970 ( specifications for coarse and fine aggregates ) . free from adherent coating, hard, durable, clean and shall not contain clay and impurities such as iron pyrites, alkalies, salt, coal, mica, shale or similar laminates or other materials exceeding the specified limits in is code aggregates for concrete. ( c ) aggregate 20 mm. stone aggregate to be crushed rock or gravel 20 mm graded conforming to is 383-1970 ( second revision ) and shall consist of angular fragments and shall be clean, hard, tough, durable and of uniform quality throughout. ( d ) aggregate 40 mm. stone aggregate to be crushed rock or gravel 40 mm graded conforming to is 383 – 1970 ( second revision ) and shall consist of angular fragments and shall be clean, hard, tough, durable and of uniform quality throughout. ( e ) quick setting compound. make: repidite / acclerex / cico / fosroc