opw provision of double storey shelter with retaining wall and drainage cijw school vairengte , supply of provision of double storey shelter with retaining wall & drainage at cijw school , portland pozzolana cement ( ppc ) in 50 kgs bags isi marked . make : ambuja / birla / l&t / jk / cci / dalmia . , fine aggregate ( natural sand ) conforming to is : 383-1978 . , coarse aggregate ( crushed stone ) 20 mm graded conforming to is-383-1979 . , coarse aggregate ( crushed stone ) 40 mm graded conforming to is-383-1979 . , hammer deressed stones for random rubble masnory wall with maximum depression on face from straight edge held against the deressed surface n exec 20mm . , pvc 110mm pipe . , brick sub class b old size best locally available ( minimum compressive strength 75kg / sqcm , water absorption not more than 20%