"Sample [first trial] mix proportions [by weight of water (W), ordinary Portland cement grade 53 (OPC 53 grade or (C) in Note below), fly ash (FA), and fine sand (FS) passing 4 mm IS sieve] ... are given in table- 1, 2 & 3. However, conclusive... proportions by actual trials may be worked out... for required workability, plastic density and compressive strength."
January 1, 1970