Water retaining concrete class C35A
For design purposes, BS 8007, Code of practice for design of concrete structures for retaining aqueous liquids, 1987 generally referred to BS 8110, Structural use of concrete. However BS 8007 specified a 35N/mm2 concrete with a minimum cement content of 325kg/m3 (compared with 300kg/m3 in BS 8110) and a maximum water/cement ratio of 0.50 (compared with 0.55 in BS 8110). This variation in constituent material limitations gave rise to the class grade C35A, where A stood for aqueous. The Code also specified maximum cement contents for reinforced concrete of 400kg/m3 for ordinary Portland cement or cements containing ggbs, or 450kg/m3 for cements containing fly ash. For prestressed concrete the quantities could be increased to 500kg/m3 and 550kg/m3 respectively.