As suggested by IS 456 ∶ 2000, the minimum grade of concrete, and the corresponding cement content(in kg/m3 units), maximum water cement ratio, for Extreme exposure conditions, in reinforced concrete work with 20 mm nominal size aggregates are respectively:
1
M45, 330, 0.45
2
M40, 300, 0.5
3
M40 ; 360, 0.4
4
M50, 360, 0.5