Concrete mix for strip foundations

The mass concrete used in the strip foundation should be – (a) in chemically aggressive soil conditions, an appropriate concrete mix as recommended in BS 8500: Part 1 and BRE Special Digest 1; and (b) in chemically non-aggressive soils, composed of Portland Cement to BS EN 197-1 & 2 and fine and course aggregate conforming to BS EN 12620, the mix being – (i) in the proportion of 50 kg of cement to not more than 155 kg (0.11 m³) of fine aggregate and 240 kg (0.16 m³) of coarse aggregate; or (ii) Grade ST2 or Grade GEN 1 to BS 8500: Part 2.