Say if you need 100 cft volume for a structural member with 1:2:4 mix (M20) can be made with 1:2:4 mix ratio or 1:1.5:3 mix ratio.
Remember that for 100 cft wet concrete you need 154 cft dry ingredients of cement sand and crush.
quantity of green concrete required = 154 cft (100*1.54)
Quantity of cement = 154*1/7 = 22 cft
where (7=1+2+4 according to mix ratio required for 1:2:4 concrete)
Quantity of sand = 154*2/7= 44cft
Quantity of crush = 154*4/7= 88 cft
REHAN SAJID
SENIOR EXECUTIVE
Pakistan State Oil Company
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