## How to calculate the quantity of water for a given concrete mix.?

Question

1. As per Is code 456-200 clauses 6.1.2

maximum free water cement ratio for M15(1:2:4) is 0.50

for 1 cubic metre concrete

1+2+4=7

cement content =1/7 *1 =0.1428 m3

density =mass/volume

density of cement =1440kg/m3 (note :- density of cement varies with grade and brand)

mass of cement =0.1428*1440=205.632 kg (note:- please consider minimum cement content also i.e. also given in clauses 6.1.2 of Is code)

w/c as per IS code is 0.50 for M15

w/c=0.50

water content=0.50*205.632=102.8 m3 =103 litre

Note:-w/c depends on various factors like moisture content of fine/coarse aggregate,workability …..

2. Obviously, water quantity cannot be decided based on the quantity mix design proportions only. There are other data which need to be known in order to be able to specify water content quantity for example, types of structural element, maximum aggregate size, and required workability. If these data are available, then the quantity of water can be easily computed from Table 6.3.3 of ACI 211.1-91.

Required slump can be determined based on the structural element type. Maximum aggregate size and slump value can be used to determine quantity of water for 1 meter cubic of concrete.