How to find out the quantity of water in a concrete mix

In this construction video tutorial, the eminent engineer S.L. Khan, briefly explains the process for estimating water of the concrete mix.

The quantity of water is computed in liters or gallons. Here, the calculation is made for cement, fine and course aggregates which are vital components of the concrete mix.

Suppose, the proportion of concrete mix is 1:2:4 (one part cement : two part sand : four part aggregates).

First Step:

At first, the calculation is performed for finding out the total volume of aggregate as follow.
Volume of one cement bag = 1.25 cft or 0.0354 cu.m
Volume of sand or fine aggregates =0.0354 x 2 = 0.07 cu.m.
Volume of crushed stone or coarse aggregates = 0.0354 x 4 = 0.141 cu.m.
Therefore,
Total volume of aggregates =0.07 + 0.141 = 0.211 cu.m.

Second Step:

Here, 5% water is chosen of aggregates volume, like
water for aggregates = 0.221 x (5%/100) = 0.01055 m3 or 0.01055 x 1000=10.55 liters (as 1 cubic meter is equivalent to 1000 liters).

Third Step:

Assume 11.667 (3 gallons) litres water for one cement bag that is 1/3 of cement bag volume.
Therefore, Water for cements = 11.667 liters
Now, total quantity of water = water for cement + water for aggregates.
Therefore, total quantity of water = 11.667 + 10.55 = 22.217liters

To get online demonstration, watch the following video tutorial.

Video Source: SL Khan