Measurement of cement and aggregates - by weight vs. by volume

Measurement of constituents for concrete is usually carried out by weight since of the following reasons:

(i) Air is trapped inside cement whereas water may be present in aggregates. As such measurement by volume necessitates the consideration of the bulking effect by air and water.

(ii) Accuracy of measurement of cement and aggregates by weight is higher when compared with measurement by volume when weighing machine is properly calibrated and maintained. This decreases the potential of deviation in material quantity with higher accuracy in measurement for the design mix and results in more economical design without the wastage of excess materials.