Concrete Mix Ratios Explained: 1:2:3, 1:2:4, M20/M25 & the Water-Cement Ratio
A 1:2:3 concrete mix means 1 part cement, 2 parts sand, 3 parts gravel by volume — about 3,000 psi. This guide decodes the cement-sand-gravel ratios, the water-cement ratio, and every grade from M5 to M40.