W/C Ratio (Water-Cement Ratio)
The ratio of the weight of water to the weight of cement in a concrete mix. The single most important factor controlling strength and durability.
Lower w/c = higher strength, lower permeability. Typical structural concrete: 0.40-0.55. Adding water at site permanently reduces strength.\n\nIS 456 prescribes maximum w/c by exposure class (e.g., 0.45 for severe exposure RCC).
The maximum compressive load a hardened concrete cube or cylinder can withstand before failure. The defining property of structural concrete.
The ability of concrete to allow fluids or gases to pass through it. Lower permeability = better durability against chloride, sulfate, and freeze-thaw attack.
The process of selecting cement, water, aggregates, and admixtures in correct proportions to produce concrete that meets strength, workability, and durability requirements.
A water-reducing admixture that improves workability without adding water, or reduces water demand by 5-12% for the same workability.