Compressive Strength
The maximum compressive load a hardened concrete cube or cylinder can withstand before failure. The defining property of structural concrete.
Reported in MPa (N/mm²) at 28 days. Standard test uses 150 mm cubes per IS 516. Acceptance criteria are defined in IS 456 Clause 16.\n\nGrades like M25, M30, M40 indicate the characteristic 28-day cube strength.
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.
The standard compressive strength test for concrete. 150 mm cubes are cured in water at 27±2°C and crushed at 7 and 28 days.
The statistical criteria in IS 456 Clause 16 for accepting concrete based on cube test results — both individual and group means.