Concrete grades indicate the compressive strength of concrete, typically measured in megapascals (MPa) or newtons per square millimetre (N/mm²) at 28 days. Common grades include:
- C20/25 to C30/37: General-purpose concrete for foundations, floors, and non-structural applications
- C32/40 to C40/50: Structural concrete for beams, columns, and suspended slabs
- C50/60 and above: High-strength concrete for specialised applications, tall buildings, and prestressed structures
The designation “C30/37” indicates a characteristic cylinder strength of 30 MPa and a characteristic cube strength of 37 MPa. Selection depends on structural requirements, durability considerations, and exposure conditions.
