The compressive strength

Strength is defined as the ability of a material to resist stress without failure. In the case of concrete, its compressive strength is the most important when thinking about structural design. Tests on compressive strength can be classified into destructive and non-destructive. In a destructive test, cylindrical samples are cast in-situ and tested to failure to get the results. In non-destructive mode, a rebound hammer is used to estimate the potential strength of the concrete.

Good quality concrete in its hardened state should achieve the specified strength required to carry loading and be durable enough to resist deterioration. Appropriate testing methods are thus conducted in a laboratory or on-site to verify the quality of concrete with that of immediate interest complies with the specifications in accordance with AS 1012.9:2014.

The compressive strength (σ) of a sample shall be calculated as follows :

σ = F/A in MPa

F = maximum applied force indicated by the testing machine, in N

A = the area the force is applied, in mm²

Figure: Dimensions of a cylindrical sample