In concrete testing, what does compressive strength measure?

Compressive strength is a fundamental property of concrete that measures its ability to resist deformation and failure when subjected to compressive loads. This property is expressed in units of force per unit area, typically pounds per square inch (psi) or megapascals (MPa).

When concrete is placed under pressure, the compressive strength indicates how much load the concrete can withstand without collapsing. This is crucial for structural applications where concrete elements must support loads from above without failing. The higher the compressive strength, the more pressure the concrete can endure, making it suitable for various construction applications.

Other options may relate to important characteristics of concrete but do not accurately describe what compressive strength represents specifically. For instance, tensile forces and the time it takes to set do not pertain to the measurement of compressive strength, nor does density, which is a separate property that influences concrete's overall performance but is not a direct measure of its strength under compression.