Concrete is considered to have set after reaching what compressive strength?

Concrete is typically considered to have set and achieved sufficient compressive strength to support loads after reaching approximately 500 psi (pounds per square inch). At this strength, the concrete has undergone initial hydration and chemical reactions, allowing it to harden to a degree that it can effectively bear weight and resist deformation under load.

This level of compressive strength is particularly important because it indicates that the concrete has transitioned from its plastic (workable) state to a solid form, enabling it to be used in construction applications. While concrete continues to gain strength over time, often reaching much higher values in standard curing conditions, the initial setting at 500 psi marks an essential milestone in its curing process, signifying it is ready for further construction processes.