Compressive strength is a fundamental property of concrete that measures its ability to withstand loads that tend to reduce size. It is directly related to the hardness and density of the cementitious matrix and the aggregate used in the concrete mix. This strength is primarily provided by the hydration of cement particles, which forms calcium silicate hydrate (C-S-H) bonds, the main source of strength in concrete. The design of the concrete mix, including the water-to-cement ratio, type of cement, and aggregate selection, critically influences the development of compressive strength.