Cured concrete

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Curing is the process of keeping concrete under a specific environmental condition until hydration is relatively complete. Because the cement used in concrete requires time to fully hydrate before it acquires strength and hardness, concrete must be cured once it has been placed.

Good curing is typically considered to use a moist environment which promotes hydration, since increased hydration lowers permeability and increases strength, resulting in a higher quality material. Allowing the concrete surface to dry out excessively can result in tensile stresses, which the still-hydrating interior cannot withstand, causing the concrete to crack. Also, the amount of heat generated by the chemical process of hydration can be problematic for very large placements.

Allowing the concrete to freeze in cold climates before the curing is complete will interrupt the hydration process, reducing the concrete strength and leading to scaling and other damage or failure.

The effects of curing are primarily a function of specimen geometry, the permeability of the concrete, curing length, and curing history.

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