Curing of Concrete

Cement hydration occurs in the water-filled capillary pores of cement paste.

Environmental factors like air temperature, humidity, and wind can cause evaporation, removing water from the surface of newly placed concrete.

Alternatively, if the concrete is sealed and its water-cement ratio is less than 0.5, the internal drying results in a loss of free water.

Curing prevents water loss from concrete by saturating the concrete to maintain adequate levels of moisture and temperature required to continue the hydration process. 

After the cement attains its final set, curing is commenced and continues until the capillaries in the hydrated cement paste get segmented due to filling up with hydration products, making the concrete impermeable and durable.

If concrete is left to dry in the air without curing, it is prone to shrinkage, leading to the formation of surface cracks. Moreover, it achieves only about 50 percent of the compressive strength of concrete that has been moist-cured continuously.

Lastly, the higher the duration of curing, the higher the compressive strength of the concrete.