The poured concrete is exposed to the air, and the water can not be replenished after evaporation, so the concrete will lose water and dry, which will affect the normal hydration of cement and even stop hydration. As long as the relative humidity is lower than 100%, concrete will start to dry.

Therefore, in order to make the concrete harden normally, there must be enough humidity for curing within a certain period of time after molding. The Code for Quality Acceptance of Concrete Structure Engineering requires that the concrete should be covered with moisture curing within 12h after the completion of concrete pouring.

Matters needing attention in concrete curing

(1) concrete curing should pay attention to both humidity and temperature. Principle: the humidity should be sufficient and the temperature should be appropriate;

(2) The concrete shall be cured immediately after pouring;

(3) The curing time of concrete made of portland cement, ordinary portland cement or slag portland cement should not be less than 7d; When other types of cement are used, the curing time should be determined according to the cement performance;

(4) The curing time of concrete prepared with retarded admixture and large mineral admixture should not be less than14d; ;

(5) The curing time of impervious concrete and concrete with strength grade of C60 and above shall not be less than14d; ;

(6) The curing time of shrinkage compensating concrete such as post-cast strip should not be less than 14d.