The curing of concrete in wet environment or water with temperature of 20 3℃ and relative humidity greater than 90% is called standard curing.
In order to accelerate the hardening process of concrete, concrete is cured by heating at a higher temperature, which is called thermal curing. The common thermal curing method is steam curing.
At normal temperature (the average temperature is not lower than +5℃), concrete curing is called natural curing, which covers concrete with appropriate materials and adopts measures such as watering and wetting, windproof and drying, heat preservation and anti-freezing. Natural curing can be divided into sprinkler curing and spray film curing liquid curing. The natural curing of concrete shall meet the following requirements.
(1) After concrete pouring, it shall be covered with heat preservation curing within 12h, and it is forbidden to water when the average temperature of that day is lower than +5℃;
(2) Water curing time of concrete: concrete mixed with portland cement, ordinary portland cement or slag portland cement shall not be less than 7d; Concrete mixed with retarding admixture or with impermeability requirements shall not be less than14d; When other types of cement are used, the curing time of concrete should be determined according to the technical performance of the cement used;
(3) The watering times should keep the concrete moist. Concrete curing water should be the same as mixing water;
(4) When plastic sheets are used for covering and curing, all exposed surfaces of concrete should be covered tightly, and condensed water should be left in the plastic sheets;
(5) The concrete strength reaches 1.2N/mm? Before, don't step on it or install templates and brackets.