Concrete curing generally starts from 12 ~ 18h after pouring. The curing time depends on the local temperature, the importance of cement variety and structure. If ordinary cement or portland cement is mixed in concrete, its curing time shall not be less than14d; ; The curing time of concrete mixed with dam cement, pozzolanic silicate cement and slag cement shall not be less than 21d; ; The curing time of important parts and late strength concrete shall not be less than 28d. Winter and summer construction of concrete, curing time according to the design requirements. Heat preservation measures should be taken in winter to reduce the number of sprinklers. When the temperature is lower than 5℃, sprinkler maintenance should be stopped.