1. In order to ensure that the newly poured concrete has suitable hardening conditions and prevent cracks caused by early drying shrinkage, after mass concrete is poured, it should be covered and watered within 12 hours. For concrete with impermeability requirements, the curing time of concrete mixed with ordinary portland cement shall not be less than 14 days; The curing time of concrete mixed with slag cement and pozzolanic cement shall not be less than 12 days. 2. The concept of mass concrete: Mass concrete refers to the concrete structure with the smallest cross-sectional size greater than 1m, and corresponding technical measures must be taken during construction to properly handle the temperature difference between the inside and outside of concrete caused by hydration heat, reasonably solve the temperature stress and control the development of cracks. 3. Its construction features are: high integrity requirements and continuous casting; The structure has a large volume, and a large temperature difference and temperature stress are formed after pouring concrete. Mass concrete engineering has the characteristics of thick structure, large volume, dense steel bars, much concrete, complex construction conditions and high technical requirements, which must meet the requirements of strength, stiffness, integrity and durability at the same time. In addition, there are problems such as how to control and prevent temperature stress and deformation cracks. With the continuous improvement of mass concrete construction technology, high-quality construction technology has become an inevitable requirement of social development. With the continuous improvement of production technology and productivity and the gradual expansion of construction field, mass concrete is gradually applied to large reinforced concrete structures. 4. Covering curing is the most commonly used method of heat preservation and moisture retention. The main measures are: after the initial setting, start covering and curing, and after the final setting (12 hours), start watering, such as covering, straw, rotten straw mats, bamboo curtains, sacks, woven cloth, etc. Watering tools can be water pipes, buckets and other tools to ensure the wettability of concrete. After pouring is completed, curing shall be carried out within 12h. Before the strength of concrete reaches C 12, it is forbidden for anyone to walk on it, install formwork supports, and do not impact or split on it.