The general steam curing time is: standing for 4 hours, heating for 3 hours, constant temperature for 24 hours and cooling for 6 hours, totaling 48 hours. If the ambient temperature is lower than 5℃ during construction, steam low-temperature pre-curing is adopted in the static stop stage, and the pre-curing temperature is 5- 10℃. Steam curing can be divided into four stages: static, heating, constant temperature and cooling. During the rest period, the temperature in the shed should be kept at not less than 5 degrees, and the temperature can only be raised after pouring for 4 hours. The heating rate should be controlled within 10℃/ hour, the steam temperature should not exceed 45℃ at constant temperature, the concrete temperature in the beam core should not exceed 60℃, and the cooling rate should be controlled within 10℃/ hour. During steam curing and when thermal insulation facilities are cancelled, the temperature difference between concrete core and surface, surface and environment should not exceed 65438 05 degrees.