Concrete curing is to artificially create certain humidity and temperature conditions, so that the newly poured concrete can be normal or accelerate its hardening and strength growth. The gradual hardening and strength increase of concrete is the result of cement hydration, which requires certain temperature and humidity conditions. If this situation does not exist in the surrounding environment, it is necessary to maintain the concrete manually.

Steam curing of concrete can be divided into four stages: static, heating, constant temperature and cooling. Steam curing of concrete shall meet the following requirements respectively:

(1) During the static stop, the ambient temperature should be kept not lower than 5℃, and the temperature of concrete can only be raised after the pouring is completed for 4 ~ 6h.

(2) The heating rate should not be greater than 65438 00℃/h. ..

(3) At constant temperature, the internal temperature of concrete should not exceed 60℃, and the maximum temperature should not exceed 65℃. Constant temperature curing time should be determined by experiments according to the demoulding strength requirements of components, concrete mixture ratio and environmental conditions.

(4) The cooling rate should not be greater than 65438 00℃/h. ..

Box beam steam method

After concrete pouring, the beam body is sealed with a curing cover, and steam is input to control the humidity and temperature around the beam body.

When the temperature is low, input steam to raise the temperature, and after the initial setting of concrete, the bridge deck and the box are stored with water to keep moisture. The heating rate shall not exceed10℃/h; The constant temperature shall not exceed 45℃, the concrete core temperature shall not exceed 60℃, and the individual maximum temperature shall not exceed 65℃. When cooling, the cooling speed shall not exceed10℃/h; When the temperature decreases to a point where the difference between the beam temperature and the ambient temperature does not exceed 15℃, remove the curing cover. The cooling of box girder cavity is slow, so ventilation measures can be taken appropriately. The temperature of all parts in the hood is consistent, and the temperature difference is not more than 65438 00℃.

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