Engineering technical knowledge: Why does concrete have natural curing and steam curing?

Natural curing refers to the curing of concrete under natural conditions (temperature not lower than +5℃ and humidity 90 ~ 100%). As mentioned above, at the natural curing temperature, the strength increases very slowly, and only 30~70% of the concrete strength after 28 days can be obtained at the age of 7 days. It takes a long time to ensure the strength of formwork removal and factory strength. This will prolong the cycle time of the whole production process, at the same time, it needs a lot of template equipment and occupies a lot of production area, increasing capital investment. In order to accelerate the growth of concrete strength, steam curing can be adopted, and the concrete can be heated by steam, so that the concrete can be quickly hardened under the conditions of high temperature (70~90℃) and high humidity (about 90% or more). However, it is still suitable for nature conservation in areas with brighter and warmer climate. This can save fuel and a corresponding set of equipment investment, and reduce costs.