The wet and hot curing system of reinforced concrete can make the hardening process and shrinkage deformation complete, so that the strength of autoclaved aerated concrete block products will not increase in the future, and the shrinkage deformation is not large.
At the same time, aerated concrete hardening in the gradient conditions between layers, as a rule, will produce micro defects in the structure, this kind of micro defects on the compressive strength of hardened concrete has little impact, but greatly reduce the frost resistance and crack resistance when products are used.
In the cooling stage of aerated concrete block products, the surface temperature and moisture content of concrete begin to decrease.The use of aerated concrete equipment in autoclaved curing, aerated concrete pores and capillary pores in the water is overheating, the entire volume of products in the boiling of water, water evaporation up to 7%-8%.The steam flow generated by evaporation will move along the pores and capillary pores of the porous structure under the action of internal and external pressure difference of concrete.
If the strength of the cementing material is not enough, it will damage the structure and generate cracks.
Therefore, the control of steam exhaust velocity in autoclave is an important condition to ensure the production of defective-free concrete structure.When the steam pressure drops to the natural atmospheric pressure, the cooling of the product becomes stable due to convective heat exchange with the medium and partial water continues to evaporate.This process is the same as the cooling process of the product in the atmospheric curing chamber.