Study on Microstructure of Concrete Cooling With Different Methods After High Temperature

摘要

The concrete on high temperature is cooled by water and air to simulate water spraying in structure fire extinguishments and cooling naturally after fire. The microstructure of the samples cooling in air and water are studied with SEM. It is found that when the heating temperature is lower than 300 ℃, the difference of microstructure between air and water cooling sample is not distinct. But when the heating temperature is higher than 300 ℃, the hydrate is destroyed on high temperature, so the microstructure of air-cooling sample is destroyed. Because the second-hydrate action, there are new hydrate crystal in the water-cooling concrete. Higher the heated temperature is, more severe the structure of concrete destroyed, and there are more new hydrate crystals in the water-cooling concrete.