Effect of heating rate on the free expansion deformation of concrete during the heating process

Concrete will expand after being heated at high temperature, and the thermal stress generated will cause cracks inside the concrete, which seriously endangers the safety of concrete. The influence of heating rate on the free expansion deformation of concrete during heating process was studied. Three heating rates were used to conduct high-temperature deformation test. The concrete specimens were heated from room temperature to the target temperature. The temperature in the furnace was maintained at the target temperature until the temperature in the center of the concrete specimen also reached the target temperature. The influences of heating rate on the linear expansion rate (LER) and thermal expansion coefficient (TEC) of concrete at different temperatures were analyzed. The results showed that in the range of 100-800 degrees C, the LER of concrete increased gradually with the increase of temperature, and the maximum value reached 1.336%. In the range of 100-400 degrees C, the deformation of concrete was slightly affected by the heating rate. In the range of 500-800 degrees C, the greater the heating rate, the greater the LER and TEC of concrete.

Automated summary

The study found that concrete will expand and generate thermal stress when heated at high temperatures, leading to cracks that endanger the safety of the concrete. The linear expansion rate of concrete gradually increases with temperature in the range of 100-800 degrees Celsius, reaching a maximum value of 1.336%. The heating rate has a significant impact on the expansion of concrete at temperatures of 500-800 degrees Celsius.