Experimental and Analytical Study on Heat Transfer of Concrete With Different Degrees of Saturation Under Elevated Temperatures

In hygrothermal conditions, structural safety is a major concern because of the occurrence of explosive spalling when concrete structures are exposed to fire. To evaluate the fire damage of concrete accurately, the effect of moisture content and water-to-cement ratio on the thermal conductivity of concrete under elevated temperatures was studied experimentally and analytically in this paper. The experimental results showed that the temperature fields had a significant change among the cases with different water-to-cement ratios while the changes between dried and saturated cases were marginal. The temperature changes of dried samples were slightly swifter than those of saturated one. It indicates that compared with mixture proportions, concrete saturation degree has an insignificant influence on concrete heat transfer in the procedure of fire exposure. Based on the test and analytical results, an analytical model for heat transfer analysis of fire-damaged concrete under hot and humid environments was proposed and showed good agreement with the test results.