Structural Evaluation and Performance of Portland Cement Concretes After Exposure to High Temperatures

We evaluated the "residual" thermal conductivity of Portland cement concretes (with characteristic compressive strength at 28 days, f ck, of 20 MPa and 50 MPa) at room temperature after heat-treating at 180 °C, 300 °C and 600 °C. The description of the geometry of the structure was carried out using mercury intrusion porosimetry and nitrogen sorption. The results showed a decreasing tendency of residual thermal conductivity, which we attributed to heat-induced concrete degradation. Furthermore, the results from mercury intrusion porosimetry and nitrogen sorption tests showed that a coarser pore structure is produced with the raise of heat-treatment temperatures