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

Abstract

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.

Keywords

• concrete
• mercury intrusion porosimetry
• nitrogen sorption
• residual thermal conductivity