Transient heating effect on high strength concrete

This study shows some differences in the properties and the behaviour at high temperature of two concretes (ordinary and high strength) made with the same calcareous aggregates. During heating tests at 1 C min-1, cylindrical samples of diameter 160 x 320 mm of high strength concrete, more dense, may explode in a critical temperature zone between 250 and 300 C. Differences in behaviour between OC and HSC appeared at high temperatures: there were disparities especially in thermo-hydric transfer, porosity and thermal stability. The dense microstructure of high strength concrete was found to slow up the escape of vaporized water. (orig.)