Aggregate's influence on thermophysical concrete properties at elevated temperature

This study investigates the thermophysical properties evolution of concretes made of three types of aggregates (quartzite, flint and limestone) during and after heating. For each aggregate type, two paste matrices (W/C = 0.3 and 0.6) were tested. The thermal conductivity and the specific heat are measured by a hot disk device. The evolutions of thermal properties are related to the mineral composition of aggregates but also to the microstructural evolution of concretes during heating. Evolutions of porosity, mass loss and cracking are investigated for the different concretes. The influence of aggregate's nature is then discussed regarding the thermal response of heated concrete cylinders. (C) 2015 Elsevier Ltd. All rights reserved.