In this paper, the physical characteristics of concretes containing three types of aggregates were examined under high temperatures. A thermal analyzer measured the thermal conductivity of the concrete samples using the transient plane source (TPS) method. Results showed that the thermal conductivity of well-crystallized concretes had a stronger inverse relationship with temperature than the poorly-crystallized samples did. As well, high-performance concretes retained their thermally conductive properties better than normal concretes....