Thermal deformation of loaded concrete during thermal cycles from 20°C to −165°C

Abstract Thermal deformation of concrete samples has been measured. Unloaded water-saturated concrete exhibits a complex strain behaviour during thermal cycles, characterized by dilatation cooling and an irreversible expansion reheating. Loaded water-saturated concrete behaves in a different way. The transition region id reversed -with respect to unloaded samples- and almost dissapears, when compressive stress of 15 MPa is applied. Also an irreversible compressive deformation is bound after reheating. A qualitative explanation of such effects, assuming that microcracking is the dominant deformation mechanism in the transition range, is offered. Further research is needed along this direction.