Changes in thermal characteristics of granites due to cyclic high-temperature treatment.

• Temperature treatment cause obvious decrease in the P-wave velocity, density, thermal conductivity, and thermal diffusivity of the granite specimens. • Degradation of granite thermal properties is caused by thermal microcracks. • There is an obvious correlation between physical properties and the thermal conductivity or thermal diffusivity of the granite specimens, while the volumetric specific heat capacity of the specimens is opposite. In this work, thermal properties (thermal conductivity (k), thermal diffusivity (λ) and volumetric specific heat capacity (C)) tests and physical properties (P-wave velocity (V P) and density (ρ)) tests were performed to assess the impact of cyclic thermal treatment on the thermal characteristics of granite. The key findings are as follows: (1) the k, λ, V P and ρ all deteriorate due to cyclic thermal treatment. Cyclic thermal treatment has a negligible effect on the C of granite, and there is no obvious relationship between cycles and C. (2) There is a good fitting relationship between the k or λ and the physical properties, which indicate physical attributes can be utilized to assess the thermal properties of granite. (3) The loss of various water, as well as the initiation and propagation of microcracks, are responsible for the deterioration of physical and thermal characteristics. [ABSTRACT FROM AUTHOR]