The effect of heating/cooling cycles on chrominance, wave velocity, thermal conductivity and tensile strength of diorite

To quantify the damages caused by thermal cycles, the chromaticity, P wave velocity, thermal conductivity and tensile strength were measured on diorite samples subjected to different heating/cooling cycles at different temperatures. The mechanism is analyzed based on dehydration, tensile stress and phase changes of the quartz mineral. It is found that the damage due to the heating/cooling cycle at 100 °C is mainly caused by the loss of the attached water in the diorite. Damage due to thermal cycles at 300–500 °C is mainly caused by the loss of the combined water and the development of tensile stress in the sample due to a high-temperature gradient between the surface and the interior of the sample. At 700 °C, the damage of diorite due to heating/cooling cycles is mainly caused by the development of new cracks due to phase changes in the quartz and tensile stress increase in the rock.