Effect of Thermal Shocks on Physico-mechanical Characteristics of Volcanic Rocks

The authors collected some samples of tuff and welded tuff from Asuwayama region in Fukui Prefecture, Oya Region in Tochigi Prefecture of Japan and from Derinkuyu in Cappadocia Region of Turkey. Thermal shock was applied up to 6 hours and cool down under room temperature. The selected temperatures were 250, 500 and 800 Celsius. The geometries and physical and mechanical properties of samples were measured before and after thermal shocks. X-CT tomography technique is used to investigate internal damage due to thermal shocks in rock samples. Physical measurements involve density, p-wave and s-wave velocities while mechanical tests involve strain-stress responses under Brazilian and uniaxial compression tests. From these tests, tensile and compressive strength were determined under four different thermal regimes. These tests also allow us to determine triaxial yield characteristics as well as deformation properties under both elastic and non-elastic regimes at different selected temperature amplitudes. The authors report the outcomes of these experimental tests and discuss their implications.