Experimental study of mechanical properties of sandstone at high temperature

Abstract

Mechanical properties of rock at high temperature are of importance for structure design and safety assessment in underground rock engineering. Brazilian disc test, axial compressive test and three-point bending test are adopted to determine the tensile strength σ_t, uniaxial compressive strength σ_c, elastic modulus E and Mode I fracture toughness K_IC of sandstone at high temperature. Test results show that all of these values (σ_t, σ_c, E and K_IC) are linearly increased with the increasing temperature below a certain temperature, 200 °C or 250 °C, and decreased above this temperature. The linear equations are σ_t=0.010 9T+2.322, σ_c = 0.181 9T+63.138, E=0.004 9T+10.498 and K_IC =0.003 1T+0.60, respectively. Mineral compositions and microstructures of natural rock material have great influences on its mechanical properities at high temperature. Dominance of drying or microcracking would lead to the improvement or degradation of mechanical properities of rock.

Keywords

tensile strength / compressive strength / elastic modulus / Mode I fracture toughness / high temperature / sandstone

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