The effect of high temperature on tensile strength of sandstone

• This paper reports the variation of tensile strength with temperature (25–900 °C).
• Relationship between tensile strength and total absorbed energy of disc is studied.
• The results indicate four phases in the variation of tensile strength.
• Tensile strength and longitudinal wave velocity are related in quadratic function.
• Tensile strength is closely related to the effect of thermal stress.

Heating at high temperature will make the tensile strength of sandstone change due to the loss of water and minerals and the effect of thermal stress. In this paper, the sandstone samples are heated from room temperature to 900 °C in a high temperature furnace and then are subjected to Brazilian test with a computer-controlled hydraulic universal testing machine. The longitudinal wave velocity, total energy absorbed per unit thickness of disc and mass loss rate are comprehensively investigated. The results show that the tensile strength changes in the following four phases: from room temperature to 300 °C, 300–600 °C, 600–800 °C and 800–900 °C, among which the tensile strength decreases rapidly in the second (300–600 °C) and fourth phases (800–900 °C) owing to the thermal stress that the most conspicuous effect is the expansion of quartz. The changing trends of tensile strength, longitudinal wave velocity and total energy absorbed per unit thickness of disc along with the temperature are similar.