Effect of thermal damage on mechanical behavior of a fine-grained sandstone

Due to difference in mineral composition, cementation, and porosity, the strength behavior of sandstone after exposure to different high temperatures is complex. From literature review, it is found that a transition temperature in the treatment exists at which the strength of sandstone changes from slow increase or decrease to fast decrease. This paper studies the effect of high temperature treatment on mechanical behavior of a fine-grained sandstone with a focus on discussion of the controlling factor that affects the various strength behavior of sandstone in response to thermal loading. The results in this study show that the transition temperature is about 500 °C for the examined sandstone. When the treatment temperature is below 500 °C, the Brazilian tensile strength (BTS), uniaxial compressive strength (UCS), and elastic modulus increase with increasing temperature in the treatment. However, when the treatment temperature exceeds 500 °C, the three parameters are found to decrease with a further increase in the treatment temperature. The relation between brittleness and treatment temperature is also examined. The brittleness indices B 3 and B 4 are found to be more effective than B 1 and B 2 to assess the brittleness of thermally damaged rock. The results in this study are useful for better understanding the mechanism of thermal damage effect on strength behavior of sandstone.