Experimental study on mechanical and porous characteristics of limestone affected by high temperature

This paper experimentally studied the changes in mechanical and porous characteristics of limestone heated to high temperature (up to 600 °C). The results showed that ① 200 °C and 500 °C are two special temperature point of limestone under the high temperature effect, and the most mechanical and pore parameters change a lot before and after them; ② Below 200 °C, the mechanical and porous characteristics of limestone samples hardly change; ③ In 200-500 °C, the cumulative pore volume, porosity, and pore volume fractal dimension rapidly increase, among which, the porosity increases by about 900%; the peak strength and elastic modulus suddenly decrease by 31.2%, and the peak strain sharply rises by 65.4%; ④ In 500-600 °C, the porous parameters are relatively stable; the peak strength slowly decreases, while the peak strain continuously increases; the elastic modulus continues to decline quickly, the Poisson's ratio drops suddenly, and the hardness decreases from mid-hard to soft. This research is of significance for the variation of physical and mechanical properties in response to thermal treatment of the rock.