Microscopic characteristics and thermodynamic property changes in limestone under high-temperature treatment.

• 500 °C serves as the threshold for altering the spatial arrangement of limestone. • 500 °C accelerates thermal motion, leading to stratification of rock walls. • Following heat treatment, the microscopic structure displays a 'thousand-layer' pattern. • The thermal conductivity and heat storage coefficient decrease by about 3 % per 100 °C. This article combines X-ray diffraction (XRD) analysis of limestone after high-temperature treatment with microscopic structural characteristics. It aims to elucidate the changes in diffraction peak characteristics from a microscopic perspective and investigate the thermodynamic property variations of the material. The research findings indicate that 500 °C is the threshold temperature at which limestone's crystalline orientation and spatial arrangement change, resulting in a decrease in peak height in the diffraction pattern. Additionally, temperatures ranging from 500 to 600 °C accelerate particle thermal motion, leading to the detachment of rock layers, the inward extension of fissures, and the formation of a sedimentary rock-like 'layered' stacking structure. The thermal conductivity, specific heat capacity, and heat storage coefficient of limestone gradually decrease after thermal treatment, with a reduction rate of approximately 3 % per 100 °C. The microstructural characteristics and thermodynamic property changes of high-temperature limestone reveal the impact of high-temperature damage on limestone structure and thermodynamic properties, facilitating the advancement of limestone material applications and damage control under high-temperature conditions. [ABSTRACT FROM AUTHOR]