On the Physical and Mechanical Responses of Egyptian Granodiorite after High-Temperature Treatments

Abstract

In the design and stability of thermal engineering applications, a thorough understanding of the evolution of damage in the rock following high-temperature treatments is crucial. Hence, this study investigates the influence of high temperatures on Egyptian granodiorite rock properties, given its widespread use as ornamental stones and aggregate material for roadways. Temperature effects up to 800 °C on its physical and mechanical responses were examined in conjunction with microstructure alterations. The results show that the density of granodiorite decreases after heat exposure due to a gain in volume and a loss in mass, with volume expansion being the most important component. In addition, the uniaxial compressive strength increases up to 400 °C before reducing linearly as the temperature increases, while the elastic modulus and P-wave velocity show a reducing trend with the temperature. This study suggests that granodiorite has a thermal damage threshold of 400 °C, beyond which its microstructure and physical and mechanical characteristics deteriorate, and granodiorite becomes less brittle and more ductile. Hence, at the mutation range (between 400 and 600 °C), the physical and mechanical responses shift from a stable to an unstable state. As a result, the microstructure of the granodiorite samples was destroyed at 800 °C, resulting in a significant drop in compressive strength and dilemmas in measuring the P-wave and elastic modulus. Accordingly, the findings of this study can be used to aid in the safe handling of this rock in high-temperature conditions.

Thermal-Induced Microstructure Deterioration of Egyptian Granodiorite and Associated Physico-Mechanical Responses

“…In addition, the leading cause of the rocks’ uniaxial compressive strength reduction was the worsening of rock microstructures and the growth of microcracks [ 20 , 21 ]. The volume and porosity of granite [ 22 , 23 , 24 ], granodiorite [ 25 , 26 ], marble [ 27 ], sandstone [ 28 , 29 ], limestone [ 30 , 31 ], and claystone [ 32 ] revealed increases with growing temperature, while density and wave velocity dropped. These changes in physical characteristics are fundamentally attached to the deterioration of the rock microstructure.…”

Application of Machine Learning and Multivariate Statistics to Predict Uniaxial Compressive Strength and Static Young’s Modulus Using Physical Properties under Different Thermal Conditions

“…In recent years, investigations into and understandings of reservoir rock behaviour under differing high temperatures (T) have become imperative for the safe implementation of engineering projects [1][2][3][4][5][6][7][8]. The behaviour of rock under high temperatures is a major concern in geological sciences, underground engineering, geothermal energy exploitation, deep mining, nuclear waste disposal, engineering structures, and coal gasification.…”