Evolution of mechanical properties and microstructure in thermally treated granite subjected to cyclic loading

• Published in: Fatigue & fracture of engineering materials & structures Vol. 47; no. 4; pp. 1431 - 1444
• Main Authors: Fan, L. F., Wang, Z., Qiu, B., Wang, M.
• Format: Journal Article
• Language: English
• Published: Oxford Wiley Subscription Services, Inc 01.04.2024
• Subjects: cyclic loading; Cyclic loads; Earthquake damage; Evolution; fatigue characteristics; Fractal geometry; Fractals; Granite; Heat treatment; high temperature; Materials fatigue; Mechanical properties; Microstructure; microstructure evolution; Modulus of elasticity; NMR; Nuclear magnetic resonance; Pore size distribution; Porosity; Strain
• ISSN: 8756-758X; 1460-2695
• DOI: 10.1111/ffe.14255

In high‐temperature geological engineering applications, cyclic loads induced by various factors (e.g., earthquakes, excavation, and blasting) can exacerbate the thermal damage of engineered rock formations. Therefore, this study investigates the mechanical properties and microstructure evolution of thermally treated granite subjected to cyclic loading. First, the mechanical property variations of thermally treated granite under cyclic loading were studied through cyclic loading experiments. Subsequently, nuclear magnetic resonance (NMR) was employed to examine the microstructure evolution of thermally treated granite under cyclic loading. Lastly, the effects of cyclic loading on maximum strain, Young's modulus, pore size distribution, and porosity of thermally treated granite were discussed. Results indicate that at the same number of cycles, maximum strain increases with increasing temperature, while Young's modulus decreases. For granite subjected to the same thermal treatment, the maximum strain increases as the cyclic number increases, while Young's modulus decreases. Concurrently, porosity and fractal dimension initially decrease and then increase with a rising number of cycles. Highlights Fatigue properties of thermal‐treated granite were studied under cyclic load. Deterioration of mechanical behavior increased as temperature increased. The effect of cycles on porosity and pore distribution of granite was studied. Porosity and fractal dimension decreased and then increased as cycles increased.