Effect of Particle Breakage of Sand Under High Oedometric Stress on its Microstructural Properties Using 3D X-ray Micro-tomography

Particle breakage in a granular material alters its microstructural properties, which changes its properties on the macroscopic and microscopic scale. In the present work, an experimental study has been performed to explore the effect of particle breakage on the microstructural and contact properties of granular materials. Oedometric tests have been performed on carbonate sand with different values of applied stress, followed by X-ray micro-tomography observations. The acquired images are processed to explore the microstructural properties evolution (porosity, specific surface area, and pore size distribution) and contact properties evolution (coordination number and contact surface area) as a function of the applied stress. The results show a decrease in porosity and mean pore size, and a proportional increase in the specific surface area with the applied stress. The contact surface area shows a proportional increase with the applied stress; however, the evolution of the coordination number has shown a strong dependence on other parameters such as the grain size and the particle fragility. The quantitative relationship between void ratio and specific surface area (SSA) is described by an exponential equation. The empirical relationship has been developed from the results of 3D image analysis, which can relate the specific surface area and the void ratio for the micro-to-macro scale or vice versa.