Evolution of Particle Shape Produced by Sand Breakage

This paper presents the results of a study on the evolution of particle shape in carbonate sands that underwent different degrees of particle breakage. Carbonate sand specimens with three different initial particle sizes were subjected to impact loadings with different input energies. The particle sizes and shapes of the tested sands were analyzed by dynamic image analysis both before and after each loading. An increase in the input energy resulted in increases in particle breakage, aspect ratio, sphericity, and roundness to steady-state values, whereas convexity was barely influenced in the tests. It was found that the Weibull distribution could be used to describe the cumulative distributions of the particle-shape parameters. A relative shape-variation index for quantitatively describing the change in particle shape was correlated with the relative breakage index, which quantitatively describes the extent of particle breakage. Based on microscopic images of the particles at different loading states, the dominant particle-breakage mode gradually transited from the initial fracture mode to the attrition and abrasion mode with an increase in input energy, leading to the production of much more rounded and spherical particles. (c) 2022 American Society of Civil Engineers.