Experimental assessment of fracture of individual sand particles at different loading rates

Fracture of individual sand particles under compressive loading at different loading rates was investigated using X-ray imaging. High speed X-ray phase contrast imaging (PCI) was utilized to study the damage mechanisms in dry and wet sand particles under dynamic compressive loading. A modified Kolsky bar setup was used to apply controlled dynamic compression on two contacting sand particles. Pulverization was observed as the sole mode of failure for dry sand particles. Under wet conditions, one of the particles was observed to break into large sub-particles which pulverized upon further loading. 3-D X-ray tomography was used to assess the failure of sand particles under static compressive loading. Breaking into large sub-particles followed by pulverization was observed under static compressive loading. The order of pulverization for the particles was observed to be random in all experiments.