DEM investigation on the size effect in the fragmentation of intact aggregates

Abstract

In this work, the size effect in the fragmentation strength of cylindrical alumina aggregate under quasi-static diametrical loading is investigated by performing Discrete Element Method (DEM) simulations. It is found that tensile stress concentration develops in the inner margin of the damage zone, ultimately leading to the emergence and propagation of diametrical crack and thus the catastrophic splitting of the compressed aggregate. Both the fragmentation strength and the dimensionless damage zone size (normalized by aggregate diameter) decrease to limit values, and the latter is around 0.1. It is found that the obtained limit value of fragmentation strength is approximately equal to the tensile fracture strength of the corresponding rectangular sample having two equal-length side cracks with length being 0.1 times the sample width. The DEM simulations thus suggest that the formation of damage zones adjacent to the loading points would induce the size effect in the fragmentation of intact aggregate.