Effect of particle size heterogeneity on fracture toughness and failure mechanism of rocks

Fracture toughness is a key parameter for studying of crack propagation and fragmentation processes in rock structures. It is a comparatively general phenomenon that rocks possess particle size heterogeneity. In the present study, an experimental investigation was made to evaluate the effect of grain size on failure mechanism and fracture toughness of rock and rock-like samples. For this purpose, some Single-Edge Cracked Brazilian Disks (SECBD) Granite specimen and Central Straight-through Crack Brazilian Disk (CSCBD) rock-like specimens were prepared. Diametrical compression load with a rate of 0.3 mm/min was applied to the disks and AE sensors were used to monitor the fracturing process of the specimens. Result of laboratory tests indicates that particle size heterogeneity influence on the number of induced fractures, so that under loading sequences, more fractures were induced in the coarse grain specimens compared to the fine grain ones. (C) 2015 Elsevier Ltd. All rights reserved.