Breakage behaviour of sand particles in point-load compression

Single-particle uniaxial compression tests are generally conducted for sands by compressing a grain between two flat platens. However, previous work has shown that due to the complex morphology of natural sands the nature of their contacts with the loading platens can influence their strength. A custom-built apparatus was therefore built to apply point loading to sand particles. Using a high-speed camera, typical failure modes were observed, which showed less variability than those seen in platen-mounted tests with most undergoing some form of splitting. The particle strength under point loading also tended to be lower than for platen loading, and again with less variability. If the point-loading tests were compared with platen-loading tests for a similar splitting breakage mode, then the strength distributions were very similar. A possible explanation is that the platen-loading tests that underwent a splitting failure were the more angular particles, and so the effect of stress concentration might be similar to that for the point-loading tests