Compressive behavior of high viscosity granular systems: Effect of particle size distribution

Abstract Granular compressive behavior has been evaluated with respect to particle size distribution. All granules were prepared with a polydimethylsiloxane (PDMS) binder with viscosity ranging from 12 to 2413 Pa·s. All granules were prepared with 90% particulates and 10% binder by mass. Granules were prepared using two unimodal particle size distributions (420–595 μm silica and 105–420 μm silica) and two bimodal particle size distributions. The bimodal size distributions were comprised of 420–595 μm silica and 0–63 μm silica in 75%/25% and 50%/50% mass fractions, where the first percentage refers to the amount of 420–595 μm silica particles included. The granules were compressed with 1, 10, and 100 mm/s velocities. The granules prepared with 420–595 μm silica particles were found to exhibit greater granular strength than those prepared with 105–420 μm particles. These results are uniquely different from those of previous studies which indicate that a smaller size fraction of particles will result in a stronger granule. The addition of a secondary particle size distribution in conjunction with the 420–595 μm silica particles results in a granule with significantly increased strength over the granule prepared with a unimodal distribution. It is suggested that the bimodal size distribution allows an increased number of interparticle contacts per unit volume to increase the granular strength.