The effect of particle size distribution on packing density

Abstract The packing density of a multi‐particle system is found to increase if the particle size distribution is extended. Results are reported for Gaussian and log‐normal size distributions using dense random packing of two sands with particle sizes of front <0.07 to 8.0 mm. Packing density is shown to be a function only of size distribution represented by a dimensionless standard deviation, and of particle shape. It is independent of particle size. Packing densities of binary mixtures of continuously distributed systems are found to depend upon the composition of the mixture, the mean‐size ratio of the components of the binary, and upon the packing density of the individual components. Maxima occur at compositions of 55 to 75% larger component, and increasing mean‐size ratios result in greater packing densities. The “increase in packing density” factor is a useful function for comparing, and setting limits to, packing densities of binary mixtures. The results should allow improved prediction and control of packing densities of many commonly encountered particle systems.