Distribution density functions of cementitious fragments formed during mechanical comminution

Abstract

The present paper reports the comminution of cementitious composites in a laboratory jaw breaker. Two samples of cement paste, one mortar sample, and samples of five different concrete mixtures were investigated. Water/cement ratio and maximum aggregate size were varied. Based on the sieve analysis, the densities of the fragment distributions were estimated and discussed. All fragment samples followed a logarithmic normal distribution. Ordinary concrete materials and cement paste samples showed bimodal distribution density functions, whereas mortar and lightweight concrete could be characterised by unimodal distribution density functions. The modal values were of comparative order for all materials, but the type of the distribution density function depended upon material structure. A preliminary explanation for the different responses of the materials is given based on SEM images of the fragments.