Water retention properties of perlite as a material with crushable soft particles

The purpose of this study is to present and discuss the experimental results of the water retention properties of an unsaturated material with crushable soft particles. Perlite was used as an artificial material due to its highly crushable behaviour on loading. In this study an approach including crushing and soft behaviour of the particles and its effect on water retention characteristics is specially proposed. The crushing effect of perlite grains is shown by the evolutions of the grain size distribution curves. The usefulness of the Weibull theory for perlite material, in order to predict the grain-size curves after the crushing, is highlighted. Using different experimental techniques on partially saturated perlite, a first insight into the water retention characteristics of the material is presented. The effect of the double porosity on water retention curve of the material is also highlighted. The evolution of the water retention characteristics with crushing is analysed, by using the Aray and Paris model in conjunction with the Weibull distribution predictions. Predicted and experimental results are compared and discussed.