The oedometric compression behavior of expanded clay including the crushability of single particles

Abstract

The objective of this paper is to study the expanded clay material behaviour considering the crushability of its single grains. The probed material is characterized by a high internal porosity; randomly distributed inside its grains. The assembly behaviour was investigated considering the oedometric path and the fragmentation amount was quantified using the relative breakage coefficient (Br). Oedometric compression tests were performed on different loose samples with similar grain size distribution. In this paper, single grain indirect tensile tests were made to identify the microscopic parameters affecting the breakage occurring. The density effect was studied using a statistical approach and the calibration was made based on the indirect tensile tests results performed on individual grains. Authors further developed a crushing algorithm based on the experimental tests results performed on several dimensions ranges of single grains. The algorithm was implemented in the PFC3D software aiming to model the material’s macroscopic behaviour using discrete elements modelling (DEM). The analysis of the macroscopic response of a loose grain’s assembly was conducted using both the stress–displacement responses and the breakage factor. The comparison between experimental and numerical simulations shows the DEM’s potential, coupled with the fragmentation algorithm of the individual grains issued from the experimental single grains study, to reproduce the assembly’s mechanical behaviour. However, basing on the breakage factor Br, the DEM simulations performed herein are not in a good agreement with experimental ones; which will be discussed in this work.