Effect of Micro-Fabric on Consolidation Behavior of Reconstituted Kaolin Clay

The effect of micro-fabric (i.e. geometric arrangement of platelets) on the one-dimensional consolidation behavior of reconstituted kaolin clay is evaluated using a series of controlled-rate-of-strain (CRS) and incremental load (IL) consolidation tests. The causes and implications of changes in micro-fabric are also explored. Micro-fabric has been altered by adding a dispersing agent to the slurry during specimen preparation; and the changes in micro-fabric have been observed with scanning electron microscope (SEM) images and x-ray diffraction analysis. Properties of the pore fluid are found to affect micro-fabric, even in the presence of significant mechanical stresses. It is observed that the changes in micro-fabric significantly affect the compressibility of reconstituted kaolin clay in the normally consolidated zone. Samples with preferred platelet orientation and closer inter-platelet spacing are significantly less compressible than those with randomly oriented platelets. In the over-consolidated zone, the compressibility is not significantly affected by changes in micro-fabric, but the compressibility does depend on the direction in which stress is applied. Samples with preferred platelet orientation show more isotropic nature of consolidation properties than samples with randomly oriented platelets. The values of the virgin compression index (Cc) and swelling index (Cs) are observed to be higher when axial load is applied parallel to the direction of preferred platelet orientation. Anisotropy observed in the normally consolidated zone is mostly due to the elastic portion of the deformation.