Short-term effects on physical properties of lime treated kaolin

In the paper an experimental multi-scale investigation on the influence of pore water chemistry on the short-term behaviour of lime treated soil is presented. Sedimentation tests on kaolin suspensions under different chemical environment have been performed and interpreted, taking into account the effects of clay particles interactions on the soil skeleton formation. The experimental evidences at volume scale of the samples have been directly related to the results of micro-scale investigations. Modification of surface charge and its influence on soil fabric has been investigated by means of zeta-potential measurements, Dynamic Light Scattering (DLS) and Scanning Electron Microscopy (SEM). The effects of lime content, cation valence and source of calcium ions on the surface charge of kaolin particles have been considered. The addition of lime increased the average size of particles aggregates in the short term. The fabric evolution affected the formation of the soil skeleton during sedimentation, influencing its void ratio and compressibility, highlighting the link between microstructural features and mechanical behaviour of lime treated samples.