Drying of a model soil

Pamela Françoise Faure (1) , Philippe Coussot (1)

1 navier umr 8205 - Laboratoire Navier

Drying experiments have been carried out with model soils made of different pastes filling granular packings. A detailed information concerning the time evolution of the water density distribution inside the sample was obtained from MRI measurements. This study makes it possible to understand the physical origin of the drying characteristics of these materials. The drying curves exhibit a CRP (constant-rate period) and a FRP (falling-rate period) but the relative durations of these periods depend on the paste structure. With a kaolin suspension the CRP lasts down to very low water densities and is associated with a homogeneous drying of the paste throughout the sample. With a bentonite suspension the CRP is shorter and the drying in the FRP results from a complex process involving fractures progressing downwards through the pasty matrix. With a gel the CRP period is even shorter and the drying in the FRP results from the progression of a dry front through the packing as a result of the shrinkage of the gel matrix. This provides an overview of the main possible processes at work when drying a soil as a function of its components, along with some practical means for slowing down drying from soils.

Domaines: Science des matériaux [cond-mat.mtrl-sci]

Pamela Françoise Faure, Philippe Coussot. Drying of a model soil. Physical Review E : Statistical, Nonlinear, and Soft Matter Physics, 2010, 82 (3), pp.036303. ⟨10.1103/PhysRevE.82.036303⟩. ⟨hal-00541797⟩