Microstructural interpretation of compression behaviour of Kaolin clay

Clay is a very complex material. There is a conceptual lack in the understanding of clay behaviour from a microstructural standpoint. For example, fundamental features of compression behaviour, i.e. plastic and elastic response, are explained from a microstructural standpoint by either referring to granular ‘interactions’, which are evidently not appropriate for clay, or to electro-chemical interactions borrowed from colloidal theories, again not representative of clay behaviour. Hence, in practice there is no conceptual model able to describe the behaviour of clay.

It is clear that the clay structure has an important impact on the clay behaviour; however this topic has only been widely studied for unsaturated soils, where conclusions about the influence of the clay structure can be hidden by the effects of suction.

The paper presents a microstructural study of Kaolin Clay subjected to one-dimensional compression. Microstructure was investigated via the Pore Size Distributions. Reconstituted samples were tested in order to generate different microstructures and have a better understanding of the role of clay microstructure in clay mechanical behaviour.