Micro–macro-experimental study of two clayey materials on drying paths

The objective of this research is to provide a better understanding of the relation between the macroscopic and microscopic behaviours of two clayey materials, a kaolinite and a mixture of kaolinite and montmorillonite. At the macroscopic scale, the approach consists of measuring the water content, void ratio and degree of saturation versus suction (s) during drying, which allows to specify the relationship between shrinkage and desaturation and highlights the characteristic phases of behaviour. At the microscopic scale, study of the orientation of the clay particles is carried out by scanning electron microscope (SEM) picture analysis under different suctions. On drying paths, the observations show an isotropy of the microfabric. The evolution of the porosity derived from mercury intrusion porosimetry tests is confirmed by SEM photograph observations.