Mechanical Behaviour of Lightweight Cemented Soils Under Triaxial Loading Using X-ray Microtomography

Abstract In the present work, in-situ x-ray microtomography, i.e. , x-ray scanning acquired during mechanical loading, on Lightweight Cemented Soils (LWCS) samples is performed in order to obtain direct three-dimensional observations of foam-induced porosity changes under triaxial loading paths. This novel experimental campaign consists of three tests performed at different confining stress levels, ranging from 50 kPa up to 500 kPa. The results show that, by increasing the confinement level, the initial stiffness of the sample remain almost the same, whereas the mechanical strength of the material increases. Test results highlight the key role of microstructural heterogeneities, i.e ., pre-existing shrinkage fractures, on the failure mechanisms governing the mechanical behaviour of LWCS. Although the samples exhibit similar macroscopic behaviour, different failure mechanisms can be identified for increasing confinement stresses.