Homogenised Elastic Properties of Lightweight Cemented Soils

Abstract Lightweight Cemented Soil (LWCS) is obtained by mixing soil, water and cement with air foam. This treatment allows a high workability of the mixture and good mechanical properties coupled with reduced unit volume weight, making the material suitable for many geotechnical applications. The complex and heterogeneous microstructure (a large pore system induced by foam in a cemented porous matrix) of the material requires a homogeneisation procedure for constitutive modelling of its hydromechanical behaviour. In this work, the stiffness modulus of LWCS was derived through the semi-analitycal Mean-Field Eshelby-based Homogenisation approaches, taking into account the chemo-physical evolution over curing time of the material. This procedure, never employed in the field of treated soils, requires several input parameters, as the artificial porosity induced by the addition of foam, the bulk and shear moduli and the Poisson’s ratio of LWCS samples. The artificial porosity was evaluated by means of X-Ray micro-CT scans, whereas the mechanical parameters were derived from experimental tests. The homogenised stiffness moduli, computed for different curing times, are in agreement with the available experimental results. The analytical homogenisation models allow predicting the elastic behaviour of the material and its evolution over time taking into account the role played by microstructure.