Homogenisation of elastic properties of foamed cemented soils based on x-ray microtomography investigations

In the present work, semi-analitycal Mean-Field Eshelby-based Homogenisation approaches are used to determine the elastic relevant mechanical parameters of Lightweight Cemented Soils (LWCS), i.e., heterogeneous materials characterised by a double porosity microstructure consisting of foam-induced large voids immersed in a cemented small-porous matrix. Homogenisation approach, never employed in the field of treated soils and applied for the first time to LWCS, allows taking into account the microstructural features of the material and their evolution over curing time. This procedure requires several input parameters, i.e ., the artificial foam-induced porosity, the bulk and shear moduli and the Poisson ratio of the phases forming LWCS samples ( i.e . cemented soil matrix, portlandite crystals). The evolution of foam-induced porosity over time is inferred from x-ray microtomography scans performed on a LWCS sample at different curing times, i.e ., 7, 28 and 60 days, whereas the mechanical parameters are derived from experimental tests, performed on cemented samples with or without foam addition. The homogenised stiffness moduli, computed for different curing times, show a good agreement with the available experimental results, confirming the feasibility of the semi-analytical homogenisation model. The use of x-ray computed microtomography coupled with the proposed homogenisation method, can efficiently predict the elastic parameters of LWCS and their evolution over time, taking into account the role played by the microstructure. • The elastic stiffness moduli of Lightweight Cemented Soils (LWCS) were derived by Mean-Field Homogenisation Approaches. • The input parameters have been estimated by experimental results at different scale levels on LWCS samples. • Complete Mori-Tanaka method for a two-phase system yields to very good predictions of the elastic stiffness over time. • Computation of homogenised elastic stiffness for three-phases system provides an overestimation of the stiffness values.