Changes of small strain shear modulus and suction for a lime-treated silt during curing

To clarify the mechanism of stiffness change by pozzolanic reaction for lime-stabilised soils during curing, it is essential to avoid the effect of water evaporation in this process. In this study, changes of small strain shear modulus G(max) and total suction of a lime-treated silt during curing were investigated, with water content kept constant to avoid the effect of water loss. The soil samples were prepared with 2% lime, and then compacted dry of optimum (17%) and wet of optimum (22%). The G(max) values were determined at various curing times using bender elements and the suction was measured using a hygrometer WP4. Results show that a two-phase development of G(max) occurs for the lime-treated samples. The G(max) increases slowly in the first phase, corresponding to the flocculation process, but then G(max) starts to increase significantly in the second phase owing to the substantial cementitious compounds produced through pozzolanic reaction. Interestingly, the suction changes follow the same two-phase pattern, suggesting that the production of cementitious compounds increases the soil stiffness; it also modifies the soil microstructure, leading to soil water redistribution and thus changes in suction.