To clarify the mechanism of stiffness change by pozzolanic reaction for lime-stabilized 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 Gmax 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 Gmax 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 Gmax occurs for the lime-treated samples. The Gmax increases slowly in the first phase, corresponding to the flocculation process, while Gmax starts to increase significantly in the second phase due to the substantial cementitious compounds produced through pozzolanic reaction. Interestingly, the suction changes follow the same two-phase pattern, suggesting that the cementitious compounds production increases the soil stiffness; it also modifies the soil microstructure, leading to soil water redistribution and thus changes in suction.