Soil stabilization with lime and hydraulic binders improve soil to low properties. In this study, a multi-scale approach was implemented to describe the effects of mixed treatment on the characteristics ans properties of stabilized silts having a different mineralogical composition. This approach has also been used to understand the physico-chemical and mechanical response of these stabilized silts durng water flow. Hydromechanical properties of stabiliezd silt are conditioned by the microstructural organization itself being dependent on soil mineralogy. In silt without micas, clay particles coat the coarser particles of the soil (quartz and feldspars)to form agglomerates. These agglomerates are overlayed hydrates products formed by rhe hydration of lime and ciment. The development of C-(A)-S-H gel ensures continuity throughout the material. The developement of mechanical performance is also satisfactory. In the other hand, the second silt, rich in micas, presents a microstructure fundamentally different. The abundance of mica platelets induces a cluster of individual particles on which are scattered the hydraulic products. As a consequence, the mechanical performance is lower. Long term effects of a contiunous water flow are conditioned by these microstructural organizations. In the case of silt without micas, the mechanical performance is maintained in response to the low leaching of cementitious products. The soil fabrix preserves the treatment effects. Inversely, silt-reach micas, cementitious phases are strongly affected by water flow. The loss of the treatment effect is then complete, alothough a delay in the water percolation can slow it down
