The effects of the different hydraulic stresses (i.e. immersion and water circulation) to which lime-treated silty soil can be exposed to when used for the construction of hydraulic earth structures or embankments situated in areas liable to flooding, on the durability of the improvements brought by lime is still uncertain. In this context, the present work aimed at experimentally simulating and assessing the effects of such stresses on the geotechnical properties of a compacted lime-treated silty soil (permeability, mechanical performance). It was established that the maintenance of the mechanical improvements is highly related to the soil permeability: the higher the permeability, the higher and the faster the loss of mechanical performances. The decrease in mechanical performances can be attributed to the partial dissolution of unconsumed lime, but also to the decalcification of the cementitious compounds formed after the addition of lime. The extent of these physico-chemical processes is a function of the soil permeability, a high permeability fastening them in contrast to a low permeability. Finally, a study was conducted on the effect of initial conditions on the soil fabric and permeability so as to determine the initial states to favour in term of durability. It was demonstrated that the addition of low lime contents and that compaction at a low energy can entail, in contrast to the use of high lime contents and compaction on the wet side, a strong permeability. To conclude, high lime contents as well as compaction on the wet side appear as means to maintain at longer term the mechanical performances of lime-treated silty soils exposed to hydraulic stresses.
