Comportement des sols salés (sols sebkha) traités par un liant hydraulique

Abstract

n this study, Ain M'lila Sebkha soil, characterized by high salinity of ECe3=23.2 dS/m and classified as chloride-sulfate soil, was investigated. The first part of this study was devoted to investigating the quick lime treatment effect of the physicochemical and mechanical properties of Sebkha with different salinity levels of ECe3= 23.2 dS/m, ECe2=8.3 dS/m, and ECe1= 2.32 dS/m. The second part was devoted to studying the potential stabilization of Sebkha at high salinity with sulfate-resistance cement (SRC). UCS, carbonation, and granulometry tests were carried out to assess the soil's physico-chemical and mechanical properties. Subsequently, XRD, FTIR, TGA, pH, and EC measurement tests were performed to understand better chemical reaction development and their potential interactions with water-soluble salt minerals.Results showed that salinity significantly affected soil's properties. In untreated soil, decreasing salinity led to increased UCS and CaCO3 precipitation, while in lime-treated soil, it increased UCS but decreased CaCO3 content. While XRD showed no minerals phase variations, TGA revealed portlandite formation with a lower quantity in ECe3 soil compared to ECe1 soil, which indicates that high concentration of Cland SO4 2- ions from dissolved salts coated finer particles and thus hindered the pozzolanic reaction in ECe3 soil, suggesting that soil treatment would be more effective in low saline soil. SRC treatment proved highly effective, showing an 11.56-fold strength increase at 14d curing with 8% content due to CSH and Friedel's salt formation. Despite minor strength reduction at 28d curing, SRC stabilization achieved a 30% reduction in pavement thickness and 5.7 times lower material costs, establishing its viability for practical applications.