Micro-mechanical analyses to understand the durability of chemically stabilized geomaterials against moisture-induced damage

Abstract

Chemical stabilization with calcium or Ca-based stabilizers, such as lime, has been used worldwide to enhance the engineering properties of problematic soils. Although lime treatment improves the mechanical properties of problematic soils, moisture intrusion is often detrimental to the stabilized layers. The extent of improvement and the durability of the lime-treated soils depend on several factors, including stabilizer dosage, curing period, and soil type. This research study was designed to investigate the influence of predominant clay minerals and stabilizer dosage on the durability and resiliency of lime-treated soils against moisture-induced damage. Two clayey sand groups bearing kaolinite and montmorillonite as the predominant clay minerals were treated with the Ca-based stabilizer as per existing recommended practice, and the strength and durability properties were studied after different curing periods. Besides engineering tests, mineralogical and microstructural analyses were also considered to identify the reasons responsible for the observed engineering behavior before and after moisture conditioning. Test results indicate that the extent of strength gained after lime treatment is less for soils with kaolinite as the predominant clay mineral than those containing montmorillonite. However, the percentage strength loss after capillary soaking was lower in lime-treated kaolinite-rich soils compared to that having montmorillonite when treated with optimum +2% lime dosage and cured for a longer time.