Stabilization of pavement subgrade soils containing rich chloride salts

Soils containing rich soluble salts are widely available. Their behaviors as pavement subgrade depend on the types and compositions of the salts, local climate, and hydrogeological conditions. In this study, various amounts of Portland cement, lime, and their combinations were used to treat a chloride-dominant saline soil. The engineering properties and microscopic structures of the treated and untreated soils were systematically examined. In addition, soils of different saline contents were artificially created to study the interactions between treatment effectiveness and saline content. Test results indicate that cement stabilization develops strength quickly, whereas lime stabilization develops strength relatively slowly but is equally effective in the long term. A combined use of cement and lime generally yields better results in strength and durability against moisture. All the soil properties deteriorate as saline content rises, and threshold application rates appear to exist for the treatments to be effective at different saline levels.