PHYSICAL PROPERTY CHANGES IN A LIME-TREATED EXPANSIVE CLAY CAUSED BY LEACHING

The effects that continuous water leaching has on the engineering and physical properties of a lime-treated expansive clay in north-central Texas were determined. Seventy laboratory-prepared lime-treated clay samples were subjected to continuous accelerated leaching for periods of 45 and 90 days in large-diameter, flexible-wall leach cylinders. The soils' physical properties were measured before and after leaching, then graphically and statistically analyzed for significant changes. Results indicated that leaching does have detrimental impact on the physical properties of lime-treated expansive clays. The property changes are related to lime content and initial moisture content. Permeability of all samples increased dramatically with the addition of lime. Maximum detrimental changes generally occurred at lime contents at or less than the lime modification optimum. At lime contents at or above the lime stabilization optimum, the detrimental effects of leaching were minimized or eliminated. Changes to properties upon leaching varied depending on their compaction water content relative to the optimum.