Impact of Moisture Content on Strength Gain in Lime-Treated Soils

Lime stabilization of clay soils can produce structural layers possessing considerable strength and permanency. Several factors contribute to the strength development, including the presence of adequate moisture to facilitate the several chemical reactions that are required to complete the process. This study examines the importance of optimizing moisture content at the time of the final compaction of the lime-treated clay material. Three clays are studied ranging in plasticity from a plasticity index of approximately 20 to a plasticity index of approximately 50. The lime percentages for stabilization are optimized for each clay, and each is mellowed according to industry standards prior to final compaction. Samples are compacted at moisture contents ranging from 4% below optimum to 4% above optimum, based upon standard Proctor curves generated on the treated materials. The specimens are then moist cured for 28 days at ambient temperature. Unconfined compressive strengths of the samples are collected and compared to determine the optimum moisture content to produce the maximum compressive strength of the mixture. In addition, comparisons are made to the dry unit weights of the cured specimens