Abstract
Proper design of lime-treated subgrade requires knowledge of the stressstrain behavior under repeated traffic load. Limited research exists regarding the resilient modulus (M-R) of lime-treated expansive soils. This study investigates the effect of lime treatment on the M-R of an expansive soil from city of Tabuk in Kingdom of Saudi Arabia. Tests were performed in accordance with AASHTO T-307. Tests variables included lime content (2%, 4% and 6% by dry weight of soil) and curing period (7 and 28 days). Experimental results mainly revealed an increase in M-R values due to lime treatment. In addition, the variation of M-R with deviatoric stress revealed trends of strain softening behavior in case of untreated soils and lime-treated soils cured for 7 days. However, lime treated soils cured for 28 days experienced some strain hardening behavior with high dependency on confining pressure. Furthermore, the M-R of lime treated expansive subgrade was observed to be highly dependent on lime content and curing period. Finally, results were fitted using the three-parameter model to determine the stiffness coefficients (k(1), k(2), k(3)).