Abstract
This study aims to investigate the long-term and immediate effects of freeze-thaw (FT) cycles on the resilient modulus (M-R) of two different expansive subgrades before and after lime-treatment. The immediate effects were examined by performing M-R test (using triaxial dynamic-system) for specimens immediately after applying successive FT cycles. For assessment of long-term effects, the specimens were subjected to 15 FT cycles and then thawing in a humidity room for different recovery periods up to 250 days before commencing M-R tests. The results indicated a reduction in M-R by about three times due to FT cycles regardless of lime-treatment. This reduction mostly took place after first FT cycle and showed a dependency on FT cycle number. On long-term performance, the reduction was not entirely recovered for all soils, and reducing the designed values of M-R is recommended when pavement subgrades are to be subjected to FT cycles even once a year.