Assessment of Molding Moisture and Suction on Resilient Modulus of Lime Stabilized Clayey Subgrade Soils

A comprehensive laboratory study was undertaken to evaluate the effects of molding moisture and suction on the resilient modulus (M-R) and unconfined compressive strength (UCS) of lime stabilized clayey subgrade soils. Two subgrade soils, AASHTO class A-6 and A-7-6, are stabilized with three percentages (0, 5, and 7 %) of lime on the basis of pH test and used to prepare cylindrical MR samples at three moisture contents: optimum moisture content (OMC), dry state (OMC-2 %), and wet state (OMC +2 %). M-R tests on lime stabilized soils are conducted with a modified stress sequence incorporated in the AASHTO T307 procedure based on past literature and laboratory experience gained in this study. Test results revealed that the effects of moisture on M-R and UCS values of lime stabilized soils were less than those on untreated soils. M-R and UCS values increased due to lime treatment, but improvement varied with soil type and lime dose. A filter paper method was used to determine the total and matric suctions at different moisture states in this study. It was observed that osmotic suction increased to 15 % of the total suction due to lime treatment. Finally, an existing M-R constitutive model was revised by incorporating total suction. The revised model was shown to have better predictive capability over existing M-R models.