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

Abstract

A comprehensive laboratory study was undertaken to evaluate the effects of molding moisture and suction on the resilient modulus (MR) 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 %). MR 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 MR and UCS values of lime stabilized soils were less than those on untreated soils. MR 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 MR constitutive model was revised by incorporating total suction. The revised model was shown to have better predictive capability over existing MR models.