Assessing the Structural Properties of Asphalt Stabilized Subgrade Soil

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Studies on the structural properties of asphalt stabilized soil are scares and scattered. In this work, the impact of asphalt stabilization on the deformation under repeated loading, compressive and tensile strength, rutting resistance, and resilient modulus were investigated. The subgrade soil usually used for roadway embankment construction was stabilized with optimum cutback asphalt and with additional 1% of asphalt above and below the optimum. Cylindrical Specimens of 100 mm diameter and 200 mm in height have been constructed and subjected to repeated compressive stress under controlled conditions at 20 ° C using the pneumatic repeated load System (PRLS). The resilient modulus, and plastic parameters were detected. The Wheel tracking test was implemented on asphalt stabilized soil specimens of 150 mm diameter and 50 mm thickness to detect the rutting resistance, while the repeated punching shear test was implemented on asphalt stabilized soil specimens of 150 mm diameter and 120 mm height to detect the resistance to permanent strain accumulation and resilient modulus under the test condition. It was concluded that the Compressive Strength increased up to the optimum Asphalt content of 6%, then decreased, while the Indirect tensile Strength (ITS) decreased up to optimum Asphalt content 6% then increased. The addition of Cut- Back Asphalt decreases the strain (% ϵ) of asphalt stabilized Soil by (65%) at 7% Asphalt content, while it increases the Resilient Modules (Mr) of stabilized Soil by (300%) at 7% Asphalt content. The resilient modulus varies with testing technique and condition.