Incorporating the Strength Provided by Subgrade Stabilization in the Flexible Pavement Design Procedures

Abstract Chemical stabilization has been successfully used to treat weak subgrade soil by permanently changing its physical and chemical properties, such as reducing plasticity and increasing stiffness and load bearing capacity, so it can serve as a construction platform during constructions and provide long-term structural stability. The Ohio Department of Transportation (ODOT) has adopted a policy to globally stabilize the subgrade for new construction. However, the strength provided by subgrade stabilization has not been incorporated into the design procedures for flexible pavement. Therefore, in this study, the impact of subgrade stabilization on the stiffness and performance of pavement layers was investigated. In situ testing, including the falling weight deflectometer (FWD) and the portable seismic pavement analyzer (PSPA), was performed on 20 pavement sections within the state of Ohio to evaluate pavement sections constructed with stabilized subgrade. Backcalculation of pavement layers’ moduli was carried out on the FWD data collected. Finite element analysis was performed using ABAQUS to validate the pavement layers’ stiffness obtained from backcalculation. The validated layer moduli were used to determine structural numbers and layer coefficients of pavement layers. The result was used to investigate the effect of subgrade stabilization on pavement design procedures. Significant reduction in the pavement thickness and distress was obtained as a result of incorporating subgrade stabilization into pavement design procedures.