Field and numerical investigation of full depth reclamation with Portland cement in Georgia
Abstract
The Full Depth Reclamation (FDR) technique has recently become a popular rehabilitation method to reconstruct old flexible pavement. Pulverized existing roadway materials are blended with stabilizing agents such as foamed asphalt and Portland cement to form a stiff base course for the new pavement. In Georgia, Portland cement is commonly used as a stabilizing agent for FDR stabilization. One of the challenges in FDR stabilization projects is to achieve uniform stiffness throughout the stabilized layer. FDR mix design often specifies a fixed rate of stabilizing agent, which could generate a range of FDR strengths due to the inherent variability in the existing pavement. Stiffness variation in the stabilized base should be minimized for optimum long-term pavement performance. This study investigates the influence of the variability in the FDR base layer stiffness on pavement performance. A series of field and laboratory tests were performed on a pavement reconstruction project in Georgia to assess variability. Tests included Unconfined Compressive Strength (UCS) tests and deflection tests with a Light Weight Deflectometer (LWD) and Falling Weight Deflectometer (FWD). Mechanistic sensitivity analyses were performed based on the field and laboratory test results to investigate the effect of variability in FDR properties on pavement performance. The results indicate both the FDR base thickness and strength have a significant influence on the predicted pavement responses. Findings presented here will be of interest to pavement engineers involved in the design and performance modeling of FDR pavement.