Georgia's Use of Cement-Stabilized Reclaimed Base in Full-Depth Reclamation

Abstract

The Georgia Department of Transportation (GDOT) has obtained favorable results from the initial use of cement-stabilized reclaimed base (CSRB) in a pilot full-depth reclamation (FDR) in rural southeast Georgia. CSRB is produced when portland cement is added to sand–clay base from an FDR, and it is used to underlie hot-mix asphalt. GDOT initiated its first FDR in 2004 on County Road (CR) 52 in Long County. A 4.8-km corridor of CR 52 was overlain with a 12.5-mm Superpave® mix, including a 1.8-km section reconstructed with FDR. Samples of the in situ sand–clay base and pavement were obtained for a mix design to determine if these materials would react satisfactorily with portland cement. With the same laboratory design strength requirement for a soil–cement base, the desired level of unconfined compressive strength was obtained at 6% cement. A provisional specification for CSRB was developed, and a 152-m trial section of 12.5-mm mix over CSRB was constructed in July 2004. Construction procedures were adjusted after the trial section was placed, and the remainder of the FDR and overlay was completed. Construction costs for the 1.8-km FDR section were reduced 42% using FDR. Falling weight deflectometer readings taken after construction indicated that deflections were significantly lower in the FDR section than in the overlay-only section. The road is performing well after nearly 1 year of use. GDOT is considering development of a permanent specification for CSRB on non–state routes.