Time-Dependent Structural Response of Full-Depth Reclamation

Abstract

Innovative pavement rehabilitation techniques, such as in-place recycling, are becoming more prevalent as highway agencies face an ever-increasing list of pavement maintenance needs and declining or stagnant budgets. Full-depth reclamation (FDR) has been shown to be a cost-effective alternative to deep milling and repaving to rehabilitate deteriorated flexible pavements. The results of previous FDR studies that investigated pavement structural capacity through the use of deflection testing suggest that long-term strength gain may be achieved through curing; however, such a strength gain has not been well quantified. This study documented the in situ structural testing, with a falling weight deflectometer, of three FDR projects constructed in 2008. Deflection testing was performed periodically at the project sites in the first 2 years after reclamation. This study showed that an accurate estimation of the final structural capacity of an FDR project may not feasibly be achieved immediately after the project has been completed and that it could vary greatly depending on the stabilizing agent used. If data from early-age testing are used to calculate design parameters for future projects, the parameters may be too conservative and result in the loss of potential cost savings through the use of unnecessary overlay materials. A cost analysis, based on data collected in this study, showed that these potential cost savings could approach $37,000 per lane mile. Further mechanistic-based studies of the time-dependent structural response of FDR materials are recommended.