Accelerated Load Testing to Compare the Performance of Full-Depth Reclamation with Foamed Asphalt Under Three Environmental Conditions

Abstract

Full-depth reclamation (FDR) with foamed asphalt has been successfully used as a rehabilitation strategy in California since 2001. Long-term field monitoring on several projects, combined with a comprehensive laboratory study, resulted in the preparation of guidelines and specification language in 2008. However, the design criteria were essentially empirical, in line with California’s design procedures for this level of rehabilitation project. There has been growing interest in the use of cement, engineered emulsion, and no-stabilizer full-depth reclamation strategies in addition to foamed asphalt, and in the use of mechanistic design in a greater range of rehabilitation projects. Consequently, the research initiative was extended to a second phase, to include accelerated load testing on an instrumented test track constructed with these four FDR strategies. The second phase gathered data for the development of performance models that can be included in mechanistic–empirical rehabilitation design procedures. This paper summarizes the results of three of the 11 tests in this accelerated loading study, which compared the performance of foamed asphalt under three environmental conditions (dry, wet, and at elevated temperature). All three sections performed well; however, performance was clearly influenced by wet conditions and higher asphalt concrete surface temperatures. As a consequence, good drainage and appropriate binder selection need to be considered when undertaking rehabilitation designs with full-depth reclamation.