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 and 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 design procedures for this level of rehabilitation project. Recently, 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 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 to gather data for the development of performance models that can be included in mechanistic–empirical rehabilitation design procedures. This paper summarizes the results of the first two tests in this accelerated loading study, which compared no stabilizer and foamed asphalt–cement strategies. The foamed asphalt section outperformed the unstabilized section in all measured aspects. The most notable observation was in rutting performance: the unstabilized section reached a terminal rut depth of 13 mm after approximately 490,000 equivalent standard-axle loads had been applied, compared with the foamed asphalt and cement section, which had a rut depth of only 4.3 mm after more than 17.7 million equivalent standard-axle loads. No cracking was observed on either section. The advantages of using foamed asphalt with cement over unstabilized pulverized material are clearly evident from the results.
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