Design and Construction Practices for Full-Depth Reclamation of Asphalt Mixtures with Bituminous and Cementitious Additives

Several highway agencies have implemented full-depth reclamation (FDR) as a sustainable technology for rehabilitating deteriorated asphalt pavements. However, the lack of standardized mix design procedures and limited field assessment, in terms of rutting and cracking resistance, pose challenges to the widespread implementation of FDR. This study addresses these challenges by synthesizing current FDR mix design and construction practices and validating highway agency-recommended practices through laboratory performance evaluation. The study objectives were achieved by (1) reviewing current FDR mix design and construction specifications of highway agencies across the US and internationally, (2) conducting surveys with highway agencies and interviews with subject matter experts (SMEs), and (3) evaluating the laboratory performance of FDR mixtures. Based on the findings from the literature, survey responses, and SME interviews, three FDR mixtures were designed in the lab: (i) cement-only, (ii) asphalt emulsion and cement, and (iii) foamed asphalt and cement. Each mix was then evaluated for rutting susceptibility using the Asphalt Pavement Analyzer (APA) and cracking resistance using the indirect tensile (IDT) test to identify optimum dosages of bituminous and cementitious additives. Laboratory results showed that FDR mixtures with 3% asphalt emulsion and 1% cement improved rutting resistance by 46% and cracking performance by 70% compared to cement-only mixtures with 4% cement. In contrast, foamed asphalt did not result in a significant improvement in FDR performance. Survey responses indicated that 89% of respondents reported good field performance of FDR, with Pennsylvania and North Dakota exhibiting excellent performance 10 years after construction.