Laboratory Development and Field Trials of Thin-Lift Hot Mix Asphalt Overlays Incorporating High Percentages of Reclaimed Asphalt Pavement with Warm Mix Asphalt Technology

摘要

In this study two pavement preservation overlay mixes, a Superpave 4.75mm and a Massachusetts Surface Treatment mixture, were developed with 0, 15, 30, and 50 percent Reclaimed Asphalt Pavement (RAP). Each of these mixtures was developed with two Performance Grade (PG) binders (PG 64-28 and a PG 52- 33) each containing 1.5 percent Sasobit(R) Warm Mix Asphalt (WMA) technology. Mixtures design data showed that most of the mixtures with high percentages of RAP could be designed to meet specification requirements for gradation and volumetrics. The developed mixtures were evaluated for stiffness and workability. Stiffness testing was conducted utilizing the Asphalt Mixture Performance Tester (AMPT) to evaluate the impact of the aged binder in the RAP on the overall mixture stiffness. Mixtures master curves developed from the AMPT data indicated that there was a degree of blending between the virgin binder added and the aged binder in the RAP. Mixture workability testing data showed that higher RAP contents decreased the workability of the mixture. Finally, several field trials of the Superpave 4.75 mm incorporating 30 percent RAP were placed in selected locations in Massachusetts during 2007. The mixtures were produced and placed without any production or construction issues.