New VTRC Report Published - Verification of Engineered Frameworks for Evaluating the Use of Recycling Agents in Surface Asphalt Mixtures

From the Abstract:

The use of reclaimed asphalt pavement (RAP) in asphalt mixtures has been steadily increasing for years, nationally and internationally, given the economic and associated environmental benefits of using such material. However, using RAP in asphalt mixtures poses some challenges regarding durability and performance that are often associated with the highly aged binder in RAP. The balanced mix design (BMD) that the Virginia Department of Transportation (VDOT) adopted for 9.5- and 12.5-mm nominal maximum aggregate size dense-graded surface mixtures with A and D designations addresses some of these challenges. Nonetheless, the gradual statewide implementation of the BMD framework and the lack of BMD specifications for certain types of asphalt mixtures that may contain RAP encourage the evaluation of other solutions to potentially mitigate some of the aforementioned challenges in the meantime. Softer binders or additives such as recycling agents (RAs) have been gaining considerable attention in the asphalt industry as a potential solution, but no specifications exist for the performance evaluation of RAs and their acceptance in Virginia. The Virginia Transportation Research Council in collaboration with North Carolina State University conducted VDOT Research Project No. 117566, Engineered Frameworks for Evaluating the Use of Recycling Agents in Surface Asphalt Mixtures for Virginia, resulting in two performance-based frameworks: one for the assessment of RA products for inclusion into VDOT’s Approved Product List and the second for designing asphalt mixtures with high RAP content and RA in accordance with VDOT’s BMD specifications.

The full report can be found here.