Center for Environmentally Sustainable Transportation in Cold Climates
Abstract
In order to properly characterize Alaskan HMA materials containing RAP, this study evaluated properties of 3 asphalt binders typically used in Alaska, PG 52-28, PG 52-40, and PG 58-34, and 11 HMA mixtures containing up to 35% RAP that were either produced in the lab or collected from existing paving projects in Alaska. Various binder and mixture engineering properties were determined, including true high binder grades, complex modulus (|G*|), and phase angle (δ) at high performance temperatures, MSCR recovery rate and compliance, BBR stiffness and m-value, DTT failure stress and strain for binders, and dynamic modulus, flow number, IDT creep stiffness and strength for mixtures. Binder cracking temperatures were determined through Thermal Stress Analysis Routine (TSAR) software along with BBR and DTT data. Mixture cracking temperatures were determined with IDT creep stiffness and strength data. It was found that rutting may not be a concern with Alaskan RAP mix, while low-temperature cracking concerns may still exist in RAP mix in Alaska. A savings of $13.3/ton was estimated for a 25% RAP mix, with consideration of Alaskan situations. Many recommendations for future RAP practice and research are recommended based on testing results and cost analysis.Alaska Department of Transportation Statewide Research Offic
