Refining the Superpave Binder Purchase Specification

completed

The contribution of asphalt binder properties to fatigue behavior of hot-mix pavements is a subject of current research (e.g., National Cooperative Highway Research Program (NCHRP) 9-59 and 9-60). New tests and parameters are being proposed to determine the impact of asphalt binder characteristics on fatigue distress in pavements. Some existing tests are theoretically sound and generally reach the conclusion that polymer modification is one key to good performance. Under this logic, it is possible for a surrogate test to be found to discriminate between polymer types and content and to develop a binder purchase specification related to fatigue resistance. Enhancements are also needed to the Superpave binder specification in the high- and low-temperature regime, due in part to, notable differences between “modern binders” and the binders used to develop the performance grade (PG) specifications.