Development of a performance based binder specification for rutting using creep and recovery testing

The inadequacy of the Superpave high temperature specification parameter, G*/sin delta, to correctly grade the superior field performance of modified asphalt binders has been demonstrated by several researchers. A new parameter that is blind to modification type and is performance based is now needed. As a replacement for the existing high temperature binder parameter (G*/sin delta), this study has developed an easy to use Multiple Stress Creep and Recovery Test (MSCR) that measures fundamental characteristics of asphalt binders.;In this study, several binder parameters proposed to replace the existing Superpave rutting parameter were validated using hot-mix testing. Several different binder tests were evaluated to determine which would provide a replacement for the Superpave high temperature binder criteria. The new test and criteria will have to be performance related and blind to modification. The results from these binder tests were compared against hot-mix rutting results from the Asphalt Pavement Analyzer, the Hamburg Wheel Tracking Test, the FHWA ALF test sections and field roadway sites. The results from the hot-mix rut testing showed that different rut testers will provide completely different ranking of binders. This difference is related to the stress level applied by the different testers. This hot-mix testing indicates that the different binders, specifically the polymer modified binders, have different stress dependencies.