Superpave Binder Specs Get Refined

SUPERPAVE BINDER SPECS GET REFINED Lewandowski, L

Abstract

To better understand the development of Superpave and polymer-modified asphalt specifications, one must look at the past and present and contemplate the future. Originally, several test methods were developed to identify the presence of certain types of polymers. These methods were provided to state Departments of Transportation to assist them in writing specifications. The next phase was the development of specifications that were unique to each type of polymer, which eventually became ASTM standards. Once the Strategic Highway Research Project ended, several products were ready for use. The Superpave Performance Based Binder Specifications received the most attention, while the mix design was being further refined. The components of Superpave consist of the Brookfield viscosity, Dynamic Shear Rheometer, Bending Beam Rheometer, the Direct Tension Test, ad well as a set of mix design and analysis tools. The implementation of these specifications has resulted in many states having more grades of asphalts than before, requiring the contractor and suppliers to acquire more tankage. The future holds a variety of events, including the widespread use by states, counties, and cities of the Superpave binder specifications; the introduction of new types of modifiers; and more combinations of modifiers being used in the binder. With polymer modification growing, the leaders in the industry will continue to prosper, and Superpave specifications will be amended for polymer-modified asphalts. Inevitably, this effort will lead to better and longer lasting pavements.