FUNDAMENTAL PROPERTIES OF ASPHALTS AND MODIFIED ASPHALTS, VOLUME I: INTERPRETIVE REPORT

The Superpave binder specification developed during the Strategic Highway Research Program (SHR)) from 1987-1993 classifies construction grade asphalts into rheologically similar groups. All asphalts in a given grade have the same rheological properties to within 6 deg C. The mission of this project was to improve the understanding of the expected performance of petroleum asphalts under service conditions. These conditions include physical behavior of thin asphalt films in contact with aggregate, rheology and oxidative aging of wet asphalt, behavior of asphalt after extended aging, and propensity of asphalt films to reconsolidate ("heal") after microcracking. These phenomena are not described by the current binder specification. The results of said exposures are included in this document and have been used to produce a comprehensive chemical model of petroleum asphalt. Finally, the results have been used to develop new analytical methods that improve the capability to predict performance of asphalt in roadway service. These 16 new tests are described in Volume II of this report.