Applicability of Superpave to Modified Asphalts: A Mixture Study

Abstract

Superpave binder and mixture specifications are currently being reviewed for their applicability to modified asphalts. This study was designed to evaluate a series of modified binders with the same Superpave performance grade (PG 76-22). The experiment was based on the following hypothesis: The performance characteristics for a given asphalt mixture will be the same for all PG 76-22 binders. The performance indicators analyzed in this study were obtained from a suite of laboratory mixture performance tests. The study, which also included a PG 64-22 asphalt to serve as the control, revealed that the hypothesis may be rejected. That is, mixture performance potential would be significantly different for various modified asphalts of the same performance grade. Loading frequency and strain dependency were noted as the most significant behaviors to address. Finally, recommendations were made for possible modifications of Superpave specifications to address these issues.