One of the key objectives in the first phase of a strategic highway research program (shrp) contract was to identify asphalt modifiers with varying levels of pavement performance. Key pavement distress categories identified by shrp were fatigue cracking, low-temperature cracking, moisture susceptibility, permanent deformation, and aging. These modifiers will be used in the second phase to evaluate laboratory binder and mixture tests suitable for development of performance-based specifications. Information on asphalt modifiers was obtained from state highway authorities and asphalt modifier manufacturers. The questionnaire results were analyzed, and modifiers with varying levels of performance were identified. Performance ratings for the modifiers evaluated are presented for each pavement distress category. This paper appears in transportation research record no. 1323, Asphalt mix materials 1991
Samenvatting