This report documents and presents the results of a study of the applicability of the superpave® specification and protocols developed for asphalt cements to modified http://gulliver.trb.org/publications/nchrp/nchrp_rpt_459.pdfasphalt binders. A survey of users and suppliers of modified binders indicated the existence This report may be accessed by Internet users at of a wide variety of modifiers that are used either routinely or on an experimental basis to produce PG grades. The survey also indicated that a majority of state agencies intend to increase the future use of modified binders. However, serious concerns remain about the lack of knowledge about how modified binders affect performance, as well as with issues related to storage stability, suitability of the Superpave aging procedures, and the lack of protocols to determine mixing and compaction temperatures. (A)
Abstract