Use of recycled polymer modified asphalt binder in asphalt concrete pavements: Fid-Bau Portal

Use of recycled polymer modified asphalt binder in asphalt concrete pavements

Negulescu, I.I. / Daranga, C. / Wu, Z. / Daly, W.H. / Mohammad, L.M. / Abadie, C.

Since polymer modified asphalt cements (PMAC) have been employed for a decade, the lifetime and wear of some of these roadbeds are reaching a stage where resurfacing will be necessary. This paper considers the potential problems associated with recycling of polymer modified asphalt cements, PMACs, in particular blending aged PMAC with tank PMAC. A standard PMAC was selected and characterized using typical asphalt binder qualification techniques, i.e., the Superpave Strategie Highway Research Protocol. Procedures were developed to separate the PMAC into its asphalt resin and polymer additive components as well as to characterize the relative concentrations of each component. Infrared and chromatographic techniques were used to identify changes in the components as a result of aging. The impact of the extraction and recovery process on binder properties has been ascertained and found to be minimal. The standard PMAC was aged under accelerated aging conditions in a Pressure Aging Vessel (PAV) that produced a material equivalent to 5 - 8 years in the field. The aged PMAC was then reanalyzed both chemically and rheologically and all changes in its properties due to aging were noted. Finally blends of the PAV aged PMAC with fresh PMAC, as well as blends where the PAV aged PMAC was replaced with road-aged binder, were prepared and analyzed. The initial results indicate that aged PMAC can be blended successfully with fresh PMAC. Thus it is anticipated that resurfacing of aging PMAC roadbeds can proceed, but further tests will be required to establish the precise conditions necessary to conduct this process.