Crumb Tire Rubber and Polyethylene Mutually Stabilized in Asphalt by Screw Extrusion

In order to put recycled rubber and plastics into practical use for asphalt's modification, the polyethylene (PE)/crumb tire rubber (CTR) blends were blended to prevent them from phase separation in asphalt during hot storage. The effect of screw extrusion on storage stability, morphology, and thermal properties of modified asphalt were investigated. The results showed that the storage stability of PE/CTR modified asphalt was significantly improved after screw extrusion in the presence of a compatibilizer. The extruded PE and CTR were more finely and uniformly dispersed in the asphalt. The rheological properties of modified asphalts were improved at both higher and lower temperature's range. The density discrepancy between asphalt and the extruded PE/CTR particles was neutralized by the combination between PE and CTR. The interactions among PE, CTR and asphalt were improved by the compatibilizer. Both the reduction of density difference and the enhanced interactions are critical to obtain a stable modified asphalt system. (C) 2014 Wiley Periodicals, Inc.