Description
The Reacted and Activated Rubber (RAR), as an Asphalt Rubber Binder, is composed of plain soft bitumen, fine crumb rubber, and an Activated Mineral Binder Stabilizer (AMBS) at optimized proportions. RAR is produced by a short- time hot blending and activation in a specially designed process to form a dried granulated activated rubber. RAR can be added to any type of Hot Mix Asphalt (HMA) – Dense, Open Graded, Gapgraded, SMA, etc., for replacing part of the asphalt cement (bitumen) at different proportions. In the mixing plant it is added directly to the pug mill or dryer drum, right after the bitumen spraying, using existing feeders (i.e. fiber feeders for SMA mixes, etc.). This paper summarizes an R&D Research effort showing that Asphalt Rubber HMA, produced with RAR, outperforms conventional HMA and even regular modified and asphalt rubber mixes. In general, it was found that RAR is an elastomeric asphalt extender that modifies the plain bitumen by increasing its PG grading, resilience, softening point and recovery properties. As shown in the paper, Different types of HMA mixes produced with RAR showed much better Stability, Rutting and Fatigue resistance under attractive cost/benefit conditions.
