Description
The performance of a devulcanized rubber asphalt modifier for the production of polymer modified asphalt binders
Geoffrey Rowe
Abatech Inc., PO Box 356, Blooming Glen, PA, 18944, USA
Tony Ferguson and Marty Kalin
Regen RBR Inc., 1601 Connecticut Ave NW, Suite 400
Washington, DC 20009, USA
tony.ferguson@regenrbr.com, marty.kalin@regenrbr.com
Viktors Haritonovs
Riga Technical University, Faculty of Civil and Mechanical Engineering, Institute of Civil Engineering, Kipsalas street 6A, Riga, LV-1048, Latvia
ABSTRACT: A process to produce a devulcanized rubber asphalt modifier (DVR -AMÔ) has been developed based upon a patented mechanical-chemical process. The final product being a pelletized asphalt modifier that is added to liquid asphalt/bitumen to produce a polymer modified binder, with or without sulfur crosslinking. This product makes a material equivalent to a polymer-modified bitumen (PmB), which is typically two grades better in performance compared to the base binder at a loading in the range of 8 to 10% by weight of binder. The use of DVR-AMÔ for asphalt modification has a significantly reduced carbon footprint when compared to the more traditional use of SBS. In addition to PmB production, DVR-AMÔ has been used as a dry-mix modifier in pavement trials in both the USA and Europe. Significant environmental advantages exist in current procurement structures where there is a need for low carbon producing materials used in the construction process.
Testing has been conducted of both binders and mixtures. With binder modification, the efficiency of DVR-AMÔ has been compared to traditional SBS solutions. Although more DVR-AMÔ is needed to achieve a similar modification effect of SBS, DVR-AMÔ generally provides a cost-benefit solution in comparison to SBS. Four-point bending beam fatigue test have been conducted and the life compared to conventional binder is typically an order of magnitude higher with the DVR-AMÔ rubber modification. Tests in the Hamburg rutting test equipment suggests similar of better performance. Results will be presented of typical binder evaluations, including PG grading, rheology and master curves. In addition, the results from mixture tests, both laboratory trials and from plant trials will be discussed in the paper.
KEYWORDS: devulcanized rubber, asphalt modification, rheology, PG grades, performance.
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