Laboratory Evaluation of Pre-Devulcanized Crumb Rubber–Modified Asphalt as a Binder in Hot-Mix Asphalt

The purpose of this study was to investigate the properties of hot-mix asphalt (HMA) prepared with devulcanized crumb rubber–modified asphalt (DCRMA), which was processed by using pre-devulcanized crumb rubber at a lower temperature (165°C). HMA with different DCRMA content in weight were investigated, and it was found that the optimal binder content was 6.1% by weight. The packing grading mixture design method was applied in the design of DCRMA HMA. A series of laboratory tests including the submerged Marshall Stability, wheel tracking test, dynamic modulus test, small beam bending test, and four-point flexural fatigue test, were carried out to characterize the properties of DCRMA HMA. From the experimental results, it could be concluded that the pre-devulcanized crumb rubber can be used as one kind of good modifier for asphalt rubber to improve hot storage stability. DCRMA could also act as a cost-effective, modified binder in dense-graded asphalt mixture, and benefit the low temperature property and prolong the fatigue life cycle.