Evaluation of aging resistance for high-performance crumb tire rubber compound modified asphalt

Abstract

The preponderances of different modifiers in terms of performance improvement are polymerized in compound modified asphalt. However, limitation still exists in the appropriate evaluation of aging resistance of compound modified asphalt, due to the inevitable aging behavior of asphalt and the various effects of aging on different modifiers. The objective of this paper was to explore reasonable aging resistance evaluation methods for compound modified asphalt. A new type of compound modified asphalt – high-performance crumb tire rubber compound modified asphalt (HR) was concerned and compared with basic SBS modified asphalt and high viscosity compound modified asphalt (HV) under the same conditions. Rotating thin film oven test (RTFOT) and pressure aging vessel (PAV) test were applied to simulate short-term and long-term aging, respectively. Rheological performances of three kinds of asphalt under different aging conditions were systematically tested in the whole temperature domain, including bending beam rheometer test (BBR), multiple stress creep recovery test (MSCR), Brookfield viscosity test (RV), and linear amplitude sweep test (LAS). A new aging index C*AI based on fatigue damage theory was established, and the evaluation effectiveness of other aging indexes on the aging resistance of compound modified asphalt was compared and analyzed. The results showed that different performances of compound modified asphalt have various sensitivity to aging, but in general, HR shows the best aging resistance performance among the three kinds of asphalt. Based on the comparison of different aging indexes, the aging index C*AI can effectively evaluate the aging resistance of compound modified asphalt.