Laboratory Simulation and Performance Evaluation of Long-Term Aging of Asphalt Mixtures at Service Temperatures

Abstract:

To address the discrepancies between existing laboratory aging simulation methods and the actual aging gradient and service temperature of asphalt pavements， this paper proposed a novel indoor long-term aging method based on the pure oxygen accelerated aging， aiming to simulate the aging behavior of asphalt mixtures at service temperatures. The investigation of the aging properties of asphalt mixtures with time and space was conducted using Fourier transform infrared spectroscopy（FTIR） and dynamic shear rheometer（DSR）. The results show that the novel aging method proposed can effectively simulate the aging behavior of compacted asphalt mixtures within the service temperature range， achieving an aging degree close to that of standard long-term aging tests. With the increase of aging time and temperature， the aging degree of AC-13 and SMA-13 mixtures both increases， and the aging degree of SMA-13 mixtures is only 1/5 of that of AC-13 mixtures. Concurrently， the high temperature performance of the two mixtures increases， while the fatigue life decreases. With the increase of aging depth， the aging index and high-temperature performance of AC-13 and SMA-13 mixtures gradually decrease， whereas the fatigue life significantly increases. Under different aging conditions， SMA-13 mixtures show a superior aging resistance and fatigue resistance than AC-13 mixtures， particularly at low strain levels. ANOVA indicates that the aging time significantly impacts the sulfoxide index and high-temperature performance， but has no significant effect on the carbonyl index， high-temperature performance， and fatigue life. The aging depth only significantly impacts non-recoverable creep compliance at 0.1 kPa， with no significant effects on the other evaluation indexes.

Key words:road engineering;asphalt mixtures;oxidative aging;long-term aging;rheological properties;Fourier transform infrared spectroscopy