Effect of Aging on Viscoelastic Properties of Asphalt Mixtures

Abstract

This study presents a comprehensive laboratory evaluation and statistical analysis of the effect of aging on the viscoelastic properties of asphalt mixtures. Asphalt mixtures were subjected to different short- and long-term aging temperatures and durations. A factorial study with three short-term aging temperatures (125°C, 135°C, and 145°C), four different short-term aging durations (2, 4, 6, and 8 h), three long-term aging temperatures (75°C, 85°C, and 95°C), and six different aging levels (0, 2, 4, 6, 8, and 10 days) was conducted. Results from dynamic modulus testing in an asphalt mixture performance tester (AMPT) indicate that aging temperature and duration have a significant effect on the viscoelastic properties of asphalt mixtures. Statistical analysis using multivariate analysis of variance (MANOVA) was also conducted to investigate the significance of short- and long-term aging temperatures and duration on the viscoelastic response of mixtures. It was found that short- and long-term aging temperatures and times have a substantial effect on the dynamic modulus. The analysis also revealed the effect of aging conditions on the fitting parameters of the master curves to provide a better insight on the changes in the viscoelastic properties of asphalt mixture as a result of aging. To evaluate the viscoelastic response of asphalt mixture due to aging, Prony analysis was also performed on the dynamic modulus data using a newly developed parameter A (i.e., oxidative aging state variable). A positive correlation was found between A and both the temperature and long-term aging duration in terms of mechanical properties (dynamic modulus) of asphalt mixture.