Effect of aging on the constitutive models of asphalt and their mixtures

• Constitutive models of asphalt and its mixtures were established. • The effect of aging on constitutive model parameters were evaluated. • Outdoor aging has the most significant impact on total and permanent strains. • Parameters in constitutive models increase overall as aging degree deepen. Aging of asphalt and mixture occurs with extension of service time, thereby reducing performance of asphalt mixtures, and causing considerable impact on the function of pavement. This study explored the dynamic mechanical behaviors and constitutive models of SBS modified asphalt and mixtures after different aging methods, including RTFOT (rolling thin film oven test), PAV (pressurized aging vessel), ultraviolet (UV) radiation and field aging for asphalt, and short and long-term aging for asphalt mixture. The effect of aging on dynamic mechanical behaviors and constitutive model parameters were evaluated. The results show that complex modulus of asphalt significantly increases after aging. The relative ranking of aging methods according to the complex modulus of asphalt places RTFOT as the least influential and outdoor aging as the most influential, with the PAV and UV aging falling in-between. Dynamic modulus of mixture shows an increasing trend as degree of aging become more serious. Parameters in Burgers model of asphalt mixture increase overall as degree of aging become more serious except η 1 at 5 °C, indicating enhanced anti-deformation ability at high-temperature and weakened anti-deformation ability at low-temperature.