The composite performance of modified asphalt is divided into inherent performance and improved performance. The inherent performance of asphalt refers to the original performance of the virgin asphalt. The performance obtained by modifying the virgin asphalt by different methods is referred to the improved performance of the asphalt. In most studies of modified asphalt, researchers pay more attention to how to improve the performance of virgin asphalt at high and low temperatures (i.e., rutting at high temperatures and cracking at low temperatures); however, little attention has been paid to the anti-aging durability of the improved performance. In this project, the macro and micro mechanisms of modified asphalt were compared and analyzed through a series of comparative experiments on the inherent and improved performance of modified asphalt to explore the anti-aging durability of the modified asphalt based on the inherent performance and improved performance at high and low temperatures.

Introduction

As an important binder for asphalt pavement construction [1], the selection and quality of asphalt determine the durability of asphalt pavement to a large degree and directly affect the service life and safety of asphalt pavement. Therefore, studying the durability of road asphalt, especially the durability of asphalt materials, is of great theoretical and practical value [2–۴]. Zhang et al. [5] investigated the change in molecular weight during the aging process of asphalt and found some new functional groups that were produced inside the asphalt; they also found that the change in molecular structure will lead to changes in the morphology and performance of the asphalt. P. Chen’s paper concluded that temperature has a great influence on the aging of asphalt. When the temperature was above 100 C, a dehydrogenated chemical reaction of the asphalt was produced. When the temperature was below 100 C, an oxidation reaction of the asphalt was produced, as well as some oxygenated compounds. The chemical reaction produced by asphalt aging has an important influence on the performance of the asphalt [6]. According to Zhu et al., as the aging time is increased, the residual needle penetration and residual ductility is decreased and the softening point is increased. This means that the high temperature performance of the asphalt is increased and the low temperature performance is decreased after aging [7]. Zhang et al. [8] indicated that the variation of the performance of the asphalt during the aging progress is mainly due to the change of its interior components. When asphalt is aging, the content of its lighter components is decreased, such as oil and gelatin, and the content of the heavier components is increased, such as asphaltene. This results in a harder asphalt, which is easily broken at low temperatures. Meanwhile, the aging of the asphalt threatens the safety of the road surface. In the aging process, the low temperature performance and water stability of the asphalt mixture is decreased. The asphalt pavement creates the risk of road fractures and the formation of a loose mixture of asphalt in cold and wet areas [9,10]. Therefore, it is of great significance to improve the service life and performance of asphalt pavement via improving the aging durability of asphalt. Because virgin asphalt cannot meet the requirements of the durability required in asphalt pavement, when paving with highgrade asphalt pavement, modified asphalt is often used as a binder for the asphalt mixture [11]. The modified asphalt mixture greatly improves the properties of the virgin asphalt mixture. Rasool et al. [12] pointed out that adding highly reclaimed rubber and SBS modifiers into virgin asphalt can greatly improve its ductility and its ability to resist aging. R. Liang’s paper reported that rubber powder can greatly improve the viscosity and rheology of the asphalt mixture; this finding was made by observing the viscosity of the rubber powder modified asphalt mixture after short-term aging and rheological tests. At the same time, the aging behavior and rheological performance of the asphalt mixture were found to have a certain linear relationship [13]. TPS and Sasobit modifiers have a significant effect on improving the mechanical performance and anti-aging ability of the asphalt mixture ability [14–۱۶]. Therefore, adding modifiers to improve the performance of asphalt has a significant effect on improving its anti-aging durability.