The purpose of this study was to characterize and evaluate the effects of UV radiation on the rheological and physicochemical properties of ASA polymer-modified asphalt. The conventional properties (penetration, softening point, ductility, and Brookfield viscosity) of ASA polymer-modified asphalt were tested. Based on rheology, the effect of different UV irradiation times on the high-temperature performance of ASA polymer-modified asphalt was systematically characterized, the thermogravimetric analyzer (TGA) was used to analyze thermogravimetric properties of ASA polymer-modified asphalt, and the micromorphological characteristics of ASA-modified asphalt under different UV irradiation times were characterized by scanning electron microscope (FIB-SEM). The results show that the ASA polymer has a significant effect on the basic properties of asphalt. Compared with the base asphalt, the high-temperature stability of the modified asphalt was decreased, and the low-temperature ductility performance was improved. ASA polymer can effectively reduce the aging effect of ultraviolet radiation on the base asphalt and inhibit the generation of microcracks. ASA polymers improve the thermal stability of asphalt binders. During the aging process, the formation of carbonyl and sulfoxide groups was inhibited, indicating that ASA polymer can effectively delay the UV aging of asphalt.
For promoting modifying application of sprayed polyurea (SPUA) in asphalt pavement materials, the effects of sprayed polyurea materials on high-temperature and fatigue performance of asphalt binders were investigated from different aspects. First, the optimal preparation parameters of sprayed-polyurea-modified asphalt binders (SPMAs) were determined by designing an orthogonal test. Then, the high-temperature and fatigue properties of sprayed-polyurea-modified asphalt binders with different contents were characterized by rheological testing methods, including Brookfield rotary viscosity (RV) test, performance grading (PG) test, multiple stress creep recover (MSCR) test, linear amplitude sweep (LAS) test and time sweeping (TS) test. Finally, the thermal properties of the asphalt binders were analyzed by differential scanning calorimetry (DSC) test. The results showed that the optimum preparation parameters were determined by the extreme difference analysis method and analysis of variance (ANOVA) method, and the shearing time was 40 min, the shearing rate was 6000 rpm and the shearing temperature was 150 °C. Sprayed polyurea positively affected high-temperature performance of asphalt binders and could improve fatigue resistance of asphalt binders. Moreover, the Brookfield rotary viscosity test, multiple stress creep recover test and linear amplitude sweep test had high sensitivity to the performance of sprayed-polyurea-modified asphalt binder, which could help to distinguish the effect of sprayed polyurea dosing on performance of asphalt binders accurately. The differential scanning calorimetry test showed that sprayed polyurea was beneficial to high-temperature stability of asphalt binders, which explains the reason why sprayed-polyurea-modified asphalt binders have excellent high-temperature performance from a microscopic perspective.
For clarifying the applying feasibility of hindered amine light stabilizers in asphalt binder, two types of hindered amine light stabilizers were chosen as a UV ageing resistance modifier and the modified asphalt was prepared with a selected UV ageing resistance modifier. The ultraviolet aging testing method of asphalt materials was proposed for UV ageing behavior characterization. Under the condition of different frequencies, the impact of UV ageing resistance modifier on asphalt was investigated through using the frequency sweep test of DSR. Under the effect of ultraviolet aging, the variation of thermal properties of UV ageing resistance-modified asphalt was deeply analyzed by means of a temperature scanning test of DSR following the increase of temperature. The change law of the surface morphology of light stabilizer-modified asphalt was characterized by atomic force microscopy (AFM) dynamically with the UV aging time extension. The research results showed that the hindered amine light stabilizer could improve the high temperature performance of asphalt and achieve the UV aging behavior of asphalt materials effectively. Meanwhile, the corresponding reaction mechanism was explored at the microscopic level.
To clarify the influence of geometric parameters of parallel plate on rheological properties of polyurea elastomer (PUA)-modified asphalt, nano-PUA powder was prepared, and nano-PUA powder modifier was modified by using high-speed shearing apparatus. The apparent viscosity of modified asphalt was evaluated by Brookfield viscosity. The rheological parameters of PUA-modified asphalt were determined by comparing the rheological test results of temperature scanning, frequency scanning, and multiple stress creep recover test using 8 and 25 mm parallel plates. Results indicated that the higher the content of nano-PUA modifier was, the better the high-temperature performance of asphalt would be. When using the 8 mm parallel plate, the high-temperature performance of modified asphalt was worse than that of matrix asphalt, and the PUA modifier would lead to a negative effect on the rheological property of asphalt. Regarding the 25 mm parallel plate, the high-temperature performance of modified asphalt was better than that of matrix asphalt, which was contrary to the results of 8 mm parallel plate. The rheological test results using 25 mm parallel plate were consistent with the results of Brookfield viscosity, indicating that 25 mm parallel plate was more suitable for evaluating the rheological performance of PUA-modified asphalt.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.