Synergistic effect of surface modified nano-zinc oxide and organic vermiculite on long-term ultraviolet and thermal-oxidative aging resistance of different asphalt binders

Asphalt pavement will be subjected to the action of thermal, oxygen and ultraviolet during long-term service, which in turn causes the ultraviolet and thermal-oxidative aging of asphalt simultaneously. Based on the long-term aging mechanism, the double retarding effect of surface modified nano-zinc oxide (ZnO) and organic vermiculite (OEVMT) in different stages of long-term aging was utilized in the research. This work investigated the synergistic effect of ZnO and OEVMT on rheological properties and chemical structures of base asphalts (70# and SK-70) and polymer modified asphalts (SBS modified asphalt and SBR modified asphalt) after long-term ultraviolet and thermal-oxidative aging. Dynamic shear rheological (DSR), bending beam rheological (BBR) and Fourier infrared spectroscopy tests were utilized to study the DSR properties, BBR properties at low tem-perature and chemical structures, respectively. Meanwhile, the synergistic effect mechanism was analyzed. Results showed that the effect of 1 % ZnO to resist the long-term ultraviolet aging of 70# base asphalt ap-proximates that of 3 % OEVMT, while the long-term thermal-oxidative anti-aging ability of 1 % OEVMT for 70# base asphalt is equivalent to that of 3 % ZnO. Besides, compared with 2 % ZnO or 2 % OEVMT, 1 % ZnO + 1 % OEVMT shows a better long-term ultraviolet and thermal-oxidative aging resistance for different asphalt binders, indicating its synergistic effect in strengthening the anti-aging performance of asphalt. Moreover, 1 % ZnO + 1 % OEVMT not only can effectively retard the oxidation rate of asphalt in the process of long-term aging, but also inhibit the degradation degree of modifiers in SBS modified asphalt. The research could propose a new design idea to effectively solve the long-term aging problem of asphalt.