Feasibility assessment of CeO2 nanoparticles as aging-resistant agent of asphalt

Abstract

Asphalt aging seriously decreases the pavement performances and service life of asphalt pavement. Previous studies have indicated that CeO2 nanoparticles reveal ultraviolet light absorption characteristics. While the function mechanism of CeO2 nanoparticles to asphalt is still not clear. To further enrich the types of aging-resistant agent and extend the service life of asphalt, the influence of CeO2 nanoparticles on the aging resistance of asphalt was explored in this paper. The optical characteristics of CeO2 nanoparticles crystal and layered double hydroxides (LDHs) crystal were analyzed by ultraviolet visible spectrophotometer. CeO2 nanoparticles modified asphalt and LDHs-modified asphalt were prepared and phase segregation tests were performed to evaluate the compatibility of modified asphalt. Subsequently, brookfield viscometer and dynamic shear rheometer (DSR) were conducted to evaluate the viscosity and rheological properties of virgin asphalt, CeO2 nanoparticles modified asphalt and LDHs modified asphalt before and after thin film oven test (TFOT), pressure aging vessel (PAV) and ultraviolet (UV) aging. And their functional group characteristics and micromorphology were investigated through fourier transform infrared spectrometer (FTIR) and atomic force microscope (AFM). The results show that CeO2 nanoparticles mainly absorb ultraviolet light, while LDHs mainly reflects ultraviolet light. The storage stability of CeO2 nanoparticles modified asphalt is slightly lower than that of LDHs modified asphalt, but the storage stability of the two modified asphalt met the specification requirements. Incorporating CeO2 nanoparticles to asphalt can augment the viscosity and complex modulus of asphalt and strengthen its anti-aging ability, especially for anti-ultraviolet aging. There is not new absorption peak on the infrared spectrum of CeO2 nanoparticles modified asphalt binder after the modification, which illustrates that modification of CeO2 into asphalt is considered to be a physical process. Moreover, LDHs modified asphalt demonstrates superior anti-aging effect than that of CeO2 nanoparticles modified asphalt. Overall, CeO2 nanoparticles can also be used as an aging-resistant agent of asphalt.