Evaluation on Feasibility of Carbon Black and Hindered Amine Light Stabilizer as UV-Resistant Additives of Asphalt Binder

Abstract Ultraviolet (UV) radiation is one of the main causes of asphalt pavement aging. The development of UV-resistant technology is of great significance to improve the durability of asphalt pavement. In order to evaluate the feasibility of carbon black (CB) and hindered amine light stabilizer (HALS) as UV-resistant additives, the modified asphalt binders were prepared by adding CB and HALS. The dispersibility of UV-resistant additives in asphalt binder was evaluated by using a fluorescence microscope. Then, the aging resistance of additives and their effects on virgin asphalt binder were qualitatively evaluated by calculating rheological parameters. The new aging-resistant index and impact index were defined. The results show that the aging-resistant index and impact index can accurately characterize the aging resistance of additives and their effect on virgin asphalt binder. The UV-resistant additives slowed down the aging rate of asphalt binder. A 3 % dosage of CB had a great adverse effect on the properties of virgin asphalt binder. HALS showed good UV resistance and had little effect on virgin asphalt binder. The aging-resistant index of asphalt binder modified by HALS was about 1.63 times that of the asphalt binder modified by CB at the same dosage (1 %). The aging-resistant index of asphalt binder modified by 1 % HALS was only about 1.31 times that of asphalt binder modified by 0.5 % HALS. In addition, the dosage of HALS was changed from 0.5 % to 1 % and the impact indexes changed to more than 2.67 times. It was considered that HALS was more suitable for improving the aging resistance of asphalt binder with an optimal dosage of 0.5 %.