Physical properties and anti-aging characteristics of asphalt modified with nano-zinc oxide powder

Abstract

Asphalt aging holds responsibility for fatigue damage of asphalt pavement. Incorporation of nano-zinc oxide (nano-ZnO) as modifier into asphalt can effectively improve anti-aging property of asphalt. In this work, different dosage of nano-ZnO was added to original asphalt to prepare modified asphalt, and physical properties of nano-ZnO modified asphalt, including storage stability, penetration (25 °C), softening point and ductility (5 °C) were tested. Effect of nano-ZnO on the rheological properties of asphalt was studied by testing rheological properties of modified asphalt before and after aging. In addition, fatigue properties of asphalt with different nano-ZnO dosage were analyzed by linear amplitude sweep (LAS) test. Furthermore, anti-aging characteristics of nano-ZnO modified asphalt were characterized by thin film oven test (TFOT) and ultraviolet aging (UV-aging) test and mechanism was interpreted by UV–visible-infrared absorption test. The results show that nano-ZnO can influence penetration (25 °C), softening point, ductility (5 °C) and storage stability of asphalt. Nano-ZnO can improve complex shear modulus (G*), phase angle (δ) and fatigue performance. Addition of nano-ZnO can evidently improve anti-UV aging ability of asphalt and make asphalt show certain viscosity recovery during aging process. In addition, nano-ZnO has strong absorption characteristics to ultraviolet light with more than 95% absorption rate, which reflects its superiority as anti-UV aging modifier for asphalt. UV absorption of nano-ZnO modified asphalt is enhanced several times than that of original asphalt. Asphalt modified with reasonable nano-ZnO dosage possesses significant and evident anti-aging characteristics.