Optical Characterization of Asphalt Binders Containing Wax Additives

Abstract

In between thermal-oxidative (heat and oxygen) and photo-oxidative (ultraviolet irradiation and oxygen) aging process of bitumen, photo-oxidative aging mainly depends on the optical properties of the asphalt binder. The higher the reflection (or the lower the absorption of the binders), the better the pavement serviceability. The literature review indicates that there is limited research conducted on the optical properties of the binder with wax additives. In this paper, the optical properties of commonly used binders (PG 64-22, Rubber modified binder, and SBS modified binder) containing wax additives (LEADCAP and Sasobit) were investigated using UV-Vis spectrometer. The result of this study showed that (1) the addition of modifiers (crumb rubber and SBS) with the base binder slightly increases the absorption of the binder; (2) the binder types and aging level have significant contribution on optical properties; (3) in general, the aged binders were observed to have higher reflectivity compared to the unaged binders; and (4) the addition of wax additives is observed to have a significant effect on the optical properties.