Effect of Waste Cooking Oil Viscosity on Basic and Rheological Properties of Aged Asphalt

Abstract

Waste cooking oil (WCO) can be used to rejuvenate aged asphalt and restore its properties. However, the influence of WCO properties on rejuvenating behavior of aged asphalt is still unknown. The objective of this study is to investigate the effect of WCO viscosity on basic and rheological properties of aged asphalt. The materials used for this study included eight kinds of WCO (fabricated by fresh soybean oil in the laboratory) and one aged asphalt (AH-90). The basic properties of rejuvenated asphalt were characterized by penetration value, softening point and ductility, then the influence of WCO viscosity on rheological properties of rejuvenated asphalts were evaluated by rotational viscosity, rutting parameter, complex modulus and phase angle master curves, and creep recovery ratio. The experimental results indicate that WCO viscosity has a great influence on the properties of rejuvenated asphalt, and different aged asphalts require WCOs with different viscosity to achieve the desirable rejuvenation effects. Basic and rheological properties of aged asphalt can be restored to some extent but there are still gaps between the basic performances of WCO rejuvenated asphalts and virgin asphalt. WCOs with too high or too low viscosity values would have an adverse impact on the performance recovery of rejuvenated asphalt. WCO with viscosity ranging from 420–700 mm2/s are preferable to restore the properties of rejuvenated asphalt in this research.