Abstract
Asphalt rubber (AR) is a sustainable paving material with merits including waste tire consumption, low traffic noise, and enhanced mechanical performance. However, the poor workability and storage stability limited its further application. This study attempted to alleviate these two concerns of AR simultaneously by incorporating heavy bio oil (HBO). To achieve this goal, bio-AR binders with three different mixing sequences were prepared. A series of rheological and chemical tests were conducted. Test results prove that the bio-AR binders exhibited superior rutting and fatigue resistance compared to AR binder. The viscosity values of bio-ARs were closed to AR modified with commercial warm mix additive, which indicates enhancement in workability. Due to the relatively high density of HBO, the density difference between the asphalt liquid phase and crumb rubber in the bio-AR system narrowed, which brought improved storage stability. Among bio-ARs prepared with different mixing sequences, the direct mixing one (ARB) had the most satisfied overall performance. The early incorporation of HBO had limited negative influence on binder performance, but allowed for more energy saving during the bio-AR binder production. Future study will be conducted on performance of bio-AR mixtures and quantitative estimation of its energy saving during the blending and compacting process.
Highlights
Asphalt mixture, composed of bituminous binder and mineral aggregates, is the most common paving material for highways and urban roads
Light fractions of bitumen are absorbed by the crumb rubber modifiers (CRM), which leads to the swelling of the crumb rubber [5,6]
Pen60/70, which was provided by Guangzhou Xinyue Transportation Technology Co., Ltd., Guangzhou, China, was selected as virgin bitumen to prepare asphalt rubber (AR) and heavy bio oil (HBO)-AR binders
Summary
Asphalt mixture, composed of bituminous binder and mineral aggregates, is the most common paving material for highways and urban roads. Due to the growing traffic loading and aggravation of axis, incorporating polymer modifiers (e.g., styrene-butadiene-styrene, crumb rubber, polyethylene) in virgin bitumen for superior adhesive and cohesive performance has become a common practice [1,2,3,4]. Among the modified bituminous binders, asphalt rubber (AR) is considered a green paving material with attractive engineering and environmental benefits. Certain amount of crumb rubber particles (usually 15–20 wt %) are blended with hot virgin bitumen. The incorporation of resilient rubber particles leads to enhanced rutting, fatigue, and low-temperature cracking resistance of asphalt pavement [8,9,10].
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
