Sustainable Recycling of Reclaimed Asphalt in Atypical Low-Asphaltene Binders Made from Athabasca Oil Sands Bitumen

Abstract

Utilization of reclaimed asphalt pavement (RAP) and reclaimed asphalt shingles (RAS) in road construction optimizes the use of natural resources by saving on virgin binder and aggregate and, therefore, reducing the overall environmental impact of the industry. This paper presents experimental results of using RAP and RAS with virgin asphalt binders from oil sands deposits in Alberta, Canada. Atypical virgin binder A from an Athabasca source and standard virgin binder C from a Cold Lake source were modified at two different levels of RAP (20% and 40% by weight) and with RAS from a single source. Each blend was tested under three different aging conditions [unaged, rolling thin film oven (RTFO)-aged and pressure aging vessel (PAV)-aged for 20 h]. The RAP sources used in this study came from rehabilitation contracts on Highway 7 and Highway 403 in Ontario, while the RAS was obtained from tear-off shingles sourced locally. Rheological results showed that atypical virgin binder A, containing lower amounts of asphaltenes, accommodates more RAP than harder binder C. The results reveal that A+20% RAP can be used as a lower cost alternative for virgin C, as the two materials possess nearly the same rheological grade (PG 58-28) and flow characteristics. Given the abundance of atypical Athabasca oil sands crudes, it is worthwhile to further investigate low-asphaltene binders produced from such sources for the improved recycling of reclaimed asphalt.