USE ATYPICAL ASPHALT BINDERS FROM ALBERTA OILSAND SOURCES FOR THE EFFECTIVE RECYCLING OF ASPHALT PAVEMENT

Abstract

Utilization of Reclaimed Asphalt Pavement (RAP) and Reclaimed Asphalt Shingles (RAS) optimizes the use of natural resources by saving the cost for virgin asphalt binders and therefore reducing their environmental footprint. This thesis presents experimental results of using RAP and RAS with virgin asphalt binders from Alberta oil sands deposits. Virgin asphalt binder A from the Athabasca deposit and virgin asphalt binder C from the Cold Lake deposit were modified at two different RAP weight percentages (20 % and 40 % by weight of the total binder). Each blend was tested under four different aging conditions (Unaged, Rolling Thin Film Oven-aged (RTFO), Pressure Aging Vessel-aged (PAV) for 20 h (PAV-20) and 40 h (PAV-40)). The RAP sources used in this study came from rehabilitation contracts on Highway 7 and Highway 403, while tear-off shingles were used as a source of RAS binder. Fourier Transform Infrared (FTIR) spectrometry was used to monitor the degree of oxidation when binders were modified with RAP and RAS and subsequently aged in RTFO and PAV. Rheological properties of the modified binders after different aging protocols were assessed using a Dynamic Shear Rheometer (DSR). Hot Mixed Asphalt (HMA) tests were conducted for neat asphalt binders, 20 % RAP-modified binders and Polyethylene Terephthalate (PET)-modified binders using the Illinois Flexibility Index Test (I-FIT) at two different temperatures (room temperature and -10 °C). Rheological results showed that virgin binder A is the softer one and therefore accommodates more RAP than C. The results also reveal that 20 % RAP added to A can be used as a lower cost alternative for virgin C, as the two materials possess nearly the same rheological grade. According to the I-FIT results, using neat A with 20 % RAP gives higher flexibility than using neat C for HMA. Finally, using PET fibers with virgin binders drastically increases the flexibility of the HMA in the semi-circular bending test.