Evaluation of Oxidative Aging with SAR-AD™ in Asphalt Recovered from Plant Produced Asphalt Mix

摘要

In Ontario, asphalt cement properties have been accepted based on Performance Graded (PG) properties, in accordance with the American Association of State and Highway Transportation Officials (AASHTO) standards, since the adoption of the Superpave technology in early 2000s. To simulate oxidative aging and its effect on the asphalt properties, two accelerated conditioning procedures are used in the Superpave PG grading system: the Rolling Thin Film Oven (RTFO) test for short-term (production and placement) aging, and the Pressure Aging Vessel (PAV) for longer-term (in-service) aging. However, these aging protocols have been shown to not correlate with actual field aging. In 2009, the Ministry of Transportation Ontario (MTO) conducted a study to determine how well the PG system correlated to field performance. The study concluded that correlation of the PG system can be improved if field aging can be better replicated in the laboratory. This paper compares the oxidative aging that is simulated by the RTFO and PAV aging in the laboratory, to the short-term aging that occurs during asphalt mix production and placement on a job site. Chemical analysis through SAR-AD™ was used to determined concentrations of the asphalt fractions (i.e., saturates, aromatics, resins, and asphaltenes).