Reclaimed asphalt recycling agents: Looking into the blueprint of their mechanisms of action

Abstract

As the global environmental crisis is reaching an irreversible point, within the roadway industry, the demand for eco-friendly products such as recycled asphalt pavement is at an all-time high. As a result, and thanks to the promising advancements made in the past decades, doubts no longer exist about the benefits of asphalt recycling. However, the current issue is how to increase the proportion of reclaimed asphalt in new road paving operations. This research study deals with one of the key factors of a successful asphalt pavement recycling; the recycling agents. Several techniques were applied to investigate the mechanism of action of two recycling agents speculated to be rejuvenators and/or flux oils using two different paving grade bitumens. In order to perform a comprehensive study, the testing scheme involved rheological, microscopic, chemical, and physicochemical analyses. Although the physical changes of the aged bitumen containing the studied recycling agents were similar, the chemical impacts were quite different as suggested by the results obtained from the tests performed in this study. The results demonstrate the rejuvenator having an edge over mere fluxing agents in the reversal of the aging phenomenon in bitumen. In fact, this could be determinant in the durability and quality of recycled asphalt pavement.