Quantification of Oxidative Aging of Polymer-Modified Asphalt Mixes Made with Warm Mix Technologies

This research investigates the oxidative aging levels of polymer-modified asphalt (PMA) mixes using gel permeable chromatography (GPC), which can help to simplify the quantification of asphalt aging. Warm-mix asphalt (WMA) technologies, namely, Aspha-min and Sasobit, were especially adapted to the PMA mixes for the purpose of the aging reduction. A short-term oven aging (STOA) procedure was used under 135 and 154°C for 2 and 4 h, respectively, to simulate the asphalt binders aged during the field operations (i.e., production, hauling, and paving construction). The aging levels were analyzed based on large molecular size (LMS) of the binders extracted from the mixes. A rolling thin-film oven (RTFO) method was also utilized using PMA binders containing those WMA additives under 135 and 163°C for 85 minutes for comparison purposes. The results showed that (1) aging time and temperature were important parameters to influence the aging; (2) the STOA procedure had a higher aging level than the RTFO method, which could be influenced by thin film thickness on aggregates; (3) the use of WMA technologies was effective to reduce the aging level of PMA mixes; and (4) it was possible to quantify the oxidative aging of PMA mixes [both hot-mix asphalt (HMA) and WMA] using the GPC technique.