Development of a Laboratory Medium-Term Oven Aging (MTOA) Protocol with Field Validation for Asphalt Mixes Containing RAP

In this study, laboratory loose mix oven aging was compared to field aging to begin calibration for a medium-term oven aging (MTOA) protocol. Five different oven aging temperatures were implemented at different durations to evaluate the change in chemical and rheological aging parameters for four plant-produced asphalt concrete (AC) mixes. The sulfoxide (SUL) index failed to show a consistent trend with aging for extracted binders obtained from both loose mixes and field slabs. The carbonyl area (CA) index was found to show a linear trend with the binders’ rheological parameters. The results of the field calibration indicate that loose mix oven aging of 20hours at 100°C can simulate field aging at 0.5 inches to 0.6 inches (12mm to 15mm) depth after six years of pavement life in the climate region and for the material tested. Based on these results for a hot climate, loose mix aging of 20hours at 100°C was proposed as the MTOA protocol for AC mixes for future studies.