Case study: Characterization of short-term field aged asphalt binders in cold mix asphalt pavement

In recent years, rejuvenators have been used in cold asphalt mixtures to assist sustainability efforts. However, most studies on this topic have focused on laboratory prepared samples only. This study characterized the shortterm field asphalt binders that were extracted from the surface layer of a field project that utilized cold mix with 100% reclaimed asphalt pavement (RAP) and rejuvenator in Florida, USA. Rheological testing was performed on the extracted RAP binders with and without rejuvenator with respect to high and intermediate temperature performance grading (PG), multiple stress creep recovery (MSCR), frequency sweep, and monotonic fracture tests. Results showed that there was no significant difference in rutting resistance between extracted rejuvenated RAP binder and extracted RAP binder. The rejuvenated RAP binder had lower stiffness and better relaxation properties than the RAP binder suggesting it can soften recycled binders. Furthermore, the rejuvenated RAP binder exhibited higher fatigue life and higher failure strain than the RAP only binder, suggesting that the addition of rejuvenator in the 100% RAP can restore the functionality and flexibility of recycled binders in a short-term field aging period.