Rheological and aging characteristics of the recycled asphalt binders with different rejuvenator incorporation methods

With the ever-increasing awareness for sustainability, the utilization of reclaimed asphalt pavement (RAP) and recycled asphalt shingles (RAS) in asphalt paving has become more and more popular in recent years. To restore the rheological and other properties of aged binders, rejuvenators are commonly used during the asphalt mixtures production containing RAP and/or RAS. The conventional rejuvenation incorporation method is to blend the rejuvenators with virgin binder first, followed by mixing with other recycled materials. This paper presents a laboratory study on asphalt binder with a different rejuvenator application procedure, which blends the rejuvenators with the recycled materials first and then incorporates the blends with the virgin binder afterwards. Rheological and aging properties of asphalt binders blended with different procedures were analyzed through the dynamic shear rheometer (DSR) test and gel permeation chromatography (GPC) tests. Compared to the conventional method, it was revealed that the method by blending the rejuvenators with the recycled materials first significantly improved the workability of the binder blends during mixing. The new method resulted in a different rheological property and caused less aging effect for the asphalt binder blends in the short-term aging. However, for the long-term aging, the two incorporation methods exhibited similar aging effects on the binder blends.