Effect of Asphalt Binder Grade and Source on the Extent of Rheological Changes in Rejuvenated Binders

Abstract

Rejuvenators are primarily added to aged binders to restore their properties by lowering their stiffness and improving their stress relaxation. The type of interaction that takes place between the rejuvenator and the binder is still under extensive study. This research aims at investigating the extent by which the performance grade (PG) and source of the original binder affect the performance of a soybean-derived rejuvenator. The rejuvenator was added at a dosage of 6% and 12% by weight of the binder to three distinctly different binders, namely a PG58-28 binder, an extracted reclaimed asphalt pavement (RAP) binder, and a residuum oil super critical extraction (ROSE) unit bottom binder. The binders were selected so that they varied significantly in terms of their properties, performance grade, and source. The rheological properties of the rejuvenated binders were studied using a dynamic shear rheometer (DSR) and bending beam rheometer (BBR) at different stages of aging. Using the DSR, temperature-frequency sweeps were conducted and the complex shear modulus master curves as well as the phase angle master curves were constructed. The data from the master curves were used to assess changes in fatigue and rutting parameters with rejuvenation. The fatigue behavior was further investigated using linear amplitude sweep testing. The results indicate that the rejuvenator had a similar effect on the binders; however, the extent of rejuvenation was more pronounced for the stiffer binders.