Influence of Rejuvenators on the Physical Properties of RAP Binders

Abstract

Abstract An experimental study was conducted to characterize the physical properties of rejuvenated RAP binders at low, intermediate, and high temperatures via dynamic shear rheometer (DSR) and differential scanning calorimeter (DSC) measurements. A dynamic shear rheometer was used to conduct frequency sweeps at temperatures ranging from −20°C to 80°C in increments of 20°C. The effect of rejuvenators on the thermal behavior of highly aged asphalt binders was also studied by temperature-modulated differential scanning calorimetry (TMDSC). Both DSR and DSC indicate that the interaction between rejuvenators and asphalt binders has different softening effects on RAP binders. Of the four concentrations used in this study, 10 wt. % of rejuvenator appears to be the optimum. 30 wt. % of rejuvenator onto highly aged binder results in material softer than the original RTFO-aged asphalt binders. Rheological results suggest that vegetable oil base and maltene base rejuvenators provide similar flow property improvement for highly aged binders. The DSC results indicate that vegetable-oil-based rejuvenator improves thermal behavior the most as compared to the other two rejuvenators. The results obtained from rheological testing agree with the results from DSC.