Rheological characteristics investigation of high percentage RAP binders with WMA technology at various aging states

• This study is to explore rheological properties of the high percentage of RAP binder.
• Viscosity, failure temperature, rutting and fatigue resistances of binders were tested.
• RAP source affected the performance properties of combined asphalt binders.
• WMA additive could offset the effect of RAP binder on the rheological properties.
• Additional RAP could improve the rutting resistance and reduce fatigue resistance.

The application of reclaimed asphalt pavement (RAP) is very promising and the research activities focusing on this subject is numerous in recent year. However, how to increase the percentage of RAP in the surface layer mixtures of asphalt pavement and meet or exceed the standards is challenging to the state highway agencies in the USA. The objective of this study is to explore the rheological properties of the high percentage (up to 50%) of RAP binder with three base binders in terms of five RAP binder content, two RAP binder sources, one HMA and one warm mix additive (WMA) technologies at three aging states. The viscosity, failure temperature, rutting resistance, fatigue resistance of various asphalt binders were tested in this study. The results indicated that the combined binders after a short term aging and a long term aging procedures still satisfied the requirement of asphalt binder set by Superpave binder specifications. In addition, increasing the RAP binder concentration could improve the rutting resistance of asphalt binder but a reduction in the fatigue resistance was noticed. However, the WMA additive could offset these properties of combined binder. Moreover, the results indicated that the RAP source typically affected the performance properties of combined asphalt binder and should be investigated individually.