Utilizing of waste polymer modified bitumen in combination with rejuvenator in high reclaimed asphalt pavement mixtures

Rejuvenating agents have been used to restore physical-rheological properties of reclaimed asphalt binder (RAB) and improve cracking resistance of asphalt mixtures containing the reclaimed asphalt pavement (RAP). Softer bitumen and polymer modified bitumen have also been successfully used to improve performance of the RAP-containing mixtures. Because the use of polymers as bitumen modifier is economically costly, possibility of using waste polymer as a cost effective and environmental-friendly material in hot asphalt recycling was evaluated in this study. The objective of this research study was to evaluate the effect of combination of waste polymer, soft bitumen and rejuvenator simultaneously on the performance of high RAP asphalt mixtures (50%RAP). In this paper the fatigue resistance, moisture susceptibility and rutting resistance of the asphalt mixture were evaluated. The four-point beam fatigue test, resilient modulus test, indirect tensile strength test and dynamic creep test were utilized for this purpose. Moreover, using the dynamic shear rheometer test, the fatigue and rutting resistance of the different asphalt binders were evaluated. The Results showed that use of rejuvenator, waste polymer and soft bitumen simultaneously in 50%RAP mixture, can dramatically enhance fatigue, rutting and moisture resistance of the mixture. Furthermore, waste polymer modified bitumen in combination with rejuvenator had softening effect in RAB-containing asphalt binders at intermediate temperatures while did not have a significant negative effect on rutting resistance of the RAB-containing asphalt binders at high temperatures. (C) 2019 Elsevier Ltd. All rights reserved.