Wearing course mixtures prepared with high reclaimed asphalt pavement content modified by rejuvenators

This paper presents an experimental investigation on the combined use of high content of reclaimed asphalt pavement (RAP) and rejuvenators, for producing asphalt mixtures for wearing courses. First, the new Binder-Fast-Characterization-Test (Bitumen Typisierungs Schnell Verfahren in German) BTSV method, recently proposed in Germany, is used to determine the amount of rejuvenator required to design recycled mixtures for a specific RAP source. Then, a set of seven asphalt mixtures for wearing course is prepared with different amounts of RAP and with three types of rejuvenators. The BTSV procedure is further applied to evaluate the rheological properties of the binder extracted from the mixtures. Resistance to permanent deformation, stiffness, fatigue, and low temperature behavior tests are then performed to determine the material response. It is observed that the use of recycled material and rejuvenators results in similar or better deformation resistance, higher stiffness and enhanced low temperature properties, with an improved fatigue behavior, also for high RAP content, when compared to mixtures prepared with virgin material. These findings suggest the possibility of using rejuvenators for field tests on wearing courses.