Rejuvenator dose optimization

Rejuvenator dose has to be optimized to ensure reduced stiffness and improved resistance to cracking without over softening the binder to cause rutting. To develop a procedure for selecting optimum rejuvenator dose the changes in RAP binder performance grade and penetration with the application of two contents of the six previously tested rejuvenators were evaluated. The study showed that for all of the rejuvenators the high and low PG temperature were reduced linearly with an increased dose while the penetration grew exponentially. All rejuvenators at an optimum dose could restore the RAP binder to the performance grade of the source PG 64-22 binder and multiple grades could be formulated by changing the dose. An outline for optimizing the rejuvenator dose was developed to account for the variability of the RAP binder due to differences in aging and source.