Determining optimum rejuvenator dose for asphalt recycling based on Superpave performance grade specifications

• Rejuvenator dose can be optimized restore RAP binder to equal PG of the source virgin binder.
• High and low PG temperatures decrease linearly when increasing rejuvenator dose.
• Intermediate PG reduces linearly up to the G*·sin δ requirement of maximum 5000 kPa.
• Penetration increases exponentially when increasing rejuvenator dose.
• Procedure for optimization of rejuvenator dose to account for RAP variability is presented.

The changes in Superpave performance grade (PG) of Reclaimed Asphalt Pavement (RAP) binder were determined after addition of two doses of six rejuvenators. The high and low PG temperatures were reduced linearly with an increased dose while the penetration grew exponentially. It was found that the grade sum of rejuvenated RAP binder is always higher than that of the corresponding virgin binder. Based on these conclusions a procedure for optimizing the rejuvenator dose to satisfy the Superpave PG requirements was developed to account for the inevitable variability of the RAP binder due to differences in aging and source.

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