Rejuvenating Agents with RAP in HMA

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CAIT project no.: FHWA-NJ-2015-008 (272-RU3920)

Fiscal Year: 2011/2012

Status: Final

Rutgers-CAIT Author(s): Thomas Bennert, Ph.D.

External Author(s): Eileen Sheehy

Sponsor(s): New Jersey Department of Transportation


One potential method to aid in the blending of the RAP and virgin binders, as well as the general softening of the RAP binder, is to use a rejuvenating agent. An asphalt rejuvenator is a manufactured product that has the ability to absorb or penetrate into the asphalt mixture/material and potentially restore reactive components—or rebalance them—that have been lost due to oxidation.

The benefit of a rejuvenating agent is that it can be preblended with the virgin asphalt binder or added during the mixing process, as opposed a softer PG-graded binder that would require an additional storage tank on site. NJDOT needed guidance as to which rejuvenating agents are more practical, environmentally friendly, and best obtain NJDOT-specified properties when they considered adopting their use.

This research study evaluated the effectiveness of various rejuvenators currently on the market. The research looked at how the rejuvenator impacted the virgin binder used in the asphalt mixture, as well as the resultant asphalt binder properties of the high RAP asphalt mixture.

Mixture performance tests were used to evaluate the rutting- and fatigue-cracking performance of the high RAP mixtures within the limits of the NJDOT High-RAP specification.