Effect of Rejuvenators on Rheological, Chemical, and Aging Properties of Asphalt Binders Containing Recycled Binders

Abstract

The use of reclaimed asphalt pavements (RAP) and recycled asphalt shingles (RAS) in pavements has already become a norm in the United States because of the substantial reduction in construction cost, energy consumption, and greenhouse gas emissions. However, highway agencies are still reluctant to increase the overall percentage of RAP and RAS in asphalt pavement mixtures because of a higher potential of premature cracking in these pavements. To avoid early pavement failures and untoward maintenance cost, rejuvenators are being increasingly used in asphalt mixtures to reconstruct the chemical structures of oxidized RAP and RAS binders. However, the overall effects of rejuvenators on the properties of asphalt binders have not been well studied in recent years and used in determining the optimum dosages for different rejuvenators. This study characterizes the effects of rejuvenators on the rheological, chemical, aging, rutting, and cracking properties of asphalt binders containing recycled binders and then uses the findings to recommend optimum dosages. To that end, PG 64-22 virgin binders were blended with different types of rejuvenators and recycled binders at various concentrations. Laboratory test results showed that rejuvenators could reduce the stiffness, oxidation, and cracking potential of these blends. Results also suggested that selecting the rejuvenator dosage and type on the basis of only one criterion could not meet the specifications of traditional virgin binders. In addition, the results showed that different rejuvenators worked differently with different mixtures.