Comparing Rheological Indexes to Optimize Rejuvenator Dosage for Asphalt Binders Containing High Ratios of Recycled Asphalt

Determining the optimum dosage of a rejuvenator is essential to fulfilling its restoration mission on aged bitumen. Inadequate rejuvenator dosage will lead to insufficient rheological property restoration, whereas excessive rejuvenator content will oversoften the binder blend, leading to impaired rutting resistance. Two different methods, namely, blending chart and response surface modeling, are used in this study to optimize the rejuvenator dosage of binder blends with a high reclaimed asphalt pavement (RAP) binder ratio. Recycled binder blends were prepared using 25 %, 50 %, and 75 % recovered RAP binder and the corresponding virgin binder proportions, with added rejuvenator contents ranging from 0 to 10 % by weight of the binder blend. Rheological tests were performed under a wide temperature range to obtain different indexes as optimization criteria. Indexes include rotational viscosity at binder mixing and compaction temperatures, critical performance grading (PG) temperatures, nonrecoverable compliance, and crossover temperature. The results indicate that indexes obtained at a higher-temperature range required more rejuvenator content to restore the properties of the recycled binder blend to reach a target value. Some indexes only reflected the decrease in stiffness without revealing the changes in the viscous behavior and relaxation capacity. In addition, the selection of optimization criteria should consider the dominant distress type for the specific region. The difference in rejuvenator dosage determined by the blending chart and response surface modeling methods was found to be marginal.


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  • Accession Number: 01880813
  • Record Type: Publication
  • Files: TRIS
  • Created Date: Apr 24 2023 4:19PM