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A high percentage of reclaimed asphalt pavement (RAP) in new asphalt concrete can lead to developing premature failure of asphalt pavements due to fatigue or low-temperature cracking. The use of softening agents in asphalt binders can resolve these problems. The aim of this study is to evaluate the effectiveness of softening agents for enhancing the properties of asphalt mixes with high RAP contents. Two waste products, namely, waste cooking oil (WCO), and engine bottom oil (EBO) along with a commercially produced rejuvenator were investigated in this study. The following three types of Performance Grade (PG) binders, each collected from two different sources, were considered in this study: PG 64-22, PG 70-22, and PG 76-22. These PG binders blended with different amounts (0, 15, 25, 40, and 60%) of RAP binders were rejuvenated with different dosages (0, 10, 15, and 20%) of the selected softening agents. Empirical tests (e.g., penetration and pH), Superpave tests, Atomic Force Microscope (AFM), Scanning Electron Microscope (SEM), Fourier Transform Infrared Spectroscopy (FTIR), and limited laboratory and field performance of asphalt mixture samples were also evaluated. It was found that the rejuvenators reduced the viscosity of the binder samples. The results showed that the rejuvenated binders reduce the production temperatures as well as the brittleness of the hard binders. The AFM results showed that modulus and deformation values of rejuvenated binders were significantly less than those of their unrejuvenated counterparts. Similarly, distinct peaks were observed in the FTIR peaks due to the rejuvenation. The findings of this study will help pavement professionals in selecting suitable rejuvenators in the construction of pavements with high RAP contents.


Tran-SET Project: 20BASU23