Study of the Diffusion of Rejuvenators and Its Effect on Aged Bitumen Binder

Abstract: Aged asphalt mixture is heavily involved in pavement maintenance and renewed construction because of the development of recycling techniques. The aged bitumen binder has partially lost its viscous behavior. Rejuvenators are therefore designed and used in this recycling procedure to enhance the behavior of such aged reclaimed bitumen. However, tests have not yet been clearly specified to understand the diffusion characteristics of rejuvenators in aged bitumen. In this research, molecular dynamic simulation is proposed and conducted with Materials Studio software to study the diffusion behavior of rejuvenators in aged bitumen at the molecular level. Two rejuvenators, named R-1 and R-2, were included. The difference between these two rejuvenators is their chemical composition of C=O. The diffusion coefficient is determined by studying the molecular movement. Results illustrate that the proposed models can be used to study the diffusion of rejuvenators in aged bitumen sufficiently. In the meantime, a dynamic shear rheometer (DSR) is used to evaluate the recovery influence on aged bitumen resulting from rejuvenators. The experimental results strengthen the model simulations and indicate that the aging index of bitumen has a significant influence on the rejuvenating effect. Research results indicate that rejuvenators have a sufficient rejuvenating effect on the long-term aged bitumen and a limited effect on short-term aged bitumen.

Keywords: bitumen binder; molecular simulation; diffusion of rejuvenator; aged bitumen; rheological properties

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About Yue

An Associate Professor from State Key Lab of Silicate Materials for Architectures in Wuhan University of Technology, China since January 2014. Received PhD degree in Road and Railway Engineering in 2013 from Delft University of Technology in the Netherlands. His research interests are on asphalt pavement surfacing, road and pavement materials, asphalt pavement design.
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