Study of rejuvenators dynamic diffusion behavior into aged asphalt and its effects: Fid-Bau Portal

Study of rejuvenators dynamic diffusion behavior into aged asphalt and its effects

Xu, Meng / Zhang, Yuzhen

Highlights • Aromatic of rejuvenators could promote its diffusing into aged asphalt. • Only if viscosity was low enough to promote the Brownian movements, the diffusion would be in progress. • Molecules with large molecular polarity and smaller molecular size were easy to diffuse. • Long-chain saturated hydrocarbon structure was not conducive to diffuse, and some large functional groups also played an obstacle role in diffusion process. • Temperature promotes diffusion process and diffusion coefficients decreased significantly with prolonged time.

Abstract Recycled asphalt pavements are widely used in road maintenance and reconstruction with techniques developing. As aged asphalt would partially lose its initial properties, rejuvenators have been developed and used in recycling process to enhance properties of such aged asphalt. In this research, three rejuvenators with different composition and three markers with typical and different molecular structures were used to study the dynamic diffusion behavior of rejuvenators into aged asphalt. Diffusion tests were designed based on the viscosity and SARA test to evaluate the diffusivity. IR tests were used to study the diffusion trace of markers. Diffusion coefficients were calculated to evaluate the dynamic diffusion behavior based on Fick’s law. The main conclusions are as follows: Aromatic content promoted the diffusion of rejuvenators into aged asphalt. Molecules with larger molecular polarity and smaller molecular size were easier to diffuse. Diffusion coefficient of dodecanoic acid was the lowest, indicating that the long-chain saturated hydrocarbon structure is not conducive to diffuse, and some large functional groups will also play an obstacle role in diffusion at microscopic level.