Finite Element Modeling of Rejuvenator Diffusion in RAP Binder Film – Simulation of Plant Mixing Process
In order to sustain the needs of the 21st century civil infrastructure, we need a paradigm shift in recycling – from current 20-40% to 100% (zero waste). The main hindrance to successful recycling of high Reclaimed Asphalt Pavement (RAP) content mixes is the lack of confidence which stems from a lack of understanding of the rejuvenation and diffusion process that is supposed to occur when a recycling agent is added to an aged asphalt mix. This research presents finite element simulation of rejuvenator diffusion into an aged asphalt binder film. Five different rejuvenators and aged RAP binder were tested to obtain the required input data for simulation – viscosity at different temperatures and molecular weight. The simulation was run assuming 100% RAP mixture and three different temperatures were simulated for three rejuvenator dosages. The final viscosity for complete diffusion and the required time to reach this state was determined. The results show significant differences in the softening potential of different rejuvenators and helps in the estimation of temperature range to reach homogeneous rejuvenator concentration within the binder film before the production process is completed. The simulation results are compared with mechanical tests of binder penetration and mixture creep compliance to confirm the softening effect.
KeywordsCreep Compliance Reclaim Asphalt Pavement Yellow Grease Aged Asphalt Virgin Aggregate
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