Recently, the use of reclaimed asphalt pavement (RAP) has become more and more popular, due to environmental and economic concerns. However, as high RAP content used over 30%, asphalt mixtures become brittle so that premature failure (cracking) may occur. In order to improve the cracking resistance of asphalt mixtures with high RAP contents, one of the approaches considered is the use of rejuvenator. Furthermore, a good rejuvenator should not only have superior regeneration and anti-aging properties, but also should have appropriate diffusion. In order to investigate the diffusion phenomenon, three types of rejuvenator were used: rubberwood bio-oil (RWO), rejuvenator-1 (RA1), rejuvenator-2 (RA2). Therefore, the objective of this study is to develop a new doughnut contact blending method to determine the diffusion level between rejuvenator and aged binder using rheological by using Dynamic Shear Rheometer (DSR) and verify by chemical analysis by Fourier Transform Infrared Spectroscopy-Attenuated Total Reflectance (FTIR-ATR). The concept of diffusion using aged binders with different rejuvenator with conditioning time, as natural diffuse and play with percentages rejuvenator adding as artificial diffuse. The trend of the curve shows that tested by standard and hollow upper plate did not give that big different for complex modulus master curve. For natural diffuse scenario, the equivalency blending level showed the biggest value for RAB-RA1, followed by RAB-RA2 and RAB-RWO. It verified by FTIR result, the absorbance peak results were consistent with DSR result. The absorbance peak of natural diffuse headed closer to absorbance peak of fully blended. The result indicates that the diffusion occurred between aged binder and rejuvenator, and an innovative testing method with doughnut contact blending to determine the diffusion level by DSR was verified.

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