Investigation of diffusion of rejuvenator in aged asphalt

Recycling asphalt pavement creates a cycle of reusing materials that optimize the use of natural resources. For optimal rejuvenation of the aged binder, the diffusion rate of the rejuvenator should be considered. However, the diffusion mechanism between the rejuvenator and aged asphalt is still far from understood. In this study, two experimental methods were conducted to research the diffusion of rejuvenator in aged asphalt. The two asphalt binders were identical in terms of asphalt A7 (60/80 pen) and asphalt A11 (100/120 pen) and two rejuvenators were identical in terms of RA (containing 90% alkyl aromatic oil and 10% saturate oil), and RS (containing 10% alkyl aromatic oil and 90% saturate oil). Experimental results indicated that two experimental methods are also an effective means to research the diffusion of rejuvenator in asphalt in spite of a slight difference. The effect of temperature on the diffusion coefficient is large and the effect of layer thickness of the rejuvenator on diffusion coefficient is obviously not. The rejuvenator RA has a high diffusion rate in asphalt over a wide range of temperatures. In addition, the diffusion coefficient of rejuvenator in asphalt A11 is larger than that in asphalt A7. The test data suggested that the use of rejuvenator with high diffusion is a viable option for recycling old asphalt mixture.