Laboratory Evaluation of Effect of Addition Methods of Rejuvenators on Properties of Recycled Asphalt Mixtures

The objective of this study was to compare the effectiveness of rejuvenators and determine how the methods of adding rejuvenators into recycled asphalt mixtures could affect their performance. In this study, five different rejuvenators (three bio-oils, one aromatic extract, and one rerefined engine oil bottom), three recycled asphalt mixtures (30% RAP mix, 40% RAP mix, and 25% RAP/5% RAS mix), and four methods of adding rejuvenators (terminal blend, belt spray, 48-h marination, and 14-day marination) were included in the experimental plan. Performance grading of the binders extracted from the mixtures and mixture performance tests to characterize the resistance of the recycled asphalt mixtures to raveling and cracking were conducted and analyzed. The results of this study indicated that tall oil could be more effective in improving binder performance grades than the other rejuvenators evaluated in this study, and the four methods of adding rejuvenators into the recycled asphalt mixtures showed statistically similar effects on the mix performance. The findings in the study are drawn based on the limited types and dosages of rejuvenators, and the conclusions could be different when other rejuvenators and dosages are used.