Effect of rejuvenator on performance characteristics of high RAP mixture

As more reclaimed asphalt pavement (RAP) is utilised in asphalt mixtures, there are increasing concerns about the potential negative effect of the aged RAP binder on the field performance, especially cracking resistance, of the high RAP mixtures. To address the concerns, there have been increasing interests in utilising rejuvenators to improve the cracking performance of high RAP mixtures. The objective of this study was to determine the benefits of using a new rejuvenator made from renewable sources in asphalt mixtures with high RAP contents. The study was conducted by determining and comparing the laboratory performance properties of three mixtures and the binders extracted from the mixes. The three mixtures evaluated in this study included two 50% RAP mixtures (RAP binder ratio = 0.55) with and without the rejuvenator and a comparable virgin mix. Results of this study suggested that the new rejuvenator was effective in improving both the intermediate and low-temperature cracking performance characteristics of the 50% RAP mix close to those of the virgin mix at the short-term laboratory ageing condition without affecting its rutting and stripping resistance. It is recommended that a field study of this rejuvenator be conducted to further evaluate its effect on the long-term field performance of high RAP mixes.