Performance Evaluation of the Thermal Cracking Resistance of Asphalt Mixtures Prepared with High RAP Content and Rejuvenators

Abstract

The utilization of reclaimed asphalt pavement (RAP) in asphalt mixtures provides significant environmental and economic benefits, however improper mix design can lead to stiffer mixtures that are prone to cracking. To restore the rheological properties of aged RAP binders, rejuvenators and recycling agents are used. Most studies focus on the rheological properties of reclaimed asphalt binders at the binder level, with limited research on low-temperature cracking performance at the mixture level. This study investigates the cracking (low- and intermediate-temperature) and rutting performance of asphalt mixtures with high RAP content (70% RAP) and two rejuvenators (tall oil and waste vegetable oil). The results show that rejuvenators significantly improve the performance of asphalt mixtures through enhancing the resistance to both low- and intermediate-temperature cracking without compromising rutting resistance. In addition, the use of rejuvenators was found more effective in improving the performance of asphalt mixtures with high RAP content than increasing the binder content by 0.5% above the optimum binder content.