Impacts of rejuvenators on performance and engineering properties of asphalt mixtures containing recycled materials

Recycled materials, such as recycled asphalt shingles (RAS) and reclaimed asphalt pavement (RAP), have been widely used in asphalt paving industry, and the trend seems to use more and more, which can save taxpayer dollars, preserve energy and protect the environment. However, these recycled materials are often highly aged and cause potential durability issue for asphaltic layers. To balance out the impact of stiff binder of recycled materials, rejuvenators have been recently evaluated. This study investigated the impacts of various rejuvenators on the performance and engineering properties of hot-mix asphalt (HMA) mixtures containing recycling materials (i.e., RAP and RAS). Various laboratory tests, including Hamburg test, overlay test, dynamic modulus test, and repeated load test, were performed to compare the performance and engineering properties of HMA mixtures without rejuvenators to those of mixtures incorporated with rejuvenators. In addition, a simple cost analysis was performed to investigate the cost benefits of using rejuvenators. The laboratory test results and the cost analysis were presented and discussed in this paper.