Implications of Including Reclaimed Asphalt Pavement Materials to Performance of Balanced Asphalt Concrete Mixes

Understanding the effect of reclaimed asphalt pavement (RAP) on the mechanical performance of asphalt concrete (AC) mixtures may lead to improved mix design aiming to maximize the use of recycled materials while yielding optimal volumetric properties and balanced performance. This paper presents an experimental evaluation of the RAP content and source on the mechanical performance of AC mixes as measured by overlay tester, Hamburg wheel tracking device, and indirect tension tests. Several Superpave mixes with 12.5 mm nominal maximum aggregate size and recycled binder replacement ratios ranging from 0 to over 50 were designed and evaluated in this study. A performance interaction diagram was used to interpret collectively the cracking susceptibility, rutting potential, and tensile strength of the AC mixes. Asphalt concrete mixes with high RAP content can be balanced with proper individual mix design and their performance assessed through mechanical characterization. Furthermore, AC mixes with RAP from different sources yielded different cracking and rutting potentials. The performance tests and analysis methodology from this study could potentially be incorporated into the balanced mix design process to provide well-performing mixes containing optimal amounts for recycled materials.