Achieving desired volumetrics and performance for mixtures with high percentage of reclaimed asphalt pavement

This paper focuses on the design and laboratory performance of asphalt mixtures with a high percentage of reclaimed asphalt pavement (RAP). Special laboratory measures were taken to process RAP material to achieve target volumetrics for the mixtures. Two aggregate sources were used to develop eight asphalt mix designs. The Bailey method of aggregate packing was used to design four asphalt mixtures with 0% (control), 30%, 40%, and 50% RAP for each material source. Apart from evaluating the moisture susceptibility of the prepared mixtures, performance tests, including dynamic modulus, wheel tracking, and beam fatigue, were also conducted. Moreover, in addition to evaluating the effect of the amount of RAP on mixture performance, the effect of binder grade bumping was also investigated. The study concluded that mixtures including RAP could provide equal or better performance in resistance against moisture susceptibility, rutting, and fatigue failure. Because consistent and similar volumetrics were achieved for all tested mixtures, it can be said with certainly that the performance properties of all tested mixtures were a function of only their mechanical properties.