Suggested Citation:
Mateos, Angel, Federico Gulisano, John T. Harvey, Kee Foo, Jeffrey Buscheck, Rongzong Wu, Ali A. Butt, Mohammad Rahman, Tanoogna Mallarapu, Brielle Moreno (2024)

Evaluating the Effect of Reclaimed Asphalt Pavement on Rubberized Hot Mix Asphalt in Pilot Projects

The study goal is to evaluate the use of up to 10 % reclaimed asphalt pavement (RAP) by aggregate replacement in rubberized hot mix asphalt-gap graded RHMA-G mixes to identify any significant potential problems for durability. Five pilot projects were built, each including a control RHMA-G (without RAP) and an RHMA-G with 10 % RAP. The mixes were sampled during production and evaluated using volumetric assessment, and performance related tests including stiffness, four-point bending fatigue resistance, fracture resistance measured with the IDEAL cracking test, and rutting resistance. Mix testing results indicate that the addition of 10 % RAP had minor effects on the mechanical properties. With a few exceptions related to the total binder content of the mixes, the effect of the RAP addition was negligible compared to normal production variability. Modeling with CalME, Caltrans mechanistic-empirical asphalt pavement design software and four-point bending testing results, indicated that RAP addition effects on pavement cracking performance were either negligible or comparable to mix-to-mix RHMA-G variability. Regarding constructability, RAP addition did not create any problems. The life cycle assessment completed in the study indicates that the addition of 10 % RAP to the RHMA-G can reduce the greenhouse gas emissions associated with the RHMA-G production (cradle-to-gate) by up to 5 %.