Evaluation of warm mix asphalt performance incorporating high RAP content

Abstract

Using reclaimed asphalt pavement (RAP) increases the sustainability benefits and can enhance the performance of warm mix asphalt (WMA) compared to traditional hot mix asphalt (HMA). However, the RAP content is generally limited in WMA because adding high RAP content may reduce the performance of WMA. In this paper, the authors studied the possibility of incorporating high RAP content from 25 to 70% by mass of WMA by using Evotherm as an additive. Laboratory performance of WMA–RAP mixtures was characterized and compared to a control HMA in terms of moisture susceptibility, rutting resistance, and fatigue characterization. Test results showed that Evotherm greatly improved the moisture resistance of WMA–RAP mixtures compared to HMA. Increasing RAP content made WMA–RAP mixtures stiffer and enhanced the rutting resistance, but decreased the fatigue resistance of the mixtures. Therefore, the maximum RAP content needs to be determined to ensure balance between the fatigue and rutting characteristics of asphalt mixtures.