Prospects of warm mix asphalt in maximizing reclaimed asphalt pavement utilization: Review on mix design and performance

Abstract

Over the last decade, pavement engineers have been in search of technology to incorporate a maximum percentage of Reclaimed Asphalt Pavement (RAP) into the mix. The production of Warm Mix Asphalt (WMA) at a lower temperature than Hot Mix Asphalt (HMA) gained the popularity of WMA-RAP technology due to its workability and reduced cost of construction. Although both WMA and RAP possess certain limitations as standalone technologies, their integration into WMA-RAP technology presents the possibility of mitigating the drawbacks associated with each when utilized jointly, particularly enhancing the performance of the WMA-RAP technology. The objective of this manuscript is to review and organize the information related to the high RAP incorporation in WMA technologies. The scope of the review is to understand the behavior of the WMA-RAP mixes and their performance all over the world. The laboratory and field evaluation of WMA-RAP mixes summarizes positive feedback on using high RAP in WMA. However, the possibility of utilizing a higher percentage of RAP content in the field and batch plant-level studies needs to be conducted to accurately assess the suitability. This manuscript is expected to aid pavement engineers in the development of WMA-RAP mixes with higher quantities of RAP content.