A review of the warm mix asphalt (WMA) technologies: Effects on thermo-mechanical and rheological properties

Abstract In pavement industry, warm mix asphalt (WMA) technologies provide a wide variety of environmental, technical, and economic benefits. WMA includes a series of technologies to mix and compact asphalt mixtures at temperatures lower than the temperatures normally used in the production of hot mix asphalt (mainly by reducing the viscosity of asphalt binders). Different WMA technologies affect in different ways on the performance of binders and mixtures. Much has been learned about the WMA technologies used in pavement industry and their effects on the thermo-mechanical properties of WMA mixtures and the rheological properties of asphalt binders. The literature on the different WMA technologies and their effects on the performance of WMA binders and mixtures is reviewed in this paper. Moreover, the performance of the WMA technologies in mixtures containing other materials such as reclaimed asphalt pavement, polymers, and crumb rubber is reviewed in here. The findings in this review indicate that, in pavement industry, WMA technologies can reduce the environmental pollution, production cost, and energy usage. Moreover, an appropriate WMA technology can provide several technical benefits. The findings in the current paper can help pavement engineers to better utilize the WMA technologies in designing the asphalt mixtures. It is also hoped that this review will be helpful for asphalt researchers to find future avenues of research about WMA technologies.