Application of Warm-Mix Modified Asphalt Mixture in Highway Maintenance Project

Abstract

Warm-mix asphalt (WMA) is a relative new technology that has been used in constructing asphalt pavements around the world. WMA offers many advantages, such as energy-saving, environmental advantage, construction cost reduction, extension of construction season, etc. Current and past researches have indicated satisfactory performance of WMA pavements. Continued application and the desire for improvement of performance of WMA have attracted great interests from pavement communities worldwide. In this research, laboratory and field evaluations were conducted to systematically study the behavior and performance of WMA mixtures modified with styrene-butadiene rubber (SBR) emulsion or epoxy resin. The results showed that the use of epoxy resin resulted in a significant change in the penetration characteristic of WMA, while the addition of styrene-butadiene rubber (SBR) emulsion improved the viscosity and temperature susceptibility of WMA mixtures. No significant changes were observed in WMA ductility. With the same aggregate gradation, SBR-modified WMA mixtures exhibited superior water stability and high-temperature performance to regular WMA mixtures and hot mix asphalt mixtures. Overall, SBR-modified WMA mixtures showed equal or better performances than conventional hot-mix asphalt mixtures did.