Moisture resistance study on PE-wax and EBS-wax modified warm mix asphalt using chemical and mechanical procedures

Abstract

Global warming, environmental concerns, and energy prices have led to increased use of wax additives to produce warm mix asphalt (WMA) as an alternative to hot mix asphalt (HMA). Despite many advantages, moisture susceptibility of WMAs is a legitimate concern. Although there have been many studies about moisture susceptibility of warm mix additives, mixtures containing ethylene-bis-stearamide (EBS) and polyethylene (PE) waxes have been less studied. In this research, moisture susceptibility of asphalt mixtures containing PE and EBS were evaluated. Furthermore, rheological and chemical evaluations of EBS and PE-wax modified binders were evaluated using dynamic shear rheometry and Fourier infrared spectroscopy, respectively. Moisture susceptibility was assessed using the modified Lottman test and the effects of aggregate type and production temperature were also evaluated. Results indicate improved moisture resistance for mixtures containing EBS. Additionally, the effect of PE-wax on moisture susceptibility was observed to be temperature dependent showing adverse effects at higher compaction temperatures.