Aging Characteristics of Warm-Mix Asphalt Binders

Warm-mix asphalt (WMA) has gained lot of interest among researchers and highway engineers in recent years because of the environmental and financial benefits associated with lower production temperatures. However, there are some characteristics of warm-mix asphalt that have not been investigated in detail. Several studies have been conducted to analyze the performance of warm asphalt mixtures, but there is a need to investigate the physical and rheological properties of warm-mix binders. This paper presents results of a study carried out to investigate the aging characteristics of warm-mix asphalt binders. WMA binders prepared with three different warm-mix additives were aged in a rolling thin-film oven (RTFO) at lower temperatures to simulate warm-mix asphalt aging while control binders were aged at 163 degrees C only. Short-term aged binders were then aged in a pressure-aging vessel (PAV) to simulate long-term aging. Several parameters like aging index, G*/sin delta, G* sin delta, m-values, and stiffness of the aged binders were evaluated and results of warm-mix binders were compared with hot-mix asphalt binders. Fourier transform infrared (FTIR) spectroscopy tests were also carried out on these binders to quantify aging of the binders with and without warm-mix asphalt additives. (C) 2017 American Society of Civil Engineers.