Effect of Water Exposure on the Physicochemical Properties of Impervious Asphalt Concrete

Abstract

Effect of water on asphalt concrete containing air voids in the range 3–5% (the typical composition used for the construction of pavements) has been widely studied. However, it is also necessary to evaluate the effect of water on mixtures with a low amount of air voids and high asphalt saturation (Va<3% and VFA>88%; the typical mixture used in impervious barriers), as it is well known that contact with water causes slow oxidation of asphalt (binder), which makes it hard and brittle. In this research, asphalt concrete cylindrical specimens with a low air void content were prepared and saturated, and kept in contact with water for up to 12 months. Then, a process of asphalt recovery was performed on the specimens. Infrared spectroscopy, rheological analyses, and saturates, aromatics, resins, and asphaltenes (SARA) fractionation were performed to characterize the asphalt binder. It was revealed for the time periods considered in this study that the asphalt oxidation level was low, which can be attributed to low air void volumes and high asphalt saturation in the as-used mixture.