Physiochemical, Rheological, and Oxidative Aging Characteristics of Asphalt Binder in the Presence of Mesoporous Silica Nanoparticles

Physiochemical and rheological properties of asphalt binder are known to directly relate to asphalt pavement performance as it relates to fatigue and low temperature cracking. While other performance criteria such as rutting is also affected by binder properties, the latter is known to be also very sensitive to aggregate skeleton and mixture gradation. To enhance pavement performance, asphalt industry has commonly used various modifiers to improve binder rheological properties both before and after it is exposed to oxidative aging. Among those additives are polymers, ground tire rubber, as well as several organic and inorganic fillers. Inorganic fillers such as nano-clay and silica fume showed to be promising candidates to enhance asphalt rheology and aging behavior. Such enhancements are typically attributed to the presence of silicate platelet and silica particles. Accordingly, this paper investigates the merits of application of mesoporous silica nano-particles in this paper referred to as nano-silica as an asphalt binder additive to enhance binder rheological properties and oxidative aging resistance. To do so, different percentages of nano-silica were added to neat asphalt binder. Asphalt binder was then exposed to short-term oxidative aging using a rolling thin film oven (RTFO). To study the distribution of nano-silica in binder as well as the change in the chemical, rheological, and morphological properties of asphalt binders due to the addition of nano-silica, the scanning electron microscopy (SEM), Superpave tests, and Fourier transform infrared spectroscopy (FTIR) were conducted. It was found that introduction of nano-silica to asphalt binder can improve the rheological properties and oxidative aging resistance of asphalt binder. (C) 2015 American Society of Civil Engineers.