The Improvement of Bitumen Properties by Adding NanoSilica

Asphalt oxidative aging is one of the prevalent causes of pavement distresses which increase pavement susceptibility to fatigue and low temperature cracking. This phenomenon is mainly studied through oxidation kinetics and through evaluating oxygen diffusivity rate into asphalt binders. While oxidative aging in pavement is inevitable, application of anti‐aging additives shown to be an effective method in delaying oxidative aging. As such this paper investigates the merit of application of nano‐silica as an anti‐aging additive. To do so, different percentages of nano‐silica was 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 change in the chemical, rheological and morphological properties of asphalt binders in presence of nano‐silica, the Superpave™ tests, Fourier transform infrared spectroscopy (FTIR) as well as SEM imaging were conducted. The FTIR study shows that nano‐silica can improve the aging resistance of the asphalt binder as reflected in lower level of carboxylic acids (observed at 1400‐ 1440 cm‐1) and sulfoxide (observed at ~1050 cm‐1) in nanosilica modified specimen compared to those in non modified specimens. Carboxylic acids occur naturally in asphalt; however its concentration has been known to be increased significantly due to oxidative aging. This in turn reduces oxidation aging in modified asphalt. In addition, it was found that presence of nano‐silica significantly increases the complex modulus (G*) and complex viscosity (η*) of the asphalt binder. This in turn improves pavement resistance to rutting. It was concluded that introduction of nano‐silica to asphalt binder can improve the anti‐aging property, rutting performance and rheological properties of asphalt binder.

並列關鍵字

Nano‐silica ； Nano Modified Asphalt ； Rheology ； Aging

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