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Surface Modification of Silica Fume with Amine Groups to Reduce Agglomeration and Improve Asphalt Resistance to Oxidation

Abstract

This paper presents a rheological study of the design and development of surface-modification schemes for silica fume particles to improve their dispersion in asphalt and increase the asphalt aging resistance. The nanoparticle surface design involves an optimum balance of the use of inert and active surface functional groups to achieve minimal nanoparticle agglomeration and enhance the reduction in oxidative aging of silica-fume-modified asphalt binder. Silica fume particles with different functional groups, including amine and phosphonate groups, were produced. Agglomeration studies using SEM and zeta potential analysis indicate that modifying asphalt binder with amine-modified silica fume particles can reduce the agglomeration of the silica fume particles. The performance characteristics of functionalized silica fume particles and non-functionalized silica fume particles are compared with those of base asphalt. The following research hypotheses were investigated: silica fume will enhance asphalt’s aging resistance; and amine groups will react with a high percentage of agglomerated silica fume particles in asphalt to reduce the agglomeration and increase the aging resistance. A rotational viscometer was used to study the effect of functionalized-silica-fume-modified binder on the high-temperature properties of the asphalt binder. Fourier transform infrared spectroscopy analysis was used to determine the chemical compounds of the aminegroup silica-fume-modified binder matrix. Scanning electron microscopy was used to observe the surface morphology and analyze microstructure characteristics of materials. Using these surface-modification schemes, fluorescent silica fume particles can be more readily conjugated with asphalt molecules and used as highly fluorescent, sensitive, and reproducible labels in asphalt applications.

Nader Abutalib, Sidharth Reddy Karnati , Daniel Oldham, Lifeng Zhang and Elham Fini

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