Surface functionalization of silica nanoparticles to enhance aging resistance of asphalt binder

Oxidation aging of asphalt pavement is among most prevalent factors causing pavement distresses. Introduction of silica nanoparticles (SNPs) has been found promising to reduce oxidation aging of asphalt binder. However, the effectiveness of SNPs is limited by their poor dispersion caused mainly by SNP agglomeration requiring significant mechanical energy in processing to ensure dispersion. This paper examined merits of surface functionalization of SNPs with (3-aminopropyl) triethoxysilane (APTES) to improve its dispersion in asphalt binder using conventional processing techniques at relatively high loading of SNPs with low mechanical energy input. The morphology, size, amount of amine functional groups of APTES surface-modified SNPs (APTES-SNPs) were characterized and optimized by scanning electron microscope (SEM), dynamic light scattering (DLS), Fourier-transform infrared spectroscopy (FTIR) and fluorescence measurement. The comparison between the surface-modified and pristine SNPs on the anti-aging and rheological properties of asphalt binder was conducted. The asphalt binders which contained APTES-SNPs demonstrated much better resistance to oxidative aging as evidenced by enhanced rheological properties compared to those containing pristine SNPs. The findings from this research provides insights as to the effect of APTES-SNPs on aging resistance of asphalt binder. (C) 2019 Elsevier Ltd. All rights reserved.