Preparation and modification mechanism analysis of graphene oxide modified asphalts

摘要

Preparation of graphene oxide (GO) by oxidative dispersion, using GO as an asphalt modifier, graphene oxide modified asphalt was prepared by high temperature melting method. The effect of GO incorporation on the basic physical properties of asphalt was investigated, and the X-ray diffraction (XRD), scanning electron microscopy (SEM), and Fourier transform infrared spectroscopy (FTIR) were used to analyze the microstructure characteristic of GO and modified asphalt. In order to reveal the bonding mechanism between GO and asphalt, a calculation model of asphalt molecules and GO molecules was constructed. Each of constructed asphalt molecules and GO molecules were placed in the primitive cells to obtain systems of asphalt with GO. Density functional theory (DFT) was used to calculate the molecular charge density, the electron density difference, the binding energy and the number of charges transferred between asphalt and GO. The results shown that the GO improved high temperature stability and heat aging resistance of the asphalt, but unable improve the crack resistance of the asphalt. GO was stably dispersed in asphalt, GO modified asphalt by forming an intercalation structure, which improves the high temperature stability of the asphalt. However, the effect of GO on asphalt was based on the physical modification, which unable crosslink each other in the asphalt, as a result, the crack resistance of the modified asphalt unable be improved. Density functional calculation results show that the bonding of resin with GO was the most stable, followed by those for aromatic with GO, and those for saturate with GO was the weakest, GO can hinder the movement of saturate and inhibit the volatilization of saturate, thereby improving the high temperature stability and heat aging resistance of asphalt. GO molecules can form hydrogen bonds with asphalt molecules, and it can also form aromatic ring stacks with aromatic and resin molecules, these non-bond interactions were the key to the stable dispersion of GO in asphalt. (C) 2019 Elsevier Ltd. All rights reserved.