The role of sucrose on enhancing properties of graphene oxide reinforced cement composites containing fly ash

Abstract

Graphene oxide (GO) has been attracted considerable attention due to its remarkable nano-reinforcing effect on cement-based composites. However, GO undergoes severe agglomerations upon contact to cement pore solution and reduces the fluidity of the fresh cement slurry. Although much attention has paid to the dispersion of GO in the matrix, few studies was reported to develop a method to simultaneously improve the dispersion of GO in alkaline cement solution and the workability of GO-blended cement mortar. In this study, the effect of sucrose (S) on the dispersion of GO in simulated cement pore solution and the fluidity, mechanical strength, microstructure and other properties of GO-fly ash–cement mortar were investigated. UV–Vis absorbance, atomic force microscope (AFM) and Zeta potential tests showed that the addition of sucrose significantly improved the uniform dispersion of GO in saturated Ca(OH)2 (CH) solution and the optimal mass ratio of sucrose/GO was 2.5:1. Sucrose could also compensate the fluidity loss of fly ash–cement mortar caused by the addition of GO. At the 0.01 wt% of GO and 0.025 wt% of sucrose, the flexural and compressive strength of GO-fly ash–cement mortar were further enhanced by 15.5%, 7.2% at 3d and 17.6%, 16.2% at 28d, compared to the 0.01 wt%-GO reference sample. The well-dispersion of GO could obviously promote cement hydration process and form the regular cement hydration products, so as to make the microstructure of hardened cement stone more compact, and greatly enhance the mechanical strength. This study might provide a new way to develop one-pot method to improve the dispersion of GO in cement pore solution and the workability of GO-blended cement mortar and had many potential practical applications.