Dispersion of silane-functionalized GO and its reinforcing effects in cement composites

The agglomeration of graphene oxide (GO) in alkaline media fundamentally restricts its reinforcement efficiency in cement composites. We investigate a method of enhancing the dispersion and reinforcement efficiency of GO via functionalization using 3-aminopropyltriethoxy silane (APTS). Our results indicated that functionalization improved the dispersion of GO in a pore solution by up to 60% primarily due to steric hindrance and electrostatic repulsive effects. Strong interactions between the silane-functionalized GO (FGO) and cement hydration products via residual oxygen functional groups on GO (confirmed by FTIR and XPS) could fundamentally improve reinforcing effects. FGO samples provided higher heat flow peaks due jointly to the nucleation effect of GO and the pozzolan reaction of silica in silane. At the similar loadings of 0.02%, FGO increased workability by up to 17%, alongside compressive and tensile strength increments of 19% and 31%, respectively at 28 days compared with the reference GO. These findings demonstrated the effectiveness and potential of enhancing nano-reinforcing effects of GO in cement composites by improving dispersion capacity while ensuring strong interactions between GO and cement hydration products.