A simple atomization approach enables monolayer dispersion of nano graphenes in cementitious composites with excellent strength gains

Abstract

Carbon nano additives (CNAs) are critical to achieving the unique properties of functionalized composites, however, controlling the dispersion of CNAs in material matrix is always a challenging task. In this study, a simple atomization approach was successfully developed to promote the dispersion efficiency of graphene nanoplatelets (GNPs) in cement composites. This atomization approach can be integrated with the direct, indirect and combined ultrasonic stirrings in a homemade automatic stirring-atomization device. Mechanical and microstructure tests were performed on hardened cement pastes blended with GNPs in different stirring and mixing approaches. Results show that the direct ultrasonic stirrings enabled more homogeneous dispersions of GNP particles with a smaller size for a longer duration. The atomized droplets with the mean size of ∼100 ​μm largely mitigated GNPs’ agglomerations. Monolayer GNPs were observed in the cement matrix with the strength gain by up to 54%, and the total porosity decrease by 21% in 0.3 ​wt% GNPs dosage. The greatly enhanced dispersion efficiency of GNPs in cement also raised the cement hydration. This work provides an effective and manpower saving technique toward dispersing CNAs in engineering materials with great industrialization prospects.