Influence of ultrasonication on the dispersion and enhancing effect of graphene oxide–carbon nanotube hybrid nanoreinforcement in cementitious composite

Nano-engineering cement binder using a hybrid of carbon nanotubes (CNTs) and graphene oxide (GO) combines the superior mechanical properties of CNTs and the good dispersibility and affinity of GO. Ultrasonication is a key process implemented in the dispersion of CNTs and GO. The present study characterizes the effect of ultrasonication on the dispersion and size of the GO/CNT particles by using an ultraviolet spectrophotometer and Zetasizer μV detector, respectively. The mechanical properties of GO/CNT-OPC pastes treated with different ultrasonication time and power levels were tested and their microstructure was investigated using scanning electron microscopy and mercury intrusion porosimetry. The results of this study not only reveal that differences in ultrasonication can cause the mechanical properties of the GO/CNT-OPC composite to vary by −11.7–78.8% but also show that the effect of the amount of ultrasonication energy can vary significantly when different ultrasonication time or power levels are adopted. The porosity of the composite is found to have a nonlinear correlation with the ultrasonication. The findings of this study can promote understanding of GO/CNT-OPC composites and help to guide the implementation of ultrasonication in the future.