The effect of graphene oxide grafted carbon fiber on mechanical properties of class G Portland cement

As described in the research, CFs were reinforced by graphene oxide (GO) and prepared by grafting-to technology and this new graphene oxide modified carbon fiber (GO-CF) showed excellent adhesion properties to cement material, which was with excellent mechanical properties and analyzed by infrared spectroscopy (FTIR), scanning electron microscope (SEM), X-ray diffraction analysis (XRD), and X-ray photoelectron spectroscopy (XPS). To deeply explore the reinforcement mechanism of graphene oxide to CFs, not only were scanning electron microscopy analysis and X-ray diffraction (XRD) analysis conducted, but triaxial strain-stress mechanical performance tests, a dynamic simulation to subsurface operation environment, were also utilized to confirm the mechanical effect of GO-CFs to cement. The results showed that GO-CF reinforced cement (GOCFRC) exhibited excellent compressive strength performance with GO of only 0.4% BWOC content. And cement compressive strength increased to over 1.18 times that of pure cement after 14-day curing period. Above all, the new kind of reinforced cement material showed superior toughness compared to pure cement. Its flexural tensile strength increased by 38.81% in 3-day curing period, 38.65% in 7-day curing period, and 41.76% in 14-day curing period. Furthermore, it displayed excellent triaxial stress-strain toughness compared to pure cement: Young's modulus increased to 150.9%, ultimate stress increased to over 121%, and ultimate strain increased to about 267%. Excellent compatible interface adhesion performance of new carbon fiber was detected through SEM analysis. Via this research, the application mechanism of GO reinforced cement material was improved, and a new type of carbon fiber reinforced cement (CFRC) with higher mechanical performance was developed.