Critical review on graphene oxide modified geopolymers: Dispersion preparation, mechanical properties, and microscopic mechanisms

In recent years, graphene oxide (GO) has been widely used in various fields owing to its high specific surface area and rich oxygen-containing functional groups. Adding an appropriate amount of GO (about 0.01–0.1 wt%) is beneficial to strengthen the soft soil foundation, which can improve the mechanical properties of the geopolymers, promote the hydration reaction, and improve the pore structure. The main mechanisms include the distortion effect, intercalation effect, template effect, bridge effect, active catalytic effect, adsorption cementation effect, and nucleation effect. Currently, GO research on cement materials mainly focuses on mortar and concrete and pays less attention to geotechnical engineering fields, such as cement soil. Therefore, to fully understand the unique advantages of GO, to clarify the method and mechanism of GO strengthening soft soil foundations, and to expand its application in geotechnical engineering, we briefly summarise the characterisation methods, dispersion of GO, analyse the influence of the single incorporation of GO on the mechanical properties of geopolymers, and discuss its microscopic mechanism. The environmental and safety effects are also discussed. Finally, the problems existing in the current research are analysed and future research directions are discussed.