Mechanical and Microscopic Properties of Cement Composite Expansive Soil with Graphene Oxide: Ecofriendly Modification Material

Cement composite soil is a more stabilized method in expansive soil foundation projects, but it is essential to find an ecofriendly modification material to reduce the content of cement and its pollution for the environment. A series of unconsolidated–undrained (UU) triaxial tests were conducted to investigate the modification effect of graphene oxide (GO) on cement-stabilized expansive soil (CS), and the contents of GO were 0.05%, 0.1%, 0.15%, and 0.2%, respectively. The test results show that (1) the deviatoric stress–strain curves of CS gradually change from a weakly softening type to a strongly softening one after adding GO. (2) The compressive strength, shear strength, and toughness of GO-modified cement-stabilized expansive soil are better than CS, and the optimal GO content is 0.05%. (3) Microscopic tests show that GO can promote the hydration reaction of cement and reduce the internal pores of CS. Consequently, the mechanical properties and microstructure of CS can be significantly improved after adding GO, and it is feasible to replace a part of the cement with GO in expansive soil foundation projects.