Engineering Properties and Micromechanisms of Subgrade Soil Solidified by Industrial G and GO Composite Cement

To improve the swelling-shrinkage characteristics of expansive soil, excessive amounts of cement are often used to solidify it. This study aims to solidify expansive soil by using industrial graphene (G) and graphene oxide (GO)-modified cement to avoid the problem of environmental pollution resulting from the excessive use of cement. A series of unconsolidated-undrained triaxial and microstructure tests were conducted to investigate the engineering properties and micromechanisms of G and GO composite cement-solidified soils. Testing results showed that the deviatoric stress-strain curves of G and GO composite cement-solidified soils showed softening types. The compressive strength, toughness, shear strength, and ductility of cement-solidified soil were significantly improved by adding both G and GO. G and GO not only acted as a template to promote cement hydration and generate regular hydration products but also played a role in pore filling. Consequently, it is feasible to apply G and GO composite cement-solidified soils in practical projects.