Effect of Graphene Oxide on Properties of Alkali-Activated Slag

Alkali-activated materials, a new kind of low-carbon cement, have received extensive attention. While in order to obtain excellent functions, the modification of alkali-activated materials by nano-materials has become one of the important research directions of alkali-activated materials. Therein, the hydration property, mechanical properties, and action mechanism of the alkali-activated slag with and without graphene oxide (GO) were analyzed and evaluated. Results showed the compressive strength of mortar decreased at 3 days and 28 days by adding GO. While the flexural strength of mortar cured for different ages increased with increasing GO content, and the flexural strength increasing rate reached up to 15.94% at 28 days, thus, the toughening effect of GO was significant. GO accelerated the hydration process of alkali-activated slag because the functional groups offered nucleation sites to induce the generation of more hydration products. Furthermore, the addition of GO increased the number of harmless pores and reduced the pore size, but also introduced a large number of harmful pores, resulting in the reduction of compressive strength.