Effects of graphene oxide on pore structure and mechanical properties of cementitious composites

The effects of graphene oxide (GO), a 2-dimensional structured nano-material, were evaluated in terms of the workability, mechanical properties, and pore structure of cementitious composites. The cementitious composites, with GO replacing 0, 0.01, 0.025, 0.03, and 0.05 wt% of the unit weight of cement, were evaluated for their workability based on the slump and air content tests, and to their mechanical properties with a compressive strength test. The pore structure for different GO replacement ratios was analyzed statistically by nitrogen absorption to demonstrate its effects on the workability and mechanical properties. As the GO replacement ratio increased, the workability was found to decrease by 22.7∼45.5%, and then to decrease further when the GO replacement ratio reaches 0.03 wt% or higher. According to pore structure analysis, when the GO replacement rate is higher than 0.03 wt%, the pore volume increases, thus suggesting the cause of the decrease in the compressive strength, which we further verified statistically.