Assessing the Impact of Graphene Nanoplatelets Aggregates on the Performance Characteristics of Cement-Based Materials

Graphene nanoplatelet aggregates (GNAs) are a low-cost, low-quality alternative to graphene nanoplatelets (GNPs), characterized by their three-dimensional stacked structure and porous surface morphology. Despite their affordability, limited research has been conducted on the effects of GNAs in cementitious systems. This study investigates the impact of GNAs on hydration kinetics, phase assemblage, mortar consistency, mechanical strength, bulk electrical resistivity, water absorption, and pore solution pH. Mortar mixtures with 0%, 0.05%, and 1% GNAs by cement weight were prepared using a water-to-cement ratio of 0.42 and cured for 28 days. The results showed that GNAs had minimal influence on hydration kinetics, with no significant changes in hydration products detected by XRD and TGA analyses. Mortar consistency consistently decreased with increasing GNA content. At 0.05%, GNAs had no significant effect on compressive strength or bulk electrical resistivity, whereas 1% GNAs reduced compressive strength by 10%. Water absorption was significantly lower in specimens with 1% GNAs as well, while pore solution pH increased at this dosage. The findings of this study indicate that the incorporation of GNAs at a 0.05% replacement level does not inherently enhance cementitious properties but can influence specific behaviors, such as workability and water absorption, when used at 1% dosages.