The influence of graphene nanoplatelet content on the mechanical properties and microstructure of sustainable concrete

The effects of the content of graphene nanoplatelets (GNPs) on the mechanical properties and microstructure of sustainable concrete were investigated. Aqueous solutions were prepared, using a wet-dispersion technique to disperse GNPs in the mixing water. Concrete batches were prepared using different GNP fractions (0.05, 0.1, 0.25, 0.5, 1 and 2% by weight of cement), and their compressive, flexural and tensile strengths were determined at 28 days. Qualitative microstructural analyses were performed using scanning electron microscopy and energy dispersive X-ray analysis. The results obtained were analysed using analysis of variance (Anova), which demonstrated improvements in all strength properties when using GNP filaments regardless of their weight fraction. The batch containing 0.5% GNPs showed the largest strength improvements, with improvements in compressive, flexural and tensile strength properties of 22.6%, 23.9% and 255.4%, respectively. Microstructural analysis showed a good dispersion of nanofilaments inside the concrete matrix through the dispersion technique used in this study. Finally, Anova revealed statistically significant relationships between the GNP content and the compressive, flexural and tensile strengths of the concrete specimens. The results highlight the importance of the GNP content in influencing the concrete's mechanical properties.