Mechanical and Microstructural Characteristics of Multifunctional Graphene Nanoplatelets Reinforced Concrete Composite

Graphene nanoplatelets (GNPs) emerged as a promising nanofiller in concrete composites, primarily due to their high surface area and ability to bridge cracks. This study comprehensively investigated the influence of GNP addition at low dosages of 0.025%, 0.05%, 0.075%, and 0.1%, respectively, on workability, strength, performance, and microstructure. The comprehensive microstructural and compositional analysis of the composite is performed using scanning electron microscopy (SEM), energy dispersive X-ray (EDX), and X-ray diffraction (XRD). The experimental results revealed that adding a small amount of GNP remarkably improved the mechanical characteristics. The optimal dosage was observed at 0.075%, which yielded the highest enhancements, specifically, a 24.72% increase in compressive strength, 20.66% in split tensile strength, and 17.54% in flexural strength compared to the control mix. The GNP addition significantly improves mechanical properties, including the static modulus of elasticity at optimal dosages. The water absorption and sorptivity of concrete mixes incorporating GNP were observed to improve significantly compared to the control concrete, indicating that GNP effectively reduces the pore volume within the matrix. The microstructural investigation showed that the incorporation of GNP refines the pore structure, reduces microcracks, enhances the matrix–aggregate bond, and significantly promotes the formation of C-S-H gel.