Mechanical and Structural Performance Evaluation of Cement-Matrix Composites Nano-Reinforced with Expanded Graphite

Abstract This study investigates the mechanical and structural performance of cement-matrix composites reinforced with expanded graphite (EG) at dosages of 0, 0.25, and 0.75 wt% of cement. The physical and chemical properties of the fine aggregates were first characterized to ensure material quality. Mechanical testing combined with microstructural analyses [scanning electron microscopy (SEM), energy-dispersive spectroscopy (EDS), helium pycnometry, and nitrogen adsorption] was then employed to evaluate the influence of EG addition. The incorporation of EG enhanced composite behavior compared to the control mixture without reinforcement. The most notable improvements in compressive strength and toughness were obtained at 0.25 wt% EG, underscoring the decisive role of dispersion in maximizing reinforcement efficiency. Furthermore, pore connectivity decreased progressively with increasing EG dosage, indicating a refinement of the pore network. This microstructural modification suggests potential durability benefits and is particularly relevant for applications requiring moisture resistance, such as protective coatings or waterproofing in wet environments.