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.

Copper functions as an exceptionally efficient conductor, garnering considerable interest in electrical and thermal applications; however, its relatively malleable nature and insufficient durability may hinder its structural effectiveness. This study focused on the development of copper-based nanocomposites by reinforcing a copper matrix with co-precipitated CuO/Al₂O₃ nanoparticles (varying from 0 to 10 wt% in increments of 2%). A thorough examination was conducted regarding the microstructural characteristics, mechanical properties, and the electrical and thermal conductivities of the composites. X-ray diffraction (XRD) and energy-dispersive spectroscopy (EDS) analysis validated the successful synthesis of nano-sized CuO and Al₂O₃ phases, with an estimated crystallite size of 33.2 ± 2.4 nm. Scanning electron microscopy revealed a relatively uniform distribution of nano-oxides within the copper matrix, albeit with signs of particle agglomeration at higher loading levels. The durability of the copper exhibited a significant enhancement attributed to the nano-oxide reinforcement, achieving an 180% increase relative to pure copper with a 10% reinforcement addition. Consequently, the tensile strength increased by approximately 68% (from around 154 MPa to nearly 260 MPa), while maintaining an exceptional level of ductility. The electrical conductivity of copper remained largely unchanged with the addition of nanoparticles; rather, a slight improvement in conductivity and a ~30% rise in thermal conductivity were observed at the maximum reinforcement level. This research work presents a copper-based nanocomposite that offers remarkable potential for applications requiring enhanced strength, wear resistance, and exceptional electrical and thermal conductivity.