Graphene deposition on sand–silica fume substrate for enhancing cement composites

Direct deposition of graphene on sand is a cost-effective and scalable method for producing advanced nano-additives to reinforce cement composites; however, the complex multi-material substrates often used can limit its applications. Here, we developed a simplified method to deposit graphene nanoplatelets (GNPs) on sand–silica fume substrates via chemical vapor deposition (CVD). Dispersion performance and the effects of GNP-sand on the mechanical and microstructural properties of cement composites were investigated. The GNPs showed good dispersion capacity in water, but a higher dosage was needed to achieve the same dispersion capacity as reference graphene oxide. The use of GNP-sand with 0.15% GNP loading increased the 28-day compressive and tensile strengths by 33.53% and 43.48%, respectively, decreased porosity by 20.94% and enhanced the interfacial transition zone (ITZ) modulus by 224.42% while reducing the ITZ thickness by 73.98%, compared to reference samples. These results demonstrate the potential of using GNP-sand in sustainable cement composites.