Mix design and performance evaluation of geopolymer composites with graphene and graphene oxide for multifunctional energy storage built-environment

There is a growing need to transform the built environment into a multifunctional platform for energy storage, generation, and CO2 capture, turning idle structures into active components of sustainable urban systems. However, a significant challenge in built-environment materials is maintaining structural integrity while incorporating additional functionalities. This study aims to develop Construction and Demolition Waste (CDW)-based geopolymer composite materials incorporating Graphene (G) and Graphene Oxide (GO), considering the potential of these carbon-based nanomaterials for multifunctional applications. Brick Waste based CDW has been used in this study. A comprehensive analysis of the composite's mechanical, microstructural, and environmental properties was conducted to ensure that the developed material achieves essential mechanical performance, structural integrity, and environmental sustainability. The study revealed that a specific combination of graphene oxide at 5 % (0.91 wt% of CDW) and graphene at 1.5 % (0.31 wt% of CDW) yielded a maximum compressive strength of 16.1 MPa, representing a modest 2.5 % improvement over the baseline (15.7 MPa), representing the maintaining of the strength with addition of the additives. At another optimized combination of GO at 10 % (1.8 wt% of CDW) and G at 3 % (0.6 wt% of CDW), the flexural strength was retained at 88.7 % of the baseline value, demonstrating the potential to sustain structural integrity. However, these improvements are coupled with complex interactions between G and GO, which influence both compressive and flexural strengths, underscoring the necessity of precise concentration balancing for optimal performance. Additionally, the study explored Graphene material as a hotspot in the developed material for its high environmental impact and analyzed the environmental performance of carbon black as an alternate carbon material. This research lays the groundwork for the future functionalization of these nano-engineered construction materials.