Sustainable Engineered Geopolymer Composites Utilizing Gamma-Irradiated PET and Graphene Nanoplatelets: Optimization and Performance Enhancement

Effective waste management is a matter of global concern. The utilization of widely recognized waste materials, such as plastics, rubber, and glass, in the construction industry is being investigated for their cost efficiency, enhanced material properties, and reduced environmental impact, contributing to broader sustainability efforts. This study investigates the development of an engineered geopolymer composite with a focus on sustainability by utilizing industrial waste materials. Gamma-irradiated polyethylene terephthalate was employed as a partial replacement for silica sand, while graphene nanoplatelets were incorporated to enhance composite properties and reduce environmental waste. A statistical technique known as response surface methodology was used to optimize the effects of gamma-irradiated polyethylene terephthalate and graphene nanoplatelets on the properties of the engineered geopolymer composite. Key findings indicate that gamma-irradiated polyethylene terephthalate, with higher crystallinity and robust interfacial bonding with the geopolymer matrix, significantly enhances compressive strength, elastic modulus, flexural strength, and flexural toughness. However, graphene nanoplatelets, while improving mechanical properties, reduce the ductility index. Optimal composite properties were achieved with 26.4% gamma-irradiated polyethylene terephthalate and 0.12% graphene nanoplatelets. This research underscores the potential of gamma-irradiated polyethylene terephthalate in creating high-performance, sustainable construction materials and highlights the trade-offs between mechanical reinforcement and ductility. Future research should explore the chain scission effects of gamma irradiation on polyethylene terephthalate, further optimize composite properties, and investigate mechanisms to enhance ductility, advancing the utilization of polyethylene terephthalate in sustainable construction materials.