Synergistic effects of graphene nanoplatelets and palm oil fuel ash on the mechanical properties and carbon footprint of concrete

• Investigates the synergistic influence of GNPs and POFA on mechanical properties. • Analyzing the influence of GNPs and POFA on embodied carbon. • Response surface methodology models the impact on mechanical properties. • Optimal properties were observed with 0.08% GNPs and 10% OPC replacement with POFA. This study investigates the combined influence of palm oil fuel ash (POFA) as a partial cement replacement and graphene nanoplatelets (GNPs) on the performance of concrete. POFA helps reduce the carbon footprint of cement production, thereby enhancing sustainability, while GNPs are incorporated to improve the material’s mechanical strength and durability. Concrete mixtures were prepared with POFA content ranging from 10% to 20% and GNPs at 0.03% to 0.1% by weight of cement. Mechanical properties, including compressive strength (CS), splitting tensile strength (STS), flexural strength (FS), and modulus of elasticity (MOE), were systematically evaluated. Additionally, embodied carbon was quantified for each mix to assess the environmental benefits of POFA substitution, alongside an analysis of eco-strength efficiency. Microstructural examinations demonstrated notable enhancements due to the additives. The optimal formulation, consisting of 10% OPC replacement with POFA and 0.08% GNPs, yielded improvements of 34.54%, 31.44%, 25.78%, and 16% in CS, STS, FS, and MOE, respectively. Predictive models were developed using response surface methodology, and multi-objective optimization identified the ideal combination as 11.03% POFA and 0.099% GNPs, achieving a desirability index of 96.8%.