Upcycling red mud into high-strength high-ductility Engineered Geopolymer Composites (EGC): Toward superior performance and sustainability

In this study, red mud (RM) was successfully adopted to produce high-strength high-ductility Engineered Geopolymer Composites (EGC). EGC with a high RM content of 50% achieved a compressive strength over 100 MPa and a tensile strain capacity over 5%. The influence of RM on the mechanical performances, reaction mechanisms, and environmental impacts of EGC was comprehensively investigated. Results revealed that the incorporation of RM would improve the reaction degree of precursors, densify the microstructures, and enhance the compressive strengths. Although RM incorporation would to some extent impair the tensile performances of EGC, the crack width could be effectively narrowed under a high RM content of 50%. Finally, the excellent sustainability and market potential of RM-incorporated EGC were demonstrated from environmental and cost analyses. The findings could help promote the RM upcycling technology and facilitate the development and engineering applications of this novel geopolymer composite for sustainable construction. © 2025 Elsevier Ltd.