Foamed Red Mud-based Concrete: A Comprehensive Review of Preparation, Microstructure and Thermo-mechanical Performance

Abstract

This review provides a systematic overview of recent advances in foamed red mud-based concrete (FRMC), a sustainable construction material that combines industrial waste valorization with thermal insulation performance. Current research is discussed from four main perspectives: (1) optimization of foaming technology and its underlying mechanisms, including foaming agent selection, process regulation, and foam stability; (2) red mud incorporation and modification, covering dosage design, mechanical, chemical, and thermal activation methods, and synergistic hydration mechanisms; (3) aggregate combination strategies, involving both conventional aggregate systems and composite lightweight aggregate systems; and (4) performance regulation and microstructural mechanisms, with emphasis on the relationship between pore structure, mechanical strength, and thermal conductivity. Existing studies indicate that, with an appropriate red mud content of 10-30% and suitable modification treatments, FRMC can achieve a 28-day compressive strength of 28.5-33.5 MPa and a thermal conductivity of 0.075-0.086 W/(m·K). These findings demonstrate that FRMC has considerable potential not only for building insulation, but also for lightweight partition walls, non-load-bearing wall panels, and other low-carbon construction applications requiring a balance between thermal insulation and mechanical performance. Future research should prioritize the development of high-red-mud-content systems, clarification of long-term durability mechanisms, expansion of multifunctional application scenarios, and establishment of engineering-oriented material design models.