Research Progress on the High-Temperature Resistance of Ultra-High Performance Concrete Incorporating Iron Tailings as a Cementitious Material

Ultra-High Performance Concrete (UHPC) is widely recognized for its superior strength, exceptional durability, and outstanding crack resistance, making it an attractive material for applications in tunnel linings, nuclear power plant structures, industrial furnace linings, and high-rise building firewalls. However, conventional UHPC is prone to spalling and rapid strength deterioration under high-temperature conditions due to internal water evaporation, pressure buildup, and the decomposition of hydration products. In recent years, iron tailings—an abundant industrial solid waste rich in SiO₂, Al₂O₃, and Fe₂O₃—have been investigated as a supplementary cementitious material to partially replace cement. This substitution not only reduces carbon emissions and production costs but also has the potential to improve the high-temperature performance of UHPC through its participation in hydration reactions and the refinement of the pore structure. This review comprehensively summarizes the chemical and physical properties of iron tailings, their inherent cementitious reactivity and activation methods, and discusses the influence of iron tailings on the evolution of UHPC mechanical properties, spalling mechanisms, and fire resistance under high temperatures. Furthermore, engineering applications and environmental safety issues are analyzed, and future research directions are proposed to provide theoretical support and technical guidance for the sustainable utilization of iron tailings in high-temperature UHPC.