Characterization of iron mining tailings for reuse in sustainable civil infrastructure

Iron ore production generates approximately 1.4 billion tonnes of tailings annually. Research worldwide has investigated the reuse and recycling of this material. In civil engineering applications, research has mostly focused on pavement construction and block manufacturing, both of which commonly require the addition of binders. This paper proposes the use of iron ore tailings from a large Brazilian iron ore production area as a sand substitute in general geotechnical applications, while also addressing the global scarcity of natural sand. A comprehensive geotechnical characterization was performed, including the determination of hydraulic conductivity, deformability, and shear strength at optimum compaction conditions and at 95% of maximum dry unit weight and water content deviations within ±2%. The results indicate that, without binders, the material is suitable for use as trench fill and backfill for containment structures, as a soft-soil replacement material, in geosynthetic-reinforced soil walls, and in geotextile-encased granular columns.