Iron Ore Tailings in Construction Materials: A Systematic Review of Composition and Water Absorption Performance

Iron ore tailings (IOTs) are generated in massive volumes by mining, posing environmental risks through land occupation, dam failures, and heavy metal contamination, while construction faces growing pressure toward sustainable materials. This systematic review evaluates IOT valorization in construction materials, focusing on composition and water absorption performance. A structured search in Scopus^® identified experimental studies (2015-2025, English), excluding reviews, simulations, and non-IOT studies. Data were synthesized narratively by matrix type. The 24 studies reporting water absorption were also assessed for methodological quality using a bespoke six-criterion checklist, as no validated risk-of-bias tool exists for such experiments. Of 145 documents screened, 74 met the inclusion criteria. IOT content ranged from below 10 wt% to full substitution across cement-based, ceramic, geopolymer, alkali-activated, and polymer matrices. Water absorption varied accordingly: cement-based blocks with full substitution achieved 4.6%, bricks reached 18.0%, geopolymer/AAC composites ranged 13.0-21.0%, polymers achieved the lowest values (0.1-0.4%), and ceramics varied broadly (0.4-49.2%). Quality assessment classified 54.2% of studies as low risk and 45.8% as moderate risk, and inconsistent variability reporting was the main limitation. Performance depended on matrix type, IOT content, and processing, supporting circular IOT reuse in construction. This review received CAPES funding and was not registered.