Evaluation of iron ore tailings as replacement for fine aggregate in concrete

• Concrete containing iron ore tailings (IOT) enhances compressive and splitting strengths.
• IOT concrete improves durability properties and resists carbonation.
• IOT as sand replacement in concrete reduces cost and environmental problems.

Millions of tons of iron ore tailings (IOT); a by-product of iron ore processing, are disposed of every year in landfills, quarries, rivers, oceans among others thereby posing environmental problems. The major aim of this study is to evaluate IOT as replacement for river sand in concrete and compare with the result of conventional concrete. Concrete mixtures containing 25%, 50%, 75% and 100% IOT as river sand replacement were prepared with 0.5 water-to-cement ratio (W/C). Compressive and splitting tensile strengths, modulus of elasticity and durability tests (drying-shrinkage, water absorption, chloride penetration and carbonation effects) were conducted on concrete containing IOT. A statistical fitted linear regression analysis was performed on compressive strength to evaluate the significant level of concretes containing IOT. According to British standard, sieve analysis results indicated that IOT were of medium grade quality. Test results indicated that the concrete workability was reduced with IOT while all other strength and modulus of elasticity data were consistently higher than conventional concrete at all levels of replacement. It is recommended that IOT should be used in concrete as sand replacement to minimize environmental problems, cost and natural resources depletion.