Assessment of iron tailings as replacement for fine aggregate in engıneering application

Abstract

This study evaluated the suitability of iron tailings as fine aggregate replacement for engineering applications. This is necessary to find economic usage for the enormous quantity of wastes from Itakpe mines. The physical properties in terms of specific gravity, bulk density, moisture content, particle size and fineness modulus as well as the mechanical properties in terms of compressive strength, compaction factor, flexural strength and relative density of the concrete made with iron tailings were determined. World Health Organization (WHO) standard methods for the examination of water and wastewater were used to analyse water used for the curing of the concrete cubes and beams to ascertain its toxicity. The result shows the workability of concrete made with 50% iron tailings to be within the standard limit. The compressive strength at 28day for 0% to 100% percentage replacement increases from 10.1N/mm2 to 15.3N/mm2, therefore replacement of sand with iron filling will improve the compressive strength of any concrete. The flexural strength analysis shows that the iron tailings concrete beam increases the flexural strength from 15N/mm2 to 16.9N/mm2 from 0 to 100% at 28day curing. There is also a linear relationship between the flexural strength and the density of the iron tailing concrete. The pH and Alkalinity tests of the water used to cure the iron tailing concrete is an indication that the alkalinity of the curing water was high (20.883 to 40.75) with a pH range of 12.1-12.4. This shows that the use of the iron tailing will not have negative effect on durability of the resulting concrete, the iron tailings is suitable for fine aggregates replacement up to 75% without altering the mechanical properties of such concrete negatively.

Keywords

• iron tailings
• fine aggregates
• compressive strength
• flexural strength
• engineering applications