Effect of sulphuric acid on concrete with iron ore tailings

Abstract

Researches into the uses of waste materials are increasingly being explored to meet up society’s needs and global protection for sustainable, safe and economic development. This paper assessed concrete with iron ore tailings (IOT) exposed to dilute sulphuric acid. Iron ore tailings are the materials left-over after separating the valuable fraction from the uneconomic fraction of an ore. To study the effect of sulphuric acid, concrete of 100 mm cube with a different mix ratios containing IOT were prepared and cured for 28 days in water. The cubes were later immersed into dilute sulphuric acid at a concentration of 5%. The compressive strength of concrete at 7, 28 and 90 days of water curing were determined. Mass loss and strength reduction due to sulphuric effect were evaluated at 7, 28 and 90 days respectively. XRD microstructure of concrete specimens was analysed. Test results indicated that the IOT could be used in concrete as sand replacement since the concrete with IOT has similar trend in compressive strength loss and mass loss to sulphuric acid attack compared to control specimen. The mineralogical crystal failure patterns due to the sulphuric acid in terms X-ray diffraction analysis are the same for control and IOT concrete.