Effects of iron ore tailings on the compressive strength and permeability of ultra-high performance concrete

Iron ore tailings (IOT) are discharged as waste after the beneficiation process to concentrate iron ore, which has triggered a series of environmental problems. The influence of IOT as a replacement for manufactured sand (MS) (0%, 20%, 40%, 60%, 80%, and 100% by weight) on the compressive strength and permeability of UHPC mortars was investigated by multiple methods including scanning electron microscopy (SEM) and mercury intrusion porosimetry (MIP). The results showed that 40% IOT replacement yielded the best performance, and 80% substitution of IOT was comparable to the control mix regarding compressive strength. Additionally, the impermeability improved with increasing IOT content. To reduce the cost of UHPC production and minimize environmental problems, it is feasible to use IOT as a fine aggregate to partly replace manufactured sand. (C) 2020 Elsevier Ltd. All rights reserved.