Study on water-repellent and corrosion-resistant properties of cement mortar using superhydrophobic iron ore tailings

Abstract

The low utilization rate of iron ore tailings (IOTs) wastes increases the cost of land occupation and leads to environmental degradation. To improve the utilization rate of IOTs, IOTs are often used to fabricate concrete as a sand substitute. However, the addition of IOTs increases the water absorption of concrete, resulting in a decrease in corrosion-resistant property. In this study, an eco-friendly green way was proposed to prepare IOTs mortar with good water-repellent and corrosion-resistant properties using the superhydrophobic iron ore tailings (S-IOTs). The obtained S-IOTs modified with eco-friendly stearic acid were used to replace part of sand to fabricate a mortar with water-repellent and corrosion-resistant properties. And the particle sizes of IOTs before and after modification were compared. The effects of different replacement amounts of S-IOTs on the wettability, consistency, hydration, water absorption, corrosion resistance and compressive strength of mortar were investigated. When the content of S-IOTs exceeded 30%, the mortar reached the hydrophobic state. The addition of appropriate amount of S-IOTs (≤30%) can promote cement hydration, improving the compressive strength of mortar. In addition, the mortar mixed with S-IOTs showed better water-repellent and corrosion-resistant properties than ordinary mortar. This method is expected to raise the corrosion resistance of mortar and broaden the application of IOTs in mortar. • The addition of superhydrophobic iron ore tailings realized the transformation of mortar from hydrophilicity to hydrophobicity. • The mortar mixed with superhydrophobic iron ore tailings significantly decreases water absorption. • Superhydrophobic iron ore tailings improved the corrosion resistance of mortar.