Experiment Study on Sulfur Iron Ore Tailings-Based Alkali-Activated Mortar

Abstract

A series of laboratory tests were conducted to investigate the possibility of using sulfur iron ore tailings (SIOT) - based alkali-activated mortar as grouting material. The mechanical, engineering and microstructural properties of the alkali-activated mortar were investigated. It is found the setting times of the mortar increase with the increase of the SIOT content. The mortar specimens with SIOT content of 25% and 50% and MK content of 10% have better sulfate resistance, freeze-thaw resistances and less drying shrinkage. The compressive strengths of the specimens nonlinearly decrease with the increase of the SIOT contents. The maximum compressive strength of the specimen cast with SIOT content of 25% was 40.2 MPa. The compressive strengths of the mortar specimens have little difference after 3 and 7 days of curing, but increase a lot after 28 days of curing. The ratios between the compressive and flexural strengths of the mortar specimens are larger than 4.5. More obvious amorphous peaks of the C-A-S-H gel were found. Some unreacted SIOT particles are still observed in the pores of the samples which may still reduce the durability of the specimens.

Keywords: Alkali activated mortar, Sulfur iron ore tailings, Grouting, Mineral waste