Application of Iron Ore Tailings and Phosphogypsum to Create Artificial Rockfills Used in Rock-Filled Concrete

Abstract

Rock-filled concrete (RFC) has good performance in terms of energy savings, cost reduction, and CO2 emissions as a novel massive concrete construction technology. There have been studies into replacing natural rocks in RFC with large blocks of solid waste, and this method has been used on several construction sites. However, the granular and powdery solid waste utilized in RFC is limited, as a consequence of the special requirement of self-compacting concrete (SCC) in RFC. The goal of this paper is to increase the amount of granular and powdery solid waste in RFC. Iron ore tailing (IOT) and phosphogypsum (PG) were used separately as granular and powdery solid waste. The modified PG, ground blast-furnace slag (GBFS), steel slag, and cement clinker are combined to form parathion gypsum slag cement in a specific proportion, with the ratio of PG, GBFS, steel slag, and cement being 47:47:2:2. To replace the natural rocks in RFC, artificial rockfills made of IOT and parathion gypsum slag cement are used to increase the dosage of solid waste. The artificial rockfills were formed using three methods: compressing, roller compacting, and normal vibrating. When the compressive strength and material costs of the three types of artificial rockfills are compared, the compressing method is the best for maximizing the IOT. In artificial rockfills, the mass fraction of granular solid waste is 83.3%, and the mass fraction of total solid waste is 99.3%.