Study on the Performance and Hydration Mechanism of Concrete Incorporating Phosphorus Tailings

Abstract

Phosphorus tailings are solid wastes generated from mineral processing. It limits the green development of phosphorus chemical industries. Phosphorus tailings mainly consist of dolomite, fluorapatite, and quartzite, so they are used as mineral admixtures to prepare concrete, which not only reduces carbon emissions but also eliminates phosphorus tailings and solves the issues caused by the large accumulation of phosphorus tailings. In this paper, C40 concrete was prepared with different content and fineness of phosphorus tailings, and the effects of phosphorus tailings on its workability, mechanical properties, and durability were investigated. The harm of heavy metals leaching of concrete mixing with phosphorus to the environment was evaluated. The mechanism of the effect of phosphorus tailings on concrete was also analyzed by using characterization methods such as heat of hydration, XRD, and SEM. The results showed that the workability of concrete increased with the phosphorus tailings amount increased, but the mechanical property of concrete decreased. The fineness of phosphorus tailings has little effect on the workability and mechanical properties of concrete. The durability properties of concrete were impaired with the increase in the admixture of phosphorus tailings, but the fineness of phosphorus tailings has no significant effect on the durability properties of concrete. With the increase of the curing time, the structure of the concrete mixed with phosphorus tailings became denser than the concrete without phosphorus tailings incorporated. The concrete mixing with phosphorus tailings had little detriment to the environment. Finally, using the particle size of 20 μm and the content of 20% of phosphorus tailing to replace the cement was suggested.