Influence of Dolomite Rock Powder and Iron Tailings Powder on the Electrical Resistivity, Strength and Microstructure of Cement Pastes and Concrete

Abstract

Dolomite rock powder (the waste stone residue in the production of machine-made sand and stone processing) and iron tailings powder formed by mineral processing industry are solid wastes, which occupy land resources, pollute the environment and release toxic substances without reasonable processing. The dolomite rock powder and iron tailings powder composing a large number of active substances could be advantageous to the cement-based materials. In this study, the electrical resistivity of cement paste and concrete was measured. Meanwhile, the influence of dolomite rock powder and iron tailings powder on the compressive strength of concrete was investigated. The electric flux of concrete was determined to estimate the chloride ion permeability. The scanning electron microscope (SEM) and X-ray diffraction were obtained to investigate the hydration of cement paste. Results showed the electrical resistivity of all specimens presented in this order: specimens with iron tailings < specimens with dolomite rock powder < blank specimens < specimens with ground granulated blast-furnace slag (GGBS) < specimens with fly ash. The correlation between electrical resistivity and curing age of cement paste or concrete has been deduced as a quadratic function. The addition of GGBS could improve the compressive strength of concrete. Meanwhile, when the other three types of mineral admixtures were added, 5% by mass ratio of the total binder materials was the optimum for the compressive strength. The curing ages, the fly ash, the GGBS and 5% dolomite rock powder or 5% iron tailings powder demonstrated a positive effect on the chloride ion impermeability. However, when higher dosages of dolomite rock powder or iron tailings powder were added, the effect was the opposite. Finally, the compactness of the microstructure and the Ca(OH)2 of cement paste could be improved by a small dosage of dolomites or iron tailings (less than 5%).

Preparation of Mineral Admixture from Iron Tailings with Steel Slag-Desulfurization Ash and Its Application to Concrete

“…Secondly, many scholars have also conducted research in the direction of mechanical properties of iron tailings concrete. Liu et al, studied the effects of dolomite powder and iron tailing powder on the resistivity, strength and microstructure of cement paste and concrete, and found that the strength of concrete increased and then decreased with the increase in iron tailing powder admixture [ 15 ]. Lu et al, investigated the effect of curing conditions on the mechanical and microstructural properties of ultra-high-performance concrete incorporating iron tailing powder and found that the strength of concrete first increased and then decreased with the increase in iron tailing powder dosing [ 16 ].…”

Experimental Research on Properties of UHPC Based on Composite Cementitious Materials System

“…High utilization solid-waste autoclaved aerated concrete (HUS-AAC) with SAC could effectively improve the stability of HUS-AAC blank and shorten the pre-curing time [17]. The iron tailing powder (ITP) could improve the compactness of the microstructure of cement paste [18]. ITP and SAC have been demonstrated the potential of replacing PC in UHPC production [19][20][21].…”

Recycling of Waste Stone Powder in High Fluidity Grouting Materials for Geotechnical Engineering Reinforcement

“…Bayesteh et al [16,17] discovered that the cement ratio also has a significant influence on strength, reporting a rapid reduction in compressive strength of cement slurry hardened body with increased cement ratio. Furthermore, the surface of stone powder particles has low activity, which can be hydrated with cement to form single-carbon calcium aluminate and semi-carbon calcium aluminate [18][19][20][21], as well as crystal nuclei, expediting the early cement reaction and improving early strength properties [22,23].…”