Effects of Curing Conditions on the MECHANICAL and Microstructural Properties of Ultra-High-Performance Concrete (UHPC) Incorporating Iron Tailing Powder

Abstract

It has been reported that iron tailing powder (ITP) has the potential to partially replace cement to prepare ultra-high-performance concrete (UHPC). However, the reactivity of ITP particles in concrete largely depends on the curing method. This study investigates the effects of curing conditions on the mechanical and microstructural properties of UHPC containing ITP. To achieve this objective, three research tasks are conducted, including (1) preparing seven concrete formulations by introducing ITP; (2) characterizing their mechanical performance under different curing regimes; and (3) analyzing their microstructure by XRD patterns, FTIR analysis, and SEM observation. The experimental results show that there is an optimum ITP dosage (15%) for their application. The concrete with 15% ITP under standard curing obtains 94.3 MPa at 7 days, their early-age strength could be even further increased by ~30% (warm-water curing) and ~35% (steamed curing). The steam curing regime stimulates the activity of ITP and refines the microstructure. This study demonstrates the potential of replacing Portland cement with ITP in UHPC production.

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

“…It is technically feasible to use iron tailings powder as concrete mineral admixture [18,19]. Lu et al [20] found that adding iron tailings powder to cement can improve the compressive strength of concrete. Song Shaomin et al [21] discovered that adding an appropriate amount of iron tailings powder can improve the chloride ion permeability and carbonation resistance of concrete.…”

Experimental Study on Sulfate Wetting–Drying Cycle of Metal Tailings Powder Concrete

“…Hou et al (2019) and Liu et al (2019) found that the strength of metal tailings powder concrete increases with the increase of fineness. Lu et al (2021) considered that the curing method has a great impact on the iron tailings micro powder concrete. Song et al (2017), Song et al (2019), and Song and Chen (2020) found that tailings powder can replace fly ash to prepare concrete.…”

Preparation of Mineral Admixture from Iron Tailings with Steel Slag-Desulfurization Ash and Its Application to 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 ]. Ling et al, conducted an environmental design study of ultra-high performance concrete using iron ore tailings as cement material and found that iron tailings promote optimization of long-term compressive strength and pore structure of concrete [ 17 ].…”