Properties of steam-cured precast concrete containing iron tailing powder

To improve iron tailings utilization, the properties of precast concrete with iron tailing powder as mineral admixture were investigated by measuring the compressive strength and chloride ion permeability of the precast concrete, and determining the chemically bound water content, pore structure, hydration products and morphology of the hardened paste. The results show that precast concrete with 50% iron tailing powder has low compressive strength, low chemically bound water content, porous structure and low resistance to chloride ion permeability compared with Portland cement concrete. Replacing a portion of iron tailing powder with slag or fly ash can reduce the adverse impact of iron tailing powder on the properties of precast concrete. The addition of iron tailing powder does not change the kinds of hydration products produced in precast concrete. Small iron tailing powder particles are beneficial to the properties of precast concrete, but large iron tailing powder particles weakly bond with surrounding hydrates. The microstructure of hardened paste with iron tailing powder and slag is much denser than that with iron tailing powder and fly ash. Iron tailing powder can be used as mineral admixture to produce precast concrete. The most advantageous properties of precast concrete are obtained when using blended mineral admixture of iron tailing powder and slag. (C) 2019 Elsevier B.V. All rights reserved.