Properties of high-volume iron tailing powder concrete under different curing conditions

The mechanical properties, microstructure and permeability of high-volume iron tailing powder (HVITP) concrete and high-volume fly ash (HVFA) concrete were comparatively investigated by measuring the adiabatic temperature rise, rate of temperature rise, compressive strength, splitting tensile strength and chloride permeability grade of concrete and determining the pore structure, bound water content and morphology of paste. The total adiabatic temperature rise of HVITP concrete are lower than that of HVFA concrete. But the early higher rate of temperature rise of HVITP concrete is obtained. The HVITP concrete shows low compressive strength and splitting tensile strength, coarse pore structure, loose microstructure and high chloride permeability compared with HVFA concrete with the same water/binder ratio. The early temperature matching curing (TMC) adversely affects the later-age properties development of HVITP concrete, but it promotes the properties development of HVFA concrete. The decrease in water/binder ratio or the partial replacement of ITP with slag improves the properties of HVITP concrete, especially for the early properties under TMC condition. But these two means still lead to properties difference between HVITP concrete and HVFA concrete due to the low reactivity of ITP. (C) 2020 Elsevier Ltd. All rights reserved.