Abstract:In order to study the effect of modified iron tailing powder on the compressive strength、working performance and durability of medium and high strength concrete, the C50 concrete were produced by different amounts of modified iron tailing powder, which completely replacing fly ash as the mineral admixture. The fly ash group with the same amount of iron tailing powder was set as a control group. The results show that the modified iron tailing powder concrete has better working performance, and the 28d compressive strength of modified iron tailing powder concrete decreases with the increase of modified iron tailing powder content. When the amount of tailing powder in total mineral admixture is 30%-60%, it can meet the compressive strength requirements of C50 concrete. When the content of modified iron tailing powder is 40%-60%, the anti-carbonation performance first increases and then weakens with the increase of tailing powder content, which is basically the same as that of the fly ash control group; the anti-permeability performance weakens with the increase of tailing powder content, but the anti-permeability grades can be consistent with the fly ash control group, which is "very low"; the anti-sulfate erosion performance and anti-freezing performance are enhanced with the increase of tailing powder content; the sulfate resistance grade can reach KS180, the antifreeze grade can reach F250, and all are better than the fly ash control group. In general, the modified iron tailing powder can be used in medium and high strength concrete instead of fly ash when the dosage of total mineral admixture is 40%-60% .