Effect of Iron Tailings Fine Powder as Admixture on the Properties of Cement Mortar and Concrete

The paper conducts feasibility tests on iron tailings fine powder as concrete mineral admixture, and compares its performance with traditional admixture fly ash and ground limestone powder to make effective use of stone powder resources. The fluidity and mechanical properties of cement mortar of the three admixtures are respectively tested. And the influence on compressive strength, shrinkage and chloride penetration resistance of C30, C35 and C40 concrete under different curing conditions. The results show that the chemical composition of iron tailings is similar to that of fly ash and belongs to siliceous powder. The 1, 2 and 3 h mobility losses of iron tailings and fly ash are similar, but higher than those of limestone powder. The mortar strength of the first three admixtures at 14d age is close to that of the other two admixtures at 14–60d age, and the activity index and strength change with age are consistent. Under different curing conditions, the compressive strength of the three kinds of admixture concrete is as follows: fly ash concrete > iron tailings powder concrete > limestone powder concrete; The addition of iron tailings is beneficial to improve the shrinkage performance and chloride ion penetration resistance of concrete, and can play a role in filling the micro-pore structure, which has the technical feasibility as an inert admixture.