The Influence Of Iron Ore Tailings Powder On The Performance Of Concrete

Large amount of tailings produced during the process of ore extraction and dressing will not only take a large number of lands to stack but also cause the threats and destruction of ecological environment.Tailings as a sort of deserted resource still at a low usage rate with respect to the aspects for the high-efficient use and high added value utilization.The iron tailings powder has been used as admixture in concrete can decrease the amount of iron ore tailings and cement and avail to the energy conservation and emission reduction,moreover,alleviate the situation of inadequate supplies of high quality of fly ash and slag in some districts.The application of iron ore tailings powder in concrete has been attracted much attention and made great process,however,the study for iron tailings powder known as the inactive admixture in concrete is still not sufficiently systematic and perfect.This paper research on the function of iron ore tailing powder for the workability in fresh concrete and the strength,the law of development,volume stability,durability,micro structure and pore structure of hardened concrete.In order to accurately understand the influence produced by iron tailings powder as an inactive admixture on the feasibility and performance of concrete,P.I Portland cement has been implemented to acquire the main technical points of iron tailings powder employed in concrete structure during the study.The experimental results illustrated that iron tailings powder was able to enhance the cohesion of concrete,which can improve the workability in medium-low grade concrete.Iron tailings powder contributes more to the early strength of concrete and less to the long term strength compared with the fly ash.The amount of iron tailings powder should be under 25% and 50% for C30 concrete and C50 concrete,respectively.With the mixture of the certain quantity of admixture,concrete age strength can be guaranteed for each state.under the suitable dosage of iron tailings powder,concrete carbonation resistance,chloride ion erosion resistance,frost resistance as well as resistance to sulfate erosion performance is no weaker than fly ash.From the point of microstructure of concrete,when iron ore tailings powder in an appropriate dosage,the piling of iron tailings in the concrete made good filling effect,the microstructure of concrete has least pore and fracture.The concrete microstructure is dense.Pore structure has been improved.Considering the low activity of iron tailings powder within a range of the active admixture,water cement ratio for concrete should appropriately reduce.