Experimental Study Of Iron Tailings On The Mechanical Performance Of Concrete And The Bonding Performance Between Concrete And Steel Bars

In recent years,with the rapid development of China’s iron and steel industry,the stock of iron tailings increases day by day.As the main mineral resource area and the most important steel production base in Hebei province,Tangshan city has accumulated a large number of iron tailings.Due to the low comprehensive utilization rate and utilization level of iron tailings in Tangshan city,a large number of iron tailings are accumulated.The accumulated iron tailings not only occupy the land and pollute the environment.At the same time,concrete as the main building materials in China has a great demand.River sand,gravel as the most common concrete fine and coarse aggregates,which consumption is naturally large.However,gravel and sand mining in mountain and river can not only destroy the ecosystem of mountain and river,but also cause serious environmental pollution.In the face of such a serious tailings accumulation problem,it is an inevitable requirement of environmental protection and an inevitable choice of sustainable development to seek a new technology and a new way to deal with and utilize iron tailings effectively.Therefore,in this paper,the iron tailings powder,iron tailings ore and iron tailings sand in Qian ’an city,the main gathering place of Tangshan iron tailings,were used to replace fly ash,gravel and river sand as concrete admixture,coarse and fine aggregates respectively,Through mix ratio test,C25 and C30 fluidity concrete with slump of 180-200mm were prepared.Then,the effects of iron tailings powder,iron tailings sand and iron tailings ore on the working performance,basic mechanical properties of all kinds of iron tailings concrete and the bonding performance between all kinds of iron tailings concrete and steel bar are studied,and compared with the performance of fly ash concrete.The study found that:In terms of the working performance of concrete,the cohesion and water retention of all kinds of iron tailings concrete meet the requirements,and the fluidity is somewhat different from that of fly ash concrete.However,the fluidity can meet the requirements of large fluidity concrete by adjusting the content of water reducer.In terms of the mechanical properties of concrete,the compressive strength of all kinds of iron tailings concrete can meet the requirements of the corresponding strength grade.Other basic mechanical properties are slightly worse than those of fly ash concrete,but the difference is not large.Moreover,the basic mechanical properties of full iron tailings concrete are more outstanding in all kinds of iron tailings concrete,and are the closest to fly ash concrete.In terms of the bond performance of concrete and steel bar,the bond performance of full iron tailings concrete and steel bar is the best among all kinds of iron tailings concrete,and is slightly better than that of fly ash concrete.The influence of concrete strength and steel diameter on the bond property of all kinds of iron tailings concrete is basically the same as that of fly ash concrete.Therefore,in terms of working and basic mechanical properties of concrete and bonding performance between concrete and steel bar.full iron tailings concrete can be used in practical engineering instead of fly ash concrete.In addition,in this test,the content of iron tailings in C30 full iron tailings concrete was up to 88.43%,and that in C25 full iron tailings concrete was up to 89.79%,which further improves the utilization rate of iron tailings,and which can provide theoretical basis for iron tailings as admixture,coarse and fine aggregates of concrete,and accelerate the application process of iron tailings concrete.