Experimental Research On Iron Tailings Used As Roadbed Materials

Iron tailings sand is a by-product in the process of iron ore mining and is one of the main industrial solid wastes in my country.The current comprehensive utilization rate of less than10% has caused a large accumulation of iron tailings,which not only takes up a lot of land,but also causes serious harm to the ecological environment.How to scientifically dispose of the huge amount of iron tailings has become an urgent problem to be solved.Aiming at the current situation of iron tailing sand accumulation in Zaozhuang area,this paper summarizes the existing iron tailing sand disposal methods,and puts forward a new disposal method on this basis.Starting from this idea,this research carried out physical performance tests,mechanical performance tests,and durability tests on the prepared cement flowing materials.Finally,referring to the requirements of the specification,the feasibility of this absorption treatment method was verified.The main conclusions are as follows:(1)This article provides a new idea for the disposal of iron tailings.That is,first use lowliquid-limit clay to improve the iron tailing sand according to the sand-soil ratio of 8:2,then mix it with a small amount of cement(5% of the total mass of sand and soil)and a large amount of water(To make the fluidity of the prepared fluid material reach 170 mm as the standard)to make it into a cement flowing material,and finally use this flowing material as a roadbed filler.In the laboratory stage,all the technical indicators of the produced fluid material meet the requirements of the subgrade filling in the specification and have good workability.(2)Under the condition that the cement content and fluidity remain unchanged,with the gradual decrease of the sand-soil ratio,the mechanical properties,crack resistance,and frost resistance of the prepared cement fluid material show a tendency to deteriorate,and bleeding Performance is the opposite.Under the condition that the cement content and the sand-soil ratio are constant,as the fluidity increases uniformly,the compressive strength of the prepared fluid material decreases unevenly,and the degree of this unevenness is related to the fluidity.(3)The shrinkage stress of the flowing material prepared in this research is mainly generated within the 14 d age after pouring,and the difference in the curing method adopted after the slurry is poured will have a greater impact on the shrinkage deformation of the flowing material.During construction,it is recommended that the slurry should be covered with a film as soon as possible within 5 hours after the completion of the pouring of the slurry.It is calculated from the date of pouring,and the strength can be checked after 7 days.(4)Under the condition that the cement content is 5%,the fluid material prepared in this research is not enough to resist the freeze-thaw cycle conditions set to simulate the seasonal freezing in the north.In this regard,this research puts forward two suggestions: 1)It is recommended that the road drainage should be done well when using in the northern seasonal frozen area to prevent water from penetrating into the ore roadbed;2)The cement content should be increased from 5% to 8%～10%.