Experimental Study On Red Mud Based Material Used In Subgrade

In recent years,with the progress of science and technology and the rapid development of aluminum industry,a large amount of red mud has been produced.Because red mud contains more alkaline substances,frosting will occur,which seriously affects the resource utilization of red mud,so more and more red mud is piled up,which not only occupies a lot of land resources,but also causes environmental pollution to the surrounding air and groundwater.it will also cause a waste of resources.In this paper,through the strength experiments of different ratios of red mud,cement and loess,the frosting phenomenon was observed,the physical and chemical properties of the experimental samples were determined,and the harmfulness of red mud was determined.The solidification mechanism of red mud test block strength and the implementability of using red mud in roadbed engineering are analyzed.The microstructure and mineral composition of red mud samples were observed by scanning electron microscope,and the reaction mechanism was analyzed.According to the determination,the liquid-plastic limit moisture content of loess is 22.5% and 14.2%respectively,the burning loss is 3.78%,and the liquid-plastic limit moisture content of red mud is 26.5% and 21.2%,respectively.The red mud block strength experiment is divided into three groups,which is adjusted according to the different amount of materials,and is molded by using the adsorption properties of loess,the aggregate function of standard sand and the hydraulic strength provided by cement mixed with red mud.The compressive strength is taken as the main test index.The experimental results show that with the increase of the content of red mud,the compressive strength increases gradually,and when the content of red mud reaches 15%,the strength of the test block reaches the maximum,and the unconfined uniaxial ultimate compressive strength is 10.13 MPa after curing for 7 days,and the unconfined uniaxial ultimate compressive strength is 10.93 MPa after curing for 14 days.After curing for 28 days,the unconfined uniaxial ultimate compressive strength is 11.54 MPa.According to the experiments of water resistance and dry-wet cycle of red mud specimens,the uniaxial ultimate compressive strength of red mud specimens after soaking is lower than that before soaking.After 7 days,14 days and 28 days of curing,the highest compressive strength of red mud blocks reaches 8.71 MPA and 10.27 MPa,respectively.The softening coefficients were 0.86,0.81 and 0.89,respectively.In the dry-wet cycle experiment,the unconfined uniaxial ultimate compressive strength of the test block decreased after 5,10 and 15 dry-wet cycles.After 5,10 and 15 dry-wet cycles,the maximum compressive strength of the test block is 10.27 MPa,9.29 MPa and8.96 MPa,respectively.The large-scale application of red mud in roadbed engineering can effectively reduce a series of problems caused by red mud storage,and it has the advantages of simple utilization,low cost and high environmental,economic and social benefits.it is a new type of building material for roadbed engineering.to find a new way for the resource utilization of red mud.