Study On The Properties Of Light Iron Tailings Ore Ceramsite Concrete For Structural Use

With the continuous development of prefabricated buildings in China,high performance ceramsite concrete has received unprecedented development opportunities because of its light weight advantages.Taking the comprehensive treatment of iron tailings in southern Shaanxi as the starting point,the fine iron tailings powder was prepared into light and high strength iron tailings ceramsite by adding binder in the fine iron tailings powder and by high temperature sintering expansion.Iron tailings ceramsite is used to replace natural coarse concrete aggregate,and the basic mixture ratio is calculated according to the loose volume method.The mixture ratio of five strength grades of concrete LC20～LC40 is obtained through trial.The physical properties and durability of LC20～LC40 were studied.At the same time,in order to further optimize the properties of iron tailings ceramsite concrete,in this study,ceramsite sand was used to replace common sand and mineral admixtures were added to optimize the mix ratio.The main research contents and results are as follows:（1）Using iron ore tailings ceramsite replace the natural coarse aggregate in concrete,found iron tailings ore ceramsite concrete optimal water consumption in 150kg/m3,the minimum dosage of cementing material is 420kg/m3,through the additive adjustment slump,found that slump should be controlled in 70mm±10mm,in order to prevent ceramsite floating.And design LC20～LC40 five strength grade concrete mix ratio,its work performance can meet the requirements of site construction.（2）By testing the physical properties and durability of LC20～LC40 and comparing with ordinary concrete,it is found that the compressive strength of LC20～LC40 meets the compound strength of grade LC20～LC35 in JGJ/T 12-2019,with the concentration of f_cu,0,the ceramsite self-strength affects the compressive strength and bending strength of concrete,the apparent density is about 1700kg/m3,30%lower than ordinary concrete,to reduce the weight of the structure.Because of the ceramsite and the micro pump effect generated by suction return water,ceramsite interface transition zone structure is more compact,it has very excellent durability,measured permeability grade for P12,chloride ion migration coefficient is only about a quarter of the normal concrete,at the same time caused by ceramsite elastic modulus low elastic coordinating role,to make it 150 times under freeze-thaw cycles,100times higher than ordinary concrete.（3）Using light ceramsite sand（LCS）instead of fine aggregate,the apparent density of iron tailings ceramsite concrete can be reduced to 1550 kg/m3,and the floating of ceramsite in concrete can be prevented.The effects of different mineral admixtures on the strength of ceramsite concrete are studied.The results show that the strength of ceramsite concrete can be improved effectively by adding wollastonite and ore powder,meanwhile,when the volume substitution rate of LCS is 48%,the maximum compressive strength of ceramsite concrete reaches 46.8 MPa.（4）Industrial production of prefabricated iron tailings ceramsite concrete exterior hanging board,stairs and other components was carried out in a new building material factory in Shaanxi,and applied in Shaanxi Energy Green Building Industrial Park,realizing the crossover development from iron tailings to prefabricated buildings.