Experimental Study On Eccentric Compression Performance Of Steel Fiber Coal Gangue Concrete Column

Coal gangue is an associated product of coal and is one of the largest solid waste in China.Large amounts of coal gangue piled up in the open air not only pollutes the environment,but also encroaches on land.Improper placement poses no harm to people’s lives.In recent years,China has extensively developed and consumed natural resources such as river sand and limestone gravel.Nowadays,we urgently hope to find a material that can replace natural aggregates and be used in construction.Therefore,this article conducts eccentric compression bearing capacity tests on coal gangue concrete columns to study their mechanical properties.Considering that the strength of coal gangue is lower than that of natural aggregates,which leads to problems such as large deformation and wide cracks in concrete structures during large eccentric loading,steel fibers are added to the preparation of coal gangue concrete to limit the development of concrete cracks.In order to explore the eccentric compression performance of steel fiber coal gangue concrete(SFCGC)columns,the following studies were conducted with different coal gangue volume content(0,30%,50%,70%),different steel fiber volume content(0%,0.5%,1%,1.5%)and different eccentricity(0,0.25,0.5)as the influencing factors:1.Studied the physical properties of coal gangue,and conducted experimental research on the mechanical properties of steel fiber coal gangue concrete cube specimens on the premise of confirming that the coal gangue meets the concrete manufacturing standards.The experimental results found that the substitution rate of coal gangue has the greatest impact on the strength of concrete,and the strength of concrete decreases with the increase of coal gangue substitution rate.Among them,the axial compressive strength of the coal gangue concrete specimen with a substitution rate of 70% is 23.8% lower than that of the coal gangue concrete specimen with a substitution rate of 0%.2.Taking different volume content of coal gangue,different volume content of steel fiber and different eccentricity as the main influencing factors,the eccentric compressive performance test of columns was carried out,including 10 SFCGC columns and 3 ordinary concrete columns.The experimental study showed that the failure mode of SFCGC columns was basically the same as that of ordinary concrete columns.As the substitution rate of coal gangue increases,the ultimate bearing capacity of the specimen continues to decrease.The ultimate bearing capacity of the coal gangue concrete specimen with a substitution rate of 70% is 23% lower than that of the coal gangue concrete specimen with a substitution rate of 0%(under large eccentric loading).Steel fibers have an inhibitory effect on the development of tensile side cracks in large eccentric compression columns.With the increase of steel fiber volume content,the cracking load of large eccentric compression columns gradually increases,and the crack spacing and width gradually decrease.3.In theoretical calculations,the influence of steel fibers on bearing capacity and cracking load is taken into account,and the calculation formula is revised.The results show that the results of SFCGC columns calculated by the modified formula are in good agreement with the test results,whether for the ultimate bearing capacity or the cracking load and average crack width of eccentrically compressed columns,which indicates that this theory of computation is applicable to SFCGC columns.4.By establishing a three-dimensional steel fiber model,the simulated bearing capacity is closer to the test results.The results show that the finite element analysis is similar to the test results.ABAQUS software can be used to simulate and analyze the bearing capacity of SFCGC columns,and subsequent finite element simulation can be performed on the influencing factors of different reinforcement ratios and slenderness ratios.