Experimental Study On Bearing Capacity Of Coal Gangue Concrete Column

Coal gangue is the solid waste associated in the process of coal production,China's current accumulated stock exceeds 5 billion tons.Due to the lack of effective utilization ways,a large number of coal gangue piles up,which not only occupies land and causes harm to the environment,but also wastes the potential resources of coal gangue.In view of the similarity of physical and chemical composition between coal gangue and natural aggregate,and considering the shortage of traditional building materials in engineering construction,this paper takes the utilization of coal gangue in Yulin-Shenmu-Fugu mining area as the breakthrough point,uses coal gangue washed from mine as coarse aggregate to prepare concrete,and carries out experimental research on compressive performance and compressive bearing capacity of coal gangue concrete column.The chemical composition and mineral composition of coal gangue were studied experimentally.The physical and chemical composition of coal gangue was mastered.After that,the coal gangue was crushed and screened into coal gangue aggregate,and the main physical indexes were tested.Through the analysis of relevant characteristics of coal gangue,it is shown that coal gangue in Yushenfu coal mine can be used as coarse aggregate to produce concrete.In order to master the basic mechanical properties of coal gangue concrete,three factors and three levels orthogonal tests were carried out with the replacement rate of coal gangue,water cement ratio and water reducing agent content as the main factors.27 groups of coal gangue concrete with different mix ratios were designed and 405 standard specimens of coal gangue concrete were poured.The mechanical properties of coal gangue concrete,such as the cubic compressive strength,axial tensile strength,elastic modulus and Poisson's ratio,were studied.The results of the test show that the substitution rate of coal gangue has the most significant effect on the strength of concrete,and the strength of concrete decreases with the increase of replacement rate of coal gangue.In addition,the conversion relationship between the strength indexes of coal gangue concrete is obtained.Taking the replacement rate and initial eccentricity of coal gangue as the main factors,the mechanical properties of 12 coal gangue concrete columns were tested.Experimental results show that the failure mode of gangue concrete column is basically similar to that of ordinary concrete column.With the increase of the replacement rate of coal gangue,the bearing capacity of columns decreases and the deformation increases.By comparing the experimental and calculated values of column bearing capacity,it is found that the calculation theory of compressive bearing capacity of normal section in ordinary concrete code is also applicable to gangue concrete column.The research results on the basic mechanical properties of coal gangue concrete and the compression properties of coal gangue concrete columns have important reference value for the application of coal gangue concrete in practical engineering.