Study On Ratio Optimization Of Coal Gangue-Gasification Slag Shotcrete And Aggregate Modification

Coal gangue is a very common solid waste in our country.The accumulation of a large number of coal gangue causes serious pollution to environment.Gasification slag is a solid waste material produced in the process of coal gasification.Gasification slag not only pollutes the daily living environment,but also causes severe weather conditions such as sandstorm under the action of wind.At present,with the progress of industrial development,more and more projects need a lot of concrete materials,and the excessive mining of natural gravel and natural river sand leads to the shortage of concrete aggregate resources.If coal gangue and gasification slag can be used as coarse aggregate and fine aggregate to make concrete,the need for natural gravel and river sand can be greatly reduced,and the environmental pollution caused by solid waste can be reduced.The main research work of this thesis is as follows:In this thesis,the physical and mechanical properties of common concrete aggregate and solid waste aggregate(coal gangue,gasification slag)are studied,and the chemical composition and microstructure of natural gravel,sand,gasification slag and coal gangue are compared and analyzed.The grain composition,natural water content,water absorption and apparent density of natural gravel,sand,gasification slag and coal gangue are tested and analyzed.It is judged that coal gangue and gasification slag can be used as aggregate of concrete.Two groups of shotcrete tests were designed with gravel and river sand as aggregate,and seven groups of shotcrete tests were designed with coal gangue and gasification slag as aggregate.A total of 72 concrete test blocks were poured to carry out uniaxial compressive strength tests.Based on the experimental data,the relationship between uniaxial compressive strength,age and water-cement ratio of shotcrete on solid waste foundation was studied.Based on the test results of uniaxial compressive strength,the stress-strain curves of shotcrete with solid waste foundation are analyzed.Compared with the aggregate technology,the solid waste aggregate was treated by surface coating modification.Six groups of shotcrete test blocks were designed for the aggregate after the modification.A total of 54 concrete test blocks were poured to carry out uniaxial compressive strength test.Based on the experimental data,the relationship between uniaxial compressive strength and age and water-cement ratio was studied.Three groups of fitting formulas were used to fit the uniaxial compressive strength and age relationship of the modified solid waste foundation shotcrete.The parameters and correlation coefficients of each group were calculated respectively,and the most suitable formulas were selected by comparative analysis.At the same time,slump and setting time of modified solid waste concrete were tested,and the test data under standard conditions were obtained and linear relationship fitting was carried out to determine the linear relationship between slump,setting time and water-cement ratio,which provided a certain theoretical basis for the subsequent research.A three-phase system model of water-silane coupling agent and kaolinite was constructed by Materials studio software,and the binding energy of the model was calculated.According to the results,it was determined that the silane coupling agent coated solid waste aggregate had hydrophobicity.