| Coal gangue is the product of coal mining,which will release harmful gases to pollute the environment and pile up a large amount of coal gangue every year.Coal gangue has a similar physical and chemical composition to natural macadam,so it can be used as coarse aggregate to prepare concrete.By using coal gangue as concrete coarse aggregate to prepare the concrete to consume coal gangue,it can solve the problem of large amount of coal gangue accumulation pollution of the environment,improve the economic and ecological benefits,in line with the concept of national sustainable development.This method can solve the problem of environmental pollution caused by the accumulation of coal gangue,improve the economic and ecological benefits,and accord with the concept of national sustainable development.The addition of steel fibers in coal gangue concrete can significantly improve the mechanical properties of concrete.At present,the study of gangue concrete mainly lies in the study of the mechanical properties of gangue concrete.In the steel fiber reinforced coal gangue concrete members such as beams,slabs,and columns of the force performance of the study is less,and the beam is a very important force member of the building.Therefore,it is necessary to carry out the study of the flexural performance of steel fiber reinforced coal gangue concrete beam.In order to study the flexural performance of steel fiber-reinforced coal gangue concrete beams,the four-point bending tests of 12 concrete beam specimens were completed.The effects of coal gangue replacement rate(0%,50%,100%),steel fiber volume content(0%,0.5%,1%,1.5%,2%),rebar ratio(0.6%,1.17%,1.94%)and beam height(200mm,300mm)on the flexural properties of members were analyzed.The bending performance indexes analyzed are cracking moment,ultimate moment,crack width,crack spacing,bending stiffness,ductility and energy dissipation,and the relevant bending performance indexes are calculated theoretically.The specific work is as follows:1.Cubic axial compression experiments,cubic splitting tensile tests,and prismatic uniaxial compression tests were conducted on steel fiber strengthened natural concrete and steel fiber strengthened coal gangue concrete respectively.The influence of coal gangue replacement rate and steel fiber volume content on the mechanical performance of steel fiber strengthened coal gangue concrete was investigated through the experiments.2.The all-defining formula for the stress-strain curve of coal gangue concrete reinforced with steel fibers is determined by stress-strain curves gained from uniaxial prismatic compression experiments.The relations between the coal gangue replacement rate and steel fiber volume content with the parameters a and b of the constitutive equation are fitted.3.Four-point bending tests were carried out on 12 beams,and the variation rules of load-deflection curve,moment-curvature curve,cracking load,ultimate load,flexural stiffness,ductility and energy dissipation of steel fiber reinforced coal gangue concrete beams were studied.4.Theoretical analysis and calculation of a steel fiber-reinforced coal gangue beam and calculation of the cracking load,bearing capacity and bending stiffness of the beam using the appropriate code formulas are carried out.The formula for computing the crack width and spacing of steel fiber strengthened coal gangue beams was altered and the results were compared with experimental values to confirm the reliability of the formula.5.Finite element analysis of steel fiber reinforced coal gangue concrete beams was undertaken,a finite element model was established and the accuracy of the model was checked by comparing it with the experimental data.The influence of coal gangue replacement rate,steel fiber volume content,rebar ratio,and beam height on the bending resistance of steel fiber reinforced coal gangue concrete beams was investigated. |
