Research On Shear Performance Of Corroded Reinforced Concrete Beam

At present,with the increase in service time of reinforced concrete structures,the durability of reinforced concrete has gradually been concerned about.In the phenomenon of steel corrosion,due to the thicker protective layer of stirrups,usually the corrosion of stirrups will be more serious than the longitudinal reinforcement,which may lead to structural brittle damage.In practical applications,the required carrying capacity of stirrups is low and the load capacity requirements are satisfied in the design.When the steel bars are corroded,which causes the decrease of mechanical properties of the bars,and the structure becomes very dangerous.In recent years,domestic and foreign researchers have found that the harm of stirrups is huge,at this stage HRB400 steel is promoted to replace the original strength of the lower bar as a stirrup.At present,there are few studies on the shear behavior of corroded reinforced concrete of using HRB400 steel as stirrups.On this basis,the shear capacity of corroded reinforced concrete beams is studied.In this paper,the corrosion mechanism of reinforced concrete is analyzed,and the corrosion of reinforced concrete is studied according to the necessary conditions which the corrosion of steel bars need.This paper analyzes the different stages of the corrosion process of reinforced concrete by the concrete carbonation and the corrosion of Chloride,from the overall analysis of reinforced concrete structure in the steel after the rust will be how to degenerate.After the reinforcement has been corroded,the performance degradation of the reinforced concrete structure is analyzed as a whole.This paper investigates the shear behavior of corroded reinforced concrete beams by means of experiment.The concrete beams were divided into two groups by different shear ratios,and different corroded rates were selected for each group of reinforced concrete beams.Comparison of the advantages and disadvantages of each method of electrification accelerated corrosion,semi-wet power is selected.The changes of the surface state of the reinforced concrete members under different corrosion rates were analyzed by observing the morphology of the members after corrosion.Finally,the shear strength of the oblique section is experimented,and the structural properties such as load-displacement relation,structural failure form,crack regularity and structural ductility are recorded.Then,analysis of relevant factors are made,which the tested beams are compared with non-corroded reinforced concrete beams.The result shows that thecracking behavior of the reinforced concrete members is different under the different internal corrosion rates,meanwhile the degree of corrosion can be estimated according to the surface morphology of the reinforced concrete members.When the corrosion rate of the concrete bar is small,the shear capacity of the inclined section is not obvious.When the corrosion rate of the steel bar is large,the shear capacity of the reinforced concrete beam decreases.The rust-proof cracks on the surface of the steel are first produced in the direction of the stirrups.The rust-proof cracks on the surface of the steel are first produced in the direction of the stirrups.As the corrosion rate increases,the cracks in the rust will appear along the direction of longitudinal reinforcement and the vertical reinforcement,at the same time the cracks will expand to the inside.Corrosion of steel bars will lead to the decrease in stiffness of reinforced concrete beams,especially when the corrosion rate is high.