| The corrosion of reinforced concrete structures by chloride ions can cause steel corrosion,resulting in deterioration of structural performance and even failure.While electrochemical repair technology can effectively remove chlorides and inhibit corrosion,it can also have a negative impact on the mechanical properties of the beam body.Currently,research on the effect of electrochemical repair on the flexural performance of longitudinally corroded beams has achieved certain results,but research on its effect on shear performance has not yet been discovered.In order to explore the durability and shear performance of longitudinally corroded beams after electrochemical repair,this paper combined the comparative analysis of chloride ion content gradient changes and weak polarization curves to analyze the corrosion resistance before and after electrochemical repair of concrete beams.Additionally,the paper analyzed the static mechanical properties before and after electrochemical repair,through load deflection curves,strain distribution of steel and concrete,and crack distribution.The main research results are as follows:（1）Accelerated corrosion tests were conducted to prepare longitudinally corroded concrete components,and the cracking and corrosion morphology of the test beams were analyzed and discussed.The study found that as the degree of corrosion of the beam worsened,the width of the rust-expansion cracks increased and showed a good linear relationship between the average width of the rust-expansion cracks（wa）and the corrosion rate（C）Additionally,after accelerated corrosion,uneven corrosion and pitting occurred in the longitudinal reinforcement.（2）To compare the distribution of chloride ion content and steel corrosion rate in longitudinal rusted beams before and after electrochemical repair,chloride ion titration test and longitudinal polarization curve test were carried out.The study found that after electrochemical repair,the chloride ion content inside the beam decreased significantly,and the chloride removal efficiency showed a trend of increasing first and then decreasing along the depth direction,with the lowest concentration near the steel layer.After repair,the open circuit potential Ecorrof the longitudinal bars increased significantly,and the corrosion current density Icorrdecreased to below 0.1u A·cm-2,restoring the passive state of the bars and effectively reducing the corrosion rate.（3）Based on the results of static load tests and longitudinal tensile tests of RC beams with corrosion of longitudinal bars,the changes in shear resistance,variation properties,and serviceability of longitudinal bars inside the beams before and after electrochemical repair were analyzed.It was found that after electrochemical repair,the RC beams still meet the assumption of plane cross-section,but the shear bearing capacity decreases,and the stiffness undergoes significant degradation.During shear failure,the spacing and number of load-bearing cracks increase.Electrochemical repair almost has no effect on the strength of the steel bars,but it reduces their plasticity,and the degree of reduction is not affected by the corrosion rate of the longitudinal bars before repair. |
