Study on the Hydrogen Evolution Reaction of Reinforced Concrete during Electrochemical Repair under the Influence of BIEM

Based on the bidirectional electromigration (BIEM) technique, a corrosion inhibitor solution was prepared by mixing 1 mol/L triethylene tetramine with deionized water. The effects of current density, charging time, and corrosion inhibitor on critical current density and hydrogen content of rebar were investigated. Subsequently, the hydrogen embrittlement risk of rebar was further characterized by mechanical property tests. Finally, the bearing capacity and crack distribution characteristics of the components during electrochemical repair were revealed based on the microstructure of the steel fracture. Studies have shown that the corrosion inhibitor in the BIEM electrolyte reduces the polarization potential, increases the critical current density, and finally inhibits the hydrogen evolution rate. The hydrogen evolution reaction increases with the increase of current density and energizing time. The critical hydrogen evolution current density of concrete specimens measured ranges from 0.796 to 0.833 A/m². In addition, the current density range of 1–7 A/m² has no effect on the yield strength, yield platform, and ultimate strength of steel. With the increase of 1 μg/g hydrogen content, the fracture energy ratio of steel bars decreases by 12.18%, and the sensitivity coefficient of hydrogen brittleness increases by 9.92%.