Degradation and Recovery Behavior for the Seismic Performance of a Chloride-Contaminated RC Pier after Electrochemical Repair

Electrochemical repair is a promising method for mitigating durability issues in RC bridge piers subjected to chloride attack in marine environments. To investigate the effect of degradation induced by electrochemical repair on the seismic performance of RC bridge piers, six specimens were subjected to electrochemical hydrogen charging (EHC) at different current densities. Taking time effects into account, the piers were categorized into those a standing period after EHC and those without a standing period. Low-cycle reciprocating tests were conducted to assess the failure modes, crack characteristics, and ductility performance of the piers. The experimental results indicate that crack characteristics vary significantly due to changes in concrete strength and degradation of bond–slip performance; however, a progressive reduction in internal hydrogen concentration was observed with extended standing time. This phenomenon was accompanied by partial recovery of bond–slip characteristics, through which the discrepancies in crack pattern features were progressively diminished. The failure mode, carrying capacity, and energy dissipation capacity remain largely unchanged across the range of parameters tested. The primary cause was attributed to the absence of significant variations observed in both the yield strength of steel reinforcement and the compressive strength of core concrete within specimens subjected to electrochemical hydrogen charging. The conclusions provide a scientific basis for applying electrochemical repair technology to RC bridges in the seismic precautionary zone.