Investigation of seismic performance of RC column with electrochemical chloride extraction-strengthening by MPC-CFRP

Abstract

The electrochemical accelerated corrosion of reinforced concrete (RC) columns was carried out with the target corrosion rate of longitudinal rebar as 15%, then the magnesium phosphate cement (MPC)-carbon fiber reinforced plastics (CFRP) as strengthening approach and electrochemical chloride extraction (ECE) method were integrated to process the RC columns. Among them, when the dechlorination period was 35d, the current density of dechlorination was selected as 1 A/m2, 2 A/m2, and 3 A/m2; when the periods of dechlorination were 21d, 35d and 49d respectively, the dechlorination current density was set as 2 A/m2. Finally, the seismic performance and dechlorination efficiency of RC columns under different dechlorination current densities and dechlorination periods were mainly analyzed by failure mode, hysteresis performance, lateral strength, ductility performance, stiffness degradation, residual deformation plus energy dissipation. Compared with the corroded RC columns, the cumulative energy dissipation capacity of the RC columns enhanced by MPC-CFRP promoted by 101.33%−206.36%. When the dechlorination period was 35d, the seismic performance of the RC columns dechlorided by the current density of 1 A/m2 and 2 A/m2 did not decrease significantly, and the seismic performance of RC columns with the dechlorination current density of 3 A/m2 greatly reduced. When 2 A/m2 was regarded as the dechlorination current density, the seismic performance of concrete columns with the dechlorination periods of 21d and 35d did not decrease significantly, and the seismic performance of the concrete columns with the dechlorination periods of 49d greatly reduced. However, it was worth noting that the chloride ion content of the interface between rebar and concrete abated significantly with the growth of the current density and the dechlorination period.