101 / 2022-04-21 13:33:46

Experimental and numerical analysis of mechanical properties of RC member with electrochemical chloride extraction-strengthening by MPC-CFRP

MPC-CFRP; Strengthening; Electrochemical chloride extraction; numerical analysis

A large number of RC structures in coastal areas failed in advance due to the corrosion of steel bars, which cannot reach the expected service life, and chloride salt was the main reason for the corrosion of steel bars in concrete. In this paper, the electrochemical accelerated corrosion of RC members was carried out, and 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 members. The reasons for the changes of mechanical properties of RC members under different dechlorination current densities were analyzed from the perspective of microscopic mechanism, and the risk of re-corrosion of steel bars after electrochemical dechlorination was evaluated. In addition, the damage and stress of concrete members under different electrochemical dechlorination conditions were discussed from the perspective of mesoscopic finite element simulation. The test results show that in the process of dechlorination, the current density was small, the dechlorination efficiency was low, and the corrosion risk of steel bars was high; When the current density was too high, the mechanical properties of RC members were seriously reduced. Considering the above factors, the current density should be controlled to 2 A/m², which can not only improve the mechanical properties of RC members, but also improve the durability of the sample. The mesoscopic simulation results show that CFRP can reduce the damage degree of mortar in the axial compression column, but has little effect on the stress of steel bars in the axial compression column. CFRP can well share the stress of the longitudinal steel bars at the bottom of the beam and inhibit the development of inclined cracks in the beam.