Influence of curing agent molecular structure and proportion on electrophoretic deposition repair of rust-cracked reinforced concrete

For the rust expansion and cracking disease of reinforced concrete, the electrophoretic deposition repair method is a new and effective means. This study focuses on the key component of the electrophoresis repair solution - aqueous cationic amine curing agent (ACACA), and systematically explores the influence mechanism of its molecular structure design and proporation parameters on the repair rate and effect of rust expansion cracks. The research results show that: 1) Introducing ether-based functional groups into the ACACA molecular chain can significantly improve the electrophoretic deposition efficiency, manifested as the simultaneous acceleration of the increment of specimen mass and the growth rate of electrophoretic deposition films (EDF) thickness; 2) The introduction of ether-based functional groups prolongs the molecular chain length and endows EDF with hydrophobicity, effectively improving its flexibility, crack resistance and water resistance, thereby enhancing the mechanical properties, carbonization resistance and impermeability of the repaired specimens. 3) When the ratio of ACACA to aqueous cationic epoxy resin (ACER) deviates from 1:1, the excess components will lead to structural defects in EDF cross-linking, manifested as increased sensitivity to film cracking and a sudden drop in impermeability. The above findings provide a theoretical basis for the design and preparation of high-performance electrophoretic repair materials.