# Experimental Study on Repairing Corroded Cracks by Electrophoretic Deposition
## 1 Introduction  
Reasonable material ratios, structural designs, and fine maintenance construction can control the development of cracks to a certain extent [1, 2]. However, given the material characteristics of concrete and other factors, the cracking of reinforced concrete structures cannot be completely inhibited [3, 4]. When cracks form on a structure, its bearing capacity decreases, further increasing the number, depth, and width of cracks [5, 6]. Crack formation not only affects the safety and reliability of a building structure, but also seriously deteriorates its durability and normal use functions [7, 8]. Indeed, even \"harmless\" cracks can affect the appearance of a building and cause fear and anxiety among users [9, 10, 11]. Therefore, when cracks in concrete structures become visible, they must be repaired to ensure that the structures remain safe, reliable, and durable [12, 13, 14, 15]. The slotting filling method is applicable in cases where the structure to be repaired features small cracks with large widths, such as the cracks of pier or pavement concrete [16, 17]. In this method, a chisel and flat showed are used to create a U-shaped groove along the crack, with a groove depth and width of approximately 3-5 cm. A brush is then used to evenly coat a layer of interface treatment slurry at the bottom and two walls of the groove. A mixed polymer cement mortar is then pressed into the groove with a spatula, compacted, and wiped flat before the slurry hardens. Grouting is another commonly used crack repair method, and grouting materials can be mainly divided into inorganic and organic materials [18, 19, 20, 21, 22]. Epoxy-based grouting materials are widely used in the industry, owing to their many advantages, including good stability, room-temperature curing, minimal shrinkage, and strong bonding force; thus, these materials are considered highly effectivereinforcement materials [23; 24]. When grout is filled into concrete cracks, the two sides of the crack are closely bonded together, thereby restoring the integrity of the structure. Moreover, because of the high bond strength and cohesive properties of the grout, the repaired concrete is stronger than the original concrete. However, the high viscosity of epoxy resin limits its use for filling tiny cracks. Thus, grouting equipment is required to achieve a certain pressure that can push the resin into the cracks [17; 25]. Electrochemical deposition has been proposed as a repair method for marine reinforced concrete cracking. This method employs a steel bar as a cathode and a titanium plate in salt solution as an anode [26; 27]. Under a direct current, cations in the salt solution accumulate in the concrete cracks and salt deposits are generated to fill the cracks via a series of chemical reactions [28; 29; 30]. Because cracks affect the mechanical properties of concrete structures, using a reinforcement method to treat the concrete structure is necessary [31; 32]. The following methods are commonly used to enhance the mechanical properties of concrete structures: increasing the load surface area of the concrete structure, applying steel plates at the corners of the structure [33; 34], prestressing [35], adding a fulcrum, and spraying concrete [36; 37; 38]. The repair methods described above are applicable to different fields and, thus, can be implemented according to the needs of a project. Rust expansion cracking is a special cracking form observed in concrete structures; this type of cracking is accompanied by steel corrosion and, thus, is quite harmful to building structures [39; 40]. To address this type of damage, [PERSON] et al. [41] proposed the electrophoretic deposition repair method. In this method, an electric field is used to electrophorese cationic ammonium epoxy resin curing agent molecules filled into corrosive cracks. After restoration, the epoxy deposited on the surface and inner cracks of the concrete will be cured; thus, the durability properties of the original reinforced concrete are enhanced. In addition, [PERSON] et al.