## 2 Pros and Cons of Anti-Corrosion Methods for Steel Rebars in Marine Structures  
There are more problems with rebar corrosion, as argued by [PERSON] et al. [3]. On the basis of theoretical research, three mathematical models were used to theoretically calculate the corrosion of hot-rolling reinforced steel bars. The results showed that different models had a high impact on the corrosion distribution of steel rebar, resulting in a large difference between the theoretical analysis and numerical simulation of steel rebar corrosion, which made it impossible to pre-protect against steel rebar corrosion. Meanwhile, [PERSON] and [PERSON] [4] pointed out that different sizes of mild steel had widely varying corrosion resistance, with the standard size having the worst corrosion resistance. Thicker mild steel had better corrosion resistance. There exist some corrosion prevention measures for steel rebars in marine structures. The advantages and disadvantages of various aspects of these are discussed below. These include a selection of high-quality raw materials, coating technology, surface modification technology, corrosion inhibition technology, cathodic protection (CP) technology, and structural corrosion design. The selection of high-quality raw materials [5] can improve structural strength, save steel rebars, lower maintenance costs, and lessen environmental pollution; however, it dramatically increases project costs, and the materials often need more tests and verification. Coating technologies [6] are low-cost, have a wide range of applications, and are easy to apply and maintain. However, most coatings only have a single function. The coating must be intact to provide protection, and corrosion can be accelerated when defects are present. Steel rebars have relatively high surface and shape requirements for electroplating, and the biological acids secreted by marine organisms may corrode the coating layer. Surface modification technology, which involves a variety of techniques, increases the bonding strength of the anti-corrosion surface layer, improving resistance. However, these methods can introduce pollution and impurities into the environment. Corrosion inhibition technology [7] can inhibit corrosion from the root and requires only a small dosage, making it economical, simple, and efficient. However, insufficient doses have the potential to cause pitting and are difficult to apply to open systems. Sacrifice anode CP technology is low cost, uses simple equipment, and benefits from easy installation, but the protection period is short, and the procedure needs to be repeated periodically. Impressed current CP technology has a long protection cycle with a controllable current/potential. However, it is high cost, requires complex equipment, and is difficult to maintain. Structural corrosion design [8] provides a solution that is effective, cost-saving, and produces low environmental pollution. However, the construction is demanding and requires much supervision while only reducing the corrosion rate. The corrosion of marine structures is influenced by chemical, physical, and biological factors. Seawater is an electrolyte, and steel rebars in seawater are mainly corroded by electrochemical action [9]. All protective measures have certain drawbacks. Compared with other measures, CP techniques are effective and reliable, as are mature technology. Additionally, most other protective measures are one-time measures, yet CP technology can play a long-term role if properly maintained. In addition, CP technology can not only be used alone but also with other measures. When other anti-corrosive protection measures fail, the CP methods can be used as a remedy. According to the principle of electrochemistry, metal can be protected as a cathode to prevent electrochemical corrosion. This is known as CP.