# Chloride Resistance of Assembled Bridge Piers Reinforced with Epoxy-Coated Steel Bars
## 5 Conclusions  
We conducted experimental research on the corrosion resistance of pre-damaged epoxy-coated steel bars and the durability of assembled bridge pier joints through electro-migration, combined with electrochemical indicators and chloride ion content. Numerical simulation methods were used to predict the service life of two types of joints when epoxy-coated steel bars with various types of damage were used. The following conclusions were drawn:  
1. The corrosion resistance of the steel bars is directly related to the integrity of the epoxy coating. The ranking from highest to lowest corrosion resistance is untreated > knocked > bent > scratched. The corrosion risk and corrosion rate of steel bars increase significantly when the damaged area ratio of the epoxy coating is higher than 5%.
2. For assembled bridge pier, the quality of the connection interfaces between components significantly impacts the chloride resistance. The grouting interface of Joint 2 exhibits more defects than the prestressed post-cast strip interface of Joint 1. The chloride ion transport rate at the interface of Joint 2 is about 5 times that of Joint 1.
3. The types of assembled interface affect the corrosion behavior of the steel bars. The critical chloride ion content of the same type of steel bars in Joint 2 is less than 40% of that in Joint 1, and the initial rust time is less than 1/2 of that in Joint 1.
4. The numerical simulation suggests that the integrity of the epoxy coating and the type of joint significantly influence the service life. For Joint 1, the service life can reach up to 100 years regardless of the treatment of the steel bars. In contrast, Joint 2 achieves a service life of approximately 100 years only when using untreated epoxy-coated steel bars. This underscores the importance of proper joint design and the prevention of epoxy coating damage as critical strategies to enhance the durability of assembled pier in cross-sea bridges.  
Conceptualization, H.W., H.X. and T.H.; methodology, H.W. and D.F.; validation, H.X.; formal analysis, H.X. and T.H.; software, investigation, data curation, visualization, writing--original draft preparation, D.F.; resources, funding acquisition, writing--review and editing, H.W.; supervision, H.X. and T.H.; project administration, H.W., H.X. and T.H.; All authors have read and agreed to the published version of the manuscript.  
This research was funded by the R&D Program of Guangxi Province, grant number AB22035031; the National Science Foundation of China, grant number 52279141, 52079123; the R&D Program of Zhejiang Province, grant number 2023C01154, 2022C04005, 2021C01022; the Shanxi-Zheda Institute of New Materials and Chemical Engineering, grant number 2021 SZ-TD010, 2022 SZ-TD016; and the Centre for Balance Architecture, Zhejiang University.  
Not applicable.  
The raw data supporting the conclusions of this article will be made available by the authors on request.  
The authors would like to extend our gratitude to [PERSON], [PERSON], [PERSON], and [PERSON] for their help during the experimental process and to [PERSON] for her guidance during the writing of the paper.  
Author [PERSON] was employed by the company China Railway Design Corporation. Author [PERSON] was employed by the company Guangxi Xinfazhan Communication Group Co., Ltd. The remaining authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.