Research on the critical chloride content of reinforcement corrosion in marine concrete - A review

Cl- erosion is the main cause of reinforcement corrosion in marine concrete. Research on the critical chloride content of reinforcement corrosion in marine concrete has continued from the last century to the present and is ongoing. Since the concept of critical chloride content was proposed, although there have been numerous studies, most people still understand the critical chloride content at a superficial level. This paper summarizes the factors influencing the critical chloride content, and analyzes the factors affecting the critical chloride content based on the experimental data from the existing literatures, and the main influencing factors of the critical chloride content are concluded. The corrosion initiation time of reinforcement in concrete structures and the determination methods of critical chloride content are systematically elaborated. The existing prediction models for the corrosion initiation time of reinforcement in concrete are analyzed and compared. According to the existing literatures, the critical chloride content fluctuates widely, which is closely related to the choice of reinforced concrete materials and external environmental factors. It can be found from the analysis of the admixtures that investigating the effect of nanomaterials on the critical chloride content has great significance. The influence of environmental factors on the critical chloride content in marine concrete is inevitable, and the concrete in the splash zone and tidal zone is more seriously affected by Clerosion, which needs to be emphasized more in the practical engineering. Determining the corrosion initiation time of reinforcement in concrete is one crucial step in studying the critical chloride content. Traditional models for predicting the corrosion initiation time of reinforcement in concrete have limitations, but machine learning models provide better predictions. Finally, the advantages of nanomaterials, the determination of critical chloride content, as well as the application of artificial intelligence in studying the critical chloride content are prospected.