Reinforcement corrosion is a major culprit that undermines the service life of reinforced concrete (RC) structures. It costs billions of dollars each year in the US alone and negatively impacts safety, reliability, resilience, and environmental performance of RC infrastructure. Corrosion monitoring of steel rebar is critical to provide early warning of deficiency, enable timely and effective maintenance strategies, and prevent catastrophes associated with premature failure of RC structures. To improve corrosion monitoring in the engineering practice, this work comprehensively reviews the state of the art of five major types of techniques, that is, electrochemical sensors, optical fiber sensors, sensors based on elastic wave methods, sensing based on electromagnetic methods, and untouched sensors. Each type of technique is systematically divided into sub-categories based on the sensing principle and key characteristics. For each sensor type, its maturity, application range, and the problems that hinder its application are discussed, aimed to provide guidance in selecting the appropriate sensors for specific engineering applications. This work concludes with an overview of opportunities and challenges, including the following six aspects for future research: spatial resolution, sensitivity, and measurement range; reliability and interpretation of the measurement; sensor selection based on three corrosion stages of steel rebar; long-term stability and service life; cost-efficiency of the sensing system; and monitoring of existing structure.

钢筋腐蚀是破坏钢筋混凝土（RC）结构使用寿命的罪魁祸首。仅在美国，它每年就花费数十亿美元，并对 RC 基础设施的安全性、可靠性、弹性和环境性能产生负面影响。钢筋腐蚀监测对于提供缺陷早期预警、制定及时有效的维护策略以及防止与 RC 结构过早失效相关的灾难至关重要。为提高工程实践中的腐蚀监测水平，本工作全面回顾了电化学传感器、光纤传感器、基于弹性波法的传感器、基于电磁法的传感和未触及的五类技术的现状。传感器。每种类型的技术都根据传感原理和关键特性系统地分为子类别。针对每种传感器类型，讨论了其成熟度、应用范围以及阻碍其应用的问题，旨在为特定工程应用选择合适的传感器提供指导。本工作总结了机遇和挑战，包括未来研究的以下六个方面：空间分辨率、灵敏度和测量范围；测量的可靠性和解释；基于钢筋三个腐蚀阶段的传感器选择；长期稳定性和使用寿命；传感系统的成本效益；和监测现有结构。讨论了其成熟度、应用范围以及阻碍其应用的问题，旨在为特定工程应用选择合适的传感器提供指导。本工作总结了机遇和挑战，包括未来研究的以下六个方面：空间分辨率、灵敏度和测量范围；测量的可靠性和解释；基于钢筋三个腐蚀阶段的传感器选择；长期稳定性和使用寿命；传感系统的成本效益；和监测现有结构。讨论了其成熟度、应用范围以及阻碍其应用的问题，旨在为特定工程应用选择合适的传感器提供指导。本工作总结了机遇和挑战，包括未来研究的以下六个方面：空间分辨率、灵敏度和测量范围；测量的可靠性和解释；基于钢筋三个腐蚀阶段的传感器选择；长期稳定性和使用寿命；传感系统的成本效益；和监测现有结构。本工作总结了机遇和挑战，包括未来研究的以下六个方面：空间分辨率、灵敏度和测量范围；测量的可靠性和解释；基于钢筋三个腐蚀阶段的传感器选择；长期稳定性和使用寿命；传感系统的成本效益；和监测现有结构。本工作总结了机遇和挑战，包括未来研究的以下六个方面：空间分辨率、灵敏度和测量范围；测量的可靠性和解释；基于钢筋三个腐蚀阶段的传感器选择；长期稳定性和使用寿命；传感系统的成本效益；和监测现有结构。