Reinforced concrete (RC) structure is the most widely used type of structure, and their durability can never be ignored. Reinforcement corrosion in RC structures is one of the most important factors leading to premature failures of the structures. The reinforcement interfacial corrosion of RC structures in high corrosion environment is easily induced in offshore engineering and the reinforcement corrosion monitoring (RCM) research is of great significance. In this paper, the issue of RCMs in offshore RC structures is studied by means of theoretical analysis, indoor test and numerical simulation, aiming at proposing a novel RCM method for offshore RC structures based on Lead Piezoelectric Zirconate Titanate (PZT) wave method. The proposed method can not only reveal the influencing law for the reinforcement corrosion level and concrete cover on the PZT-based wave propagation behaviors, but also can quantitatively characterize the reinforcement corrosion thickness. For the purpose, the frequency dispersion and energy attenuation characteristics of guided ultrasonic waves (GUWs) in corroded steel bars is first studied. Then, the quantitative relation between parameters such as corrosion level and signal characteristics is investigated and established by finite element method (FEM). Finally, through an electrochemical corrosion monitoring test, the reinforcement corrosion process is monitored, the corrosion affecting factors that induce the change of the GUW propagation properties are extracted, and a damage detection index and the corresponding evaluation method based on the GUW energy change are proposed. The results show that the uniform corrosion of the reinforcement in RC structures is revealed to a certain extent, the GUW energy is captured by PZT sensors, and the longer corrosion time results in the more serious corrosion damage and the smaller echo sensing signal energy.
Due to its strong bearing capacity and good ductility, reinforced concrete (RC) structures have been widely used in large buildings such as dams, bridges, nuclear power plants, industrial and civil construction (Zhu, 2016; Wu, 2015). With its wide application, problems of RC structures have been increasingly obvious. With the increasing complexity of the environment in which large buildings are used, such as the application of snow melting agents on both sides of the road and the rise of offshore engineering pose new challenges to RC structures. Long-term service and special service environment can cause steel rebar corrosion in the structure, and steel corrosion is regarded as one of the most important factors leading to structural failure.
