海洋环境混凝土中钢筋锈蚀场变响应、监测与损伤识别

Accurate monitoring on corrosion degree and the site of steel bars, and cracking time-space point of concrete; as well as damage identification of reinforced concrete are the key problems in the durability assessment and performance recovery of reinforced concrete structures in marine environment. In this project, the micro and macro properties evolution of the reinforced concrete servicing in the marine environment, and their induction to the changes of physical fields including the stress/strain field and electromagnetic field are studied. Detecting the signal of electromagnetic field in the steel bar corrosion process and realizing its quantification processing by information entropy theory, so as to obtain the response rule of electromagnetic field of steel bar corrosion in marine environment. The monitoring system of electromagnetic field to detect the corrosion degree and the site of steel bar in concrete would be developed. The acoustic emission response to crack process of reinforced concrete induced by corrosion of steel bar would be studied. The key time-space point is determined based on the critical crack equation of concrete induced by steel bar corrosion and the application of acoustic emission monitoring technique. The essential relationship between field response and the micro/macro properties in the corrosion process of steel bar is revealed and the damage identification method of reinforced concrete in marine environment would be proposed. According to field response monitoring data and the numerical simulation method, the corrosion degree and the damage state of concrete structure real-timely and quantitatively would be evaluated, which will provide the evidence for safety warning and performance recovery of damaged concrete structure in marine environment.

混凝土中钢筋起锈、锈蚀程度、锈胀开裂时空关键点准确监测与损伤识别是海洋环境钢筋混凝土结构耐久性评估与性能恢复面临的关键问题。本项目针对海洋工程钢筋混凝土服役过程中微、宏观性能随时间演变，并诱发应力/应变场、电磁场等物理场变化的特点。监测钢筋锈蚀过程中的电磁场场变信号并利用信息熵原理实现该信号的定量处理，获得海洋环境下混凝土中钢筋锈蚀的电磁场场变响应规律。发明钢筋锈蚀电磁场场变监测系统实现钢筋锈蚀程度及锈蚀源的精准监测。研究钢筋锈蚀诱导混凝土开裂过程的声发射响应规律，通过钢筋混凝土开裂临界状态方程建立以及声发射监测技术运用，捕捉钢筋锈蚀诱导混凝土开裂时空关键点。揭示场变响应与钢筋混凝土微、宏观性能演变间的本质联系，建立海洋环境钢筋混凝土损伤识别理论，依据场变响应监测数据与数值模拟方法实时、定量评价混凝土中钢筋锈蚀程度及损伤状态，为海洋工程钢筋混凝土劣化预警与性能恢复提供依据。

混凝土中钢筋锈蚀并诱导其开裂是海洋工程服役寿命第二阶段，准确监测与识别混凝土中钢筋脱钝、锈蚀程度以及锈胀开裂时空关键点是海洋钢筋混凝土耐久性评估与性能恢复的关键问题。本项目分析钢筋钝化膜组成与形貌，基于电化学阻抗谱和分子动力学分析钢筋钝化膜形成过程及其稳定性，揭示温度、氧浓度对钢筋钝化的定量影响规律，揭示海洋环境混凝土中钢筋钝化与脱钝机制。建立钢筋均匀锈蚀与非均匀锈蚀对电磁场场变信号定量影响方程，开发基于钢筋锈蚀电磁场场变响应的检测装置，提出环境与材料等对钢筋锈蚀电磁场场变响应信号的修正系数；发明埋入式钢筋锈蚀电磁场场变响应监测传感器。推导混凝土中钢筋均匀锈蚀与非均匀锈蚀状态下的锈胀应力计算方程，基于数字图像技术（DIC）与XCT动态追踪了混凝土中钢筋锈蚀历程并计算出钢筋混凝土不同位置的应力/应变场演变。提出了利用钢筋锈蚀电磁场场变响应与数字图像技术和声发射实现混凝土中钢筋起锈到后期混凝土锈胀开裂全过程监测技术，实现了混凝土中钢筋起锈、锈蚀源和开裂点的精准监测。开发多系列混凝土中钢筋锈蚀及保护层不同深度钢筋锈蚀临界氯离子浓度监测装置，发明钢筋混凝土监测信号无线采集与传输系统，建立海洋环境下钢筋混凝土长期性能监测系统并应用于青连铁路跨海大桥，实现海洋环境下钢筋混凝土长期性能演变识别。开发具有高导电能力的高饱水水泥基阳极材料以及兼具修复功能的导电水泥砂浆；发展双向电迁移、脉冲电流、不锈钢网-砂浆双阳极除盐技术，针对海洋裂缝钢筋混凝土提出电化学除氯与沉积修复提升技术，延长海洋钢筋混凝土服役寿命。