基于场变响应与信息熵理论的海洋混凝土结构钢筋锈蚀与损伤累积定量表征研究

Initiation and location of steel corrosion as well as quantitative characterization of corrosion rate and damage accumulation of reinforced concrete in marine environment are the key issues needing to be solved. Based on the principles of magnetic field effects, an innovative home-made corrosion evaluation apparatus will be developed to evaluate the corrosion status of reinforcement in concrete. The quantitative relationship between the magnetic field change signal and the steel corrosion in concrete will be studied and further a computational model of magnetic field will be established to quantitatively describe the evolution of steel corrosion. The time-frequency characteristics and dispersion characteristics of acoustic emission signals induced by steel corrosion and concrete degradation will be analyzed to precisely locate the corrosion position and initial time. The entropy growth model of steel corrosion and damage accumulation in concrete structure will be established by wavelet analysis and information entropy theory calculation to reveal the relationship between frequency-information entropy evolution of AE signals and damage accumulation of concrete structures. The key points of degradation process of reinforced concrete structures caused by steel corrosion under marine environment will be identified, which provides theoretical supports for establishing the early warning system of performance degradation of reinforced concrete structures.

钢筋起锈点准确定位以及锈蚀程度与损伤累积定量表征是海洋混凝土结构耐久性评估亟待解决的关键难题。基于磁场效应原理，本项目自行研发钢筋锈蚀磁场场变监测仪器，测量钢筋锈蚀物引起的磁场时空演化规律，研究磁场场变信号与混凝土中钢筋锈蚀度之间的定量关系，建立钢筋锈蚀演化进程的磁场场变模型，科学表征混凝土中钢筋的锈蚀程度；采用水泥基压电声发射系统研究钢筋锈蚀与混凝土劣化的频谱特征与频散特性，确定钢筋锈蚀膨胀裂缝所引起的动态应力场与应变场，准确识别、定位钢筋起锈时空关键点；通过小波分析与信息熵理论计算，建立不同锈蚀程度钢筋与混凝土结构损伤累积的熵增模型，感知海洋环境下混凝土材料与结构全寿命性能退化进程，甄别由于钢筋锈蚀引起的损伤劣化时空关键点，为建立混凝土结构性能劣化预警体系提供理论支撑。

本项目基于磁场效应原理研发了钢筋锈蚀监测装置，揭示了钢筋锈蚀物引起的磁场时空演化规律，探明了磁场场变信号与混凝土中锈蚀钢筋质量损失之间的线性关系，实现了混凝土中钢筋锈蚀程度的科学表征。基于声发射信号在钢筋中的传播规律，采用连续小波变换分析了声发射信号的频散特征，确定了钢筋锈蚀膨胀裂缝所引起的动态应力场与应变场，实现了混凝土中钢筋起锈时空关键点的准确识别与定位。采用声发射技术对外部荷载与侵蚀性离子耦合作用下钢筋混凝土构件的锈蚀劣化过程进行实时在线监测，研究了钢筋锈蚀与混凝土劣化诱发的声发射信号时频域特征，通过小波分析与信息熵理论计算，建立了不同锈蚀程度钢筋混凝土结构损伤累积的熵增模型。探明了钢筋混凝土中离子的传输过程与侵蚀机理，通过改善水化产物的微结构，提升了混凝土材料在复杂海洋环境下的耐久性。项目研究成果为钢筋混凝土结构的耐久性评估提供了理论基础与技术支持。