School of Civil Engineering, Dalian University of Technology, Dalian 116024, China.
Sensors (Basel). 2011;11(11):10798-819. doi: 10.3390/s111110798. Epub 2011 Nov 16.
In this paper, a novel kind of method to monitor corrosion expansion of steel rebars in steel reinforced concrete structures named fiber optic coil winding method is proposed, discussed and tested. It is based on the fiber optical Brillouin sensing technique. Firstly, a strain calibration experiment is designed and conducted to obtain the strain coefficient of single mode fiber optics. Results have shown that there is a good linear relationship between Brillouin frequency and applied strain. Then, three kinds of novel fiber optical Brillouin corrosion expansion sensors with different fiber optic coil winding packaging schemes are designed. Sensors were embedded into concrete specimens to monitor expansion strain caused by steel rebar corrosion, and their performance was studied in a designed electrochemical corrosion acceleration experiment. Experimental results have shown that expansion strain along the fiber optic coil winding area can be detected and measured by the three kinds of sensors with different measurement range during development the corrosion. With the assumption of uniform corrosion, diameters of corrosion steel rebars were obtained using calculated average strains. A maximum expansion strain of 6,738 με was monitored. Furthermore, the uniform corrosion analysis model was established and the evaluation formula to evaluate mass loss rate of steel rebar under a given corrosion rust expansion rate was derived. The research has shown that three kinds of Brillouin sensors can be used to monitor the steel rebar corrosion expansion of reinforced concrete structures with good sensitivity, accuracy and monitoring range, and can be applied to monitor different levels of corrosion. By means of this kind of monitoring technique, quantitative corrosion expansion monitoring can be carried out, with the virtues of long durability, real-time monitoring and quasi-distribution monitoring.
本文提出并探讨了一种监测钢筋混凝土结构中钢筋腐蚀膨胀的新型光纤线圈缠绕方法，该方法基于光纤布里渊传感技术。首先，设计并进行了应变标定实验，以获得单模光纤的应变系数。结果表明，布里渊频率与施加应变之间存在良好的线性关系。然后，设计了三种具有不同光纤线圈缠绕包装方案的新型光纤布里渊腐蚀膨胀传感器。将传感器嵌入混凝土试件中，以监测由钢筋腐蚀引起的膨胀应变，并在设计的电化学腐蚀加速实验中研究了它们的性能。实验结果表明，三种传感器在腐蚀发展过程中，可以检测和测量不同测量范围的光纤线圈缠绕区域的膨胀应变。假设均匀腐蚀，通过计算平均应变得到腐蚀钢筋的直径。监测到的最大膨胀应变为 6,738 με。此外，建立了均匀腐蚀分析模型，并推导出了在给定腐蚀锈膨胀率下评估钢筋质量损失率的评价公式。研究表明，三种布里渊传感器可以用于监测钢筋混凝土结构的钢筋腐蚀膨胀，具有良好的灵敏度、准确性和监测范围，可用于监测不同程度的腐蚀。通过这种监测技术，可以进行定量腐蚀膨胀监测，具有耐久性长、实时监测和准分布式监测的优点。
