光纤布拉格光栅钢筋腐蚀传感器

Optical Fiber Grating Sensors for Monitoring Corrosion of Reinforcing Steel

基于钢筋混凝土中钢筋锈胀和光纤布拉格光栅(fiber Bragg grating,简称FBG)应变、温度测量原理,设计了一种灵敏度较高的FBG钢筋腐蚀传感器。传感器主要由两个FBG(FBG-1,FBG-2)和带有轴向通孔、轴向通槽、环形槽及盲孔的钢筋件组成,FBG-1用于监测钢筋件的锈胀应变,FBG-2用作温度补偿器。为了提高传感器的成活率,在FBG-1外紧密包裹一层滤纸,并用水泥砂浆封装。此外,推导了钢筋件的腐蚀率计算公式,根据光纤解调仪采集的波长变化值可以计算得到钢筋件的腐蚀率。依据法拉第电解定律设计了电化学加速腐蚀实验,探究传感器的工作性能。实验结果表明,该传感器能够监测到0.7%以内的质量腐蚀率,灵敏度较高,且测量范围大于5%。该传感器能够有效监测混凝土中钢筋的早期腐蚀过程,准确估算保护层开裂时间,具有实际工程应用价值。

Based on the expand behavior of the corrosion product and the strain and temperature measurement principle of fiber Bragg grating(FBG),a sensitive FBG reinforcement corrosion sensor is proposed.The sensor consists of two FBG sensors and a customized rebar which has an axial through-hole,an axial groove,a ring groove,and a blind hole.The FBG-1 sensor is designed to monitor the expansion strain caused by steel bar corrosion,and the FBG-2 sensor is used as a temperature compensator to eliminate the cross-sensitivity of the FBG-1 sensor.In order to increase the survival rate of the FBG corrosion sensor,a layer of filter paper is tightly wrapped outside the FBG-1 sensor and the FBG corrosion sensor is sealed with cement mortar.The calculation formula of reinforcement corrosion rate can be calculated according to the wavelength value collected by FBG interrogation system.In addition,based on Faraday′s law of electrolysis,electrochemical accelerated corrosion experiment is designed to explore the working performance of the FBG corrosion sensor.The experimental results show that the sensor can accurately monitor mass loss rate within 0.7%,the measurement range of which is greater than 5%.The sensor can effectively monitor the early corrosion process of reinforcement,which will minimize maintenance costs.