混凝土结构缺陷的红外热成像检测识别技术

Infrared Thermal Imaging Detection and Recognition Technology for Defects in Concrete Structure

根据红外热辐射原理,研发出对混凝土结构主动激励、红外成像采集、红外图像处理分析等设备和系统,并进行了桥梁结构内部空洞病害类等缺陷检测的模型试件试验及公路桥梁实桥试验研究;试验研究表明通过接收来自混凝土表面的热辐射值,可以对其结构内部的缺陷状态作出基本判断。但混凝土结构在无主动激励时,其周围介质的温度差值较小,红外图像不会反映出内部缺陷状态;在对混凝土进行人为主动激励的条件下,结构内部缺陷介质的影响使其产生温度场发生变化,通过自主研发的数字热红外成像仪,采集获得了混凝土表面温度场分布的热像图谱,从而实现混凝土内部缺陷识别判定,不但完成了主动激励的混凝土结构模型试件的试验工作,还成功应用于运营桥梁结构体的缺陷检测工作;采集到桥梁结构表面非常清晰的温度场图谱,实现了对桥梁结构混凝土内部空洞类等缺陷的有效检测和识别。并对内部设有缺陷的模型试件试验及已运营的实桥检测试验对比、分析验证了主动激励红外检测方法的准确性及可靠性,成功攻克了快速检测混凝土内部缺陷病害识别的难题。

Based on the principle of infrared heat radiation, the equipment and system of active excitation, infrared imaging acquisition, processing and analysis of concrete structures are developed, the model specimen test for detecting the defects such as cavities in the bridge structure and the test of highway bridge are carried out. The experimental study shows that （ 1 ） By receiving the heat radiation from the surface of concrete, it is possible to make a basic judgment on the defect state inside the structure. However, the temperature difference of the surrounding medium is small, the infrared image does not reflect the internal defect state when there is not active excitation on concrete structure. （2） Under the condition of the artificial active excitation on the concrete, the influence of the internal defect medium can change the temperature field. The thermal image of the concrete surface temperature field is collected by the self-developed digital thermal infrared imager, so the identification of the defects inside the concrete is realized. This research not only completed the experimental work of the concrete structural model specimen under active excitation, but also successfully applied to the defect detection of the bridge structures in service. The well-developed temperature field map of the bridge structure surface is collected, and the defects such as hollow, etc. in the concrete are effectively detected and identified. The accuracy and reliability of the active excitation infrared detection method are verified and analyzed by the result of the internal defective model test and the detection result of the concrete defect in actual bridge in service, and the difficulties in the rapid detection of defects in concrete are successfully overcome.