Detectability of delamination regions using infrared thermography in concrete members strengthened by CFRP jacketing
Detectability of delamination regions using infrared thermography in concrete members strengthened by CFRP jacketing
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DOI：
10.1016/j.compstruct.2020.112328
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发表时间：
2020-08-01
影响因子：
6.3
通讯作者：
Naito, Hideki
中科院分区：
文献类型：
--
作者：
Gu, Jian-Cheng;Unjoh, Shigeki;Naito, Hideki
在这项研究中，我们分析了使用红外热像仪检测cfrp夹套混凝土构件分层的无损检测（NDT）方法的准确性。以某既有桥梁为研究对象，进行了4个CFRP加固试件的设计与评价。在这些标本中建立了16个不同参数的人工分层。人工分层的条件包括尺寸和深度、表面覆盖砂浆的存在以及分层空隙中的含水量作为试验参数。采用红外热像仪对主动加热的试样进行了分析。捕获表面温度随时间的变化，分析各像元表面温度的时程变化。提出并研究了一种识别分层边界和区域的方法。结果表明，可选性与分层的大小和深度呈正相关，而表面覆盖砂浆和水的存在降低了检测的准确性。所提出的方法可以成功地识别大小至少为5 cm x 5 cm的分层区域。然而，它无法识别只有分层但几乎没有可测量深度的区域，因为这些区域的空隙中隔热空气较少。
In this study, we analyzed the accuracy of a nondestructive testing (NDT) method using infrared thermography for detecting delamination in CFRP-jacketed concrete members. Based on an existing bridge strengthened by CFRP jacketing, four specimens were designed and evaluated. Sixteen artificial delaminations with different parameters were created in these specimens. The conditions of the artificial delaminations, including size and depth, presence of surface cover mortar, and water content in the delamination void, were considered as test parameters. The infrared thermography was applied to the specimens with active heating. Changes in the surface temperature were captured with time, and the time history change of the surface temperature in each pixel was analyzed. A method to identify the boundaries and regions of delamination was proposed and studied. The results showed that the delectability was positively correlated with the size and depth of the delamination, while the presence of surface cover mortar and water decreased the accuracy of the detection. The proposed method could successfully identify delamination regions that were at least 5 cm x 5 cm in size. However, it failed to identify the regions with just the delamination but almost no measurable depth, because these regions had less heat-insulated air in voids.