Detection of corrosion in reinforced concrete with infrared thermography and ultrasound

Abstract Steel corrosion is one of the main pathological manifestations found in reinforced concrete. Its early detection can avoid costly repairs and damage to users. This paper proposes using infrared thermography and ultrasound to detect corrosion in reinforced concrete. The methodology consisted of preparing six specimens of 30x20x10 cm each including three 12.5-mm steel bars inserted and 2.5, 5.0 and 7.5-cm coatings. Those are the most commonly used and and recommended types of coating for reinforced concrete structures. The test specimens were subjected to an accelerated corrosion process, in a differentiated manner, in order to analyze three different degrees of corrosion. Subsequently, the specimens were submitted to infrared thermography tests and finally, ultrasound tests. The results showed that infrared thermography has many limitations regarding corrosion detection, but those limitations are reduced during the morning period; in very advanced conditions of deterioration, and on steel covered with only limited coating. On the other hand, the ultrasound showed a clear distinction in the results for the specimens, since wave propagation speed varies according to the corrosion degree and the quality of the concrete. Even though both tests present some limitations, using them in combination is a more effective way to detect the problem, since thermography can locate affected areas and ultrasound can better characterize any problems by comparing these areas against other intact concrete areas.

摘要 钢筋锈蚀是钢筋混凝土（reinforced concrete）中最主要的病害表现之一，对其开展早期检测可避免高昂的维修成本与使用者损失。本文提出采用红外热成像（infrared thermography）与超声波（ultrasound）检测技术对钢筋混凝土内的锈蚀状况进行检测。本次研究的试验流程为：制备6块尺寸为30×20×10 cm的试样，每块试样内植入3根直径12.5 mm的钢筋，且钢筋保护层厚度分别设置为2.5 cm、5.0 cm与7.5 cm——该类保护层配置是钢筋混凝土结构中最常用且被推荐的类型。为分析三种不同锈蚀程度的试样，研究人员对试样采用差异化方式进行加速腐蚀（accelerated corrosion）处理。随后，依次对试样开展红外热成像检测与超声波检测。研究结果表明，红外热成像技术在锈蚀检测方面存在诸多局限，但这些局限在晨间时段、钢筋锈蚀程度已十分严重且仅带有极薄保护层的工况下会有所缓解。另一方面，超声波检测的结果可清晰区分不同试样：由于超声波的传播速度会随锈蚀程度与混凝土密实度的变化而改变，因此可有效区分不同状态的试样。尽管两种检测技术均存在一定局限性，但将二者结合使用可更为高效地检测锈蚀问题：红外热成像可定位受锈蚀影响的区域，而超声波则可通过将受影响区域与完好混凝土区域进行对比，实现对锈蚀问题的精准定性表征。

搜集汇总

背景与挑战

背景概述

该数据集聚焦于使用红外热成像和超声波技术检测钢筋混凝土中的腐蚀问题。研究通过制备六个不同涂层厚度的样本，进行加速腐蚀处理，并比较两种检测方法的性能。结果表明，红外热成像在特定条件下（如早晨或腐蚀严重时）有效，而超声波能更准确地区分腐蚀程度，结合使用可提高检测效果。