Arumaikani Thirumalaiselvi, Sasmal Saptarshi, Kundu Tribikram
Special and Multi-functional Structures Laboratory, Council of Scientific and Industrial Research-Structural Engineering Research Centre, Chennai 600113, India.
Civil and Architectural Engineering and Mechanics, University of Arizona, Tucson, Arizona 85721, USA.
J Acoust Soc Am. 2022 Feb;151(2):1341. doi: 10.1121/10.0009621.
Structural failure caused by corrosion of the reinforcing steel in concrete structures is quite common. In most cases, corrosion cracks appear on the surface at a late stage, leaving inadequate time for taking any measures. This paper investigates the detection of corrosion damage in reinforced concrete elements by using nonlinear ultrasonic (NLU) techniques. Various linear ultrasonic and NLU techniques were adopted to identify the most sensitive technique and ultrasonic parameters for corrosion induced damage detection at its early stage. It is observed that the linear techniques are not very effective in detecting corrosion induced damage. The sideband peak count-index (or SPC-I), a relatively new and promising technique, has been found to be an excellent indicator for the detection of corrosion induced damage initiation. However, its efficacy for detecting corrosion induced damage has not yet been reported. The present study shows that the SPC-I-based NLU technique outperforms (with the highest sensitivity) all other NLU techniques for detecting the onset of corrosion in steel and micro-crack formation in the surrounding material. As the corrosion progresses and cracks appear on the surface of the concrete, the efficiency of the SPC-I slowly weakens and other technique(s) are found to be quite efficient at that stage.
混凝土结构中钢筋腐蚀导致的结构破坏十分常见。在大多数情况下，腐蚀裂缝在后期才出现在表面，使得采取措施的时间不足。本文研究了利用非线性超声（NLU）技术检测钢筋混凝土构件中的腐蚀损伤。采用了各种线性超声和NLU技术来确定在早期检测腐蚀引起的损伤时最敏感的技术和超声参数。结果表明，线性技术在检测腐蚀引起的损伤方面不太有效。边带峰值计数指数（或SPC-I）是一种相对新颖且有前景的技术，已被发现是检测腐蚀引起的损伤起始的极佳指标。然而，其检测腐蚀引起的损伤的功效尚未见报道。本研究表明，基于SPC-I的NLU技术在检测钢材腐蚀的起始和周围材料中的微裂纹形成方面优于（灵敏度最高）所有其他NLU技术。随着腐蚀的进展以及混凝土表面出现裂缝，SPC-I的效率会逐渐减弱，而在那个阶段会发现其他技术相当有效。
