ABSTRACT This article aims to improve the knowledge on ‘crack classification’ in reinforced concrete (RC) beams using acoustic emission (AE) testing and ultrasonic pulse velocity (UPV) test. The present study reports on usage of AE and UPV testing methods on fracture mode in RC structures. Gaussian mixture modelling (GMM) method was used for crack classification. Support vector machine (SVM) method was used for separating AE data related to tensile cracking and shear cracking. It was observed that the UPV along the span of the RC beam reduced at places where cracks were formed. The locations in the RC beam where the cracks developed, an increase in the travel time between receiver and transmitter was observed. More AE hits were observed at locations where UPV value was less. It was observed that at 60–100% of the load, the RC beam with shear reinforcement exhibit higher shear hits (e.g. approximately 20–30%) while the beam without shear reinforcement exhibit much less, showing the effect of the shear stirrups. The RC beam without shear reinforcement failed more like a plain concrete beam due to tension. The observations made in this study provide a reference for conducting non-destructive testing of large RC structures.

中文翻译：

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声发射技术与超声脉冲速度试验相结合的钢筋混凝土结构裂缝分类研究

摘要 本文旨在通过声发射 (AE) 测试和超声波脉冲速度 (UPV) 测试提高对钢筋混凝土 (RC) 梁中“裂缝分类”的认识。本研究报告了 AE 和 UPV 测试方法对 RC 结构断裂模式的使用。高斯混合建模（GMM）方法用于裂纹分类。支持向量机（SVM）方法用于分离与拉伸开裂和剪切开裂相关的声发射数据。观察到沿 RC 梁跨度的 UPV 在形成裂纹的地方减少。在 RC 梁中裂纹发展的位置，观察到接收器和发射器之间的传播时间增加。在 UPV 值较小的位置观察到更多的 AE 命中。据观察，在 60-100% 的负载下，有抗剪钢筋的 RC 梁表现出更高的剪切冲击（例如大约 20-30%），而没有抗剪钢筋的梁表现出的要少得多，显示了剪切箍筋​​的影响。由于张力，没有抗剪钢筋的 RC 梁更像普通混凝土梁。本研究的观察结果为大型钢筋混凝土结构的无损检测提供了参考。