Internal Discontinuity Detection in Concrete by Lamb Waves

The feasibility of detecting anomalies or discontinuities in concrete beams using lamb waves is investigated in this paper. The traditional ultrasonic methods for inspecting discontinuities in concrete use the reflection, transmission and scattering of longitudinal waves by internal discontinuities. Signal amplitude and time of flight measurements provide information about the internal anomalies in concrete. However, these methods are time consuming and, as will be shown in this paper, the traditional techniques often fail to detect honeycombs, dosed cracks and small anomalies. In this paper the potential of the lamb wave technique to detect those anomalies in large concrete beams is investigated. The lamb wave technique is found to be reliable for detecting such anomalies.