Attenuation characteristics of stress wave in cracked concrete beam using smart aggregate transducers enabled time-reversal technique

Piezoelectric enabled stress wave methods for concrete structural health monitoring have been widely researched. However, the attenuation characteristics of stress wave in cracked concrete structures have barely been studied. As a result, it is hard to quantify the damage levels of the concrete structure. In this paper, the attenuation characteristics of stress wave in cracked concrete beam are studied using stress wave with the time-reversal technique. The attenuation model of stress waves related to the focused signal amplitude and the total crack width of concrete beam is proposed. In this study, a series of 18 concrete beams were tested using a four-point loading. During the test procedure, the signals of stress wave from the piezoelectric smart aggregate transducers in all the test specimens were collected to facilitate the proposed model. The test data of 12 beams are used to determine the attenuation coefficient of stress wave per unit crack width, and the test data of the other six beams are used to validate the accuracy of the proposed attenuation model. The results indicate that the prediction results based on the stress wave attenuation model are in good agreement with the test results of cracked concrete beams.