Experimental study of concrete damage evaluation based on acoustic emission technique

Deformation and fracture will occur when materials or structures bear the internal or external force, and strain energy will be released in form of elastic waves, which is called acoustic emission (AE) activity. It has been shown that the AE characteristics in concrete can be related to damage magnitude of concrete by testing concrete core samples. In this paper an AE test is conducted on 4 concrete core samples which were taken out of an existing bridge. The relation between the stress distribution and the accumulated number of AE events of these concrete-core samples can be found in the experiment, consequently, the equation relating AE characteristic parameters to damage magnitude of concrete is built by combing the AE rate process theory with damage mechanics. Furthermore, the largest stress of the 4 concrete-core samples in the stress history can be obtained through analyzing AE events during the loaded process by utilizing Kaiser effect. The experimental results show that the damage can be detected quantitatively by AE without knowing the original state at construction.