2-DIMENSIONAL ELECTRONIC-SPECKLE-PATTERN INTERFEROMETRY AND CONCRETE-FRACTURE PROCESSES

Electronic-speckle-pattern interferometry (ESPI) is an optical nondestructive testing technique. A two-dimensional in-plane displacement sensitive interferometer was designed to observe progressive development of microcracking of carbon-fiber-reinforced concrete specimens subjected to tension. By using the two-dimensional ESPI system, the fracture processes, crack initiation and crack propagation of concrete specimens were monitored qualitatively and in real time. The displacement and strain fields were analyzed quantitatively by using digital image processing techniques.