Study on Fracture Characteristics of Concrete by White Light Digital Image Analysis in Frequency Domain

White light digital image analysis in frequency domain has the characteristics of whole-field, non-contact measurement. The measuring system of this method is very simple and the coherent light is not demanded. Gray images before and after deformation which are recorded using CCD camera, digitalized and then analyzed by frequency domain correlation arithmetic can be used to obtain the displacement information. This method is used to study the fracture characteristics of concrete and measure the stress intensity factor of I type crack tip. Comparing the experimental results and theoretical values of the stress intensity factor of I type crack tip, the applicability of this method was certified, which shows that this method is very proper to study the deformation and fracture characteristics of concrete.