Evaluation of concrete fracture behavior based on digital image correlation

Fracture is the most common damage form of concrete buildings. Due to the opaqueness of concrete, the internal structure can be hardly observed so that it is difficult to predict the occurrence and development of cracks. Therefore, an image-based modeling method using digital image correlation (DIC) is proposed in this work. The realistic distribution of each phase in a concrete structure is captured by a camera, and the corresponding concrete models are then established for further simulation. With the image-based models, a series of three-point and four-point bending experiments are carried out experimentally and numerically, and their fracture processes are compared. It is revealed that the simulation analysis is in good agreement with the experimental result on crack propagation and the trend of strain in three-point bending tests. It should also be remarked that the image-based model needs to be optimized for simulating crack development in four-point bending tests because of the randomness of crack position, although the strain field of simulation is close to one of the experiments.