Evaluation of Fracture Process Zone in the Flexural Response of Different Concrete Materials Using DIC Method

Abstract

In the present paper, a digital image correlation (DIC) method is used to study the development of fracture process zones (FPZ) of different concrete materials in three-point bending test. Different concrete materials including original concrete, rubber concrete, self-compacting rubber concrete and pervious concrete are investigated. Firstly, the image of the FPZ and the crack opening displacement (COD) in FPZ is obtained by acquiring strain field and displacement field information. The relationship between the development of FPZ and the mechanical properties is further studied. It is found that there is a strong correlation between the FPZ and the post-peak strength reduction of concrete. The development characteristics of FPZ of different concrete materials are analyzed. The addition of rubber will result in stronger strain concentration in pre-peak stage compared to original concrete, and the FPZ will emerges at the earlier loading stage, but it can enhance the crack resistance of concrete in the post-peak stage. Self-compacting rubber concrete was observed to have higher bearing capacity and cracking resistance during fracture than that of the others. Pervious concrete has weak resistance to fracture, and there is almost no decline of the FPZ development rate in fracture process.