关键词: 混凝土;拱形三点弯曲梁;数字图像相关方法;裂缝扩展过程;双K断裂参数

Abstract: Through the arch three-point bending beam experiment of concrete, double-K fracture parameters were calculated by the experimental curve, then the influence of different seam height ratios on double-K fracture parameters was studied.Based on the digital image correlation ( DIC) method, the field strain information of the crack propagation direction of concrete was obtained, and the process of fracture propagation was studied.The results show that Pini/Pmax value was between 0.60 and 0.85.The double-K fracture parameters were not related to the initial seam-height ratio of the specimen, and they could describe the fracture characteristics of arch specimens.Compared with the preload phase of peak load, the crack propagation speed increased significantly after the peak load.

Key words: concrete;arch three-point bending beam;digital image correlation method;crack propagation process;double-K fracture parameters