Three‐point bending tests of the full‐graded concrete under different loading rates were carried out. The cracks were quantitatively analyzed by digital image correlation (DIC). The toughening mechanism during the crack development process was observed, and there are obvious crack branching and aggregate interlocking during the crack propagation. At the same load level, the crack opening width increases with the increase of the loading rate. DIC detects a decrease in the tortuosity of the fracture morphology. And at the same time, the damage of the dam concrete was evaluated by the frequency analysis and the damage type analysis from acoustic emission (AE) signals. The signal strength increases at a higher loading rate as well as the tensile type cracks. The results show that the monitoring results of DIC and AE technique are in agreement with each other, which is very effective for determining the fracture behaviour of concrete materials.

中文翻译：

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基于数字图像相关和声发射技术的全级配混凝土断裂行为分析

在不同的加载速率下对全级配混凝土进行了三点弯曲试验。通过数字图像相关（DIC）定量分析了裂纹。观察到了裂纹扩展过程中的增韧机理，并且在裂纹扩展过程中存在明显的裂纹分支和聚集体互锁。在相同载荷水平下，裂纹开口宽度随载荷率的增加而增大。DIC检测到断裂形态的曲折度降低。同时，通过频率分析和声发射（AE）信号的损伤类型分析来评估大坝混凝土的损伤。信号强度在较高的加载速率下也会增加，并且会出现拉伸型裂纹。