Abstract In this paper, the fracture process zone (FPZ) of dam concrete under different loading rates is measured, and the formation process of FPZ is studied by applying digital image correlation (DIC) and acoustic emission (AE) technique. The results show that the FPZ development of dam concrete presents the characteristics of stepwise growth. The FPZ has emerged before the peak load, and the rapid growth is basically complete shortly after the peak load. Large aggregate plays an important role in the FPZ development of dam concrete. It can cause the bifurcation and tortuous development path of FPZ, which lead to the enhancement of fracture toughness and fracture energy of dam concrete. The maximum loads of specimens increase accordingly at a higher rate. Meanwhile, the development of FPZ also have the rate effect. Higher loading rate will weaken the effect of aggregate constrained force, resulting in more direct development of FPZ. The damage also seems to be more serious under the same loading stage from AE results.

中文翻译：

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DIC和声发射在三点弯曲作用下全级配大坝混凝土断裂过程区的发展

摘要 本文测量了不同加载速率下大坝混凝土的断裂过程区（FPZ），并应用数字图像相关（DIC）和声发射（AE）技术研究了FPZ的形成过程。结果表明，大坝混凝土FPZ发展呈现阶梯式增长的特点。FPZ在峰值负荷之前就已经出现，在峰值负荷后不久就基本完成了快速增长。大骨料在大坝混凝土FPZ开发中发挥着重要作用。它会导致FPZ分叉和曲折的发展路径，从而导致大坝混凝土断裂韧性和断裂能的增强。试样的最大载荷相应地以更高的速率增加。同时，FPZ的发展也有速率效应。较高的加载率会削弱集料约束力的作用，导致FPZ的发展更加直接。从AE结果来看，在相同的加载阶段，损坏似乎也更严重。