Abstract The fracture energy constitutes an important input parameter for non-linear finite element analysis of concrete structures. Characterization of such parameter based on standard RILEM three-point bending test or wedge splitting test is known to depend on the size of the specimen. For the assessment example of large hydraulic structures using non-linear finite elements, it is important to develop an experimental protocol for characterizing a size-independent fracture energy, or asymptotic fracture energy representative of the size of these structures. Characterization of the asymptotic fracture energy requires specimens with very large sizes and thus represents an important experimental challenge. This work aims to develop a new experimental protocol based on wedge splitting test on specimen with moderate size and using digital image correlation technique. The new protocol is based on the disturbed fracture process zone (DFPZ) theory developed in this work, as an interpretation theory for the boundary effect theory of Duan et al. [8]. It uses the same hypothesis of bilinear distribution of the local fracture energy as in the simplified boundary effect method (SBEM) (Abdalla and Karihaloo [1], Karihaloo et al. [21]) but requires only one set of specimens with a specific notch over depth (a/D) ratio rather than two sets of specimens with two different a/D ratios. In order to validate the developed approach and theory, an experimental programme of 14 concrete specimens is conducted. Two concrete mixtures are considered with two maximum aggregate sizes: 38 mm and 76 mm, representative of hydraulic structures. Assessment of the fracture energy using the new protocol and the protocol based on SBEM resulted in similar values for both mixtures and thus validates the new developed theory.

中文翻译：

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用于评估混凝土渐近断裂能的扰动断裂过程区理论

摘要 断裂能是混凝土结构非线性有限元分析的重要输入参数。已知基于标准 RILEM 三点弯曲试验或楔形劈裂试验的此类参数的表征取决于试样的尺寸。对于使用非线性有限元的大型水利结构的评估示例，重要的是制定实验协议来表征与尺寸无关的断裂能，或代表这些结构尺寸的渐近断裂能。渐近断裂能量的表征需要非常大尺寸的试样，因此是一项重要的实验挑战。这项工作旨在开发一种新的实验方案，基于对中等尺寸样本的楔形分裂测试，并使用数字图像相关技术。新协议基于在这项工作中开发的扰动断裂过程区 (DFPZ) 理论，作为 Duan 等人的边界效应理论的解释理论。[8]。它使用与简化边界效应方法 (SBEM)（Abdalla 和 Karihaloo [1]、Karihaloo 等人 [21]）中相同的局部断裂能双线性分布假设，但只需要一组具有特定缺口的试样过深度 (a/D) 比，而不是具有两个不同 a/D 比的两组试样。为了验证所开发的方法和理论，进行了 14 个混凝土试件的实验程序。两种混凝土混合物被认为具有两种最大骨料尺寸：38 毫米和 76 毫米，代表水力结构。使用新协议和基于 SBEM 的协议评估断裂能量导致两种混合物的值相似，从而验证了新开发的理论。