Fracture resistance on aggregate bridging crack in concrete

被引：4

作者：

Zhang X. ^{[1
]}

Xu S. ^{[1
]}

机构：

[1] School of Civil and Hydraulic Engineering, Dalian University of Technology

来源：

Frontiers of Architecture and Civil Engineering in China | 2007年 / 1卷 / 1期

基金：

中国国家自然科学基金;

关键词：

Concrete; Fracture energy; Fracture process zone; Fracture resistance; Quasi-brittle materials;

D O I：

10.1007/s11709-007-0006-2

中图分类号：

学科分类号：

摘要：

Fracture toughening exhibited in quasi-brittle materials such as concrete is often mainly related to the action of aggregate bridging, which leads to the presence of a fracture process zone ahead of stress-free cracks in such materials. In this investigation, the fracture resistance induced by aggregate bridging, denoted by G I-bridging, in the primary focus. In order to quantitatively determine it, a general analytical formula is firstly developed, based on the definition of fracture energy by Hillerborg. After this, we further present the calculated procedures of determining this fracture resistance from the recorded load vs. crack opening displacement curve. Then, both numerical simulations and fracture experiments are performed on concrete three-point bending beams. Utilizing the obtained load against crack opening displacement curve, the value of G I-bridging at any crack extension as well as the change of G I-bridging with the crack extension is examined. It is found that G I-bridging will firstly increase with the development of crack and then stay constant once the initial crack tip opening displacement reaches the characteristic crack opening displacement w 0. The effects of material strength and specimen depth on this fracture resistance are also investigated. The results reveal that the values of G I-bridging of different specimens at any crack propagation are strongly associated with the values of fracture energy of specimens. If the values of fracture energy between different specimens are comparable, the differences between G I-bridging are ignored. Instead, if values of fracture energy are different, the G I-bridging will be different. This shows that for specimens with different strengths, G I-bridging will change greatly whereas for specimens that are different in depth, whether G I-bridging exhibits size effect depends on whether the fracture energy of specimens considered in the calculation of G I-bridging is assumed to be a size-dependent material parameter. © Higher Education Press 2007.

引用

页码：63 / 70

页数：7

共 10 条

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