Determination of Tensile Strength and Fracture Toughness of Granite Using Notched Three-Point-Bend Samples

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• 作者：Yusuo Wang ; Xiaozhi Hu
• 关键词：Fracture toughness ; Tensile strength ; Fictitious crack ; Fracture process zone ; Three ; point ; bending
• 刊名：Rock Mechanics and Rock Engineering
• 出版年：2017
• 出版时间：January 2017
• 年：2017
• 卷：50
• 期：1
• 页码：17-28
• 全文大小：
• 刊物类别：Earth and Environmental Science
• 刊物主题：Geophysics/Geodesy; Civil Engineering;
• 出版者：Springer Vienna
• ISSN：1434-453X
• 卷排序：50

文摘

Direct tensile strength and fracture toughness of rock and concrete, important properties for many applications, are cumbersome to measure directly. In this study, granite is chosen as an example to show how the tensile strength and fracture toughness can be measured from small three-point-bend samples of a single size but with different notches. An existing fracture mechanics model has been extended to include the stable fictitious crack growth before peak loads, which is then linked to the granite grain size. Both tensile strength and fracture toughness of granite can be estimated by the maximum load measurements from those notched three-point-bend samples. In total, 72 three-point-bend granite samples with different notches have been tested, and the estimated tensile strength and fracture toughness are compared with those available in the literature. The modified fracture mechanics model is then used to predict the fracture behaviour of smaller samples of the same granite. The theoretical prediction is confirmed by the experimental results of those smaller samples. Finally, the fracture model and its relation with the American Society for Testing and Materials (ASTM) standard on fracture toughness are discussed.