Issue 42

S. Seitl et alii, Frattura ed Integrità Strutturale, 42 (2017) 56-65; DOI: 10.3221/IGF-ESIS.42.07 56 Focused on Mechanical Fatigue of Metals Comparison of fracture toughness values of normal and high strength concrete determined by three point bend and modified disk-shaped compact tension specimens Stanislav Seitl Academy of Sciences of the Czech Republic, Institute of Physics of Materials, v. v. i., Žižkova 22, 616 62 Brno, Czech Republic seitl@ipm.cz, http://orcid.org/0000-0002-4953-4324 José D. Ríos, Hector Cifuentes Grupo de Estructuras, ETSI, Universidad de Sevilla, Camino de los descubrimientos s/n, 41092 Sevilla, Spain. jdrios@us.es , bulte@us.es, http://orcid.org/0000-0001-6302-418X A BSTRACT . The modified disk shaped compact tension test is a configuration derived from standard compact tension test that is used for measuring fracture mechanical properties of primarily metallic materials. The compact tension configuration is commonly used for measurement fracture mechanical properties as e.g. fracture toughness, Young’s modulus, work of fracture etc. The modified compact tension tests imply significant modifications of the specimen morphology in order to avoid premature failure. The modified compact tension test is not proper for quasi-brittle materials due to its complicated shape (steel-concrete interface), but it is easily extracted from drill core and we do not need large amount of material for obtaining fracture properties as we need for e.g. three- or four- point bend test. Since it is a new test method, a wide range of tests is needed to be done before it can be applied. In the paper the selected outputs of the experiments performed on normal and high strength concrete will be processed and the values of fracture mechanical parameters will be discussed. K EYWORDS . Concrete; Stress intensity factor; T-stress; Compact tension test; Fracture behavior; Fracture mechanics; Constraint. Citation: Seitl, S., Ríos, J.D., Cifuentes, H. Comparison of fracture toughness values of normal and high strength concrete determined by three point bend and modified disk-shaped compact tension specimens, Frattura ed Integrità Strutturale, 42 (2017) 56-65. Received: 31.05.2017 Accepted: 08.06.2017 Published: 01.10.2017 Copyright: © 2017 This is an open access article under the terms of the CC-BY 4.0, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. I NTRODUCTION he assessment of residual life of existing concrete structures has been an attractive topic for the researchers for decades. This could be carried out to regularly monitor the health of old/important concrete structures and/or to evaluate damaged concrete structures to conserve the structural integrity and for constructional issues i.e. repair and T