Issue 42

S. Seitl et alii, Frattura ed Integrità Strutturale, 42 (2017) 119-127; DOI: 10.3221/IGF-ESIS.42.13 119 Focused on Mechanical Fatigue of Metals Evaluation of mixed mode I/II fracture toughness of C 50/60 from Brazilian disc test Stanislav Seitl, Petr Miarka Brno University of Technology, Faculty of Civil Engineering, Institute of Structural Mechanics, Veveří 331/95, 602 00 Brno, Czech Republic Seitl.s@fce.vutbr.cz, http://orcid.org/0000-0002-4953-4324 Miarka.p@fce.vutbr.cz A BSTRACT . Durability and sustainability of structures made from concrete like materials is getting more into an interest of civil engineers. Structures are subjected not only to uniaxial load, this means if there is a crack inside the load could be divided into mode I and shear mode II, but also to a mixed mode I/II. Therefore, it is necessary to perform test, which covers mixed mode loads and could be used for specimen made from concrete core-drill. Recommended test specimens used for evaluation of fracture mechanical parameters has usually a prismatic or rectangular shape. The cost of reshaping cylinder into rectangular is expensive and not very efficient, therefore it is very effective to use Brazilian disc test specimen with central notch to obtain mixed mode fracture parameters. The contribution deals with numerical support for Brazilian disc test to obtain calibration curves for mode I and mode II, evaluation of experimental results and compare them with data adapted from literature. K EYWORDS . Fracture Mechanics; Fracture Toughness; Centrally Cracked Brazilian disc; Mixed Mode I/II; Concrete. Citation: Seitl, S., Miarka, P., Evaluation of mixed mode I/II fracture toughness of C 50/60 from Brazilian disc test, Frattura ed Integrità Strutturale, 42 (2017) 119-127. Received: 12.06.2017 Accepted: 16.06.2017 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 oday’s trends in civil engineering pushes investors and owners of concrete structures more often into renovation, than into demolition of structures. This fact leads into need for knowledge of material characteristics such as bulk density, Young’s modulus of elasticity [1], compressive strength [2], flexural strength [3], etc. Some types of civil engineering structures are subjected to mixed mode loading I and II, therefore the knowledge of fracture mechanical parameters is necessary to predict life-time of concrete structures (bridges, cooling towers). To obtain material sample from considered structure, a core-drill is used, which drills out a cylindrical sample from a structure. This specimen is tested to obtain mechanical properties, but not for fracture mechanical parameters. T