Issue 30

A. Fernández-Canteli et al., Frattura ed Integrità Strutturale, 30 (2014) 383-393; DOI: 10.3221/IGF-ESIS.30.46 383 Focussed on: Fracture and Structural Integrity related Issues Determining fracture energy parameters of concrete from the modified compact tension test A. Fernández-Canteli, L. Castañón, B. Nieto, M. Lozano University of Oviedo, Gijón, Spain afc@uniovi.es , labres@uniovi.es T. Holušová, S. Seitl Institute of Physics of Materials, Academy of Science of the Czech Republic, Brno, Czech Republic and Brno University of Technology, Faculty of Civil Engineering, Institute of Structural Mechanics, Brno, Czech Republic holusova.t@fce.vutbr.cz , seitl@ipm.cz A BSTRACT . The modified compact tension (MCT) test, though not yet recognized as a valid test for determining fracture energy of concrete, is believed to represent a plausible and suitable alternative versus other well established procedures, such as the wedge-splitting test (WST) and the three point (3PB) or four point bending (4PB) tests, due to its simplicity and low cost. The aim of the paper is twofold: Firstly, to demonstrate the necessary correspondence between the experimental MCT test setup and finite element simulations and secondly, to initiate the way of establishing the desirable conversion between the fracture energy parameter values resulting from the MCT test and the standard conventional procedures. MCT tests are carried out and compared with the numerical results from 2-D and 3-D finite element calculations using the commercial codes ABAQUS and ATENA, the latter being specifically developed for applications on concrete structures and elements. In this way, the usability of the modified compact tension test for practical purposes is confirmed. K EYWORDS . Concrete fracture energy; Modified compact tension test; Concrete; Numerical simulation. I NTRODUCTION AND MOTIVATION ne of the relevant parameters that characterize concrete fracture is its fracture energy. The most extended procedure for it to be obtained is the three point bending test [1 - 3], whose guidelines are collected in RILEM draft recommendation (50-FMC) [4, 5]. The wedge-splitting test [6, 7] represents some advantages compared to the three point bending test and it is also often used [8]. From any of those tests, the Load-displacement or Load-COD (crack open displacement) curve is obtained (Fig. 1) [9, 10], the area under which represents the work of fracture ( W f ), from which the fracture energy ( G f ) is defined as: f f lig G W A  (1) where A lig is a ligament area. That previous kind of tests are carried out in testing machines implying specific devices and auxiliary tooling; moreover, the manufacture of such specimens is not simple; the test execution is far from being trivial and, finally, a relatively large O