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Comparison Between EN 14651 and EFNARC Three Point Bending Test on Square Panel with Notch

Alberto Meda
University of Rome Tor Vergata, Rome, Italy.

Benoit De Rivaz 

Bekaert Maccaferri Underground Solutions, Aalst, Belgium.

Abstract: The design of Fibre Reinforced Concrete (FRC) tunnels is often made adopting the indication of FIB Model Code. This Model Code is considered as reference document in several guidelines for tunnels. In order to classify and characterize the FRC in tension, FIB suggests using the EN 14651 bending test. The EN 14651 test is made on beams having a square section 150x150 mm and a length between 550 and 700 mm. This beam geometry is suitable to cast concrete. The interest on sprayed FRC for permanent applications is now increasing. Sprayed FRC is currently largely used in traditional excavated tunnels, where a temporary lining is cast. Design of temporary sprayed FRC lining is usually made considering the energy values given by EN 14488-5 tests. EN 14488-5 tests are made on 600x600 mm panel with a thickness of 100 mm. In order to design permanent structures made with sprayed FRC, it is necessary to make a material characterization (e.g. classification according to Model Code). EN 14651 beam tests can be hardly performed due to the difficulty in preparing specimens with sprayed concrete. In order to fulfil this need, EFNARC prepared a document suggesting the use of bending tests on panel having the same geometry of EN 14488-5 (600x600x100 mm) and proposing a correla-tion between EFNARC bending test and EN 14651 bending test. The analysis of the results of tests, made with the same concrete mixes and adopting EN 14651 and EFNARC tests will be presented in this paper.