Publications

Round-robin test on various test-methods for flexural behavior of steel fiber reinforced sprayed concretes

Plückelmann, S. and Breitenbücher, R.

AMERICAN CONCRETE INSTITUTE, ACI SPECIAL PUBLICATION
Volume: SP-343 Pages: 2-11
DOI: 10.35789/fib.BULL.0095.Ch01
Published: 2020

Abstract
According to the actual European standard EN 14487-1 the potential of steel fiber reinforced sprayed concrete is characterized by flexural strength tests (first peak, ultimate and residual). In most cases, this is performed by a four-point bending test on beam specimens, specified in EN 14488-3. As an alternative test method, a three-point bending test on square panels with notch is recommended by EFNARC. It is argued as main benefit of the latter test method, that the geometry and dimensions of the panels are equal to those of specimens used for measuring the energy absorption capacity according to EN 14488-5. Hence, the specification of the ductility of fiber reinforced concretes according to EN 14487-1 in terms of residual strength and energy absorption capacity can be achieved preparing only one type of specimen. Furthermore, the EFNARC guideline points out a smaller scatter of test results, compared to the beam tests according to EN 14488-3. Before the EFNARC method will be considered in EN 14487-1, the relevant CEN TC 104/WG10 requests for adequate proofs. These were performed within a round-robin test (RRT) on testing the flexural behavior of steel fiber reinforced sprayed concrete by the standardized EN 14488-3 method as well as by the proposed EFNARC method. The aim of this RRT was to investigate the comparability and correlation between the two test methods. Furthermore, the scatter of both methods was assessed. The RRT has been organized by Ruhr University Bochum, in whose labs the steel fiber reinforced sprayed concrete specimens (beams according to EN 14488-3 and square panels according to EFNARC guideline) were produced using a robotic spraying machine. The specimens were then tested in five independent laboratories Europe-wide. The results of this RRT are presented in detail. With regard to the residual strength, the relevant material parameter for steel fiber reinforced sprayed concrete, a tendency towards a slightly lower scatter was detected for the EFNARC test method. © 2020 American Concrete Institute. All rights reserved.

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