Effect of Mixed Fibers on the Ductility of Concrete
Publication: Journal of Materials in Civil Engineering
Volume 29, Issue 9
Abstract
In recent years, fiber reinforced concrete has been increasingly used not only for industrial floors but for many other loadbearing structures as well. The different types of synthetic fibers have distinct effects on concrete: micro fibers to reduce plastic shrinkage cracking of concrete, and macro fibers to give higher fracture toughness. This paper investigates whether when using mixed fibers (a blend of micro and macro fibers) the advantages of the two types remain separate or whether a new effect arises. Three-point bending tests are made to examine the effect of the different fiber types on the ductility of concrete. The existing theoretical smeared models’ predictions of expected experimental results are not accurate enough because of the high deviation of the data. In this study a new mechanical model is applied which takes into consideration the real distribution of the fibers in the concrete matrix. Comparing the experimental results with the theoretical model proves that micro fibers help the embedding of macro fibers by reducing micro cracks, and consequently the use of mixed fibers results in an increased fracture toughness.
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Acknowledgments
The authors would like to thank concrete technologist Vilmos Óvári and Ottó Sebestyén for helping prepare of the beams. The cement was provided by LAFARGE Cement Magyarország Kft. The fibers and the blender were provided by Fiberguru Kft. The use of the Zwick/Roell Z150 universal material testing machine was financed by TÁMOP 4.2.1/B-09/1/KMR-2010-0002 competition. The venue for the experiments was provided by the Czakó Adolf Laboratory of Materials and Structures of the Department of Mechanics, Materials and Structures at Budapest University of Technology and Economics.
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Information & Authors
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Published In
Journal of Materials in Civil Engineering
Volume 29 • Issue 9 • September 2017
Copyright
©2017 American Society of Civil Engineers.
History
Received: May 21, 2016
Accepted: Dec 30, 2016
Published ahead of print: Apr 10, 2017
Published online: Apr 11, 2017
Published in print: Sep 1, 2017
Discussion open until: Sep 11, 2017
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