Strength Classes of Concrete versus Strength Classes of Fibre Concrete

Abstract:

Basic characteristics of each produced concrete and fibre reinforced concrete are characterized by the compression strength recorded by the standard sets of tests performed on cylinders and cubes. In addition, for the fibre reinforced concrete, the characteristic tensile strength at formation of microcracks and cracks of standard widths is required. Proofs of the referred characteristic tensile strength should be carried out also by the destructive tests on standard specimens including the methodology provided for their implementation.The rapid development of fibre reinforced concrete, accelerated by manufacturers of fibres and their interest to apply the fibre reinforced concrete in structural practice from where the beneficial effects of the tensile strength can be obtained, resulted in conclusion that there is currently no uniform methodology for evaluation of the tensile strength. Tensile strength studies are performed, for example, according to National standardization Committees and research institutes.At present, the two very different methodologies can be applied to test tensile characteristics of fibre reinforced concrete - MODEL CODE and the Czech national standard – ČSN P 73 2452. The results of the destructive tests, obtained in accordance with the mentioned methodologies are so different that the same strength class for the tested fibre reinforced concrete is not possible to be defined.The paper proves the diversity of methodologies to perform destructive testing, by which it is possible to obtain the tensile characteristics of fibre reinforced concrete needed to define the same strength class. Procedures for evaluation of tensile characteristics from results of destructive tests are also assessed. Significance of the obtained strengths from the point of view of objectivity for the practical application of the fibre concrete in the load-carrying structures are discussed.

• Periodical: Solid State Phenomena (Volume 249)
• Pages: 112-118
• DOI: https://doi.org/10.4028/www.scientific.net/SSP.249.112
• Online since: April 2016
• Authors: Jan Vodicka, Vladimír Křístek, Václav Ráček*
• Keywords: ČSN P 73 2452, Fibre-Concrete, MC 2010, Strength Class, Tensile Characteristics

References

[1] ČSN P 73 2450 FRC – Specifications, performance, production and conformity.

[2] ČSN P 73 2451 Testing of fresh fibre reinforced concrete (FRC).

[3] EN206-1 (Z3) Concrete – Part 1: Specific., performance, production and conformity, (2014).

[4] Model Code 2010, Final draft – Volume 1, FIB Buletin 65, ISBN: 1562-3610. (2012).

[5] ČSN P 73 2452 Testing of hardened fibre reinforced concrete (FRC).

[6] EN 14 651 (A1) Test method for metallic fibered concrete – Measuring the flexural tensile strength (limit of proportionality (LOP), residual), (2005).

DOI: 10.3403/30092475