SIST EN 14721:2005

• Abstract:

  This European Standard specifies two methods of measuring the fibre content of metallic fibre concrete. Method A measures the fibre content of a hardened concrete specimen. Method B measures the fibre content of a fresh concrete specimen.

• Status: Published
• Publication Date: 30-Nov-2005
• Withdrawal Date: 06-Nov-2007
• ICS: 91.100.30 - Concrete and concrete products
• Technical Committee: BBB - Concrete, reinforced concrete and prestressed concrete
• Current Stage: 9900 - Withdrawal (Adopted Project)
• Start Date: 05-Nov-2007
• Due Date: 28-Nov-2007
• Completion Date: 07-Nov-2007
• Ref Project: EN 14721:2005 - Test method for metallic fibre concrete - Measuring the fibre content in fresh and hardened concrete

• Consolidated By: SIST EN 14721:2005+A1:2008 - Test method for metallic fibre concrete - Measuring the fibre content in fresh and hardened concrete
• Effective Date: 01-Mar-2008

SIST EN 14721:2005 is the Slovenian adoption of EN 14721:2005, a European Standard from CEN for measuring the fibre content of metallic fibre concrete. It specifies two test methods: Method A for hardened concrete specimens and Method B for fresh concrete specimens, so laboratories, precast producers and quality-control teams can determine the amount of metallic fibre present in a sample.

What does SIST EN 14721:2005 specify?

SIST EN 14721:2005 specifies a test method for metallic fibre concrete and sets out two alternative ways to measure fibre content, depending on whether the concrete is fresh or hardened. In practice, that lets users choose the method that matches the stage of production or the product available for testing.

The standard is organized into nine clauses:

• Clause 1 - Scope
• Clause 2 - Normative references
• Clause 3 - Principle
• Clause 4 - Apparatus
• Clause 5 - Test specimens
• Clause 6 - Testing procedures
• Clause 7 - Expression of results
• Clause 8 - Test report
• Clause 9 - Precision

What are the key requirements of SIST EN 14721:2005?

SIST EN 14721:2005 determines fibre content by extracting fibres from a concrete sample and relating the recovered fibre mass to the sample volume. That matters because both the sampling method and the volume measurement directly affect the reported fibre content.

Method A and Method B

Clause 1 defines two routes. Method A is for a hardened concrete specimen, and Method B is for a fresh concrete specimen. This gives users a choice between testing drilled product cores and testing material taken directly from the fresh mix.

Sampling and specimen size

Clause 5 requires at least 3 test cores for Method A, with each core at least 1 dm3 and the total test specimen volume at least 5 dm3. For Method B, the fresh test specimen consists of at least 3 test samples, each at least 3 dm3. In practice, the minimum sample size and replication help reduce the effect of local variation in fibre distribution.

Apparatus for each method

Clause 4 lists the equipment needed. Method A uses core drilling equipment, measuring tools, a balance for weighing in air and water, a water tank, and a balance for recovered fibres. Method B uses a watertight container, a scoop, compaction equipment, a steel trowel or float, weighing equipment, and sieve or filter equipment for washing out fines. This tells the user what must be available before testing starts.

Sampling procedure

Clause 6 says Method A cores shall be drilled perpendicular to the product surface, with the drill held rigidly. For Method B, increments are taken from the discharging stream, avoiding the first and last parts, and spread across the width and thickness of the stream. This matters because poor sampling can bias the fibre result.

Volume determination

Clause 6.2 requires the sample volume to be determined by measurement or water displacement for hardened cores, and by calibration of the container for fresh concrete. For Method B, the volume is either the filled container volume or the container volume less the added water needed to fill it after compaction. Accurate volume measurement is essential because it is part of the final fibre-content calculation.

Fibre separation and weighing

Clause 6.3 covers how fibres are recovered. Hardened cores are crushed so the fibres can be separated; fresh samples are washed through sieve or filter equipment to remove cement and fine material. Magnetic fibres may be collected with a magnet, then the fibres are cleaned and weighed to the stated accuracy. This is the practical work that produces the mass value used in the result.

Result calculation and precision

Clause 7 states that fibre content is calculated from fibre mass and sample volume and reported in kg/m3. Clause 9 adds that only indicative precision information is available, and notes that Method A may lose up to 5% of fibre mass during crushing and collection, while Method B does not involve fibre loss. That helps users judge which method is better suited to a specific comparison or acceptance check.

What terms does SIST EN 14721:2005 define?

• Fibre content - the amount of metallic fibre in the concrete, calculated from the recovered fibre mass and the measured sample volume.
• Method A - the test route for a hardened concrete specimen, based on drilling and crushing a core.
• Method B - the test route for a fresh concrete specimen, based on sampling the fresh mix in a container and washing out fines.
• Test core - a hardened concrete core taken from the product for Method A.
• Test sample - a fresh concrete portion prepared in the container for Method B.
• Magnetic fibres - fibres that can be collected with a magnet during separation.

Who uses SIST EN 14721:2005?

SIST EN 14721:2005 is used by testing laboratories, precast concrete manufacturers, and quality-control teams working with metallic fibre concrete. It is also relevant to specifiers, inspectors and buyers who need to verify that the fibre content measured in a sample matches the intended mix or product control plan. The standard supports production checks, acceptance testing, and investigation of inconsistent fibre distribution.

Which standards are used with SIST EN 14721:2005?

SIST EN 14721:2005 relies on two normative references:

• EN 12350-6 - used for calibration of the fresh-concrete container in Method B.
• EN 12390-7 - used for determining the volume of hardened test cores in Method A by water displacement.

These references support the volume measurements that feed directly into the fibre-content calculation.

What does the SIST EN 14721:2005 document contain?

SIST EN 14721:2005 contains the apparatus lists for both methods, including the tools for coring, weighing, compaction, washing and fibre recovery. It also gives the sampling steps, the ways to determine sample volume, and the procedure for separating and weighing fibres. Clause 8 sets out what the test report shall include, such as specimen identification, method used, sample volume, fibre mass, calculated fibre content, average value, deviations and a conformity statement. Clause 9 provides the precision note needed to interpret results in practice.

2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.Preskusna metoda za beton s kovinskimi vlakni – Merjenje deleža vlaken v svežem in strjenem betonuPrüfverfahren für Beton mit metallischen Fasern - Bestimmung des Fasergehalts in Frisch- und FestbetonMéthode d'essai du béton de fibres métalliques - Mesurage de la teneur en fibres du béton frais ou durciTest method for metallic fibre concrete - Measuring the fibre content in fresh and hardened concrete91.100.30Beton in betonski izdelkiConcrete and concrete productsICS:Ta slovenski standard je istoveten z:EN 14721:2005SIST EN 14721:2005en01-december-2005SIST EN 14721:2005SLOVENSKI
STANDARD
EUROPEAN STANDARDNORME EUROPÉENNEEUROPÄISCHE NORMEN 14721August 2005ICS 91.100.30English versionTest method for metallic fibre concrete - Measuring the fibrecontent in fresh and hardened concreteMéthode d'essai du béton de fibres métalliques - Mesuragede la teneur en fibres du béton frais ou durciPrüfverfahren für Beton mit metallischen Fasern -Bestimmung des Fasergehalts in Frisch- und FestbetonThis European Standard was approved by CEN on 27 June 2005.CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this EuropeanStandard the status of a national standard without any alteration. Up-to-date lists and bibliographical references concerning such nationalstandards may be obtained on application to the Central Secretariat or to any CEN member.This European Standard exists in three official versions (English, French, German). A version in any other language made by translationunder the responsibility of a CEN member into its own language and notified to the Central Secretariat has the same status as the officialversions.CEN members are the national standards bodies of Austria, Belgium, Cyprus, Czech Republic, Denmark, Estonia, Finland, France,Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Slovakia,Slovenia, Spain, Sweden, Switzerland and United Kingdom.EUROPEAN COMMITTEE FOR STANDARDIZATIONCOMITÉ EUROPÉEN DE NORMALISATIONEUROPÄISCHES KOMITEE FÜR NORMUNGManagement Centre: rue de Stassart, 36
B-1050 Brussels© 2005 CENAll rights of exploitation in any form and by any means reservedworldwide for CEN national Members.Ref. No. EN 14721:2005: ESIST EN 14721:2005
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