SIST EN 13161:2008

Natural stone test methods - Determination of flexural strength under constant moment

This European Standard specifies a method to determine the flexural strength of natural stones under constant moment. This European Standard contains provision for both an identification test and for a technological test.

Prüfverfahren für Naturstein — Bestimmung der Biegefestigkeit unter Drittellinienlast

Diese Europäische Norm legt das Verfahren zur Bestimmung der Biegefestigkeit von Naturstein unter
Drittellinienlast fest. Diese Europäische Norm enthält Festlegungen für eine Identitätsprüfung und für eine
technologische Prüfung.

Méthodes d´essai pour pierres naturelles — Détermination de la résistance en flexion sous moment constant

La présente Norme européenne spécifie une méthode de détermination de la résistance en flexion des pierres
naturelles sous moment constant. La présente Norme européenne prévoit un essai d’identification et un essai
technologique.

Preskušanje naravnega kamna - Ugotavljanje upogibne trdnosti z obremenitvijo na tretjini razpona

General Information

• Status: Published
• Public Enquiry End Date: 14-Jan-2008
• Publication Date: 04-Jun-2008
• ICS: 73.020 - Mining and quarrying
• ICS: 91.100.15 - Mineral materials and products
• Technical Committee: IKER - Ceramics
• Current Stage: 6060 - National Implementation/Publication (Adopted Project)
• Start Date: 09-May-2008
• Due Date: 14-Jul-2008
• Completion Date: 05-Jun-2008
• Ref Project: EN 13161:2008 - Natural stone test methods - Determination of flexural strength under constant moment

Relations

• Replaces: SIST EN 13161:2002/AC:2003 - Natural stone test methods - Determination of flexural strength under constant moment
• Effective Date: 22-Dec-2008
• Replaces: SIST EN 13161:2002 - Natural stone test methods - Determination of flexural strength under constant moment
• Effective Date: 01-Jul-2008

Overview

EN 13161:2008 - Natural stone test methods - Determination of flexural strength under constant moment is a CEN standard that describes a repeatable laboratory method for measuring the flexural strength of natural stone using a constant-moment (third‑point) two-point loading arrangement. The standard covers both an identification test (reference specimens) and a technological test (final products or specimens sawn from final products).

Key topics and technical requirements

• Specimens and sampling
  • Minimum of 10 specimens from a homogeneous batch for identification testing.
  • Surface finishes: sawn, honed or polished (identification); final-product finishes (flamed, sandblasted, etc.) allowed for technological tests.
• Dimensions and tolerances
  • Thickness h: 25–100 mm, and greater than twice the largest crystal size.
  • Length L = 6 × h; support span l = 5 × h.
  • Width b: 50 mm ≤ b ≤ 3 × h, and b ≥ h.
  • Dimensional tolerance: ±1 mm; perpendicularity deviation ≤ 2% (max 2 mm) for identification tests.
• Anisotropy
  • If planes of anisotropy exist (bedding, foliation), mark specimen orientation. If use orientation is unknown, test all three loading arrangements - increasing sample size to 3 × 10 specimens.
• Conditioning
  • Dry specimens at (70 ± 5) °C to constant mass (mass change ≤ 0.1% over 24 ± 2 h) then equilibrate at (20 ± 10) °C and test within 24 h.
• Apparatus & procedure
  • Test machine per EN 12390-4 and two-point loading device per EN 12390-5.
  • Clean rollers; align specimen centrally; load increased uniformly at 0.25 ± 0.05 MPa/s until failure.
  • Record maximum load to nearest 10 N and flexural strength to nearest 0.1 MPa.
• Result calculation
  • Flexural strength R (MPa) calculated as specified in the standard (R = (F × l) / (2 × b × h^2) as given).
• Statistical evaluation
  • Annex A provides methods for mean, standard deviation, coefficient of variation and lower expected value using log‑normal assumptions.

Applications and who uses it

• Laboratories performing natural stone testing and certification for compliance and product data sheets.
• Quarry operators and stone producers for quality control of blocks and finished products.
• Architects, structural engineers and specifiers who need validated flexural strength values for design and safety assessments.
• Manufacturers of stone products (paving, cladding, countertops) to verify performance in intended end-use orientation.

Related standards

• EN 12390-4 / EN 12390-5 (testing machine and two-point loading references)
• Other natural stone test series referenced in the standard (e.g., EN 1936, EN 12372, EN 14146) for complementary physical and mechanical properties.

Keywords: EN 13161:2008, natural stone test methods, flexural strength, constant moment, two-point loading, specimen conditioning, anisotropy, stone testing, third‑point loading.

Standards Content (Sample)

SLOVENSKI STANDARD
01-julij-2008
1DGRPHãþD
SIST EN 13161:2002
SIST EN 13161:2002/AC:2003
Preskušanje naravnega kamna - Ugotavljanje upogibne trdnosti z obremenitvijo na
tretjini razpona
Natural stone test methods - Determination of flexural strength under constant moment
Prüfverfahren für Naturstein — Bestimmung der Biegefestigkeit unter Drittellinienlast
Méthodes d´essai pour pierres naturelles — Détermination de la résistance en flexion
sous moment constant
Ta slovenski standard je istoveten z: EN 13161:2008
ICS:
73.020 Rudarstvo in kamnolomsko Mining and quarrying
izkopavanje
91.100.15 Mineralni materiali in izdelki Mineral materials and
products
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

EUROPEAN STANDARD
EN 13161
NORME EUROPÉENNE
EUROPÄISCHE NORM
April 2008
ICS 73.020; 91.100.15 Supersedes EN 13161:2001
English Version
Natural stone test methods - Determination of flexural strength
under constant moment
Méthodes d'essai pour pierres naturelles - Détermination Prüfverfahren für Naturstein - Bestimmung der
de la résistance en flexion sous moment constant Biegefestigkeit unter Drittellinienlast
This European Standard was approved by CEN on 28 March 2008.
CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this European
Standard the status of a national standard without any alteration. Up-to-date lists and bibliographical references concerning such national
standards may be obtained on application to the CEN Management Centre or to any CEN member.
This European Standard exists in three official versions (English, French, German). A version in any other language made by translation
under the responsibility of a CEN member into its own language and notified to the CEN Management Centre has the same status as the
official versions.
CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Cyprus, Czech Republic, Denmark, Estonia, Finland,
France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal,
Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland and United Kingdom.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION
EUROPÄISCHES KOMITEE FÜR NORMUNG
Management Centre: rue de Stassart, 36  B-1050 Brussels
© 2008 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN 13161:2008: E
worldwide for CEN national Members.

Contents Page
Foreword.3
1 Scope.5
2 Normative references.5
3 Principle.5
4 Symbols.5
5 Apparatus.5
6 Preparation of specimens.6
6.1 Sampling.6
6.2 Test specimens.6
6.2.1 Surface finish.6
6.2.2 Dimensions.7
6.2.3 Limit deviations.7
6.2.4 Planes of anisotropy .7
6.2.5 Conditioning before testing.9
7 Test procedure.9
8 Expression of results.10
9 Test report.10
Annex A (normative) Statistical evaluation of the test results.12
A.1 Scope.12
A.2 Symbols and definitions .12
A.3 Statistical evaluation of test results .12
Bibliography .15

Foreword
This document (EN 13161:2008) has been prepared by Technical Committee CEN/TC 246 “Natural stones”,
the secretariat of which is held by UNI.
This European Standard shall be given the status of a national standard, either by publication of an identical
text or by endorsement, at the latest by October 2008, and conflicting national standards shall be withdrawn at
the latest by October 2008.
Attention is drawn to the possibility that some of the elements of this document may be the subject of patent
rights. CEN [and/or CENELEC] shall not be held responsible for identifying any or all such patent rights.
This document supersedes EN 13161:2001.
This European Standard is one of the series of European Standards for tests on natural stone.
Test methods for natural stone consist of the following parts:
EN 1925, Natural stone test methods — Determination of water absorption coefficient by capillarity
EN 1926, Natural stone test methods — Determination of uniaxial compressive strength
EN 1936, Natural stone test methods — Determination of real density and apparent density and of total
porosity and open porosity
EN 12370, Natural stone test methods — Determination of resistance to salt crystallisation
EN 12371, Natural stone test methods — Determination of frost resistance
EN 12372, Natural stone test methods — Determination of flexural strength under concentrated load
EN 12407, Natural stone test methods — Petrographic examination
EN 13364, Natural stone test methods — Determination of the breaking load at dowel hole
EN 13373, Natural stone test methods — Determination of geometric characteristics on units
EN 13755, Natural stone test methods — Determination of water absorption at atmospheric pressure
EN 13919, Natural stone test methods — Determination of resistance to ageing by SO action in the presence
of humidity
EN 14066, Natural stone test methods — Determination of resistance to ageing by thermal shock
EN 14146, Natural stone test methods — Determination of the dynamic modulus of elasticity (by measuring
the fundamental resonance frequency)
EN 14147, Natural stone test methods — Determination of resistance to ageing by salt mist
EN 14157, Natural stone test methods — Determination of abrasion resistance
EN 14158, Natural stone test methods — Determination of rupture energy
EN 14205, Natural stone test methods — Determination of Knoop hardness
EN 14231, Natural stone test methods — Determination of the slip resistance by means of the pendulum
tester
EN 14579, Natural stone test methods — Determination of sound speed propagation
EN 14580, Natural stone test methods — Determination of static elastic modulus
EN 14581, Natural stone test methods — Determination of linear thermal expansion coefficient
According to the CEN/CENELEC Internal Regulations, the national standards organizations of the following
countries are bound to implement this European Standard: Austria, Belgium, Bulgaria, Cyprus, Czech
Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia,
Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain,
Sweden, Switzerland and the United Kingdom.
1 Scope
This European Standard specifies a method to determine the flexural strength of natural stones under
constant moment. This European Standard contains provision for both an identification test and for a
technological test.
2 Normative references
The following referenced documents are indispensable for the application of this document. For dated
references, only the edition cited applies. For undated references, the latest edition of the referenced
document (including any amendments) applies.
EN 12390-4, Testing hardened concrete — Part 4: Compressive strength — Specification for testing machines
EN 12390-5, Testing hardened concrete — Part 5: Flexural strength of test specimens
3 Principle
After appropriate preparation a specimen of the rock to be tested is laid and centred between two supports.
Thereafter the specimen is subjected to a load using two parallel rollers acting on the top surface of the
specimen. These loading rollers are centred and located a distance of one third of the length of span. The
loads are steadily increased until failure.
4 Symbols
R flexural strength at constant moment, in Megapascals;
tc
F load at failure in Newtons;
b specimen width
...