FprEN 12372
(Main)Natural stone test methods - Determination of flexural strength under concentrated load
Natural stone test methods - Determination of flexural strength under concentrated load
This document specifies a test method for determination of flexural strength under a concentrated load for natural stone. Both an identification and a technological product testing procedure are included.
Prüfverfahren für Naturstein - Bestimmung der Biegefestigkeit unter Mittellinienlast
Dieses Dokument legt ein Prüfverfahren für die Beurteilung von Naturstein durch die Bestimmung der Biegefestigkeit unter Mittellinienlast fest. Es sind sowohl eine Identitätsprüfung als auch eine Produktprüfung enthalten.
Méthodes d'essai pour pierres naturelles - Détermination de la résistance à la flexion sous charge centrée
Le présent document spécifie une méthode d'essai permettant de déterminer la résistance à la flexion sous charge centrée des pierres naturelles. Il comprend un mode opératoire d'essai d'identification ainsi qu'un mode opératoire d'essai technologique du produit.
Preskušanje naravnega kamna - Ugotavljanje upogibne trdnosti s koncentrirano obremenitvijo na sredini razpona
General Information
RELATIONS
Standards Content (sample)
SLOVENSKI STANDARD
oSIST prEN 12372:2021
01-marec-2021
Preskušanje naravnega kamna - Ugotavljanje upogibne trdnosti s koncentrirano
obremenitvijo na sredini razpona
Natural stone test methods - Determination of flexural strength under concentrated load
Prüfverfahren für Naturstein - Bestimmung der Biegefestigkeit unter Mittellinienlast
Méthodes d'essai pour pierres naturelles - Détermination de la résistance à la flexion
sous charge centréeTa slovenski standard je istoveten z: prEN 12372
ICS:
73.020 Rudarstvo in kamnolomsko Mining and quarrying
izkopavanje
91.100.15 Mineralni materiali in izdelki Mineral materials and
products
oSIST prEN 12372:2021 en,fr,de
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.
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oSIST prEN 12372:2021
DRAFT
EUROPEAN STANDARD
prEN 12372
NORME EUROPÉENNE
EUROPÄISCHE NORM
January 2021
ICS 91.100.15 Will supersede EN 12372:2006
English Version
Natural stone test methods - Determination of flexural
strength under concentrated load
Méthodes d'essai pour pierres naturelles - Prüfverfahren für Naturstein - Bestimmung der
Détermination de la résistance à la flexion sous charge Biegefestigkeit unter Mittellinienlast
centréeThis draft European Standard is submitted to CEN members for enquiry. It has been drawn up by the Technical Committee
CEN/TC 246.If this draft becomes a European Standard, 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.
This draft European Standard was established by CEN 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-CENELEC
Management Centre has the same status as the official versions.CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia,
Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway,
Poland, Portugal, Republic of North Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and
United Kingdom.Recipients of this draft are invited to submit, with their comments, notification of any relevant patent rights of which they are
aware and to provide supporting documentation.Warning : This document is not a European Standard. It is distributed for review and comments. It is subject to change without
notice and shall not be referred to as a European Standard.EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION
EUROPÄISCHES KOMITEE FÜR NORMUNG
CEN-CENELEC Management Centre: Rue de la Science 23, B-1040 Brussels
© 2021 CEN All rights of exploitation in any form and by any means reserved Ref. No. prEN 12372:2021 E
worldwide for CEN national Members.---------------------- Page: 3 ----------------------
oSIST prEN 12372:2021
prEN 12372:2021 (E)
Contents Page
European foreword ...................................................................................................................................................... 3
1 Scope .................................................................................................................................................................... 4
2 Normative references .................................................................................................................................... 4
3 Terms, definitions and symbols ................................................................................................................ 4
3.1 Terms and definitions ................................................................................................................................... 4
3.2 Symbols .............................................................................................................................................................. 4
4 Principle ............................................................................................................................................................. 4
5 Apparatus .......................................................................................................................................................... 4
5.1 Balance ............................................................................................................................................................... 4
5.2 Ventilated oven ................................................................................................................................................ 5
5.3 Linear measuring device .............................................................................................................................. 5
5.4 Testing machine .............................................................................................................................................. 5
5.5 Device for applying loads on the specimen by a centre-point load .............................................. 5
5.6 Room .................................................................................................................................................................... 5
6 Preparation of the specimens .................................................................................................................... 5
6.1 Sampling ............................................................................................................................................................. 5
6.2 Test specimens ................................................................................................................................................ 5
6.2.1 Surface finish .................................................................................................................................................... 5
6.2.2 Dimensions........................................................................................................................................................ 5
6.2.3 Tolerance ........................................................................................................................................................... 6
6.2.4 Planes of anisotropy ...................................................................................................................................... 6
6.2.5 Conditioning before testing......................................................................................................................... 6
7 Test procedure ................................................................................................................................................. 6
8 Expression of the results .............................................................................................................................. 6
9 Test report ......................................................................................................................................................... 7
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
Annex B (informative) Calculation of flexural strength for off-centre sample fracture .................. 15
Bibliography ................................................................................................................................................................. 17
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prEN 12372:2021 (E)
European foreword
This document (prEN 12372:2021) has been prepared by Technical Committee CEN/TC 246 “Natural
stones”, the secretariat of which is held by UNI.This document is currently submitted to the CEN Enquiry.
This document will supersede EN 12372:2006.
In comparison with the previous edition, the following technical modifications have been made:
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oSIST prEN 12372:2021
prEN 12372:2021 (E)
1 Scope
This document specifies a test method for determination of flexural strength under a concentrated load
for natural stone. Both an identification and a technological product testing procedure are included.
2 Normative referencesThe following documents are referred to in the text in such a way that some or all of their content
constitutes requirements 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 (all parts), Testing hardened concrete3 Terms, definitions and symbols
3.1 Terms and definitions
No terms and definitions are listed in this document.
ISO and IEC maintain terminological databases for use in standardization at the following addresses:
• ISO Online browsing platform: available at https://www.iso.org/obp• IEC Electropedia: available at http://www.electropedia.org/
3.2 Symbols
For the purposes of this document, the following symbols apply.
Symbol Quantity Unit
F breaking load N
L total length of the specimen mm
R flexural strength MPa
V loading rate N/s
a load rate MPa/s
b width of the specimen adjacent to the plane of fracture mm
h thickness of the specimen adjacent to the plane of fracture mm
l distance between the supporting rollers mm
4 Principle
The principle of this method is to place a specimen on two rollers and to progressively load the
specimen in the middle. The breaking load is measured and the flexural strength calculated.
5 Apparatus5.1 Balance
A balance capable of weighing the specimen with an accuracy of 0,01 % of the mass of the specimen.
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prEN 12372:2021 (E)
5.2 Ventilated oven
A ventilated oven capable of maintaining a temperature of (70 ± 5) °C.
5.3 Linear measuring device
A linear measuring device with an accuracy of 0,05 mm.
5.4 Testing machine
A testing machine of appropriate force, in accordance with EN 12390 and calibrated according to this
document.5.5 Device for applying loads on the specimen by a centre-point load
A device for applying loads on the specimen by a centre-point load. It consists of two lower rollers
(supporting rollers) and one upper roller (load-applying roller) which shall be centred exactly in the
middle between the two supporting rollers (see Figure 1). The distance between the two supporting
rollers shall be reported as requested in 6.2.2.5.6 Room
A room which can be maintained at a temperature of (20 ± 10) °C.
6 Preparation of the specimens
6.1 Sampling
The sampling is not the responsibility of the test laboratory except where specially requested. At least
10 specimens shall be selected from a homogeneous batch (see also 6.2.4).6.2 Test specimens
6.2.1 Surface finish
As a standard reference, the surface finish of the faces of the specimens shall be sawn, honed or
polished (identification test). In case of necessity to test specimens with other surface finishes (e.g.
flamed, sandblasted) as required for application, this may be done (technological test). For the
technological test the specimens may be final products or sawn from final products. The surface
intended for use shall be in contact with the two supporting rollers (facing downwards). In any case the
kind of surface finish shall be stated in the report.6.2.2 Dimensions
For stones with a size of the largest grain lower than 25 mm, preferred dimensions are
50 mm × 50 mm × 300 mm.Other dimensions are possible, but shall fulfil the following requirements:
— the thickness h shall be between 25 mm and 100 mm and shall be greater than twice the size of the
largest grain in the stone;— the total length L shall be equal to six times the thickness;
— the width b shall be between 50 mm and three times the thickness (50 mm ≤ b ≤ 3h), and in
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