SIST EN 12372:2007

2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.Natural stone test methods - Determination of flexural strength under concentrated loadPreskušanje naravnega kamna - Ugotavljanje upogibne trdnosti s koncentrirano obremenitvijo na sredini razponaMéthodes d'essai pour pierres naturelles - Détermination de la résistance a la flexion sous charge centréePrüfverfahren für Naturstein - Bestimmung der Biegefestigkeit unter MittellinienlastTa slovenski standard je istoveten z:EN 12372:2006SIST EN 12372:2007en91.100.15Mineralni materiali in izdelkiMineral materials and products73.020Rudarstvo in kamnolomsko izkopavanjeMining and quarryingICS:SIST EN 12372:2000/AC:2003SIST EN 12372:20001DGRPHãþDSLOVENSKI
STANDARDSIST EN 12372:200701-marec-2007







EUROPEAN STANDARDNORME EUROPÉENNEEUROPÄISCHE NORMEN 12372December 2006ICS 73.020; 91.100.15Supersedes EN 12372:1999
English VersionNatural stone test methods - Determination of flexural strengthunder concentrated loadMéthodes d'essai pour pierres naturelles - Déterminationde la résistance à la flexion sous charge centréePrüfverfahren für Naturstein - Bestimmung derBiegefestigkeit unter MittellinienlastThis European Standard was approved by CEN on 25 October 2006.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, Romania,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© 2006 CENAll rights of exploitation in any form and by any means reservedworldwide for CEN national Members.Ref. No. EN 12372:2006: E



EN 12372:2006 (E) 2 Contents Page Foreword.3 1 Scope.4 2 Normative references.4 3 Principle.4 4 Symbols.4 5 Apparatus.4 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.5 6.2.4 Planes of anisotropy.5 6.2.5 Conditioning before testing.6 7 Test procedure.6 8 Expression of the results.6 9 Test report.6 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.13 Bibliography.15



EN 12372:2006 (E) 3 Foreword This document (EN 12372:2006) 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 June 2007, and conflicting national standards shall be withdrawn at the latest by
June 2007. This document supersedes EN 12372:1999. The change of the specimens’ dimensions requested a revision of this European Standard. According to the CEN/CENELEC Internal Regulations, the national standards organizations of the following countries are bound to implement this European Standard: Austria, Belgium, 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.



EN 12372:2006 (E) 4 1 Scope This European Standard 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 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 (all parts), Testing hardened concrete 3 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. 4 Symbols For the purposes of this document, the following symbols apply. Rtf flexural strength, in Megapascals F breaking load, in newtons a load rate, in Megapascals/second V loading rate, in newtons/second l distance between the supporting rollers, in millimetres b width of the specimen adjacent to the plane of fracture, in millimetres h thickness of the specimen adjacent to the plane of fracture, in millimetres L total length of the specimen, in millimetres 5 Apparatus 5.1 A balance capable of weighing the specimen with an accuracy of 0,01 % of the mass of the specimen. 5.2 A ventilated oven capable of maintaining a temperature of (70 ± 5) °C. 5.3 A linear measuring device with an accuracy of 0,05 mm. 5.4 A testing machine of appropriate force, in accordance with the EN 12390 and calibrated according to this European Standard.



EN 12372:2006 (E) 5 5.5 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 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 tha
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