1、BRITISH STANDARDBS EN 12372:2006Natural stone test methods Determination of flexural strength under concentrated loadThe European Standard EN 12372:2006 has the status of a British StandardICS 73.020; 91.100.15g49g50g3g38g50g51g60g44g49g42g3g58g44g55g43g50g56g55g3g37g54g44g3g51g40g53g48g44g54g54g44g
2、50g49g3g40g59g38g40g51g55g3g36g54g3g51g40g53g48g44g55g55g40g39g3g37g60g3g38g50g51g60g53g44g42g43g55g3g47g36g58Licensed Copy: Wang Bin, na, Fri Mar 23 00:49:18 GMT+00:00 2007, Uncontrolled Copy, (c) BSIBS EN 12372:2006This British Standard was published under the authority of the Standards Policy and
3、 Strategy Committee on 31 January 2007 BSI 2007ISBN 978-0-580-49920-3National forewordThis British Standard was published by BSI. It is the UK implementation of EN 12372:2006. It supersedes BS EN 12372:1999 which is withdrawn. The UK participation in its preparation was entrusted to Technical Commit
4、tee B/545, Natural stone.A list of organizations represented on B/545 can be obtained on request to its secretary.This publication does not purport to include all the necessary provisions of a contract. Users are responsible for its correct application.Compliance with a British Standard cannot confe
5、r immunity from legal obligations.Amendments issued since publicationAmd. No. Date CommentsLicensed Copy: Wang Bin, na, Fri Mar 23 00:49:18 GMT+00:00 2007, Uncontrolled Copy, (c) BSIEUROPEAN STANDARDNORME EUROPENNEEUROPISCHE NORMEN 12372December 2006ICS 73.020; 91.100.15 Supersedes EN 12372:1999 Eng
6、lish VersionNatural stone test methods - Determination of flexural strengthunder concentrated loadMthodes dessai pour pierres naturelles - Dterminationde la rsistance la flexion sous charge centrePrfverfahren fr Naturstein - Bestimmung derBiegefestigkeit unter MittellinienlastThis European Standard
7、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 n
8、ationalstandards 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 no
9、tified 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, Netherla
10、nds, Norway, Poland, Portugal, Romania,Slovakia, Slovenia, Spain, Sweden, Switzerland and United Kingdom.EUROPEAN COMMITTEE FOR STANDARDIZATIONCOMIT EUROPEN DE NORMALISATIONEUROPISCHES KOMITEE FR NORMUNGManagement Centre: rue de Stassart, 36 B-1050 Brussels 2006 CEN All rights of exploitation in any
11、 form and by any means reservedworldwide for CEN national Members.Ref. No. EN 12372:2006: ELicensed Copy: Wang Bin, na, Fri Mar 23 00:49:18 GMT+00:00 2007, Uncontrolled Copy, (c) BSIEN 12372:2006 (E) 2 Contents Page Foreword3 1 Scope 4 2 Normative references 4 3 Principle4 4 Symbols 4 5 Apparatus .4
12、 6 Preparation of the specimens 5 6.1 Sampling.5 6.2 Test specimens5 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 testing6 7 Test procedure.6 8 Expression of the results6 9 Test report 6 Annex A (normative) Statistical evaluatio
13、n 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 Licensed Copy: Wang Bin, na, Fri Mar 23 00:49:18 GMT+00:00 2007, Uncontrolled Copy, (c) BSIEN 12372:2006 (E) 3 Foreword This document (EN 12372:2006) has been prepared
14、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
15、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 impleme
16、nt 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 K
17、ingdom. Licensed Copy: Wang Bin, na, Fri Mar 23 00:49:18 GMT+00:00 2007, Uncontrolled Copy, (c) BSIEN 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
18、 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 amendm
19、ents) 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 d
20、ocument, the following symbols apply. Rtfflexural 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 millimet
21、res 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 temperatu
22、re 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. Licensed Copy: Wang Bin, na, Fri Mar 23 00:49:18 GMT+00:00 2007, Uncontrolled Copy, (c) BSIEN 123
23、72:2006 (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
24、 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 sha
25、ll 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.
26、 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 k
27、ind 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
28、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 no case it shall be less than the thickness. The distance between the sup
29、porting rollers l shall be equal to five times the thickness. 6.2.3 Tolerance The tolerance on the distance between the supporting rollers l shall be 1 mm. 6.2.4 Planes of anisotropy If the stone shows planes of anisotropy (e.g. bedding, foliation) the specimens shall be prepared in accordance with
30、at least one of the arrangements shown in Figures 2 to 4 and the direction of the planes of anisotropy shall be marked on each specimen by at least two parallel lines. If the use of the stone in respect of the position of the planes of anisotropy is known, the test shall be carried out with the forc
31、e applied on the face that will be loaded during use. Licensed Copy: Wang Bin, na, Fri Mar 23 00:49:18 GMT+00:00 2007, Uncontrolled Copy, (c) BSIEN 12372:2006 (E) 6 If the way of use of the stone is not known but the position of the planes of anisotropy is indicated on the specimens (by means of at
32、least two parallel lines), the test shall be carried out on each of the three arrangements shown in Figures 2 to 4; the total number of specimens will then be 3 times 10. 6.2.5 Conditioning before testing The specimens shall be dried at (70 5) C to a constant mass. Constant mass is reached when the
33、difference between two weighings carried out (24 2) h apart is no greater than 0,1 % of the first of the two masses. After drying and prior to testing the specimens shall be stored at (20 5) C until the thermal equilibrium is reached. After that the test shall be performed within 24 h. 7 Test proced
34、ure Wipe the surface of the rollers clean and remove any loose grits from the faces of the specimen that will be in contact with the rollers. The specimen is placed centrally on the supporting rollers (see Figures 1 to 4). The loading roller is placed in the middle of the specimen. The load is incre
35、ased uniformly at a rate of (0,25 0,05) MPa/suntil the specimen breaks. NOTE 1 The breaking load is rounded to the nearest 10 N and also the place where the fracture occurs. The width and the thickness of the specimen are measured adjacent to the fracture plane and the dimensions are expressed in mi
36、llimetres to the nearest 0,1 mm. NOTE 2 Where the loading rate (V) is needed in N/s the following equation can be used to determine the required rate in N/s: labhV322= (N/s) (1) 8 Expression of the results The flexural strength Rtfof each specimen is calculated using the following equation: Rtf=322F
37、lbh(2)The result shall be expressed in Megapascals to the nearest 0,1 MPa. If the fracture is situated more than 15 % of the distance between the supporting rollers from the middle of the specimen and/or flaws are present (veins, fissures etc.) it shall be mentioned in the test report. 9 Test report
38、 The test report shall contain the following information: a) unique identification number of the report; b) the number, title and date of issue of this European Standard, i.e. EN 12372; Licensed Copy: Wang Bin, na, Fri Mar 23 00:49:18 GMT+00:00 2007, Uncontrolled Copy, (c) BSIEN 12372:2006 (E) 7 c)
39、the name and address of the test laboratory and the address where the test was carried out if different from the test laboratory; d) the name and address of the client; e) it is the responsibility of the client to supply the following information: the petrographic name of the stone; the commercial n
40、ame of the stone; the country and region of extraction; the name of the supplier; the direction of any existing plane of anisotropy (if relevant to the test) to be clearly indicated on the sample or on each specimen by means of two parallel lines; the name of the person or organization which carried
41、 out the sampling; the surface finish of the specimens (if relevant to the test); f) the date of delivery of the sample or of the specimens; g) the date when the specimens were prepared (if relevant) and the date of testing; h) the number of specimens in the sample; i) the dimensions of the specimen
42、s; j) the surface finish of the specimens; k) the rate of loading in Megapascals per second to the nearest 0,05 MPa/s;l) for each specimen: the width and thickness adjacent to the fracture plane and the distance between the supporting rollers in millimetres to the nearest 0,1 mm, the orientation of
43、the force relatively to any plane of anisotropy following Figures 2 to 4, the breaking force in newton to the nearest 10 N, the flexural strength in Megapascals to the nearest 0,1 MPa, the location of the fracture and any anomalies observed; m) for each relevant direction of loading the mean value R
44、 tfof the flexural strength and the standard deviations, in Megapascals to the nearest 0,1 MPa; n) all deviations from the standard and their justification; o) remarks. The test report shall contain the signature(s) and the role(s) of the responsible(s) for the testing and the date of issue of the r
45、eport. It shall also state that the report shall not be partially reproduced without written consent of the test laboratory. Licensed Copy: Wang Bin, na, Fri Mar 23 00:49:18 GMT+00:00 2007, Uncontrolled Copy, (c) BSIEN 12372:2006 (E) 8 Key 1 loading roller 2 supporting roller Figure 1 Arrangement of
46、 loading of test specimen (centre point loading) Licensed Copy: Wang Bin, na, Fri Mar 23 00:49:18 GMT+00:00 2007, Uncontrolled Copy, (c) BSIEN 12372:2006 (E) 9 Key 1 loading roller 2 supporting roller Figure 2 Test arrangement for a specimen with the load applied perpendicular to the planes of aniso
47、tropy Licensed Copy: Wang Bin, na, Fri Mar 23 00:49:18 GMT+00:00 2007, Uncontrolled Copy, (c) BSIEN 12372:2006 (E) 10 Key 1 loading roller 2 supporting roller Figure 3 Test arrangement for a specimen with the load applied parallel to the planes of anisotropy Licensed Copy: Wang Bin, na, Fri Mar 23 0
48、0:49:18 GMT+00:00 2007, Uncontrolled Copy, (c) BSIEN 12372:2006 (E) 11 Key 1 loading roller 2 supporting roller Figure 4 Test arrangement for a specimen with the load applied perpendicular to the edges of the planes of anisotropy Licensed Copy: Wang Bin, na, Fri Mar 23 00:49:18 GMT+00:00 2007, Uncon
49、trolled Copy, (c) BSIEN 12372:2006 (E) 12 Annex A (normative) Statistical evaluation of the test results A.1 Scope This annex establishes a method for the statistical treatment of test results obtained following the natural stone test methods described in this European Standard. A.2 Symbols and definitions Measured values x1, x2, xi, xnNumber of measured values n Mean value=iixnx1Standard deviation1)(=nxxsiCoefficient of variation v = xs(for individual values) Logarithmic meanxln=1nln xiiLogarithmic standard
