EN 12390-6-2009 en Testing hardened concrete - Part 6 Tensile splitting strength of test specimens《硬化混凝土试验 第6部分 试样劈裂拉伸强度》.pdf

1、BS EN12390-6:2009ICS 91.100.30NO COPYING WITHOUT BSI PERMISSION EXCEPT AS PERMITTED BY COPYRIGHT LAWBRITISH STANDARDTesting hardenedconcretePart 6: Tensile splitting strength of testspecimensThis British Standardwas published under theauthority of the StandardsPolicy and StrategyCommittee on 30 June

2、2010 BSI 2010ISBN 978 0 580 67068 8Amendments/corrigenda issued since publicationDate CommentsBS EN 12390-6:2009National forewordThis British Standard is the UK implementation of EN 12390-6:2009. Itsupersedes BS EN 12390-6:2000 which is withdrawn.The UK participation in its preparation was entrusted

3、 to TechnicalCommittee B/517/1, Concrete production and testing.A list of organizations represented on this committee can be obtained onrequest to its secretary.This publication does not purport to include all the necessary provisionsof a contract. Users are responsible for its correct application.C

4、ompliance with a British Standard cannot confer immunityfrom legal obligations.BS EN 12390-6:2009EUROPEAN STANDARD NORME EUROPENNE EUROPISCHE NORM EN 12390-6 December 2009 ICS 91.100.30 Supersedes EN 12390-6:2000English Version Testing hardened concrete - Part 6: Tensile splitting strength of test s

5、pecimens Essais sur bton - Partie 6 : Dtermination de la rsistance en traction par fendage dprouvettes Prfung von Festbeton - Teil 6: Spaltzugfestigkeit von Probekrpern This European Standard was approved by CEN on 1 November 2009. CEN members are bound to comply with the CEN/CENELEC Internal Regula

6、tions 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 E

7、uropean 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

8、 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

9、 and United Kingdom. EUROPEAN COMMITTEE FOR STANDARDIZATION COMIT EUROPEN DE NORMALISATION EUROPISCHES KOMITEE FR NORMUNG Management Centre: Avenue Marnix 17, B-1000 Brussels 2009 CEN All rights of exploitation in any form and by any means reserved worldwide for CEN national Members. Ref. No. EN 123

10、90-6:2009: EBS EN 12390-6:2009EN 12390-6:2009 (E) 2 Contents Page Foreword 3 Introduction .41 Scope 52 Normative references 53 Principle 54 Apparatus .55 Test specimens 66 Procedure .77 Expression of results 88 Test report 99 Precision .9Annex A (normative) Determination of tensile splitting strengt

11、h using cubic or prismatic specimens . 10BS EN 12390-6:2009EN 12390-6:2009 (E) 3 Foreword This document (EN 12390-6:2009) has been prepared by Technical Committee CEN/TC 104 “Concrete and related products”, the secretariat of which is held by DIN. This European Standard shall be given the status of

12、a national standard, either by publication of an identical text or by endorsement, at the latest by June 2010, and conflicting national standards shall be withdrawn at the latest by June 2010. Attention is drawn to the possibility that some of the elements of this document may be the subject of pate

13、nt rights. CEN and/or CENELEC shall not be held responsible for identifying any or all such patent rights. This document supersedes EN 12390-6:2000. This document has been prepared under a mandate given to CEN by the European Commission and the European Free Trade Association, and supports essential

14、 requirements of EU Directive(s). This standard is one of a series concerned with testing concrete. EN 12390, Testing hardened concrete consists of the following parts: Part 1: Shape, dimensions and other requirements of specimens and moulds Part 2: Making and curing specimens for strength tests Par

15、t 3: Compressive strength of test specimens Part 4: Compressive strength Specification for testing machines Part 5: Flexural strength of test specimens Part 6: Tensile splitting strength of test specimens Part 7: Density of hardened concrete Part 8: Depth of penetration of water under pressure The m

16、ain change from the previous edition of this European Standard has been to provide an alternative specification for packing strips and requires the selected loading rate to be applied after the initial load does not exceed approximately 20 % of the anticipated failure load. According to the CEN/CENE

17、LEC 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, Luxemb

18、ourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland and the United Kingdom. BS EN 12390-6:2009EN 12390-6:2009 (E) 4 Introduction This test method was one of a number examined in a laboratory inter-comparison part-funded by the EC under Measurem

19、ent and Testing programme, contract MAT1-CT94-0043. The programme and other references showed the following: a) Tensile splitting strengths measured between the normal plane platens of testing machines gave the same results as those using the special curved platens, originally described in ISO 4018.

20、 Although, therefore these curved platens have been optionally retained in this standard, they are not necessary for the measurement. b) The material used for the packing strips affects the apparent tensile strength measured. This has led to the decision to standardize on hardboard strips, since the

21、y provided the lowest standard deviations. c) The apparent tensile strength measured depends upon the shape and size of the test specimen used: 1) cubes gave higher measured tensile strengths than cylinders, by approximately 10 %; 2) 150 mm cubes gave lower measured tensile strengths than 100 mm cub

22、es; 3) the effect of cylinder size on measured tensile strength was not found to be significant, possibly due to the variability of the data. As a result of these conclusions from the laboratory programme, this standard restricts the measurement of tensile splitting strength to cylindrical specimens

23、 used with hardboard packing strips, which is the reference method. However, as some countries still test cubical or prismatic specimens, their use has been retained in a normative annex. In cases of dispute, the reference method is the use of cylinders of 150 mm diameter and 300 mm length. It is re

24、cognized good practice to include measurement of density prior to the determination of tensile splitting strength, as a check on compaction. BS EN 12390-6:2009EN 12390-6:2009 (E) 5 1 Scope This European Standard specifies a method for the determination of the tensile splitting strength of cylindrica

25、l test specimens of hardened concrete. A method using cubic or prismatic specimens is included in normative Annex A. 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 ref

26、erences, the latest edition of the referenced document (including any amendments) applies. EN 12350-1, Testing fresh concrete Part 1: Sampling EN 12390-1, Testing hardened concrete Part 1: Shape, dimensions and other requirements of specimens and moulds EN 12390-2, Testing hardened concrete Part 2:

27、Making and curing specimens for strength tests EN 12390-4, Testing hardened concrete Part 4: Compressive strength Specification for testing machines EN 316, Wood fibre boards Definition, classification and symbols 3 Principle A cylindrical specimen is subjected to a compressive force applied to a na

28、rrow region along its length. The resulting orthogonal tensile force causes the specimen to fail in tension. 4 Apparatus 4.1 Testing machine, conforming to EN 12390-4, curved steel loading pieces may be used in place of conventional plane platens, when tests are carried out on cubic or prismatic spe

29、cimen. 4.2 Jig (optional), for positioning the specimen and the packing strips. The jig shall not restrict the deformation of the specimen during the test. NOTE Suitable jig for cylindrical specimens is shown in Figure 1. 4.3 Packing strips, conforming to EN 316, made of hardboard, of density equal

30、or greater than 900 kg/m and dimensions, width (a) = (15 1) mm; thickness (t) = (4 1) mm and a length greater than the length of the line of contact of the test specimen. Alternatively, packing strips may be used if they meet the following hardness criterion: When submitted to a punching test by mea

31、ns of a rod of circular cross section, having a diameter of (16 0,5) mm and applying a force at a rate of (48 10) kN/min, the instantaneous penetration when the force of (20 5) kN is achieved shall be equal to (1,2 0,4) mm. Packing strips shall be used only once. BS EN 12390-6:2009EN 12390-6:2009 (E

32、) 6 Key 1 Steel loading piece 2 Hardboard packing strips L Length of specimen d Diameter of specimen Figure 1 Jig for testing cylindrical specimens 5 Test specimens 5.1 General The test specimens shall be cylindrical, conforming to EN 12390-1, but a length/diameter ratio as low as 1 shall be accepta

33、ble for cores. Specimens cast in moulds shall conform to EN 12390-1 and EN 12390-2. The specimens shall be examined and any abnormalities observed shall be reported. 5.2 Adjustment of test specimens Where the dimensions or shapes of the test surfaces of the specimens do not conform to EN 12390-1, be

34、cause they exceed the respective tolerances, they shall be rejected or adjusted to comply with the standard as follows: a) uneven surfaces shall be levelled by grinding; b) the deviation of angles shall be corrected by cutting and/or grinding. BS EN 12390-6:2009EN 12390-6:2009 (E) 7 5.3 Marking Unle

35、ss a centring jig is used, two lines shall be marked along which to apply the load. These lines shall be opposite each other in an axial plane and the extremities of the two lines shall be connected over each end of the specimen, to define clearly the plane of loading. 6 Procedure 6.1 Specimen prepa

36、ration For specimens stored in water, wipe any excess moisture from the surface of the specimen before placing in the testing machine. Wipe the bearing surfaces of the jig, packing strips, loading pieces and platens. Clean and remove any loose grit or other extraneous material from the surface of th

37、e specimen that will be in contact with the packing strips. 6.2 Specimen positioning Place the test specimen centrally in the testing machine, optionally using a jig. Carefully position packing strips and, if required, loading pieces, along the top and bottom of the plane of loading of the specimen.

38、 Ensure that the upper platen is parallel with the lower platen, during loading. Dimensions in millimetres Key 1 Steel loading piece d Height of specimen 2 Hardboard packing strips R Radius of loading piece 3 Segment may be trimmed a Width of packing strip L Length of specimen t Thickness of packing

39、 strip Figure 2 Curved loading pieces BS EN 12390-6:2009EN 12390-6:2009 (E) 8 6.3 Loading Ensure that the specimen remains centred when the load is first applied, either by means of a jig or by temporary supports. Select a constant rate of stress within the range 0,04 MPa/s (N/mms) to 0,06 MPa/s (N/

40、mms). After the application of the initial load, which does not exceed approximately 20 % of the failure load, apply the load to the specimen without shock and increase continuously, at the selected constant rate 10 %, until no greater load can be sustained. The required loading rate is given by the

41、 formula: 2dLsR=where: R is the required loading rate, in Newtons per second (N/s); L is the length of the specimen, in millimetres (mm) (see Figure 2); d is the designated cross-sectional dimension, in millimetres (mm); s is the stress rate, in megapascals per second (MPa/s) or in Newtons per squar

42、e millimetre per second (N/mms). When using manually controlled testing machines, correct any tendency for the selected rate of loading to decrease, as specimen failure is approached, by appropriate adjustment of the controls. When using automatically controlled testing machines, check the rate of l

43、oading periodically, to ensure that the rate is constant. Record the maximum load indicated. 6.4 Examination of specimen Examine the fractured specimen and the appearance of the concrete and record, if unusual. 7 Expression of results The tensile splitting strength is given by the formula: dLFf=2ctw

44、here ctf is the tensile splitting strength, in megapascals (MPa) or in Newtons per square millimetre (N/mm); F is the maximum load, in Newtons (N); L is the length of the line of contact of the specimen, in millimetres (mm); d is the designated cross-sectional dimension, in millimetres (mm). BS EN 1

45、2390-6:2009EN 12390-6:2009 (E) 9 NOTE For deviations from the standard method in respect of the dimensions of the specimen, the strength calculation may be based on the actual dimensions of the test specimen. Express the tensile splitting strength to the nearest 0,05 MPa (or N/mm). 8 Test report The

46、 test report shall include: a) identification of the test specimen; b) details of adjustment (if appropriate); c) surface moisture condition at time of test; d) date of test; e) appearance of concrete and type of fracture (if unusual); f) tensile splitting strength of specimen, to nearest 0,05 MPa (

47、or N/mm); g) any deviation from the standard test method; h) a declaration from the person technically responsible for the test that it was carried out in accordance with this document, except as detailed in item g). The report may include: i) condition of specimen on receipt for storage; j) age of

48、specimen at time of test (if known); k) appearance of the concrete (if unusual). 9 Precision There is currently no precision data for this test. BS EN 12390-6:2009EN 12390-6:2009 (E) 10 Annex A (normative) Determination of tensile splitting strength using cubic or prismatic specimens A.1 Scope This

49、annex specifies a method for the determination of the tensile splitting strength of cubic and prismatic test specimens of hardened concrete. A.2 Normative references See Clause 2. A.3 Principle A prismatic specimen is subjected to a compressive force applied to a narrow region. The resulting orthogonal tensile force causes the specimen to fail in tension. A.4 Apparatus A.4.1 Testing Machine, conforming to EN 12390-4, curved steel loading pieces may be used in place of