BS EN 1052-5-2005 Methods of test for masonry - Determination of bond strength by the bond wrench method《圬工的试验方法 粘结扭转法测定粘结强度》.pdf

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1、BRITISH STANDARD BS EN 1052-5:2005 Methods of test for masonry Part 5: Determination of bond strength by the bond wrench method The European Standard EN 1052-5:2005 has the status of a British Standard ICS 91.080.30 BS EN 1052-5:2005 This British Standard was published under the authority of the Sta

2、ndards Policy and Strategy Committee on 9 August 2005 BSI 9 August 2005 ISBN 0 580 46380 X National foreword This British Standard is the official English language version of EN 1052-5:2005. The UK participation in its preparation was entrusted by Technical Committee B/519, Masonry and associated te

3、sting, to Subcommittee B/519/4, Masonry tests, which has the responsibility to: A list of organizations represented on this subcommittee can be obtained on request to its secretary. Cross-references The British Standards which implement international or European publications referred to in this docu

4、ment may be found in the BSI Catalogue under the section entitled “International Standards Correspondence Index”, or by using the “Search” facility of the BSI Electronic Catalogue or of British Standards Online. This publication does not purport to include all the necessary provisions of a contract.

5、 Users are responsible for its correct application. Compliance with a British Standard does not of itself confer immunity from legal obligations. aid enquirers to understand the text; present to the responsible international/European committee any enquiries on the interpretation, or proposals for ch

6、ange, and keep the UK interests informed; monitor related international and European developments and promulgate them in the UK. Summary of pages This document comprises a front cover, an inside front cover, the EN title page, pages 2 to 15 and a back cover. The BSI copyright notice displayed in thi

7、s document indicates when the document was last issued. Amendments issued since publication Amd. No. Date CommentsEUROPEANSTANDARD NORMEEUROPENNE EUROPISCHENORM EN10525 April2005 ICS91.080.30 Englishversion MethodsoftestformasonryPart5:Determinationofbond strengthbythebondwrenchmethod Mthodesdessaid

8、elamaonneriePartie5: Dterminationdelarsistancelarupturedunjointde muretselonlamthodedumomentdeflexionenttede muret PrfverfahrenfrMauerwerkTeil5:Bestimmungder Biegehaftzugfestigkeit ThisEuropeanStandardwasapprovedbyCENon14February2005. CENmembersareboundtocomplywiththeCEN/CENELECInternalRegulationswh

9、ichstipulatetheconditionsforgivingthisEurope an Standardthestatusofanationalstandardwithoutanyalteration.Uptodatelistsandbibliographicalreferencesconcernings uchnational standardsmaybeobtainedonapplicationtotheCentralSecretariatortoanyCENmember. ThisEuropeanStandardexistsinthreeofficialversions(Engl

10、ish,French,German).Aversioninanyotherlanguagemadebytra nslation undertheresponsibilityofaCENmemberintoitsownlanguageandnotifiedtotheCentralSecretariathasthesamestatusast heofficial versions. CENmembersarethenationalstandardsbodiesofAustria,Belgium,Cyprus,CzechRepublic,Denmark,Estonia,Finland,France,

11、 Germany,Greece,Hungary,Iceland,Ireland,Italy,Latvia,Lithuania,Luxembourg,Malta,Netherlands,Norway,Poland,Portugal, Slovakia, Slovenia,Spain,Sweden,SwitzerlandandUnitedKingdom. EUROPEANCOMMITTEEFORSTANDARDIZATION COMITEUROPENDENORMALISATION EUROPISCHESKOMITEEFRNORMUNG ManagementCentre:ruedeStassart,

12、36B1050Brussels 2005CEN Allrightsofexploitationinanyformandbyanymeansreserved worldwideforCENnationalMembers. Ref.No.EN10525:2005:EEN 1052-5:2005 (E) 2 Contents Page Foreword. 3 1 Scope 4 2 Normative references . 4 3 Principle . 4 4 Terms, definitions and symbols 4 5 Materials. 6 6 Apparatus 6 7 Pre

13、paration and curing of specimens. 8 8 Procedure 9 9 Measurements and observations 10 10 Replications. 10 11 Calculations. 10 12 Evaluation of results. 11 13 Test report . 12 Annex A (normative) Failure modes which provide a valid bond strength result 13 Bibliography . 15 EN 1052-5:2005 (E) 3 Forewor

14、d This document (EN 1052-5:2005) has been prepared by Technical Committee CEN/TC 125 “Masonry“, the secretariat of which is held by BSI. 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 200

15、5, and conflicting national standards shall be withdrawn at the latest by October 2005. 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,

16、 Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Slovakia, Slovenia, Spain, Sweden, Switzerland and United Kingdom. EN 1052-5:2005 (E) 4 1 Scope This document specifies a method for determining

17、the bond strength of horizontal bed joints in masonry using a bond wrench. Guidance is given on the preparation of the specimens, the conditioning required before testing, the testing equipment, machine, the method of test, the method of calculation and the contents of the test report. 2 Normative r

18、eferences 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 772-1, Methods of test for masonry u

19、nits Part 1: Determination of compressive strength EN 772-10, Methods of test for masonry units Part 10: Determination of moisture content of calcium silicate and autoclaved aerated concrete units EN 998-2, Specification for mortar for masonry Part 2: Masonry mortar EN 1015-3, Methods of test for mo

20、rtar for masonry Part 3: Determination of consistence of fresh mortar (by flow table) EN 1015-7, Methods of test for mortar for masonry Part 7: Determination of air content of fresh mortar EN 1015-11, Methods of test for mortar for masonry Part 11: Determination of flexural and compressive strength

21、of hardened mortar 3 Principle The bond strength of masonry by the bond wrench method is derived from the strength of small masonry specimens tested to destruction. The specimen is rigidly held and a clamp is applied to the top unit. A bending moment is applied to the clamp by a lever until the top

22、unit is pulled from the remainder. The characteristic value, calculated from the maximum stresses achieved by the samples is considered to be the bond strength of the masonry. 4 Terms, definitions and symbols For the purposes of this document, the following terms and definitions apply. 4.1 masonry a

23、ssemblage of masonry units laid in a specified pattern and jointed together with mortar 4.2 bond strength strength of a masonry specimen when subjected to a locally applied normal force and bending moment so as to remove a single unit from the specimen EN 1052-5:2005 (E) 5 4.3 hydraulic cement morta

24、r mortar with cement or cement and air-lime as the binder where the mass of air lime does not exceed 50 % of the total binder mass 4.4 lime based mortar mortar with cement and air-lime as the binder where the mass of cement does not exceed 50 % of the total binder mass 4.5 air-lime limes mainly cons

25、isting of calcium oxcide or hydroxide which slowly harden in air by reacting with atmospheric carbon dioxide. Generally they do not harden under water as they have no hydraulic properties 4.6 Symbols e 1 distance from the applied load to the tension face of the specimen in mm e 2 distance from the c

26、entre of gravity of the lever and upper clamp from the tension face of the specimen in mm W weight of masonry unit pulled of the specimen and any adherent mortar in N F 1applied load in N F 2weight of the bond wrench in N f wiindividual bond strength in N/mm 2f wmean bond strength in N/mm 2f wkchara

27、cteristic bond strength in N/mm 2d mean depth of the specimen in mm b mean width of the bed joint tested in mm Y ilogarithm of the individual bond strength (f wi ) Z section modulus of the projected plan area of the failure surface in mm 3 n number of individual values s standard deviation of the lo

28、garithmic values k numerical factor EN 1052-5:2005 (E) 6 5 Materials 5.1 Masonry units 5.1.1 Conditioning of the units Record the method of conditioning the masonry units prior to laying. Measure the moisture content by mass of autoclaved aerated concrete and calcium silicate units in accordance wit

29、h EN 772-10. For other types of masonry unit, record the method of conditioning the units prior to laying. Record the age of non-autoclaved concrete units at the time of testing the masonry specimens. 5.1.2 Testing Determine the compressive strength of a sample of masonry units, using the test metho

30、d given in EN 772-1. For non-autoclaved concrete units determine the compressive strength at the time of testing the masonry specimens. 5.2 Mortar The mortar, its mixing procedure and its flow value shall conform to the requirements of EN 998-2, unless otherwise specified, and these shall be reporte

31、d in the test report. Take representative samples of fresh mortar from the masons board to make mortar prism specimens, to determine the flow value in accordance with EN 1015-3 and to determine the air content in accordance with EN 1015-7. Determine the mean compressive strength at the time of testi

32、ng the masonry specimens in accordance with EN 1015-11. 6 Apparatus A support frame and clamp which holds in place the unit beneath the top bed joint of the stack bonded specimen without applying any significant bending moment to any lower units. A lever which has a clamp at one end which can be app

33、lied to the top unit of the stack bonded specimen. The lever arm should be at least 1 m in length. The tensile stress applied to a specimen due to the weight of the lever and clamp should not exceed 0,05 N/mm 2 . A means of applying downward force to the lever arm without shock and a means of measur

34、ing this force with an accuracy of 1 %. An example of a suitable clamping arrangement is shown in Figure 1. The specimen should not be subjected to any torsional stress, either from the weight of the lever or the applied force. Where highly perforated bricks with thin shells are to be tested, the fa

35、ces of the clamp will need to be as large as is practicable so as to avoid local crushing of the units under the action of the clamping force. Weighing device capable of weighing a masonry unit to an accuracy of 1 %. Apparatus capable of measuring the dimensions of the specimens to an accuracy of 1

36、mm. EN 1052-5:2005 (E) 7 F 1 F 2 e 1 e 2 A d 10 mm _ 10 mm _ 1 2 3 AKey 1 Specimen 2 Height adjustable 3 Enlargement of area A Figure 1 Example of a suitable support frame and clamps EN 1052-5:2005 (E) 8 7 Preparation and curing of specimens 7.1 Preparation of masonry specimens Prepare sufficient sp

37、ecimens such that there are at least ten bed joints available for test. The number of specimens will depend on the height of the units in order that they can be conveniently handled and fitted into the test equipment. Examples of suitable specimens are shown in Figure 2. In the case of very large un

38、its it may be necessary to cut them down, if this is necessary ensure that the surfaces bonded together for testing are the original and not the cut faces. If the units are cut in order to reduce their length ensure that the bed faces of the cut units have a geometry that is representative of that o

39、f the whole bed face. A B B AStack bonded prism made with relatively small units giving 5 results Couplet made with original units giving 1 result Couplet made with parts of a large unit (original bed faces are bonded) giving 1 result Figure 2 Examples of suitable specimen formats NOTE It will usual

40、ly be necessary to build sufficient specimens to ensure that at least ten results are available after any have been discarded because the failure was not considered to be a valid result (see Clause 10 and Annex A). EN 1052-5:2005 (E) 9 Build the specimens within 30 min after completion of the condit

41、ioning of the units. Use mortar mixed not more than one hour beforehand unless it is designed to be used over a more prolonged period. The bearing surfaces of the masonry units shall be wiped clean of any adherent dust. The lower unit shall be laid on a clean level surface. The next unit shall be la

42、id so that the thickness of the mortar joint is as specified. The masonry unit shall be checked for linear alignment and level using a setsquare and spirit level. Excess mortar shall then be struck off with a trowel. Repeat this operation until the required number of units have been stack bonded. 7.

43、2 Curing and conditioning of the specimens Immediately after building, pre-compress each specimen using a uniformly distributed mass to give a vertical stress between 2,0 10 -3N/mm 2and 5,0 10 -3N/mm 2 . Then cure the specimens and maintain them precompressed and undisturbed until testing. For other

44、 than lime based mortars, prevent the test specimens from drying out during the curing period by close covering with polyethylene sheet, and maintain the specimens undisturbed until testing, unless otherwise specified. Test each specimen made with hydraulic cement mortars at an age of 28 d 1 d, unle

45、ss otherwise specified. For lime-based mortars an alternative curing regime and period may be necessary and should be specified. Determine the compressive strength of the mortar following the method in EN 1015-11 at the same age as that at which the bond strength is measured. 7.3 Cutting bed faces W

46、here low strength units are being used with a mortar that produces a high bond strength it may be necessary to reduce the area of the bonded surface to be tested. Their width may be reduced using a saw to leave a rectangular bonded area, b x d i.e. reduced width x depth. 8 Test procedure Securely cl

47、amp the prism in the retaining frame such that the second from top unit has a reasonable degree of restraint against rotation but the joint to be tested is between ten and fifteen millimetres clear of the clamp. The clamp may be faced with thin layers of a resilient material such as plywood to ensur

48、e an even grip. If the mortar joint is pointed in a way which reduces the overall bonded width, the test should be set up with this face in tension. Support the clamp to stabilise it against the overturning moment generated during loading. Clamp the top unit carefully again, using thin layers of resistant material such as plywood, to ensure an even grip, if necessary and adjust to make the lever arm horizontal. Apply the load smoothly so as to give a rate of increase of flexural stress such that failure occu