BS EN 302-4-2013 Adhesives for load-bearing timber structures Test methods Determination of the effects of wood shrinkage on the shear strength《承重木结构用胶粘剂 试验方法 木材收缩对剪切强度影响的测定》.pdf

1、raising standards worldwideNO COPYING WITHOUT BSI PERMISSION EXCEPT AS PERMITTED BY COPYRIGHT LAWBSI Standards PublicationBS EN 302-4:2013Adhesives for load-bearing timber structures T e s t m e t h o d sPart 4: Determination of the effects of wood shrinkage on the shear strengthBS EN 302-4:2013 BRI

2、TISH STANDARDNational forewordThis British Standard is the UK implementation of EN 302-4:2013. It supersedes BS EN 302-4:2004, which is withdrawn.The UK participation in its preparation was entrusted to T e c h n i c a l C o m m i t t e e P R I / 5 2 , A d h e s i v e s .A list of organizations repr

3、esented on this committee 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. The British Standards Institution 2013. Published by BSI Standards Limited 2013.ISBN 978 0

4、 580 75258 2 ICS 83.180 Compliance with a British Standard cannot confer immunityfrom legal obligations.This British Standard was published under the authority of the Standards Policy and Strategy Committee on 30 April 2013.Amendments issued since publicationDate T e x t a f f e c t e dBS EN 302-4:2

5、013EUROPEAN STANDARD NORME EUROPENNE EUROPISCHE NORM EN 302-4 March 2013 ICS 83.180 Supersedes EN 302-4:2004English Version Adhesives for load-bearing timber structures - Test methods - Part 4: Determination of the effects of wood shrinkage on the shear strength Adhsifs pour structures portantes en

6、bois - Mthodes dessai - Partie 4: Dtermination de linfluence du retrait du bois sur la rsistance au cisaillement Klebstoffe fr tragende Holzbauteile - Prfverfahren - Teil 4: Bestimmung des Einflusses von Holzschwindung auf die Scherfestigkeit This European Standard was approved by CEN on 5 February

7、2013. 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. Up-to-date lists and bibliographical references concerning such national standards may be obtaine

8、d on application to the CEN-CENELEC Management Centre or to any CEN member. This European 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-C

9、ENELEC 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, Former Yugoslav Republic of Macedonia, France, Germany, Greece, Hungary, Iceland, Ireland, I

10、taly, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and United Kingdom. EUROPEAN COMMITTEE FOR STANDARDIZATION COMIT EUROPEN DE NORMALISATION EUROPISCHES KOMITEE FR NORMUNG Management Centre: Avenue Marnix

11、 17, B-1000 Brussels 2013 CEN All rights of exploitation in any form and by any means reserved worldwide for CEN national Members. Ref. No. EN 302-4:2013: EBS EN 302-4:2013EN 302-4:2013 (E) 2 Contents Page Foreword 3 Introduction .4 1 Scope 6 2 Normative references 6 3 Principle 6 4 Apparatus .6 5 M

12、ethod 7 5.1 General 7 5.1.1 Selection of timber.7 5.1.2 Preparation of cover pieces 7 5.1.3 Preparation of core pieces 7 5.1.4 Conditioning .8 5.2 Preparation of the bonded assemblies8 5.3 Number of bonded assemblies . 11 5.4 Dry storage treatment 11 5.5 Preparation of the test piece . 11 5.6 Climat

13、ic storage 12 5.7 Test procedure 12 6 Expression of results . 12 7 Test report . 13 7.1 The adhesive . 13 7.2 Preparation of the samples and the testing procedures 13 7.3 Test results 13 Bibliography . 14 BS EN 302-4:2013EN 302-4:2013 (E) 3 Foreword This document (EN 302-4:2013) has been prepared by

14、 Technical Committee CEN/TC 193 “Adhesives”, the secretariat of which is held by AENOR. 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 September 2013 and conflicting national standards shall be w

15、ithdrawn at the latest by September 2013. Attention is drawn to the possibility that some of the elements of this document may be the subject of patent rights. CEN and/or CENELEC shall not be held responsible for identifying any or all such patent rights. This document supersedes EN 302-4:2004. The

16、following modifications have been made: The wood density requirement for Norwegian spruce has been altered; A recommended time period is given for the dry storage treatment. According to the CEN-CENELEC Internal Regulations, the national standards organizations of the following countries are bound t

17、o implement this European Standard: Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia, Finland, Former Yugoslav Republic of Macedonia, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, R

18、omania, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and the United Kingdom. BS EN 302-4:2013EN 302-4:2013 (E) 4 Introduction This document is one of a series dealing with adhesives for use with timber structures, and is published in support of EN 1995, Eurocode 5: Design of timber structu

19、res. The series consists of three classification and performance requirements for adhesives for load-bearing timber structures, phenolic and aminoplastic adhesives (EN 301), one component polyurethane adhesives (EN 15425) and emulsion polymerised isocyanate adhesives (prEN 16254), and all together e

20、leven test methods (EN 302 Parts 1 to 7 and EN 15416 Parts 2 to 5). These European Standards have the following titles: EN 301, Adhesives, phenolic and aminoplastic, for load-bearing timber structures Classification and performance requirements EN 15425, Adhesives One component polyurethane for load

21、 bearing timber structures Classification and performance requirements prEN 16254, Adhesives Emulsion polymerized isocyanate (EPI) for load-bearing timber structures Classification and performance requirements EN 302, Adhesives for load-bearing timber structures Test methods Part 1: Determination of

22、 longitudinal tensile shear strength Part 2: Determination of resistance to delamination Part 3: Determination of the effect of acid damage to wood fibres by temperature and humidity cycling on the transverse tensile strength Part 4: Determination of the effects of wood shrinkage on the shear streng

23、th Part 5: Determination of maximum assembly time under referenced conditions Part 6: Determination of the minimum pressing time under referenced conditions Part 7: Determination of the working life under referenced conditions EN 15416, Adhesives for load bearing timber structures other than phenoli

24、c and aminoplastic Test methods Part 2: Static load test of multiple bondline specimens in compression shear Part 3: Creep deformation test at cyclic climate conditions with specimens loaded in bending shear Part 4: Determination of open assembly time for one component polyurethane adhesives Part 5:

25、 Determination of conventional pressing time Safety statement Persons using this document should be familiar with the normal laboratory practice, if applicable. This document cannot address all of the safety problems, if any, associated with its use. It is the responsibility of the user to establish

26、 appropriate safety and health practices and to ensure compliance with any regulatory conditions. BS EN 302-4:2013EN 302-4:2013 (E) 5 Environmental statement It is understood that some of the material permitted in this standard can have a negative environmental impact. As technological advantages le

27、ad to better alternatives for these materials, they will be eliminated from this standard to the greatest extent possible. At the end of the test, it is recommended that the user of the standard take care to carry out an appropriate disposal of the wastes, according to local regulations. BS EN 302-4

28、:2013EN 302-4:2013 (E) 6 1 Scope This European Standard specifies a method for determining the influence of shear strength in crosswise gluing by wood shrinkage under drying conditions. It is suitable for the following applications: a) for assessing the compliance of adhesives with EN 301, EN 15425

29、and prEN 16254; b) for assessing the suitability and quality of adhesives for load-bearing timber structures; c) for determining if the adhesive is capable of withstanding stresses due to wood shrinkage without unacceptable loss of strength. This test is intended primarily to obtain performance data

30、 for the classification of adhesives for load-bearing timber structures according to their suitability for use in defined climatic environments. This test is carried out on Norway spruce (Picea abies L.). This method is not intended for use to provide numerical design data and does not necessarily r

31、epresent the performance of the bonded member in service. 2 Normative references The following documents, in whole or in part, are normatively referenced in this document and are indispensable for its application. For dated references, only the edition cited applies. For undated references, the late

32、st edition of the referenced document (including any amendments) applies. EN 301, Adhesives, phenolic and aminoplastic, for load-bearing timber structures Classification and performance requirements EN 13183-1, Moisture content of a piece of sawn timber Part 1: Determination by oven dry method ISO 5

33、893, Rubber and plastics test equipment Tensile, flexural and compression types (constant rate of traverse) Specification ISO 6344-2, Coated abrasives Grain size analysis Part 2: Determination of grain size distribution of macrogrits P12 to P220 3 Principle A crosswise double joint with 0,5 mm thick

34、 glue line is submitted to a dry storage treatment and then strained to failure by a compressive shear force. 4 Apparatus 4.1 Testing machine, which shall be either: a) capable of maintaining a constant rate of loading of (20 5) kN/min; or b) capable of maintaining a constant crosshead speed as desc

35、ribed in ISO 5893. BS EN 302-4:2013EN 302-4:2013 (E) 7 4.2 Climatic cabinets, which shall be capable of maintaining the bonded assemblies under the following conditions: a) (40 2) C and a relative humidity of (30 2) % and an air speed of (0,7 0,15) m/s measured in the centre of an empty cabinet; b)

36、(20 2) C and a relative humidity of (65 5) %; c) (20 2) C and a relative humidity of (75 to 80) %. 5 Method 5.1 General 5.1.1 Selection of timber Use Norway spruce (Picea abies L.) having a density of (450 25) kg/m measured at 12 % moisture content as determined by oven drying (according to EN 13183

37、-1). 5.1.2 Preparation of cover pieces From three boards with a length of at least 1 200 mm, prepare three pairs of solid Norway spruce cover pieces that are knot-free, straight grained with growth rings that are approximately tangential to the face and have a radius of 60 mm to 140 mm. The cover pi

38、eces shall be a) 400 mm in length, b) 140 mm in width, and c) (20 0,5) mm in thickness after conditioning, measurement of moisture content (oven dry method according to EN 13183-1) and final preparation. Each matching pair of cover pieces is intended for the production of a specimen. 5.1.3 Preparati

39、on of core pieces Prepare three laminated spruce core pieces that are knot-free, straight-grained and with annual rings at an angle of 35 to 55 relative to the surface (see Figure 1). The dimensions of the core pieces shall be a) 400 mm in length, b) 140 mm in width, and c) (40,0 0,5) mm in thicknes

40、s after conditioning, measurement of moisture content (oven dry method according to EN 13183-1) and final preparation. These laminated core pieces shall be produced of two boards with a width of (75 2) mm, and a thickness of at least 48 mm. The two boards shall be bonded together longitudinally with

41、 a phenol-resorcinol-formaldehyde adhesive which passed EN 301 (used according to the adhesive manufacturers instructions), with an annual ring orientation as indicated in Figure 1. BS EN 302-4:2013EN 302-4:2013 (E) 8 Dimensions in millimetres Key 1 phenolic-resorcinol-formaldehyde (PRF) adhesive gl

42、ue line angle of annual line orientation to the surfaces Figure 1 Cross-section of the laminated Norway spruce core piece before planing and cutting to the required dimensions of 140 mm wide by (40,0 0,5) mm thick 5.1.4 Conditioning Condition the core and cover pieces such that the average moisture

43、content of all three pieces used in an assembly is (17,5 0,5) %. Individual core and cover pieces may have a moisture content of (17 1) %, as determined by the oven-dry method, according to EN 13183-1. NOTE Storage at (20 2) C and 75 % to 80 % relative humidity would be expected to give rise to a mo

44、isture content in the wood of between 16 % and 18 %. Not more than 8 h before bonding, either lightly plane or lightly sand, using a grade P100 abrasive paper as defined in ISO 6344-2, each surface to be bonded. Remove any dust carefully. Do not touch or soil the prepared surface. 5.2 Preparation of

45、 the bonded assemblies Before bonding the specimens together, take a sample from each of the core and cover pieces for the wood moisture content determination, using the oven-dry method, according to EN 13183-1. Calculate and record each specimens mean moisture content using the following formula: U

46、m= 42 321 UUU +where Umis the specimens mean moisture content in percent; U1is the moisture content of the first cover piece in percent; U2is the moisture content of the second cover piece in percent; U3is the moisture content of the core piece in percent. Prepare the bonded assemblies as shown in F

47、igure 2 with the curvature of the growth rings of the cover pieces away from the surfaces to be bonded (Figure 2 c), and the grain of the cover pieces at right angles to the grain of the core piece (Figures 2 a) and 2 b). Fix two (0,5 0,01) mm thick aluminium spacer frames BS EN 302-4:2013EN 302-4:2

48、013 (E) 9 (Figure 3), one spacer on the core piece and one spacer on the cover piece to limit the bond area to (100 0,1) mm x (100 0,1) mm and the nominal bond line thickness to 0,5 mm. If no other instructions are provided by the adhesive manufacturer, apply the adhesive on the surface of the core

49、piece to be bonded as well as on the surface of the cover piece to be bonded, to ensure good surface wetting. To aid in the removal of the leftover, hardened adhesive after bonding, it is recommended to use tape strips on the lateral sides of the core and cover pieces before bonding. Bonding shall take place at standard climate (20 2) C and a relative humidity of (65 5) %). Apply a load of (7,7 0,1) kN and maintain for 24 h. This load corresponds to a pressure