1、Timber structures Bond performance of adhesives Part 2: Additional requirements Structures en bois Performance dadhrence des adhsifs Partie 2: Exigences supplmentaires ISO 2011 Reference number ISO 20152-2:2011(E) First edition 2011-07-15 ISO 20152-2 INTERNATIONAL STANDARDISO 20152-2:2011(E)COPYRIGH
2、T PROTECTED DOCUMENT ISO 2011 All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized in any form or by any means, electronic or mechanical, including photocopying and microfilm, without permission in writing from either ISO at the address below or
3、ISOs member body in the country of the requester. ISO copyright office Case postale 56 CH-1211 Geneva 20 Tel. + 41 22 749 01 11 Fax + 41 22 749 09 47 E-mail copyrightiso.org Web www.iso.org Published in Switzerland ii ISO 2011 All rights reservedForeword ISO (the International Organization for Stand
4、ardization) is a worldwide federation of national standards bodies (ISO member bodies). The work of preparing International Standards is normally carried out through ISO technical committees. Each member body interested in a subject for which a technical committee has been established has the right
5、to be represented on that committee. International organizations, governmental and non-governmental, in liaison with ISO, also take part in the work. ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization. International St
6、andards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 2. The main task of technical committees is to prepare International Standards. Draft International Standards adopted by the technical committees are circulated to the member bodies for voting. Publication as an I
7、nternational Standard requires approval by at least 75 % of the member bodies casting a vote. Attention is drawn to the possibility that some of the elements of this document may be the subject of patent rights. ISO shall not be held responsible for identifying any or all such patent rights. ISO 201
8、52-2 was prepared by Technical Committee ISO/TC 165, Timber structures. ISO 20152 consists of the following parts, under the general title Timber structures Bond performance of adhesives: Part 1: Basic requirements Part 2: Additional requirements ISO 20152-2:2011(E) ISO 2011 All rights reserved iiiI
9、ntroduction ISO 20152 was developed by ISO/TC 165 to provide additional performance requirements for adhesive bonds formed in structural wood products. It is required only in some jurisdictions (the high temperature creep and shear strength at elevated temperatures) and under some circumstances (sit
10、uations where a gap filling requirement exists). This International Standard focuses on bond line performance and is directed principally at the evaluation of wood adhesives. When used in this manner, the tests and assessments are made against standardized wood species, but it would apply to the bon
11、d lines in wood products involving other wood species and possibly preservative and fire-retardant treated wood. It is expected that product standards (e.g. for glulam, laminated veneer timber, etc.) would insist that selected requirements be met in the establishment of a new production line or the
12、introduction of a new product, new adhesive, new species, etc. on an existing production line as part of qualification procedures. The matter of high temperature performance has been controversial in that various national standards have requirements for: strength testing at 220 C or higher, creep te
13、sting at 180 C or higher, creep testing at 70 C or higher, all purporting to deal adequately with high temperature performance. In the event, ISO/TC 165 determined that the CSA O112.9 and CEN EN 15416-2 tests at 70 C would be placed in ISO 20152-1: Basic requirements. The tests and requirements for
14、high temperature strength at 220 C or higher (based on an ASTM requirement), the creep resistance at 180 C or higher (based on CSA O112.9) together with a gap filling capacity, would be placed in this part of ISO 20152. Manufacturers of adhesive should familiarize themselves with local building regu
15、lations to determine if the “additional” requirements are necessary. Users of this International Standard are reminded that local building regulations are a matter for determination by local and/or national governments or regulatory authorities and cannot be mandated in an International Standard. IS
16、O 20152-2:2011(E)iv ISO 2011 All rights reservedINTERNATIONAL STANDARD ISO 20152-2:2011(E) Timber structures Bond performance of adhesives Part 2: Additional requirements 1 Scope This International Standard specifies the performance requirements of wood bond lines in prefabricated structural timber
17、components. 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. ISO 3130, Wood
18、 Determination of moisture content for physical and mechanical tests ISO 12579, Timber structures Glued laminated timber Method of test for shear strength of glue lines ISO 20152-1, Timber structures Bond performance of adhesives Part 1: Basic requirements ASTM D 7247, Standard Test Method for Evalu
19、ating the Shear Strength of Adhesive Bonds in Laminated Wood Products at Elevated Temperatures 3 Terms and definitions For the purposes of this document, the following terms and definitions apply. 3.1 specific gravity ratio of the oven dry mass of a specimen to the mass of a volume of water equal to
20、 the volume of the specimen at specified moisture content 3.2 oven dry specific gravity expression of the specific gravity based on oven dry mass of wood and its oven dry volume after drying to constant mass in a ventilated oven at a temperature between 100 C and 105 C 3.3 wood failure percentage pe
21、rcentage of wood fibre ruptured during the separation of an adhesive/adherend interface and used to evaluate the effectiveness of adhesive bonding 4 Application The evaluation of the adhesive bond detailed in this part of ISO 20152 is based on the performance of the adhesive as measured by the follo
22、wing properties: a) resistance to creep at high temperature (180 C or higher) (see 5.2), b) resistance to shear rupture at high temperature (220 C or higher) (see 5.3), c) ability to provide adequate shear strength in thick bond lines (greater than 1,0 mm in thickness) (see 5.4). ISO 2011 All rights
23、 reserved 1The performance requirements are optional in the sense that they are not required in all jurisdictions (high temperature creep and high temperature shear rupture) and for all applications (gap filling is not required normally for finger joints, edge and face joints of glulam, plywood, or
24、LVL). Where local building regulations specify that some of these requirements be met, it shall be necessary to test bond lines as specified herein. 5 Requirements 5.1 Adhesive details, mixing and application The adhesive shall be mixed and applied to the wood substrate in accordance with the adhesi
25、ve manufacturers specification. The type and amount of fillers and/or extenders used in the adhesive shall comply with the adhesive manufacturers specification. 5.2 Creep resistance at elevated temperatures 5.2.1 General High temperature (180 C or higher) creep resistance tests shall be carried out
26、in accordance with 6.3 and shall meet the requirements in 5.2.2. 5.2.2 Requirements High temperature creep resistance shall be demonstrated by testing in accordance with 6.3. The average creep displacement (see Figure 6 of ISO 20152-1 and Annex A of this part of ISO 20152) for all bonded cross- sect
27、ions for each specimen shall not exceed 0,6 mm and the maximum average creep displacement at any single bonded cross-section for each specimen shall not exceed 2,9 mm after the prescribed load period. NOTE Temperatures in the range of 180 C to 220 C in 5.2.2 are generally appropriate for assessing a
28、dhesives used in small cross-section members in fire-protected assemblies. 5.3 Shear strength at elevated temperatures 5.3.1 General High temperature (220 C or higher) shear strength resistance tests shall be carried out in accordance with 6.4 and shall meet the requirements in 5.3.2. 5.3.2 Requirem
29、ents Reference shall be made to the relevant national product standard, manufacturer of the laminated wood product, qualified agency and/or code evaluation agency to specify a combination of test temperature and exposure durations, or shear strength retention. The performance of bonded specimens sha
30、ll be compared to that of solid control specimens. 5.4 Gap filling strength 5.4.1 General Gap filling tests shall be undertaken when bond lines in structural wood products of thickness typically in excess of 1,0 mm are required to exhibit adequate strength. The test is conducted on bond lines at a t
31、hickness exceeding 1,0 mm and up to 2,0 mm, but tests at other thicknesses shall be permitted upon agreement between the manufacturer and the user. ISO 20152-2:2011(E)2 ISO 2011 All rights reserved5.4.2 Requirements The performance requirements shall be subject to agreement between the adhesive manu
32、facturer and user. Basic adhesive performance for gap-filling adhesives shall conform to the requirements specified in ISO 20152-1. 6 Sample preparation and test methods 6.1 Specimen requirements 6.1.1 Evaluation of hardwoods Adhesives for hardwoods tested in accordance with 6.3, 6.4 and 6.5 shall b
33、e evaluated on hard maple (acer saccharum or acer nigrum). Additional species shall be permitted to be tested, as specified by the relevant national product standard, manufacturer of the laminated wood product, qualified agency and/or code evaluation agency when meeting the requirements specified in
34、 ISO 20152-1. 6.1.2 Evaluation of softwoods Adhesives for softwoods tested in accordance with 6.3, 6.4 and 6.5 shall be evaluated on one of the following species when meeting the requirements specified in ISO 20152-1: a) lodgepole pine (pinus contorta var. latifolia), b) black spruce (picea mariana)
35、, c) Douglas fir (pseudotsuga menziesii), or d) a species specified by the relevant national product standard, manufacturer of the laminated wood product, qualified agency and/or code evaluation agency. 6.1.3 Wood oven dry specific gravity 6.1.3.1 A 25 mm long full cross-section shall be cut at leas
36、t 150 mm from the end of each board used to provide wood samples for the tests described in 6.3 to 6.5. 6.1.3.2 The wood oven dry specific gravity of each full cross-section shall be as follows: a) not less than 0,65 for hardwoods; b) not less than 0,49 for softwoods. 6.2 Wood moisture content 6.2.1
37、 The moisture content shall be determined in accordance with ISO 3130. 6.2.2 The moisture content of the wood samples at the time of assembly shall be as specified by the adhesive manufacturer. 6.2.3 When the adhesive sample is designated as suitable for bonding green timber, the moisture content of
38、 all the samples shall be greater than 30 % at the time of bonding. ISO 20152-2:2011(E) ISO 2011 All rights reserved 36.3 Creep resistance test 6.3.1 Preparation of test assemblies Preparation of assemblies and test specimens for the creep test shall be as described in ISO 20152-1. It is permissible
39、 to use the same specimens used in the creep test in Environment B of ISO 20152-1 for this creep resistance test at an elevated temperature. 6.3.2 Conditioning of test specimens The specimens shall be conditioned before testing at (20 2) C and (65 5) % relative humidity until a constant weight is at
40、tained. When the specimen tested in Environment B of ISO 20152-1 is used, the specimen shall be unloaded from the test jig and allowed to cool to the ambient temperature prior to reloading. 6.3.3 Test procedure The specimen shall be loaded in accordance with ISO 20152-1 and maintained at a stress le
41、vel of (2,1 0,1) MPa for a period of 2 h. The applied stress level shall be increased to compensate for the decrease in the spring constant when the creep jig is heated to 180 C or higher. The amount of required increase can be determined by comparing the spring constant of the spring at room temper
42、ature to that when the spring is heated to the specified temperature. NOTE The spring constant changes with the temperature. The required creep load at an elevated temperature can be calibrated with a load cell. 6.3.4 Interpretation of results Interpretation of results shall follow Clause 7.8.1.5 of
43、 ISO 20152-1. 6.4 Shear strength test at elevated temperatures NOTE This method follows the general principle of ASTM D 7247. 6.4.1 Preparation of test assemblies 6.4.1.1 The wood species used for the tests shall be the wood species specified in 6.1.1 and 6.1.2. The timber shall have the annual grow
44、th rings oriented 45 to 90, as measured from the wide face (vertical grain), and be free of defects. The moisture content of the specimens shall be between 10 % and 12 %, except for tropical species that shall be between 12 % and 15 %, prior to bonding or as recommended by the adhesive manufacturer.
45、 Timber having a minimum thickness of 35 mm is required to manufacture the test specimens. 6.4.1.2 Specimens shall be prepared in accordance with the general principles of ISO 12579. An example of the shear specimen cutting pattern is shown in Figure 1. Care shall be exercised to ensure the same ann
46、ual ring orientation when bonding the timber together into a bonded assembly. 6.4.1.3 The adhesive preparation, spread rate, clamping pressure, and clamping time shall follow the adhesive manufacturers recommendations and the production conditions, such as wood moisture content, adhesive spread rate
47、, press pressure and curing temperature. 6.4.1.4 A minimum of 20 bonded specimens shall be prepared in accordance with Figure 2. An equal number of solid wood (without the bond line) control specimens side-matched with the bonded specimens shall be prepared, as shown in Figure 1. The side-matched so
48、lid wood specimens shall be surfaced to the same thickness as the bonded specimens. The bonded and matched solid wood control specimens shall be prepared as 20 pairs. 6.4.1.5 A total of 10 pairs of bonded and matched solid wood control specimens shall be tested at ambient temperature and the remaini
49、ng 10 pairs of bonded and matched solid wood control specimens shall be tested at the targeted elevated temperature. ISO 20152-2:2011(E)4 ISO 2011 All rights reserved6.4.1.6 For specimens tested at the elevated temperature, a hole shall be drilled through one lamination at a 90 angle to the bond line and reaching to within 1,6 mm of the bond line. The drilled hole shall allow the thermocouple wire casing to fit snugly inside the hole with the exposed portion of the thermocouple wire touching the
