ASTM_C_1681_-_14.pdf

Designation:C168114Standard Test Method forEvaluating the Tear Resistance of a Sealant Under ConstantStrain1This standard is issued under the fixed designation C1681;the number immediately following the designation indicates the year oforiginal adoption or,in the case of revision,the year of last revision.A number in parentheses indicates the year of last reapproval.Asuperscript epsilon()indicates an editorial change since the last revision or reapproval.1.Scope1.1 This test method evaluates the impact of an induced tearon a sealant specimen that is dimensioned,cured according tothe guidelines in Test Method C719 and then subjected to aconstant strain.It is effective in differentiating between seal-ants that are used in dynamic joints subject to abrasion,punctures,tears,or combination thereof.1.2 Since this test method is for the evaluation of tearpropagation,an adhesive failure to the substrates provides nousable data regarding tear propagation.This would be consid-ered a failed test and that data would be discarded,or at leastseparated from the other data from specimens that did notexperience an adhesive failure.1.3 This standard does not purport to address all of thesafety concerns,if any,associated with its use.It is theresponsibility of the user of this standard to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.1.4 The committee with jurisdiction over this standard is notaware of any comparable standards published by other orga-nizations.2.Referenced Documents2.1 ASTM Standards:2C717 Terminology of Building Seals and SealantsC719 Test Method for Adhesion and Cohesion of Elasto-meric Joint Sealants Under Cyclic Movement(HockmanCycle)3.Terminology3.1 DefinitionsRefer to Terminology C717 for definitionsof the following terms used in this test method:casting spacer.3.2 separatorsrigid spacers used to maintain a constantstrain on the joint specimens during the testing period whilemaintaining parallel bond surfaces.4.Summary of Test Method4.1 Test specimens are fabricated and cured in accordancewith Test Method C719.At the end of the 21-day cure period,an induced tear is created in the specimens by making a cutwith a sharp blade in the midpoint of the joint.The specimensare then extended to a specified strain at both standardconditions and at 26 6 2C(15 6 3F).Propagation of theinduced tear is measured at 0,24 and 168 h.5.Significance and Use5.1 This test method is intended to determine if a joint thatis subjected to a mechanically induced cut will resist tearpropagation during normal joint movement.A sealant with ahigh resistance to tear propagation will typically perform betterthan a sealant with a low resistance to tear propagation.6.Apparatus6.1 A device capable of extending the test specimens to thespecified strain.6.2 Freezer,to maintain a constant temperature of 26C 62C.6.3 A suitable measuring device such as calipers able tomeasure the induced tears to 0.01 mm.6.4#17 Knife Blade,9 mm(38in.)wide.7.Reagents and Materials7.1 Spatulas,for use in applying the sealant.7.2 Caulking Gun,for extruding sealant from cartridgeswhen applicable.7.3 Substratestwelve substrates,with minimum dimen-sions of 25 by 75 mm(1 by 3 in.)of the same finish arerequired for each product to be tested.Glass is the defaultsubstrate,however as mentioned in the scope,this is not anadhesion test,therefore the sealant must exhibit excellentadhesion to the substrate.Other rigid substrates in the abovenoted dimension are acceptable.Substrate blocks or plates1This test method is under the jurisdiction ofASTM Committee C24 on BuildingSeals and Sealants and is the direct responsibility of Subcommittee C24.20 onGeneral Test Methods.Current edition approved June 1,2014.Published July 2014.Originally approvedin 2009.Last previous edition approved in 2009 as C1681-09.DOI:10.1520/C1681-14.2For referenced ASTM standards,visit the ASTM website,www.astm.org,orcontact ASTM Customer Service at serviceastm.org.For Annual Book of ASTMStandards volume information,refer to the standards Document Summary page onthe ASTM website.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1 should be of adequate thickness or reinforced such that they donot flex or break during the testing.7.4 Casting SpacersMade from polytetrafluoroethylene(PTFE)or a suitable rigid material shall be used with each testspecimen to which the test sealant will not bond and willprovide the appropriate joint dimensions and configurations.The spacers provide joint dimensions of 12.7 by 12.7 by 50.8mm(12by12by 2 in.).See Fig.5 in Test Method C719.7.5 Separators,to provide a constant strain on the specimenwhile maintaining parallel bond surfaces.7.6 Substrate Cleaning Material.7.7 Primer,if required on the substrates.7.8 Asuitable measuring device,such as calipers,capable ofmeasuring the induced cut in the sealant and additional changesin the cut to 0.01 mm.7.