ASTM_C_1735_-_17.pdf

Designation:C173517Standard Test Method forMeasuring the Time Dependent Modulus of Sealants UsingStress Relaxation1This standard is issued under the fixed designation C1735;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 covers a procedure for measuring thetime dependence of modulus in elastomeric joint sealants in atest specimen configuration described in Test Method C719.These sealant materials are typified by highly filled rubbermaterials.Any Mullins effect is first assessed and mitigated intwo loading-unloading cycles.Time dependence of modulus inmaterials is then determined using a stress relaxation proce-dure.1.2 The values stated in SI units are to be regarded as thestandard.The values in parentheses are for information only.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.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)E4 Practices for Force Verification of Testing MachinesE177 Practice for Use of the Terms Precision and Bias inASTM Test MethodsE631 Terminology of Building ConstructionsE691 Practice for Conducting an Interlaboratory Study toDetermine the Precision of a Test Method3.Terminology3.1 Definitions:3.1.1 For definitions of terms used in this test method,referto Terminologies E631 and C717.4.Summary of Test Method4.1 This test method consists of two loading cycles wherestrain is increased from a 0%to a user-defined maximumstrain and one stress relaxation procedure at a strain no greaterthan23of the user-defined maximum strain.A schematicdiagram of this test strain history is shown in Fig.1.4.2 The motivation for the two loading-unloading cycles isto assess if any Mullins effect is present and to mitigate any ofthis effect in the subsequent stress relaxation test.As long asthe maximum strain achieved during the first deformation isnot exceeded,however,all subsequent loadings follow thesame stress-strain curve.4.3 Stress relaxation procedure is based on a sudden impo-sition of either a tensile or compressive strain on the testspecimen at a value of no more than23of the maximum strainand the measurement of the load required to maintain thistensile or compressive strain as a function of time.4.4 The conversion of load relaxation values to apparentmodulus and fractional change in apparent modulus is accom-plished by inputting information about the specimen geometryand the amount of deformation into an equation that is based onthe statistical theory of rubber-like elasticity.5.Significance and Use5.1 The intent of this test method is to determine the timedependence of modulus in building joint sealants using twoloading-unloading cycles to identify and mitigate any Mullinseffect,and followed by a stress relaxation procedure todetermine the time dependent modulus.5.2 This test method has found applications in screening theperformance of building joint sealants since the modulus is oneindicator of the ability of elastomeric building sealant towithstand environmental induced movements.6.Apparatus6.1 Testing MachineAny testing machine in compliancewith Practices E4,capable of producing a constant crosshead1This 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 Jan.1,2017.Published February 2017.Originallyapproved in 2011 as C1735-11.Last previous edition C1735-11.DOI:10.1520/C1735-17.2For 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 StatesThis international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for theDevelopment of International Standards,Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade(TBT)Committee.1 displacement rate in displacement control and equipped withmeans for recording complete load versus displacement curvesduring the test.6.2 Load CellThe load cell of the testing machine shall becapable of recording the load with an accuracy of 61%of themaximum indicated value.6.3 Loading Fixtur