Standard Test Method for Measuring the Time Dependent Modulus of Sealants Using Stress Relaxation

SIGNIFICANCE AND USE
5.1 The intent of this test method is to determine the time dependence of modulus in building joint sealants using two loading-unloading cycles to identify and mitigate any Mullins effect, and followed by a stress relaxation procedure to determine the time dependent modulus.  
5.2 This test method has found applications in screening the performance of building joint sealants since the modulus is one indicator of the ability of elastomeric building sealant to withstand environmental induced movements.
SCOPE
1.1 This test method covers a procedure for measuring the time dependence of modulus in elastomeric joint sealants in a test specimen configuration described in Test Method C719. These sealant materials are typified by highly filled rubber materials. Any Mullins effect is first assessed and mitigated in two loading-unloading cycles. Time dependence of modulus in materials is then determined using a stress relaxation procedure.  
1.2 The values stated in SI units are to be regarded as standard. The values given in parentheses after SI units are provided for information only and are not considered standard.  
1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use.  
1.4 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.

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Publication Date
30-Apr-2021
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ASTM C1735-17(2021) - Standard Test Method for Measuring the Time Dependent Modulus of Sealants Using Stress Relaxation
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This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the
Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
Designation: C1735 − 17 (Reapproved 2021)
Standard Test Method for
Measuring the Time Dependent Modulus of Sealants Using
Stress Relaxation
This standard is issued under the fixed designation C1735; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope ASTM Test Methods
E631 Terminology of Building Constructions
1.1 This test method covers a procedure for measuring the
E691 Practice for Conducting an Interlaboratory Study to
time dependence of modulus in elastomeric joint sealants in a
Determine the Precision of a Test Method
test specimen configuration described in Test Method C719.
These sealant materials are typified by highly filled rubber
3. Terminology
materials. Any Mullins effect is first assessed and mitigated in
3.1 Definitions:
two loading-unloading cycles. Time dependence of modulus in
3.1.1 For definitions of terms used in this test method, refer
materials is then determined using a stress relaxation proce-
to Terminologies E631 and C717.
dure.
1.2 The values stated in SI units are to be regarded as
4. Summary of Test Method
standard. The values given in parentheses after SI units are
4.1 This test method consists of two loading cycles where
provided for information only and are not considered standard.
strain is increased froma0%toa user-defined maximum
1.3 This standard does not purport to address all of the
strain and one stress relaxation procedure at a strain no greater
safety concerns, if any, associated with its use. It is the
than ⁄3 of the user-defined maximum strain. A schematic
responsibility of the user of this standard to establish appro-
diagram of this test strain history is shown in Fig. 1.
priate safety, health, and environmental practices and deter-
4.2 The motivation for the two loading-unloading cycles is
mine the applicability of regulatory limitations prior to use.
to assess if any Mullins effect is present and to mitigate any of
1.4 This international standard was developed in accor-
this effect in the subsequent stress relaxation test. As long as
dance with internationally recognized principles on standard-
the maximum strain achieved during the first deformation is
ization established in the Decision on Principles for the
not exceeded, however, all subsequent loadings follow the
Development of International Standards, Guides and Recom-
same stress-strain curve.
mendations issued by the World Trade Organization Technical
Barriers to Trade (TBT) Committee.
4.3 Stress relaxation procedure is based on a sudden impo-
sition of either a tensile or compressive strain on the test
2. Referenced Documents
specimen at a value of no more than ⁄3 of the maximum strain
and the measurement of the load required to maintain this
2.1 ASTM Standards:
tensile or compressive strain as a function of time.
C717 Terminology of Building Seals and Sealants
C719 Test Method for Adhesion and Cohesion of Elasto-
4.4 The conversion of load relaxation values to apparent
meric Joint Sealants Under Cyclic Movement (Hockman
modulus and fractional change in apparent modulus is accom-
Cycle)
plished by inputting information about the specimen geometry
E4 Practices for Force Verification of Testing Machines
andtheamountofdeformationintoanequationthatisbasedon
E177 Practice for Use of the Terms Precision and Bias in
the statistical theory of rubber-like elasticity.
5. Significance and Use
ThistestmethodisunderthejurisdictionofASTMCommitteeC24onBuilding
5.1 The intent of this test method is to determine the time
Seals and Sealants and is the direct responsibility of Subcommittee C24.20 on
General Test Methods.
dependence of modulus in building joint sealants using two
Current edition approved May 1, 2021. Published May 2021. Originally
loading-unloading cycles to identify and mitigate any Mullins
approved in 2011. Last previous edition approved in 2017 as C1735-17. DOI:
effect, and followed by a stress relaxation procedure to
10.1520/C1735-17R21.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or determine the time dependent modulus.
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
5.2 This test method has found applications in screening the
Standards volume information, refer to the standard’s Document Summary page on
the ASTM website. performance of building joint sealants since the modulus is one
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
C1735 − 17 (2021)
The value of t is 20 s and t is typically 2000 s.
0 1
FIG. 1 Strain History Used for Two Loading-Unloading Cycles and a Stress Relaxation Measurement
indicator of the ability of elastomeric building sealant to which involves cleaning the substrate by wiping the surface
withstand environmental induced movements. with methyl ethyl ketone or similar solvent. Then dip the
surfaceinadetergentsolution.Analternativewouldbea0.1%
6. Apparatus
solution of a clear hand dishwashing detergent.These solutions
should be made up in distilled or deionized water. Rinse the
6.1 Testing Machine—Any testing machine in compliance
surface (without touching it) in distilled or deionized water and
with Practices E4, capable of producing a constant crosshead
allow it to air dry.
displacement rate in displacement control and equipped with
means for recording complete load versus displacement curves
7.3 Where use of primer is recommended by the sealant
during the test.
manufacturer, substrate materials shall be primed with the
recommended primer or primers.
6.2 Load Cell—The load cell of the testing machine shall be
capable of recording the load with an accuracy of 61%ofthe
7.4 Mix thoroughly for 5 min at least 250 g of base
maximum indicated value.
compound with the appropriate amount of curing agent being
careful not to generate excess heat. For single-component
6.3 Loading Fixtures—Used to mount specimens to the
sealants, no mixing of components is required. Dispense the
testing machine so that the surface of the substrate is perpen-
compoundfromacartridgeintoaspecimencavity50.8by12.7
dicular to the direction of the applied load and to minimize any
by 12.7 mm (2 by 0.5 by 0.5 in.) formed by two parallel
eccentric loading in the test specimen.
substrate faces 50.8 by 12.7 mm (2 by 0.5 in.) with a
6.4 Air-circulating Oven—To condition specimens at the
polytetrafluoroethylene (PTFE) film on the back and PTFE
specific temperature and relative humidity.
spacers12.7by12.7by12.7mm(0.5by0.5by0.5in.)oneach
6.5 Mechanical Fastener or Rubber Bands—To hold a
end, as shown in Fig. 2.
specimen assembly together before and after filling it with
7.5 Use appropriate mechanical fasteners or rubber bands to
sealant compound.
hold the specimen cavity together before and after filling it
6.6 Geometry Measuring Tool—To measure the dimensions
with the compound.
ofaluminumsubstrateandsealanttoanaccuracyofatleast 65
7.6 Condition the specimen in the fixture at the standard
mm (0.2 in.). Because stress is the load per area exerted on the
conditionsoftemperatureandrelativehumidityforaminimum
test specimen, an accurate measurement of the geometry is
critical.
7. Preparation of Test Specimen
7.1 Test conditions of temperature and relative humidity
used throughout this test method are defined in Terminology
C717.
7.2 The standard substrate used in the test shall be alumi-
num alloy 76.2 by 12.7 by 12.7 mm (3 by 0.5 in. by 0.5 in.),
6063-T5, or 6061-T6 with anodizing process AA-
M10C22A31. Prior to use, the aluminum alloy shall be cleaned
FIG. 2 Illustration of Specimen Preparation Before Filling it with
according to a procedure described in the Test Method C719, the Sealant Compound
C1735 − 17 (2021)
of 5 h. Then remove the mechanical fasteners or rubber bands 9.9 Inspect the sample to note the locus of joint failure, if
and the PTFE backing film. Keep the PTFE spacers and the any f
...

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