ASTM C961-06(2011)

Standard Test Method for Lap Shear Strength of Sealants

SIGNIFICANCE AND USE
Sealants are generally subjected to longitudinal and lateral shear stresses in end use applications. This test method measures the cohesive strength of sealants when subjected to shear stresses, and also provides information regarding the adhesive bond to the substrates being tested.
SCOPE
1.1 This test method covers a laboratory procedure for determining the lap shear strength of sealants. It also provides information on the adhesive bond of the sealants to the tested substrates.
1.2 The values stated in SI units are to be regarded as the standard. The values given in parentheses are for information only.
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 and health practices and determine the applicability of regulatory limitations prior to use.
1.4 The subcommittee with jurisdiction of this standard is not aware of any similar or equivalent ISO standard.

General Information

• Status: Historical
• Publication Date: 30-Nov-2011
• ICS: 91.100.50 - Binders. Sealing materials
• Technical Committee: C24 - Building Seals and Sealants
• Drafting Committee: C24.30 - Adhesion

Relations

• Replaces: ASTM C961-06 - Standard Test Method for Lap Shear Strength of Sealants
• Effective Date: 01-Dec-2011
• Replaced By: ASTM C961-15 - Standard Test Method for Lap Shear Strength of Sealants
• Effective Date: 01-Dec-2015
• Referred By: ASTM C1021-08(2023) - Standard Practice for Laboratories Engaged in Testing of Building Sealants
• Effective Date: 01-Dec-2011
• Referred By: ASTM C717-19 - Standard Terminology of Building Seals and Sealants
• Effective Date: 01-Dec-2011

Standards Content (Sample)

NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
Contact ASTM International (www.astm.org) for the latest information
Designation: C961 − 06(Reapproved 2011)
Standard Test Method for
Lap Shear Strength of Sealants
This standard is issued under the fixed designation C961; 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 measures the cohesive strength of sealants when subjected to
shear stresses, and also provides information regarding the
1.1 This test method covers a laboratory procedure for
adhesive bond to the substrates being tested.
determining the lap shear strength of sealants. It also provides
information on the adhesive bond of the sealants to the tested
6. Apparatus
substrates.
6.1 Sealant Applicator or Oven, capable of maintaining the
1.2 The values stated in SI units are to be regarded as the
sealant within 62.8°C (65°F) of the specified temperature.
standard. The values given in parentheses are for information
only. 6.2 Substrates, of annealed glass that are 25.4 mm wide by
76.2 mm long and 6.35 mm thick (1 by 3 by 0.25 in.). Other
1.3 This standard does not purport to address all of the
substrates may be used when specified (Fig. 1).
safety concerns, if any, associated with its use. It is the
responsibility of the user of this standard to establish appro-
6.3 Template, to provide 3.18-mm ( ⁄8-in.) sealant thickness
priate safety and health practices and determine the applica-
(Fig. 2).
bility of regulatory limitations prior to use.
6.4 Hot Knife or Spatula.
1.4 The subcommittee with jurisdiction of this standard is
6.5 Tension Testing Machine, capable of pulling a specimen
not aware of any similar or equivalent ISO standard.
at a rate of 12.7 mm (0.5 in.)/min.
2. Referenced Documents
7. Sampling
2.1 ASTM Standards:
C717 Terminology of Building Seals and Sealants
7.1 Sealant shall be free of external surface contaminants
such as talc, oil, dust, and moisture. Handling of the sealant
3. Terminology
surfaces in contact with the substrate shall be minimized.
3.1 Definitions—The definitions of the following terms used
7.2 A 1.0-kg (2.2-lb) representative sample shall be taken
in this test method are found in Terminology C717, 4.1:
from bulk stock for testing.
adhesive failure, cohesive failure, sealant, and substrate.
8. Test Specimens
4. Summary of Test Method
8.1 Prepare six test specimens from the bulk sample by
4.1 The sealant is placed between two glass substrates. The
using the applicator or the oven method.
sample is placed in a tensile tester and pulled at a constant rate
8.1.1 Applicator Method:
to failure. The maximum shear force and mode of failure is
8.1.1.1 Clean the substrate surface with soap and water
noted. Maximum shear stress is calculated and reported.
followed by a water rinse and solvent wipe with methyl ethyl
5. Significance and Use
ketone (MEK).
5.1 Sealants are generally subjected to longitudinal and
NOTE 1—At the request of the sealant manufacturer, an alternative
lateral shear stresses in end use applications. This test method
cleaning procedure may be used.
8.1.1.2 Using an appropriate die or nozzle, apply a 25.4 by
ThistestmethodisunderthejurisdictionofASTMCommitteeC24onBuilding
25.4-mm (1 by 1-in.) layer of sealant onto one end of the
Seals and Sealants and is the direct responsibility of Subcommittee C24.30 on
substrate surface at a thickness that when compressed will
Adhesion.
comply with 8.1.1.4. Substrates shall be at a temperature of 23
Current edition approved Dec. 1, 2011. Published January 2012. Originally
6 2°C, 50 6 10 % relative humidity (73.4 6 3.6°F).Apply the
approved in 1981. Last previous edition approved in 2006 as C961–06. DOI:
10.1520/C0961-06R11.
sealant at the specified temperature 62.8°C (65°F) (Fig. 1).
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
8.1.1.3 Immediately after sealant application place a second
contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM
substrate onto the sealant to form an overlap of 6.45 cm (1
Standards volume information, refer to the standard’s Document Summary page on
the ASTM website. in.)(Fig. 1).
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
C961 − 06 (2011)
10. Procedure
10.1 Attach each specimen to the jaws of the tension testing
machine and separate at a crosshead speed of 12.7 mm (0.5
in.)/min to failure (separation) (Fig. 4). Align the testing
machine jaws to prevent cocking of test assembly.
10.2 Visually inspect and record the mode of bond failure
(cohesiveoradhesive)andtheapproximatepercentageofeach.
10.3 Observe and record the maximum shear force in
newtons (or pounds-force).
11. Calculation
11.1 Calculate the maximum shear stress, S, as follows:
S 5 F/A (1)
where:
S = maximum shear stress, Pa (or lbf/in. ),
F = maximum shear force, N (or lbf), and
A = contact area of the specimen with one substrate, m (or
in. ).
11.2 Average the results of the six specimens tested.
Length
Dimension mm in.
G, J 76.2 ± 0.25 (3.00± 0.01)
12. Report
H, K, M 25.4 ± 0.25 (1.00 ± 0.01)
I, L 6.35 ± 0.10 (0.250± 0.004) 12.1 Report the following information:
12.1.1 Equipment used to apply the sealant,
FIG. 1 Assembly of Test Sealant on Substrates
12.1.2 Average maximum lap shear stress and range of
values in Pa (or psi),
12.1.3 Any substrate deforma
...