ASTM C961-97

Standard Test Method for Lap Shear Strength of Hot-Applied Sealants

SCOPE
1.1 This test method covers a laboratory procedure for determining the lap shear strength of hot-applied sealants, hereinafter referred to as sealant. 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: 09-Jun-2001
• ICS: 91.100.50 - Binders. Sealing materials
• Technical Committee: C24 - Building Seals and Sealants
• Drafting Committee: C24.20 - General Test Methods

Relations

• Replaced By: ASTM C961-01 - Standard Test Method for Lap Shear Strength of Hot-Applied Sealants
• Effective Date: 10-Jun-2001
• Referred By: ASTM C1021-08(2023) - Standard Practice for Laboratories Engaged in Testing of Building Sealants
• Effective Date: 10-Jun-2001
• Referred By: ASTM C717-19 - Standard Terminology of Building Seals and Sealants
• Effective Date: 10-Jun-2001

Standards Content (Sample)

NOTICE: This standard has either been superseded and replaced by a new version or discontinued.
Contact ASTM International (www.astm.org) for the latest information.
Designation: C 961 – 97
Standard Test Method for
Lap Shear Strength of Hot-Applied Sealants
This standard is issued under the fixed designation C 961; 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 (e) indicates an editorial change since the last revision or reapproval.
1. Scope 6. Apparatus
1.1 This test method covers a laboratory procedure for 6.1 Applicator or Oven, capable of maintaining the sealant
determining the lap shear strength of hot-applied sealants, within 62.8°C (65°F) of the specified temperature.
hereinafter referred to as sealant. It also provides information 6.2 Substrates, of annealed glass that are 25.4 mm wide by
on the adhesive bond of the sealants to the tested substrates. 76.2 mm long and 6.35 mm thick (1 by 3 by 0.25 in.). Other
1.2 The values stated in SI units are to be regarded as the substrates may be used when specified (Fig. 1).
standard. The values given in parentheses are for information 6.3 Template, to provide 3.18-mm ( ⁄8-in.) sealant thickness
only. (Fig. 2).
1.3 This standard does not purport to address all of the 6.4 Hot Knife.
safety concerns, if any, associated with its use. It is the 6.5 Tension Testing Machine, capable of pulling a specimen
responsibility of the user of this standard to establish appro- at a rate of 12.7 mm (0.5 in.)/min.
priate safety and health practices and determine the applica-
7. Sampling
bility of regulatory limitations prior to use.
7.1 Sealant shall be free of external surface contaminants
2. Referenced Documents
such as talc, oil, dust, and moisture. Handling of the sealant
2.1 ASTM Standards: surfaces in contact with the substrate shall be minimized.
C 717 Terminology of Building Seals and Sealants 7.2 A 1.0-kg (2.2-lb) representative sample shall be taken
from bulk stock for testing.
3. Terminology
8. Test Specimens
3.1 Definitions:
3.1.1 The definitions of the following terms used in this test 8.1 Prepare six test specimens from the bulk sample by
method are found in Terminology C 717, 4.1: adhesive failure, using the applicator or the oven method.
cohesive failure, hot applied sealant, sealant, and substrate. 8.1.1 Applicator Method:
3.2 Definitions of Terms Specific to This Standard: 8.1.1.1 Clean the substrate surface with soap and water
3.2.1 The following definitions of terms are found in Ter- followed by a water rinse and solvent wipe with methyl ethyl
minology C 717, 4.2: applicator and specified temperature. ketone (MEK).
NOTE 1—At the request of the sealant manufacturer, an alternative
4. Summary of Test Method
cleaning procedure may be used.
4.1 The sealant is placed between two glass substrates. The
8.1.1.2 Using an appropriate die, apply a 25.4 by 25.4-mm
sample is placed in a tensile tester and pulled at a constant rate
(1 by 1-in.) layer of sealant onto one end of the substrate
to failure. The maximum shear force and mode of failure is
surface at a thickness that when compressed will comply with
noted. Maximum shear stress is calculated and reported.
8.1.1.4. Substrates shall be at a temperature of 23 6 2°C, 50 6
5. Significance and Use 10 % relative humidity (73.4 6 3.6°F). Apply the sealant at the
specified temperature 62.8°C (65°F) (Fig. 1).
5.1 Sealants are generally subjected to longitudinal and
8.1.1.3 Immediately after sealant application place a second
lateral shear stresses in end use applications. This test method
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substrate onto the sealant to form an overlap of 6.45 cm (1 in. )
measures the cohesive strength of sealants when subjected to
(Fig. 1).
shear stresses, and also provides information regarding the
8.1.1.4 Using a template (Fig. 2), compress the overlayed
adhesive bond to the substrates being tested.
sealant to form the 3.18-mm ( ⁄8-in.) thick overlap (Fig. 3).
This test method is under the jurisdiction of ASTM Committee C-24 on
Building Seals and Sealants and is the direct responsibility of Subcommittee C24.20 The sole source of supply of the apparatus known to the committee at this time
on General Sealant Standards. is the Pyles Bulk Melters, Pyles Industries, Inc., 28990 Wixom Rd., Wixom, MI
Current edition approved Feb. 10, 1997. Published April 1997. Originally 48096. If you are aware of alternative suppliers, please provide this information to
published as C 961 – 81. Last previous edition C 961 – 87 (1992). ASTM Headquarters. Your comments will receive careful consideration at a meeting
2 1
Annual Book of ASTM Standards, Vol 04.07. of the responsible technical committee, which you may attend.
Copyright © ASTM, 100 Barr Harbor Drive, West Conshohocken, PA 19428-2959, United States.
C 961
10.2 Visually inspect and record the mode of bond failure
(cohesive or adhesive) and the approximate percentage of each.
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
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.
12. Report
12.1 Report the following information:
12.1.1 Equipment used to apply the sealant,
12.1.2 Average maximum lap shear stress and range of
values in Pa (or psi),
Length
12.1.3 Any substrate deformation during testing and degree
Dimension mm in.
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