ASTM D3931-93a(2005)
(Test Method)Standard Test Method for Determining Strength of Gap-Filling Adhesive Bonds in Shear by Compression Loading
Standard Test Method for Determining Strength of Gap-Filling Adhesive Bonds in Shear by Compression Loading
SIGNIFICANCE AND USE
Structural design based on strength-of-materials principles requires knowledge of the mechanical properties of the structural components, including adhesives. By nature of their use, the most important property of adhesive is shear strength.
Shear strength measured by this test method is suitable for use in adhesive development, manufacturing quality control, and in materials performance specifications, as well as structural design.
SCOPE
1.1 This test method covers the determination of comparative shear properties of gap-filling adhesives in wood-to-wood joints at specified thicknesses of bondline in the dry condition, when tested on standard specimens under specified conditions of preparation, conditioning, and loading in compression. This test method is intended as an evaluation of gap-filling adhesives such as those used to bond plywood to lumber, lumber to lumber, and other similar materials in building constructions.
1.2 This test method also may be used to determine shear properties of gap-filling adhesives in species of wood and in thicknesses of bondline other than those specified for the comparative tests of shear properties within this test method. All procedures specified herein are applicable, excepting requirements for wood species and specific gravity, and thicknesses of bondlines.
1.3 The values stated in inch-pound units are to be regarded as standard. The values given in parentheses are mathematical conversions to SI units that are provided for information only and are not considered standard.
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.
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Standards Content (Sample)
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Designation:D3931–93a(Reapproved2005)
Standard Test Method for
Determining Strength of Gap-Filling Adhesive Bonds in
Shear by Compression Loading
This standard is issued under the fixed designation D 3931; 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 Bonds in Shear by Compression Loading
D 1151 TestMethodforEffectofMoistureandTemperature
1.1 This test method covers the determination of compara-
on Adhesive Bonds
tive shear properties of gap-filling adhesives in wood-to-wood
E 171 Specification for Standard Atmospheres for Condi-
joints at specified thicknesses of bondline in the dry condition,
tioning and Testing Materials
when tested on standard specimens under specified conditions
of preparation, conditioning, and loading in compression. This
3. Terminology
test method is intended as an evaluation of gap-filling adhe-
3.1 Definitions:
sives such as those used to bond plywood to lumber, lumber to
3.1.1 gap-filling adhesive, n—an adhesive capable of form-
lumber, and other similar materials in building constructions.
ing and maintaining a bond between surfaces that are not
1.2 This test method also may be used to determine shear
close-fitting.
properties of gap-filling adhesives in species of wood and in
3.1.1.1 Discussion—Close-fitting is relative to a given ma-
thicknesses of bondline other than those specified for the
terial and industry; for example, standards in construction
comparative tests of shear properties within this test method.
differ from standards in electronics. Some adhesives will bond
All procedures specified herein are applicable, excepting re-
by bridging without completely filling the gap; others by filling
quirements for wood species and specific gravity, and thick-
the gap completely.
nesses of bondlines.
1.3 The values stated in inch-pound units are to be regarded
4. Significance and Use
as standard. The values given in parentheses are mathematical
4.1 Structural design based on strength-of-materials prin-
conversions to SI units that are provided for information only
ciples requires knowledge of the mechanical properties of the
and are not considered standard.
structural components, including adhesives. By nature of their
1.4 This standard does not purport to address all of the
use, the most important property of adhesive is shear strength.
safety concerns, if any, associated with its use. It is the
4.2 Shear strength measured by this test method is suitable
responsibility of the user of this standard to establish appro-
for use in adhesive development, manufacturing quality con-
priate safety and health practices and determine the applica-
trol, and in materials performance specifications, as well as
bility of regulatory limitations prior to use.
structural design.
2. Referenced Documents
5. Apparatus
2.1 ASTM Standards:
5.1 Testing Machine, having a capacity of about 15 000 lb
D 143 Test Methods for Small Clear Specimens of Timber
(6818 kg) in compression or of sufficient capacity to test the
D 905 Test Method for Strength Properties of Adhesive
adhesive in use. The machine shall be fitted with a shearing
tool containing a self-aligning seat to ensure uniform lateral
distribution of the load. The machine shall be capable of
This test method is under the jurisdiction of ASTM Committee D14 on
maintainingauniformrateofloadingsuchthattheloadmaybe
Adhesives and is the direct responsibility of Subcommittee D14.70 on Construction
applied with a continuous motion of the movable head to
Adhesives.
maximum load at a rate of 9.20 in. (5.0 mm)/min with a
Current edition approved April 1, 2005. Published April 2005. Originally
e 1
approved in 1980. Last previous edition approved in 1999 as D 3931–93a (1999) .
permissible variation of 625 %. The shearing tool shown in
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
Fig. 1 of Test Method D 905 has been found satisfactory.
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
Locate the testing machine in an atmosphere such that the
Standards volume information, refer to the standard’s Document Summary page on
the ASTM website.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
D3931–93a (2005)
moisture content of the specimens, developed under the con- been found to be satisfactory for this purpose. The moisture
ditions prescribed in 7.3, is not noticeably altered during content shall be from 8 to 10 % (conditions prescribed in7.3.1)
testing. based on ovendry weight as determined on representative
samples in accordance with the final measurement section
6. Test Specimen and Sample
under radial and tangential shrinkage and the weighing section
6.1 Test specimens for adhesive bonds shall conform to the under moisture determination in Test Methods D 143. Surface
form and dimensions shown in Fig. 1. Prepare bonded assem- the blocks just prior to gluing, preferably with a hand-feed
blies as described in 7.1. Prepare test specimens for testing as jointer. Make sure the surfaces remain unsanded and free from
described in 7.2. dirt.
6.2 Determine mean shear strengths of bonds at bondline
7.1.2 Use spacer strips to control bondlines to specified
thicknesses of 0.006 and 0.060 in. (0.15 and 1.52 mm). Tests
thicknesses between blocks. Spacers shall be wood veneer or
for strengths of bonds at other thicknesses, in addition to those 1 1
plastic, and measure approximately ⁄2 by 3 ⁄2 in. (13 by 89
specified, shall be optional upon agreement between the
mm)long.Placespacerscrosswiseattheendsandcenterofthe
manufacturer and the user.
lower test joint block. Apply adhesive in sufficient quantity to
6.3 Test a minimum of 28 specimens, representing seven
ensure squeezeout at the ends of the joint when blocks are
differentbondedassemblies,todeterminemeanshearstrengths
under pressure (Note 2).
of bonds at each bondline thickness.
NOTE 2—If the adhesive is to be applied as an extruded bead, the bead
3 1
should be ⁄8 to ⁄2 in. (10 to 13 mm) in diameter to ensure squeezeout in
7. Procedure
bondlinethicknessesnear0.060in.(1.5mm).Useasmallerdiameterbead
7.1 Preparation of Bonded Assemblies:
of adhesive for thinner bondlines.
7.1.1 Prepare bonded assemblies with hard maple blocks
7.1.2.1 Take care to avoid air entrapment in the bondline.
(Acer saccharum or Acer nigrum) conditioned as described in
Do not spread the adhesive closer than ⁄2 in. (13 mm) to any
7.3. The blocks shall have a minimum specific gravity of 0.65,
spacer because adhesive may be entrapped between block and
based on ovendry weight and ovendry volume (Note 1).
spacer, thereby increasing bondline thickness. Assemble the
NOTE 1—A method for selecting maple blocks of satisfactory specific
blocks immediately, unless specified otherwise by agreement
gravity is described in theAppendix of Test Method D 905. For reference
between the manufacturer and user of the adhesive. Apply a
tests, the specific gravity of blocks may be determined in accordance with
15-lb (7.0-kg) load uniformly over the entire bond area to
the Weight and Moisture Content Section under Nail Withdrawal of Test
Methods D 143. ensure firm contact between spacers and blocks of the assem-
bly. Maintain the pressure on test joints at the conditions
7.1.1.1 These blocks shall be straight-grained and free of
prescribed in 7.1.
defects, including knots, splits, birdseye, short grain, decay,
7.1.3 Curing time for bonded assemblies shall be as speci-
and any unusual discoloration within the shearing area. The
fied by the ma
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