ASTM D5574-94(1999)e1
(Test Method)Standard Test Methods for Establishing Allowable Mechanical Properties of Wood-Bonding Adhesives for Design of Structural Joints
Standard Test Methods for Establishing Allowable Mechanical Properties of Wood-Bonding Adhesives for Design of Structural Joints
SCOPE
1.1 These test methods cover the principles for establishing allowable mechanical properties for adhesives that can be used to design adhesive-bonded joints for structural components and assemblies of wood or wood with other materials. These test methods are modeled after Test Method D245.
1.2 The properties determined are allowable shear stress, allowable tensile stress, and allowable shear modulus.
1.3 In determination of allowable shear- and tensile-stress levels, these test methods are limited by the horizontal shear and tension perpendicular-to-the-grain capacity of the wood adherends (hard maple, Acer saccharum , Marsh.). The adhesives so tested may actually have shear or tensile allowable stresses exceeding the wood, but the determined allowable design stress levels are limited (upper bounded) by the wood in these test methods. If a wood other than hard maple is used for testing the adhesive, then the allowable strengths are upper bounded by the properties of that particular wood.
1.4 The strength properties are determined by standard ASTM test methods. As a result, only procedural variations from the standards and special directions for applying the results are given in these test methods.
1.5 Time-to-failure data derived from creep-rupture testing (see Test Method D4680) provide a measure of the ultimate strength of an adhesive bond as a function of time at various levels of temperature and moisture.
1.5.1 With proper caution, useful service life at a given shear stress level may be extrapolated from relatively short loading periods.
1.6 The resistance of the adhesive to permanent loss of properties due to aging (permanence) is assessed by means of strength tests after constant elevated-temperature and moisture aging of test specimens.
1.6.1 If the subject adhesives will be used to bond wood that has been treated with a preservative, fire retardant, or any other chemical to modify its properties, then the permanence of the adhesive shall be tested using wood adherends treated in the same manner.
1.7 Factors for durability, permanence, and creep derived by shear tests and analysis, are assumed to apply to tension (normal-to-the-bond) strength as well.
1.8 Requirements for production, inspection, and certification of adhesives evaluated under these test methods are not included.
1.9 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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e1
Designation:D5574–94(Reapproved1999)
Standard Test Methods for
Establishing Allowable Mechanical Properties of Wood-
Bonding Adhesives for Design of Structural Joints
This standard is issued under the fixed designation D 5574; 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.
e NOTE—Keywords were added in April 1999.
1. Scope 1.6.1 Ifthesubjectadhesiveswillbeusedtobondwoodthat
has been treated with a preservative, fire retardant, or any other
1.1 These test methods cover the principles for establishing
chemical to modify its properties, then the permanence of the
allowable mechanical properties for adhesives that can be used
adhesive shall be tested using wood adherends treated in the
todesignadhesive-bondedjointsforstructuralcomponentsand
same manner.
assemblies of wood or wood with other materials. These test
1.7 Factors for durability, permanence, and creep derived by
methods are modeled after Test Method D 245.
shear tests and analysis, are assumed to apply to tension
1.2 The properties determined are allowable shear stress,
(normal-to-the-bond) strength as well.
allowable tensile stress, and allowable shear modulus.
1.8 Requirements for production, inspection, and certifica-
1.3 In determination of allowable shear- and tensile-stress
tion of adhesives evaluated under these test methods are not
levels, these test methods are limited by the horizontal shear
included.
and tension perpendicular-to-the-grain capacity of the wood
1.9 This standard does not purport to address all of the
adherends (hard maple, Acer saccharum, Marsh.). The adhe-
safety concerns, if any, associated with its use. It is the
sives so tested may actually have shear or tensile allowable
responsibility of the user of this standard to establish appro-
stresses exceeding the wood, but the determined allowable
priate safety and health practices and determine the applica-
design stress levels are limited (upper bounded) by the wood in
bility of regulatory limitations prior to use.
these test methods. If a wood other than hard maple is used for
testing the adhesive, then the allowable strengths are upper
2. Referenced Documents
bounded by the properties of that particular wood.
2.1 ASTM Standards:
1.4 The strength properties are determined by standard
D 245 Practice for Establishing Structural Grades and Re-
ASTM test methods. As a result, only procedural variations
lated Allowable Properties for Visually Graded Lumber
from the standards and special directions for applying the
D 897 Test Method for Tensile Properties of Adhesive
results are given in these test methods.
Bonds
1.5 Time-to-failure data derived from creep-rupture testing
D 905 Test Method for Strength Properties of Adhesive
(see Test Method D 4680) provide a measure of the ultimate
Bonds in Shear by Compression Loading
strength of an adhesive bond as a function of time at various
D 907 Terminology of Adhesives
levels of temperature and moisture.
D 1101 Test Methods for Integrity of Glue Joints in Struc-
1.5.1 With proper caution, useful service life at a given
tural Laminated Wood Products for Exterior Use
shear stress level may be extrapolated from relatively short
D 1151 TestMethodforEffectofMoistureandTemperature
loading periods.
on Adhesive Bonds
1.6 The resistance of the adhesive to permanent loss of
D 2555 Test Methods for Establishing Clear Wood Strength
properties due to aging (permanence) is assessed by means of
Values
strength tests after constant elevated-temperature and moisture
D 2559 Specification for Adhesives for Structural Lami-
aging of test specimens.
nated Wood Products for Use Under Exterior (Wet Use)
Exposure Conditions
These test methods are under the jurisdiction of ASTM Committee D-14 on
Adhesives and are the direct responsibility of Subcommittee D14.70 on Construc-
tion Adhesives. Annual Book of ASTM Standards, Vol 04.10.
Current edition approved June 15, 1994. Published August 1994. Annual Book of ASTM Standards, Vol 15.06.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
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D5574–94 (1999)
D 2915 Practice for Evaluating Allowable Properties for 3.2.1 allowable shear modulus, n—the modulus calculated
Grades of Structural Lumber in accordance with Section 14, that is used for the design of a
D 3931 Practice for Determining Strength of Gap-Filling structural joint.
Adhesive Bonds in Shear by Compression Loading
3.2.2 basicshearmodulus,n—theaverageshearmodulusof
D 3983 Test Method for Measuring Strength and Shear
30 specimens fabricated and tested in accordance with 13.1.
Modulus of Nonrigid Adhesives by the Thick-Adherend
3.2.3 basic shear strength, n—a near minimum value of the
Tensile-Lap Specimen
shear strength distribution determined as the one-sided lower
D 4027 Test Method for Measuring Shear Properties of
confidence interval on the fifth percentile as determined in
Structural Adhesives by the Modified-Rail Test
accordance with 7.1. (See lower 5 % tolerance limit.)
D 4502 Test Method for Heat and Moisture Resistance of
3.2.4 basictensilestrength,n—anearminimumvalueofthe
Wood-Adhesive Joints
tensile strength distribution determined as the one-sided lower
D 4680 Test Method for Creep and Time to Failure of
confidence interval on the fifth percentile as determined in
Adhesives in Static Shear by Compression Loading
accordance with 9.1. (See lower 5 % tolerance limit.)
(Wood-to-Wood)
3.2.5 creep factor, n—for modulus, the monotonic modulus
D 4896 Guide for Use of Adhesive-Bonded Single Lap-
as a function of loading rate expressed as the decimal fraction
Joint Specimen Test Results
of the basic modulus.
E 380 Practice for Use of the International System of Units
(SI) (The Modernized Metric System) 3.2.6 creep factor, n—for strength, the estimated 30 year
creep rupture limit as a decimal fraction of the basic strength.
3. Terminology
3.2.7 delamination factor, n—a pass/fail factor based on the
3.1 Definitions:
percentage of delamination on the end grain of a laminate after
3.1.1 allowable design stress, n—a stress to which a mate-
cyclic delamination treatment.
rial can be subjected under stated service conditions with low
3.2.7.1 Discussion—The factor is 0 or l: 0 if end-grain
probability of mechanical failure within the design lifetime.
delamination is greater than 10 % of total end-grain bondline;
(D4896)
1 if less than 10 % after cyclic soak-dry treatment.
3.1.1.1 Discussion—Allowable design stress is obtained by
3.2.8 durability factor, n—the average strength under el-
multiplying the basic stress by a safety factor and possibly one
evated test conditions expressed as a decimal fraction of the
or more modification factors as required by the intended
strength at standard condition.
service environment.
3.2.8.1 Discussion—Increases in temperature and moisture
3.1.2 allowable shear stress, n—in an adhesive-bonded
level usually lower strength temporarily, as long as the speci-
joint, the allowable design stress for structural joints subjected
men is not so weakened that fracture occurs. Decreases in
to shear force.
temperature and moisture level usually increase strength.
3.1.3 allowable tensile stress, n—in an adhesive-bonded
Exceptions occur when increasing the temperature raises the
joint, the allowable design stress for structural joints subjected
level of adhesive cure and strength, or decreasing the tempera-
to tension force.
ture or moisture induces brittleness and stress concentrations.
3.1.4 creep rupture, n—the fracture of a material resulting
from a sustained stress (or sum of stresses) above the creep 3.2.9 lower 5 % nonparametric tolerance limit [NTL],
rupture limit. n—an estimate of the one-sided lower confidence bond on the
3.1.4.1 Discussion—The material may experience creep fifth percentile of the strength distribution determined as the
through the primary, secondary, and tertiary stages of rupture. lowest ranked value (fast order statistic) of sample of speci-
3.1.5 creep-rupture limit, n—the stress level below which mens from a population.
creep rupture will not occur within a given time in a specified
3.2.10 lower 5 % parametric tolerance limit [PTL], n—an
environment. See creep rupture.
estimate of the lower confidence bound on the fifth percentile
3.1.6 durability, n—as related to adhesive joints, the endur-
of the strength distribution calculated as the mean of a sample
ance of joint strength relative to the required service condi-
minus the sample standard deviation multiplied by a confi-
tions. (D907)
dence level factor.
3.1.6.1 Discussion—Service conditions may include water
3.2.11 lower 5 % tolerance limit, n— an estimate of the
and other chemicals, temperature, stress, radiation, microor-
one-sided lower confidence bound on the fifth percentile of the
ganisms, and other environmental factors.
strength distribution of a population of specimens.
3.1.7 permanence, n—the resistance of an adhesive bond to
3.2.12 modification factor, n—any external or internal fac-
deteriorating influences. (D907)
tor of the service environment that temporarily or permanently
3.1.8 structural adhesive, n—a bonding agent used for
alters the strength or stiffness of an adhesive.
transferring required loads between adherends exposed to
3.2.13 multiaxial stress, n—stress in two or three perpen-
service environments typical for the structure involved.
dicular directions, bi- or triaxial stress.
(D907)
3.2.13.1 Discussion—In most wood structures bonded with
3.2 Definitions of Terms Specific to This Standard:
structural adhesives, multiaxial stress consists of a shear stress
in the plane of, and tension stress normal to the plane of the
Annual Book of ASTM Standards, Vol 14.02. adhesive layer.
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D5574–94 (1999)
3.2.14 permanence factor, n—the estimated residual 5. Significance and Use
strength at 30 years expressed as a decimal fraction of the
5.1 Safe and reliable mechanical properties for adhesives
original strength at standard conditions.
are necessary to achieve the full structural benefit of adhesives
3.2.14.1 Discussion—This factor accounts for permanent,
in bonded structural components and assemblies.
usually long-term, changes in strength or modulus due to the
5.2 An adhesive’s properties exhibit a natural variation or
effects of factors such as heat, moisture, chemicals, ultraviolet
distribution of values. The allowable design stress for an
light, and biological agents.
adhesive must be adjusted to allow for variability and environ-
3.2.15 safety factor, n—a reduction factor to account for
mental effects to ensure human safety and prevent premature
uncertainty in establishing an allowable design stress. failure of costly structures.
3.2.15.1 Discussion—The safety factor accounts for pos- 5.3 Modification factors can be applied to the allowable
design stress by the design engineer as deemed appropriate for
sible differences between laboratory and end-use conditions,
differences in adhesive production lots, bonding variables, and the expected service conditions of the adhesive, or in accor-
dance with the requirements of a building code.
the assumption that there is no interaction between modifica-
tion factors. 5.4 The allowable properties developed under these meth-
ods apply only to the actual adhesive formulation tested and
analyzed.
4. Summary of Test Methods
5.5 Theallowablepropertiesdevelopedforagivenadhesive
4.1 These test methods are based on a conservative estimate
shall apply only to adhesive bondlines with thicknesses in the
of the near minimum value of the distribution of adhesive
range for which data is available.
strengths measured by a standard test method. The basic
strength of the adhesive is the lower 5 % nonparametric
6. Adhesive and Wood Preparation
tolerance limit obtained by a sample of 59 specimens. The
6.1 Obtain a representative sample from each lot of adhe-
allowabledesignstressisthebasicstrengthreducedbyasafety
sive to be tested.
factor as a minimum:
6.1.1 For liquid or paste adhesives, take a sample from each
allowable design stress 5 basic strength 3 safety factor
lot of at least 1 qt (446 mL).
The allowable shear modulus is the mean modulus of a
6.1.2 For adhesives consisting of more than one part, take a
group of specimens measured by a standard test method and
sufficient sample of each part to prepare at least 2 lb (908 g) of
adjusted by modification factors similar to those for strength as
adhesive at the time of test-specimen fabrication.
required by the service environment.
6.1.3 For dry adhesives, take a sample from each lot
4.2 The allowable design stress (or modulus) can be modi-
weighing at least 1 kg (1.1 lb).
fied by one or more modification factors that are appropriate
6.2 Follow the adhesive manufacturer’s specifications for
for the intended-service exposure of the adhesive.
proper packing, mixing, and handling of the sample.
4.3 The modification factors used in these test methods are
6.3 Follow the adhesive manufacturer’s instructions for
durability, permanence, delamination, and creep.
proper use of the adhesive. The information needed will vary
4.3.1 Temperature and moisture are the principal variables for different types of adhesive. Important information may
of both the durability and permanence factors. Chemicals, such include:
as preservatives or fire retardants, may constitute a third 6.3.1 The acceptable moisture-content range for the wood.
element of the durability and permanence factors. These
6.3.2 Complete mixing directions for the adhesive.
factors are shown in Appendix X1. Stress level and time, in 6.3.3 The acceptable range of conditions for adhesive ap-
addition to temperature and moisture, are important elements
plication, such as rate of spread, thickness of wet film, bead
of the creep favor. Chemicals may be important to the creep size, number of coats to be applied, minimum temperature for
factoriftheyplasticizeorotherwisesoftentheadhesive.Cyclic
application, single or double spread, and conditions for drying
gradientsofmoistureandtemperatureareprincipalelementsof where more than one coat is required.
the delamination factor.
6.3.4 The acceptable range of open- and closed-assembly
time over the ambient temperature and humidity range speci-
4.3.2 Modification factors are derived from standard test
methods and specimens under critical-use conditions such as fied.
6.3.5 The acceptable range of curing conditions, including
extreme temperature, moisture, chemical, or stress levels
expect
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