ASTM D5574-94(2012)

Standard Test Methods for Establishing Allowable Mechanical Properties of Wood-Bonding Adhesives for Design of Structural Joints

SIGNIFICANCE AND USE
Safe and reliable mechanical properties for adhesives are necessary to achieve the full structural benefit of adhesives in bonded structural components and assemblies.
An adhesive's properties exhibit a natural variation or distribution of values. The allowable design stress for an adhesive must be adjusted to allow for variability and environmental effects to ensure human safety and prevent premature failure of costly structures.
Modification factors can be applied to the allowable design stress by the design engineer as deemed appropriate for the expected service conditions of the adhesive, or in accordance with the requirements of a building code.
The allowable properties developed under these methods apply only to the actual adhesive formulation tested and analyzed.  
The allowable properties developed for a given adhesive shall apply only to adhesive bondlines with thicknesses in the range for which data is available.
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 Practice 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 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.

General Information

• Status: Historical
• Publication Date: 31-May-2012
• ICS: 83.180 - Adhesives
• Technical Committee: D14 - Adhesives
• Drafting Committee: D14.70 - Construction Adhesives

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: D5574 − 94 (Reapproved 2012)
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 D5574; 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 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 Factorsfordurability,permanence,andcreepderivedby
methods are modeled after Practice D245.
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 The values stated in inch-pound units are to be regarded
adherends (hard maple, Acer saccharum, Marsh.). The adhe-
as standard. The values given in parentheses are mathematical
sives so tested may actually have shear or tensile allowable
conversions to SI units that are provided for information only
stresses exceeding the wood, but the determined allowable
and are not considered standard.
design stress levels are limited (upper bounded) by the wood in
these test methods. If a wood other than hard maple is used for
2. Referenced Documents
testing the adhesive, then the allowable strengths are upper
bounded by the properties of that particular wood.
2.1 ASTM Standards:
D245 Practice for Establishing Structural Grades and Re-
1.4 The strength properties are determined by standard
lated Allowable Properties for Visually Graded Lumber
ASTM test methods. As a result, only procedural variations
D897 Test Method for Tensile Properties ofAdhesive Bonds
from the standards and special directions for applying the
D905 Test Method for Strength Properties of Adhesive
results are given in these test methods.
Bonds in Shear by Compression Loading
1.5 Time-to-failure data derived from creep-rupture testing
D907 Terminology of Adhesives
(see Test Method D4680) provide a measure of the ultimate
D1101 Test Methods for Integrity of Adhesive Joints in
strength of an adhesive bond as a function of time at various
Structural Laminated Wood Products for Exterior Use
levels of temperature and moisture.
D1151 Practice for Effect of Moisture and Temperature on
1.5.1 With proper caution, useful service life at a given
Adhesive Bonds
shear stress level may be extrapolated from relatively short
D2555 PracticeforEstablishingClearWoodStrengthValues
loading periods.
D2559 Specification for Adhesives for Bonded Structural
Wood Products for Use Under Exterior Exposure Condi-
1.6 The resistance of the adhesive to permanent loss of
tions
properties due to aging (permanence) is assessed by means of
D2915 Practice for Sampling and Data-Analysis for Struc-
strength tests after constant elevated-temperature and moisture
tural Wood and Wood-Based Products
aging of test specimens.
D3931 Test Method for Determining Strength of Gap-Filling
Adhesive Bonds in Shear by Compression Loading
These test methods are under the jurisdiction of ASTM Committee D14 on
Adhesives and are the direct responsibility of Subcommittee D14.70 on Construc-
tion Adhesives. For referenced ASTM standards, visit the ASTM website, www.astm.org, or
Current edition approved June 1, 2012. Published June 2012. Originally contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM
approved in 1994. Last previous edition approved in 2005 as D5574 – 94 (2005). Standards volume information, refer to the standard’s Document Summary page on
DOI: 10.1520/D5574-94R12. the ASTM website.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
D5574 − 94 (2012)
D3983 Test Method for Measuring Strength and Shear 3.2.3 basic shear strength, n—a near minimum value of the
Modulus of Nonrigid Adhesives by the Thick-Adherend shear strength distribution determined as the one-sided lower
Tensile-Lap Specimen confidence interval on the fifth percentile as determined in
D4027 Test Method for Measuring Shear Properties of accordance with 7.1. (See lower 5 % tolerance limit.)
Structural Adhesives by the Modified-Rail Test
3.2.4 basic tensile strength, n—anearminimumvalueofthe
D4502 Test Method for Heat and Moisture Resistance of
tensile strength distribution determined as the one-sided lower
Wood-Adhesive Joints
confidence interval on the fifth percentile as determined in
D4680 Test Method for Creep and Time to Failure of
accordance with 9.1. (See lower 5 % tolerance limit.)
Adhesives in Static Shear by Compression Loading
3.2.5 creep factor, n—for modulus, the monotonic modulus
(Wood-to-Wood)
as a function of loading rate expressed as the decimal fraction
D4896 Guide for Use ofAdhesive-Bonded Single Lap-Joint
of the basic modulus.
Specimen Test Results
IEEE/ASTM SI 10 Standard for Use of the International 3.2.6 creep factor, n—for strength, the estimated 30 year
creep rupture limit as a decimal fraction of the basic strength.
System of Units (SI): The Modern Metric System
3.2.7 delamination factor, n—a pass/fail factor based on the
3. Terminology
percentage of delamination on the end grain of a laminate after
cyclic delamination treatment.
3.1 Definitions:
3.2.7.1 Discussion—The factor is 0 or l: 0 if end-grain
3.1.1 allowable design stress, n—a stress to which a mate-
rial can be subjected under stated service conditions with low delamination is greater than 10 % of total end-grain bondline;
1 if less than 10 % after cyclic soak-dry treatment.
probability of mechanical failure within the design lifetime.
(D4896)
3.2.8 durability factor, n—the average strength under el-
3.1.1.1 Discussion—Allowable design stress is obtained by
evated test conditions expressed as a decimal fraction of the
multiplying the basic stress by a safety factor and possibly one
strength at standard condition.
or more modification factors as required by the intended
3.2.8.1 Discussion—Increases in temperature and moisture
service environment.
level usually lower strength temporarily, as long as the speci-
3.1.2 allowable shear stress, n—in an adhesive-bonded
men is not so weakened that fracture occurs. Decreases in
joint, the allowable design stress for structural joints subjected
temperature and moisture level usually increase strength.
to shear force.
Exceptions occur when increasing the temperature raises the
level of adhesive cure and strength, or decreasing the tempera-
3.1.3 allowable tensile stress, n—in an adhesive-bonded
ture or moisture induces brittleness and stress concentrations.
joint, the allowable design stress for structural joints subjected
to tension force.
3.2.9 lower 5 % nonparametric tolerance limit [NTL],
n—an estimate of the one-sided lower confidence bond on the
3.1.4 creep rupture, n—the fracture of a material resulting
fifth percentile of the strength distribution determined as the
from a sustained stress (or sum of stresses) above the creep
lowest ranked value (fast order statistic) of sample of speci-
rupture limit.
mens from a population.
3.1.4.1 Discussion—The material may experience creep
through the primary, secondary, and tertiary stages of rupture.
3.2.10 lower 5 % parametric tolerance limit [PTL], n—an
estimate of the lower confidence bound on the fifth percentile
3.1.5 creep-rupture limit, n—the stress level below which
creep rupture will not occur within a given time in a specified of the strength distribution calculated as the mean of a sample
minus the sample standard deviation multiplied by a confi-
environment. See creep rupture.
dence level factor.
3.1.6 durability, n—as related to adhesive joints, the endur-
ance of joint strength relative to the required service condi- 3.2.11 lower 5 % tolerance limit, n— an estimate of the
tions. (D907)
one-sided lower confidence bound on the fifth percentile of the
3.1.6.1 Discussion—Service conditions may include water strength distribution of a population of specimens.
and other chemicals, temperature, stress, radiation,
3.2.12 modification factor, n—any external or internal factor
microorganisms, and other environmental factors.
of the service environment that temporarily or permanently
3.1.7 permanence, n—the resistance of an adhesive bond to
alters the strength or stiffness of an adhesive.
deteriorating influences. (D907)
3.2.13 multiaxial stress, n—stress in two or three perpen-
3.1.8 structural adhesive, n—a bonding agent used for
dicular directions, bi- or triaxial stress.
transferring required loads between adherends exposed to
3.2.13.1 Discussion—In most wood structures bonded with
service environments typical for the structure involved. (D907)
structural adhesives, multiaxial stress consists of a shear stress
in the plane of, and tension stress normal to the plane of the
3.2 Definitions of Terms Specific to This Standard:
adhesive layer.
3.2.1 allowable shear modulus, n—the modulus calculated
in accordance with Section 14, that is used for the design of a
3.2.14 permanence factor, n—the estimated residual
structural joint.
strength at 30 years expressed as a decimal fraction of the
original strength at standard conditions.
3.2.2 basic shear modulus, n—the average shear modulus of
30 specimens fabricated and tested in accordance with 13.1. 3.2.14.1 Discussion—This factor accounts for permanent,
D5574 − 94 (2012)
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-
mental effects to ensure human safety and prevent premature
3.2.15 safety factor, n—a reduction factor to account for
failure of costly structures.
uncertainty in establishing an allowable design stress.
3.2.15.1 Discussion—The safety factor accounts for pos-
5.3 Modification factors can be applied to the allowable
sible differences between laboratory and end-use conditions,
design stress by the design engineer as deemed appropriate for
differences in adhesive production lots, bonding variables, and
the expected service conditions of the adhesive, or in accor-
the assumption that there is no interaction between modifica-
dance with the requirements of a building code.
tion factors.
5.4 The allowable properties developed under these meth-
ods apply only to the actual adhesive formulation tested and
4. Summary of Test Methods
analyzed.
4.1 These test methods are based on a conservative estimate
of the near minimum value of the distribution of adhesive
5.5 Theallowablepropertiesdevelopedforagivenadhesive
strengths measured by a standard test method. The basic
shall apply only to adhesive bondlines with thicknesses in the
strength of the adhesive is the lower 5 % nonparametric
range for which data is available.
tolerance limit obtained by a sample of 59 specimens. The
allowabledesignstressisthebasicstrengthreducedbyasafety
6. Adhesive and Wood Preparation
factor as a minimum:
6.1 Obtain a representative sample from each lot of adhe-
allowable design stress 5 basic strength 3safety factor
sive to be tested.
6.1.1 For liquid or paste adhesives, take a sample from each
The allowable shear modulus is the mean modulus of a
lot of at least 1 qt (446 mL).
group of specimens measured by a standard test method and
6.1.2 For adhesives consisting of more than one part, take a
adjusted by modification factors similar to those for strength as
sufficient sample of each part to prepare at least 2 lb (908 g) of
required by the service environment.
adhesive at the time of test-specimen fabrication.
4.2 The allowable design stress (or modulus) can be modi-
6.1.3 For dry adhesives, take a sample from each lot
fied by one or more modification factors that are appropriate
weighing at least 1 kg (1.1 lb).
for the intended-service exposure of the adhesive.
6.2 Follow the adhesive manufacturer’s specifications for
4.3 The modification factors used in these test methods are
proper packing, mixing, and handling of the sample.
durability, permanence, delamination, and creep.
6.3 Follow the adhesive manufacturer’s instructions for
4.3.1 Temperature and moisture are the principal variables
of both the durability and permanence factors. Chemicals, such proper use of the adhesive. The information needed will vary
for different types of adhesive. Important information may
as preservatives or fire retardants, may constitute a third
element of the durability and permanence factors. These include:
6.3.1 The acceptable moisture-content range for the wood.
factors are shown in Appendix X1. Stress level and time, in
addition to temperature and moisture, are important elements 6.3.2 Complete mixing directions for the adhesive.
of the creep favor. Chemicals may be important to the creep 6.3.3 The acceptable range of conditions for adhesive
factoriftheyplasticizeorotherwisesoftentheadhesive.Cyclic application, such as rate of spread, thickness of wet film, bead
gradientsofmoistureandtemperatureareprincipalelementsof size, number of coats to be applied, minimum temperature for
the delamination factor. application, single or double spread, and conditions for drying
4.3.2 Modification factors are derived from standard test where more than one coat is required.
methods and specimens under critical-use conditions such as
6.3.4 The acceptable range of open- and closed-assembly
extreme temperature, moisture, chemical, or stress levels
time over the ambient temperature and humidity range speci-
expected in service. fied.
6.3.5 The acceptable range of curing conditions, including
4.4 Flow charts showing tests and calculations required to
the pressure to be applied, if any; whether this pressure may be
est
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