1、Designation: D 5574 94 (Reapproved 2005)Standard Test Methods forEstablishing Allowable Mechanical Properties of Wood-Bonding Adhesives for Design of Structural Joints1This standard is issued under the fixed designation D 5574; the number immediately following the designation indicates the year ofor
2、iginal adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon (e) indicates an editorial change since the last revision or reapproval.1. Scope1.1 These test methods cover the principles for establishingallo
3、wable mechanical properties for adhesives that can be usedto design adhesive-bonded joints for structural components andassemblies of wood or wood with other materials. These testmethods are modeled after Test Method D 245.1.2 The properties determined are allowable shear stress,allowable tensile st
4、ress, and allowable shear modulus.1.3 In determination of allowable shear- and tensile-stresslevels, these test methods are limited by the horizontal shearand tension perpendicular-to-the-grain capacity of the woodadherends (hard maple, Acer saccharum, Marsh.). The adhe-sives so tested may actually
5、have shear or tensile allowablestresses exceeding the wood, but the determined allowabledesign stress levels are limited (upper bounded) by the wood inthese test methods. If a wood other than hard maple is used fortesting the adhesive, then the allowable strengths are upperbounded by the properties
6、of that particular wood.1.4 The strength properties are determined by standardASTM test methods. As a result, only procedural variationsfrom the standards and special directions for applying theresults are given in these test methods.1.5 Time-to-failure data derived from creep-rupture testing(see Te
7、st Method D 4680) provide a measure of the ultimatestrength of an adhesive bond as a function of time at variouslevels of temperature and moisture.1.5.1 With proper caution, useful service life at a givenshear stress level may be extrapolated from relatively shortloading periods.1.6 The resistance o
8、f the adhesive to permanent loss ofproperties due to aging (permanence) is assessed by means ofstrength tests after constant elevated-temperature and moistureaging of test specimens.1.6.1 If the subject adhesives will be used to bond wood thathas been treated with a preservative, fire retardant, or
9、any otherchemical to modify its properties, then the permanence of theadhesive shall be tested using wood adherends treated in thesame manner.1.7 Factors for durability, permanence, and creep derived byshear tests and analysis, are assumed to apply to tension(normal-to-the-bond) strength as well.1.8
10、 Requirements for production, inspection, and certifica-tion of adhesives evaluated under these test methods are notincluded.1.9 The values stated in inch-pound units are to be regardedas standard. The values given in parentheses are mathematicalconversions to SI units that are provided for informat
11、ion onlyand are not considered standard.2. Referenced Documents2.1 ASTM Standards:2D 245 Practice for Establishing Structural Grades and Re-lated Allowable Properties for Visually Graded LumberD 897 Test Method for Tensile Properties of AdhesiveBondsD 905 Test Method for Strength Properties of Adhes
12、iveBonds in Shear by Compression LoadingD 907 Terminology of AdhesivesD 1101 Test Methods for Integrity of Adhesive Glue Jointsin Structural Laminated Wood Products for Exterior UseD 1151 Practice for Effect of Moisture and Temperature onAdhesive BondsD 2555 Test Methods for Establishing Clear Wood
13、StrengthValuesD 2559 Specification for Adhesives for Structural Lami-nated Wood Products for Use Under Exterior (Wet Use)Exposure ConditionsD 2915 Practice for Evaluating Allowable Properties forGrades of Structural LumberD 3931 Test Method for Determining Strength of Gap-Filling Adhesive Bonds in S
14、hear by Compression Loading1These test methods are under the jurisdiction of ASTM Committee D14 onAdhesives and are the direct responsibility of Subcommittee D14.70 on Construc-tion Adhesives.Current edition approved April 1, 2005. Published April 2005. Originallyapproved in 1994. Last previous edit
15、ion approved in 1999 as D 557494(1999)e1.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.1Copyright ASTM Inte
16、rnational, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.D 3983 Test Method for Measuring Strength and ShearModulus of Nonrigid Adhesives by the Thick-AdherendTensile-Lap SpecimenD 4027 Test Method for Measuring Shear Properties ofStructural Adhesives by the Mod
17、ified-Rail TestD 4502 Test Method for Heat and Moisture Resistance ofWood-Adhesive JointsD 4680 Test Method for Creep and Time to Failure ofAdhesives in Static Shear by Compression Loading(Wood-to-Wood)D 4896 Guide for Use of Adhesive-Bonded Single Lap-Joint Specimen Test ResultsIEEE/ASTM SI 10 Stan
18、dard for Use of the InternationalSystem of Units (SI): The Modern Metric System3. Terminology3.1 Definitions:3.1.1 allowable design stress, na stress to which a mate-rial can be subjected under stated service conditions with lowprobability of mechanical failure within the design lifetime.(D 4896)3.1
19、.1.1 DiscussionAllowable design stress is obtained bymultiplying the basic stress by a safety factor and possibly oneor more modification factors as required by the intendedservice environment.3.1.2 allowable shear stress, nin an adhesive-bondedjoint, the allowable design stress for structural joint
20、s subjectedto shear force.3.1.3 allowable tensile stress, nin an adhesive-bondedjoint, the allowable design stress for structural joints subjectedto tension force.3.1.4 creep rupture, nthe fracture of a material resultingfrom a sustained stress (or sum of stresses) above the creeprupture limit.3.1.4
21、.1 DiscussionThe material may experience creepthrough the primary, secondary, and tertiary stages of rupture.3.1.5 creep-rupture limit, nthe stress level below whichcreep rupture will not occur within a given time in a specifiedenvironment. See creep rupture.3.1.6 durability, nas related to adhesive
22、 joints, the endur-ance of joint strength relative to the required service condi-tions. (D 907)3.1.6.1 DiscussionService conditions may include waterand other chemicals, temperature, stress, radiation, microor-ganisms, and other environmental factors.3.1.7 permanence, nthe resistance of an adhesive
23、bond todeteriorating influences. (D 907)3.1.8 structural adhesive, na bonding agent used fortransferring required loads between adherends exposed toservice environments typical for the structure involved.(D 907)3.2 Definitions of Terms Specific to This Standard:3.2.1 allowable shear modulus, nthe mo
24、dulus calculatedin accordance with Section 14, that is used for the design of astructural joint.3.2.2 basic shear modulus, nthe average shear modulus of30 specimens fabricated and tested in accordance with 13.1.3.2.3 basic shear strength, na near minimum value of theshear strength distribution deter
25、mined as the one-sided lowerconfidence interval on the fifth percentile as determined inaccordance with 7.1. (See lower 5 % tolerance limit.)3.2.4 basic tensile strength, na near minimum value of thetensile strength distribution determined as the one-sided lowerconfidence interval on the fifth perce
26、ntile as determined inaccordance with 9.1. (See lower 5 % tolerance limit.)3.2.5 creep factor, nfor modulus, the monotonic modulusas a function of loading rate expressed as the decimal fractionof the basic modulus.3.2.6 creep factor, nfor strength, the estimated 30 yearcreep rupture limit as a decim
27、al fraction of the basic strength.3.2.7 delamination factor, na pass/fail factor based on thepercentage of delamination on the end grain of a laminate aftercyclic delamination treatment.3.2.7.1 DiscussionThe factor is 0 or l: 0 if end-graindelamination is greater than 10 % of total end-grain bondlin
28、e;1 if less than 10 % after cyclic soak-dry treatment.3.2.8 durability factor, nthe average strength under el-evated test conditions expressed as a decimal fraction of thestrength at standard condition.3.2.8.1 DiscussionIncreases in temperature and moisturelevel usually lower strength temporarily, a
29、s long as the speci-men is not so weakened that fracture occurs. Decreases intemperature and moisture level usually increase strength.Exceptions occur when increasing the temperature raises thelevel of adhesive cure and strength, or decreasing the tempera-ture or moisture induces brittleness and str
30、ess concentrations.3.2.9 lower 5 % nonparametric tolerance limit NTL,nan estimate of the one-sided lower confidence bond on thefifth percentile of the strength distribution determined as thelowest ranked value (fast order statistic) of sample of speci-mens from a population.3.2.10 lower 5 % parametr
31、ic tolerance limit PTL, nanestimate of the lower confidence bound on the fifth percentileof the strength distribution calculated as the mean of a sampleminus the sample standard deviation multiplied by a confi-dence level factor.3.2.11 lower 5 % tolerance limit, n an estimate of theone-sided lower c
32、onfidence bound on the fifth percentile of thestrength distribution of a population of specimens.3.2.12 modification factor, nany external or internal fac-tor of the service environment that temporarily or permanentlyalters the strength or stiffness of an adhesive.3.2.13 multiaxial stress, nstress i
33、n two or three perpen-dicular directions, bi- or triaxial stress.3.2.13.1 DiscussionIn most wood structures bonded withstructural adhesives, multiaxial stress consists of a shear stressin the plane of, and tension stress normal to the plane of theadhesive layer.3.2.14 permanence factor, nthe estimat
34、ed residualstrength at 30 years expressed as a decimal fraction of theoriginal strength at standard conditions.3.2.14.1 DiscussionThis factor accounts for permanent,usually long-term, changes in strength or modulus due to theeffects of factors such as heat, moisture, chemicals, ultravioletlight, and
35、 biological agents.3.2.15 safety factor, na reduction factor to account foruncertainty in establishing an allowable design stress.D 5574 94 (2005)23.2.15.1 DiscussionThe safety factor accounts for pos-sible differences between laboratory and end-use conditions,differences in adhesive production lots
36、, bonding variables, andthe assumption that there is no interaction between modifica-tion factors.4. Summary of Test Methods4.1 These test methods are based on a conservative estimateof the near minimum value of the distribution of adhesivestrengths measured by a standard test method. The basicstren
37、gth of the adhesive is the lower 5 % nonparametrictolerance limit obtained by a sample of 59 specimens. Theallowable design stress is the basic strength reduced by a safetyfactor as a minimum:allowable design stress 5 basic strength 3 safety factorThe allowable shear modulus is the mean modulus of a
38、group of specimens measured by a standard test method andadjusted by modification factors similar to those for strength asrequired by the service environment.4.2 The allowable design stress (or modulus) can be modi-fied by one or more modification factors that are appropriatefor the intended-service
39、 exposure of the adhesive.4.3 The modification factors used in these test methods aredurability, permanence, delamination, and creep.4.3.1 Temperature and moisture are the principal variablesof both the durability and permanence factors. Chemicals, suchas preservatives or fire retardants, may consti
40、tute a thirdelement of the durability and permanence factors. Thesefactors are shown in Appendix X1. Stress level and time, inaddition to temperature and moisture, are important elementsof the creep favor. Chemicals may be important to the creepfactor if they plasticize or otherwise soften the adhes
41、ive. Cyclicgradients of moisture and temperature are principal elements ofthe delamination factor.4.3.2 Modification factors are derived from standard testmethods and specimens under critical-use conditions such asextreme temperature, moisture, chemical, or stress levelsexpected in service.4.4 Flow
42、charts showing tests and calculations required toestablish allowable shear stress, allowable tensile stress per-pendicular to bond, and allowable shear modulus for a givenadhesive are shown in Appendix X2.NOTE 1The sequence described in the procedure sections of these testmethods are not absolute. T
43、he delamination factor sets a pass/fail criteriafor a given adhesive for exterior wet-use applications. If there is any doubtthat the adhesive will pass the delamination requirement, the user canconduct this test before all others in order to save the expense ofconducting the other tests needlessly.
44、5. Significance and Use5.1 Safe and reliable mechanical properties for adhesivesare necessary to achieve the full structural benefit of adhesivesin bonded structural components and assemblies.5.2 An adhesives properties exhibit a natural variation ordistribution of values. The allowable design stres
45、s for anadhesive must be adjusted to allow for variability and environ-mental effects to ensure human safety and prevent prematurefailure of costly structures.5.3 Modification factors can be applied to the allowabledesign stress by the design engineer as deemed appropriate forthe expected service co
46、nditions of the adhesive, or in accor-dance with the requirements of a building code.5.4 The allowable properties developed under these meth-ods apply only to the actual adhesive formulation tested andanalyzed.5.5 The allowable properties developed for a given adhesiveshall apply only to adhesive bo
47、ndlines with thicknesses in therange for which data is available.6. Adhesive and Wood Preparation6.1 Obtain a representative sample from each lot of adhe-sive to be tested.6.1.1 For liquid or paste adhesives, take a sample from eachlot of at least 1 qt (446 mL).6.1.2 For adhesives consisting of more
48、 than one part, take asufficient sample of each part to prepare at least 2 lb (908 g )of adhesive at the time of test-specimen fabrication.6.1.3 For dry adhesives, take a sample from each lotweighing at least 1 kg (1.1 lb).6.2 Follow the adhesive manufacturers specifications forproper packing, mixin
49、g, and handling of the sample.6.3 Follow the adhesive manufacturers instructions forproper use of the adhesive. The information needed will varyfor different types of adhesive. Important information mayinclude:6.3.1 The acceptable moisture-content range for the wood.6.3.2 Complete mixing directions for the adhesive.6.3.3 The acceptable range of conditions for adhesive ap-plication, such as rate of spread, thickness of wet film, beadsize, number of coats to be applied, minimum temperature forapplication, single or double spread, and conditions for
