1、Designation: D5574 94 (Reapproved 2012)Standard Test Methods forEstablishing Allowable Mechanical Properties of Wood-Bonding Adhesives for Design of Structural Joints1This standard is issued under the fixed designation D5574; the number immediately following the designation indicates the year oforig
2、inal adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.1. Scope1.1 These test methods cover the principles for establishingallowab
3、le 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 Practice D245.1.2 The properties determined are allowable shear stress,allowable tensile stress, a
4、nd 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 have sh
5、ear 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 of that
6、 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 Test Meth
7、od D4680) 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 of the ad
8、hesive 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 any othe
9、rchemical 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 Require
10、ments 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 information only
11、and are not considered standard.2. Referenced Documents2.1 ASTM Standards:2D245 Practice for Establishing Structural Grades and Re-lated Allowable Properties for Visually Graded LumberD897 Test Method for Tensile Properties of AdhesiveBondsD905 Test Method for Strength Properties of AdhesiveBonds in
12、 Shear by Compression LoadingD907 Terminology of AdhesivesD1101 Test Methods for Integrity of Adhesive Joints inStructural Laminated Wood Products for Exterior UseD1151 Practice for Effect of Moisture and Temperature onAdhesive BondsD2555 Practice for Establishing Clear Wood Strength Val-uesD2559 Sp
13、ecification for Adhesives for Bonded StructuralWood Products for Use Under Exterior Exposure Condi-tionsD2915 Practice for Sampling and Data-Analysis for Struc-tural Wood and Wood-Based ProductsD3931 Test Method for Determining Strength of Gap-Filling Adhesive Bonds in Shear by Compression Loading1T
14、hese 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 June 1, 2012. Published June 2012. Originallyapproved in 1994. Last previous edition approved in 2005 as D5574 -
15、 94 (2005).DOI: 10.1520/D5574-94R12.2For 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 Internati
16、onal, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.D3983 Test Method for Measuring Strength and ShearModulus of Nonrigid Adhesives by the Thick-AdherendTensile-Lap SpecimenD4027 Test Method for Measuring Shear Properties ofStructural Adhesives by the Modified-R
17、ail TestD4502 Test Method for Heat and Moisture Resistance ofWood-Adhesive JointsD4680 Test Method for Creep and Time to Failure ofAdhesives in Static Shear by Compression Loading(Wood-to-Wood)D4896 Guide for Use ofAdhesive-Bonded Single Lap-JointSpecimen Test ResultsIEEE/ASTM SI 10 Standard for Use
18、 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.(D4896)3.1.1.1 Discussi
19、onAllowable 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 joints subjectedto
20、 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.3.1.4.1 Discussion
21、The 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 joints, the
22、endur-ance of joint strength relative to the required service condi-tions. (D907)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 bond todeterio
23、rating influences. (D907)3.1.8 structural adhesive, na bonding agent used fortransferring required loads between adherends exposed toservice environments typical for the structure involved.(D907)3.2 Definitions of Terms Specific to This Standard:3.2.1 allowable shear modulus, nthe modulus calculated
24、in 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 determined as the one
25、-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 percentile as determi
26、ned 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 decimal fraction of t
27、he 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 bondline;1 if less than
28、 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, as long as the sp
29、eci-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 stress concentratio
30、ns.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 % parametric tolerance lim
31、it 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 confidence bound
32、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 in two or three p
33、erpen-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 estimated residualstren
34、gth 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 biological agen
35、ts.3.2.15 safety factor, na reduction factor to account foruncertainty in establishing an allowable design stress.D5574 94 (2012)23.2.15.1 DiscussionThe safety factor accounts for pos-sible differences between laboratory and end-use conditions,differences in adhesive production lots, bonding variabl
36、es, 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 basicstrength of the adhesi
37、ve 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 agroup of specimen
38、s 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 exposure of the
39、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 constitute a thirdeleme
40、nt 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 adhesive. Cyclicgradie
41、nts 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 charts showing te
42、sts 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. The delamination f
43、actor 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.5. Significance a
44、nd 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 stress for anadhesive
45、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 conditions of the a
46、dhesive, 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 bondlines with thic
47、knesses 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 than one part, t
48、ake asufficient sample of each part to prepare at least 2 lb (908 g) ofadhesive 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, mixing, and handling of
49、 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 dryingwhere more
