1、Designation: A 1061/A 1061M 09Standard Test Methods forTesting Multi-Wire Steel Strand1This standard is issued under the fixed designation A 1061/A 1061M; the number immediately following the designation indicates theyear of original adoption or, in the case of revision, the year of last revision. A
2、 number in parentheses indicates the year of lastreapproval. A superscript epsilon () indicates an editorial change since the last revision or reapproval.1. Scope1.1 These test methods describe procedures for testing themechanical as well as relaxation properties of multi-wire steelstrand.1.2 These
3、test methods are intended for use in evaluatingspecific strand properties prescribed in specifications for multi-wire steel strand, but they do not quantify acceptance criteriaspecified in the applicable specification for the strand beingtested.1.3 The values stated in either SI units or inch-pound
4、unitsare to be regarded separately as standard. The values stated ineach system may not be exact equivalents; therefore, eachsystem shall be used independently of the other. Combiningvalues from the two systems may result in non-conformancewith the standard.1.4 This standard does not purport to addr
5、ess all of thesafety concerns, if any, associated with its use. It is theresponsibility of the user of this standard to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:2A 370 Test Met
6、hods and Definitions for Mechanical Testingof Steel ProductsE4 Practices for Force Verification of Testing MachinesE83 Practice for Verification and Classification of Exten-someter SystemsE 328 Test Methods for Stress Relaxation for Materials andStructures3. Terminology3.1 Definitions of Terms Speci
7、fic to This Standard:3.1.1 free span, nthe distance between the gripping jawsoccupied by the length of strand to be tested in which the strandis not contacted or detrimentally influenced by the grippingsystem.3.1.2 length of lay, nthe axial distance required to makeone complete revolution of any wir
8、e of a strand.3.1.3 strand, ntwo or more steel wires wound together ina helical form.4. Significance and Use4.1 The mechanical properties of the strand are determinedby a test in which fracture of the specimen occurs in the freespan between the jaws of the testing machine.4.2 Mechanical properties o
9、f the strand will be negativelyaffected if proper care is not taken to prevent damage such assevere bending, abrasion, or nicking of the strand duringsampling.4.3 Premature failure of the test specimens may result ifthere is appreciable notching, cutting, or bending of thespecimen by the gripping de
10、vices of the testing machine.4.4 Errors in testing will result if the wires constituting thestrand are not loaded uniformly.4.5 The mechanical properties of the strand will be materi-ally affected by excessive heating during specimen collectionor preparation.4.6 Gripping difficulties will be minimiz
11、ed by following thesuggested methods of gripping described in Section 7.5. Apparatus5.1 Tensile test machine calibrated in accordance withPractices E4.5.2 Class B-1 extensometer as described in Practice E83.5.3 Class D extensometer as described in Practice E83.6. Sampling6.1 Unless otherwise specifi
12、ed in the material standard, testspecimens shall be taken from the finished product prior topackaging. The number of test specimen(s) shall be taken asspecified in the applicable specification for the material strandbeing tested.7. Gripping Devices7.1 Due to inherent physical characteristics of indi
13、vidualtesting machines, it is not practical to recommend a universalgripping procedure that is suitable for all testing machines.Therefore, it is necessary to determine which of the methods ofgripping described in 7.1.1-7.1.5 is most suitable for the testingequipment available. The gripping devices
14、shall be designedsuch that during testing the load is distributed along the entire1These test methods are under the jurisdiction of ASTM Committee A01 onSteel, Stainless Steel and Related Alloys and is the direct responsibility ofSubcommittee A01.05 on Steel Reinforcement.Current edition approved Ju
15、ne 1, 2009. Published June 2009.2For 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 International
16、, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.length of the grips. The effective gripping length as a minimumshall be equal to the length of lay of the strand.7.1.1 Standard V-Grips with Serrated Teeth (Note 1).7.1.2 Standard V-Grips with Serrated Teeth (Note
17、1), UsingCushioning MaterialIn this method, material is placed be-tween the grips and the specimen to minimize the notchingeffect of the teeth. Materials that have been used include, butare not limited to lead foil, aluminum foil, carborundum cloth,and brass shims. The type and thickness of material
18、 required isdependent on the shape, condition, and coarseness of the teeth.7.1.3 Special Grips with Smooth, Semi-Cylindrical Grooves(Note 2)The grips can be used as is or in conjunction with anabrasive slurry applied to the grooves of the grips and thegripped portion of the specimen to prevent slipp
19、age. The slurryconsists of abrasive such as Grade 3-F aluminum oxide and acarrier such as water or glycerin.7.1.4 Dead-End Eye SplicesThese devices are availablein sizes designed to fit each size of strand to be tested.7.1.5 Chucking DevicesUse of chucking devices of thetype generally used for apply
20、ing tension to strands in castingbeds is not recommended for testing purposes.NOTE 1The number of teeth should be 15 to 30 per inch 25 mm.NOTE 2The radius of curvature of the grooves should be approxi-mately the same as the radius of the strand being tested. To prevent the twogrips from closing tigh
21、tly when the specimen is in place, the grooveshould be located132 in. 0.79 mm above the flat face of the grip.8. Speed of Testing8.1 The speed of testing shall not be greater than that atwhich load and strain readings can be made accurately. Referto speed of testing in Test MethodsA 370 on TestingAp
22、paratusand Operations.9. Test Procedures9.1 Yield StrengthUse a Class B-1 extensometer (Note 3)as described in Practice E83. Apply an initial load of 10 % ofthe required minimum breaking strength to the specimen,attach the extensometer and adjust it to a reading of 0.1 % ofgage length. Increase the
23、load until the extensometer indicatesan extension of 1 %. Record the load for this extension as theyield strength. The extensometer may be removed from thespecimen after the yield strength has been determined. Dataacquisition software is available that allows automatic collec-tion of yield strength
24、data. (See Note 4.)9.2 ElongationUse a Class D extensometer (Note 3)asdescribed in Practice E83, having a gage length of not lessthan 24 in. 600 mm (Note 3). Apply an initial load of 10 % ofthe required minimum breaking strength to the specimen.Attach the extensometer and adjust it to a zero reading
25、.Increase the load until the extensometer indicates an elongationvalue equal to or greater than the minimum specified in theapplicable specification. It is not necessary to determine thetotal percent elongation at maximum force.9.2.1 In practice, the total percent elongation at maximumforce may be d
26、etermined by measuring the movement betweenthe gripping jaws using a linear dial gage or a linear precisionruler. After the yield strength is achieved loading is stoppedand the extensometer removed. The distance between thegripping jaws is measured. Loading is then continued untilfailure of one or m
27、ore wires. The distance between the jaws isagain measured. The total percent elongation is calculated as apercentage of the change in the jaw-to-jaw distance and addingthis value to the value obtained by the extensometer. In anycase, the total elongation value is determined when one ormore wires fai
28、l during the test. (See Note 5.)9.3 Breaking StrengthContinue loading to determine themaximum load at which one or more wires of the strand arefractured. Record this load as the breaking strength of thestrand. (See Note 6.)NOTE 3The yield-strength extensometer and the elongation exten-someter may be
29、 the same instrument or two separate instruments. It isadvisable to use two separate instruments since the more sensitiveyield-strength extensometer, which could be damaged when the strandfractures, may be removed following the determination of yield strength.The elongation extensometer may be const
30、ructed with less sensitive partsor be constructed in such a way that minimal damage would result iffracture occurs while the extensometer is attached to the specimen.NOTE 4Automatic Yield Strength Data CollectionComputerizeddata collection systems can be set to replicate the yield strength testmetho
31、d defined in 9.1. When using a computerized system, the strain isautomatically set to 0.1 % of gage length at 10 % load even if theextensometer is attached to the specimen prior to the initial load. Asadditional load is applied, the computer will project a line connecting twospecified load points al
32、ong the proportional length of the stress-straincurve back to the strain axis (x-axis). Given the consistent elastic modulusinherent in PC strand, this line will intercept the stress (load) and strainaxes at the zero-point for both. The 1 % elongation under load (EUL)point is identified by adding 1
33、% strain to the projected zero-point. This1 % strain value is then paired with the corresponding stress (or load) toidentify the 1 % EUL yield strength.NOTE 5Material for which specimens break outside the extensometeror in the jaws while measuring yield strength or elongation and yet meetthe minimum
34、 specified values is considered to meet the mechanicalproperty requirements for yield strength and elongation of the applicablespecification, regardless of the gripping method used. Test of specimensthat break outside of the extensometer gage length or in the gripping jawsand do not meet the minimum
35、 specified values is an invalid test. Theresults are to be discarded and the test repeated on a new specimen.Material for which specimens break within the extensometer gage lengthor outside the gripping jaws and do not meet the minimum specifiedvalues is subject to retest as provided in the section
36、on Rejection andRetesting in the applicable specification.NOTE 6Material for which specimens break in the gripping jawswhile measuring breaking load and yet meet the minimum specified valuesare considered as meeting the mechanical property requirement forbreaking load of the product specification, r
37、egardless of gripping methodused. Test of specimens that break in the gripping jaws and do not meetthe minimum specified values is an invalid test. The results are to bediscarded and the test shall be repeated on a new specimen. Material forwhich specimens break outside the gripping jaws and do not
38、meet theminimum specified values are subject to retesting as provided in thesection on Rejection and Retesting in the applicable specification.9.4 Relaxation PropertiesIn addition to the general testprocedures described in Test Methods E 328, Test Method A,the following specific procedures for testi
39、ng steel strand shallbe followed:9.4.1 The temperature of the test specimen shall be main-tained at 68 6 3.5F 20 6 2C.9.4.2 The test specimen shall not be subjected to loadingprior to the relaxation test.A 1061/A 1061M 0929.4.3 The initial load shall be applied uniformly over aperiod of not less tha
40、n 3 min and not more than 5 min. Thegage length shall be maintained constant.9.4.4 Load-relaxation readings shall commence 1 min afterapplication of the total load.9.4.5 Over-stressing of the test specimen during the loadingoperation shall not be permitted.9.4.6 The duration of the test shall be 100
41、0 h or a shorterperiod of at least 200 h, provided it can be shown by recordsthat an extrapolation of the shorter period test results to 1000 hwill provide similar relaxation values as the full 1000 h test.9.4.7 The test gage length shall be at least 60 times thenominal diameter. If this gage length
42、 exceeds the capacity ofthe extensometer or testing machine, then it is permitted tosubstitute a gage length of 40 times the nominal stranddiameter.10. Report10.1 A report shall be prepared with the following informa-tion included as a minimum:10.1.1 Strand size and grade,10.1.2 Manufacturer of stra
43、nd,10.1.3 Date of test,10.1.4 Test Number, and10.1.5 Mechanical properties determined in accordancewith applicable specification.11. Precision and Bias11.1 No statement is made on the precision and bias of thesetest methods since the test results indicate only whether thereis conformance to given cr
44、iteria and no generally acceptedmethod for determining precision of these test methods iscurrently available. General guidelines provided herein for thespecimens, instrumentation, and procedures make the resultsintractable to calculation of meaningful values by statisticalanalysis for precision at t
45、his time.11.2 BiasSince there is no accepted reference materialsuitable for determining the bias in this test method, nostatement on bias is made.12. Keywords12.1 multi-wire steel strand; strand-gripping devices; strandpropertiesASTM International takes no position respecting the validity of any pat
46、ent rights asserted in connection with any item mentionedin this standard. Users of this standard are expressly advised that determination of the validity of any such patent rights, and the riskof infringement of such rights, are entirely their own responsibility.This standard is subject to revision
47、 at any time by the responsible technical committee and must be reviewed every five years andif not revised, either reapproved or withdrawn. Your comments are invited either for revision of this standard or for additional standardsand should be addressed to ASTM International Headquarters. Your comm
48、ents will receive careful consideration at a meeting of theresponsible technical committee, which you may attend. If you feel that your comments have not received a fair hearing you shouldmake your views known to the ASTM Committee on Standards, at the address shown below.This standard is copyrighte
49、d by ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959,United States. Individual reprints (single or multiple copies) of this standard may be obtained by contacting ASTM at the aboveaddress or at 610-832-9585 (phone), 610-832-9555 (fax), or serviceastm.org (e-mail); or through the ASTM website(www.astm.org).A 1061/A 1061M 093
