1、Designation: A910/A910M 10Standard Specification forUncoated, Weldless, 2- and 3-Wire Steel Strand forPrestressed Concrete1This standard is issued under the fixed designation A910/A910M; the number immediately following the designation indicates the yearof original adoption or, in the case of revisi
2、on, 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*1.1 This specification covers two types and two grades of 2-and 3-wire, uncoated steel strand for use in
3、pretensioned andposttensioned prestressed concrete construction. The two typesof strand are low-relaxation and stress-relieved (normal-relaxation). Low-relaxation shall be regarded as the standardtype. Stress-relieved (normal-relaxation) strand will not befurnished unless specifically ordered, or by
4、 arrangement be-tween purchaser and supplier. The two grades are 1725 (250)and 1860 (270). Grades 250 and 270 have minimum tensilestrengths of 1725 MPa (250 ksi) and 1860 MPa (270 ksi)respectively, based on the nominal area of the strand.1.2 The values stated in either inch-pound units or SI unitsar
5、e to be regarded as the standard. Within the text, theinch-pound units are shown in parentheses. The values statedin each system are not exact equivalents; therefore, eachsystem must be used independently of the other. Combiningvalues from the two systems may result in nonconformancewith the specifi
6、cation.2. Referenced Documents2.1 ASTM Standards:2A1061/A1061M Test Methods for Testing Multi-Wire SteelStrand2.2 U.S. Military Standards:3MIL-STD-129 Marking for Shipment and StorageMIL-STD-163 Steel Mill Products Preparation for Ship-ment and Storage2.3 Federal Standards:3Fed. Std. No. 123 Marking
7、 for Shipments (Civil Agencies)3. Terminology3.1 Definitions of Terms Specific to This Standard:3.1.1 strand, nall strands shall be comprised of either twowires or three wires helically wound around each other; theyshall have a uniform pitch of not less than 12 nor more than 16times the nominal diam
8、eter of the strand.3.1.2 DiscussionThe direction of lay may be either rightor left hand; however, strands of different lays shall not bespliced together.4. Ordering Information4.1 It shall be the responsibility of the purchaser to specifyall requirements that are necessary for material ordered to th
9、isspecification. Such requirements shall include, but are notlimited to, the following:4.1.1 Quantity (meters feet),4.1.2 Diameter of strand (Section 7),4.1.3 Number of wires (2 or 3),4.1.4 Grade of strand (see 1.1 and Table 1 and Table 2),4.1.5 Type of strand (see 1.1 and Table 2),4.1.6 Packaging (
10、Section 14),4.1.7 ASTM designation and year of issue, and4.1.8 Special requirements, if any.NOTE 1A typical ordering description is as follows: 100 000 m(325 000 ft) of 6.2 mm (0.244 in.) diameter, three wire, Grade 1860 MPa(270 ksi), low-relaxation strand in 10 000 m (32 500 ft) reelless packsconfo
11、rming to ASTM A910/A910MXX.5. Materials and Manufacture5.1 Base MetalThe base metal shall be carbon steel ofsuch quality that when drawn to wire, fabricated into strandand then thermally treated, it shall have the properties andcharacteristics prescribed in this specification.5.2 WireThe wire from w
12、hich the strand is to be fabri-cated shall be round and have a dry-drawn finish.NOTE 2This product is a composite of two or three wires and isproduced to mechanical properties only, of which the chemical composi-tion of all wires or any individual wire is not pertinent to this application,and heat i
13、dentity is not necessarily maintained. It is possible that wire1This specification is under the jurisdiction of ASTM Committee A01 on Steel,Stainless Steel and Related Alloys and is the direct responsibility of SubcommitteeA01.05 on Steel Reinforcement.Current edition approved April 1, 2010. Publish
14、ed July 2010. Originallyapproved in 1992. Last previous edition approved in 2005 as A910/A910M 05.DOI: 10.1520/A0910_A0910M-10.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information
15、, refer to the standards Document Summary page onthe ASTM website.3Available from U.S. Government Printing Office Superintendent of Documents,732 N. Capitol St., NW, Mail Stop: SDE, Washington, DC 20401, http:/www.access.gpo.gov.1*A Summary of Changes section appears at the end of this standard.Copy
16、right ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.from more than one heat may be used in the manufacture of a reel or pack.Traceability is based on pack identity as maintained and reported by themanufacturer.5.3 TreatmentAfter stranding, lo
17、w-relaxation strand shallbe subjected to a continuous thermo-mechanical treatment toproduce the prescribed mechanical properties. For stress-relieved (normal-relaxation) strand, only thermal treatment isnecessary. Temper colors that result from the stress-relievingoperation are considered normal for
18、 the finished appearance ofthis strand.6. Mechanical Properties6.1 Tests for mechanical properties shall be conducted inaccordance with Test Methods A1061/A1061M. Low-relaxation strand shall also be tested as prescribed in TestMethods A1061/A1061M.6.2 Breaking StrengthThe breaking strength of the fi
19、n-ished strand shall conform to the requirements prescribed inTable 1.6.3 Yield StrengthYield strength in kN (lbs) shall bemeasured at 1 % extension under load. The minimum yieldstrength shall be 90 % for low-relaxation strand and 85 % forstress-relieved (normal relaxation) strand of the breakingstr
20、ength listed in Table 1. Initial loads for the test and minimumyield strengths are listed in Table 2.6.4 ElongationThe total elongation under load shall notbe less than 3.5 %. It shall be permissable to determine the totalelongation value by adding to the 1.0 % yield extension thepercent extension o
21、r movement between the jaws gripping thestrand after yield determination. The percent is calculated onthe new base length of jaw-to-jaw distance.TABLE 1 Breaking Strength RequirementsDescription and Diameter of StrandBreaking Strength ofStrandSteel Area ofStrandWeight ofStrandin. mmDescriptionNomina
22、lDiameterDescriptionNominalDiameterlbf kN in.2mm2lbs/1000 ft kg/1000 mGRADE 250 (1725 MPa)2 3 0.114 0.228 2 3 2.90 5.8 5000 22.2 0.020 13.2 69.9 104.03 3 0.089 0.189 3 3 2.25 4.8 4750 21.1 0.019 12.0 63.3 94.23 3 0.095 0.205 3 3 2.40 5.2 5250 23.4 0.021 13.6 71.9 107.03 3 0.114 0.244 3 3 2.90 6.2 77
23、50 34.5 0.031 19.8 104.0 155.03 3 0.118 0.256 3 3 3.00 6.5 8250 36.7 0.033 21.3 112.0 167.03 3 0.138 0.295 3 3 3.50 7.5 11 250 50.0 0.045 29.0 153.0 228.03 3 0.158 0.340 3 3 4.00 8.6 14 500 64.5 0.058 37.4 200.6 298.4GRADE 270 (1860 MPa)2 3 0.114 0.228 2 3 2.90 5.8 5400 24.0 0.020 13.2 69.9 104.03 3
24、 0.089 0.189 3 3 2.25 4.8 5130 22.8 0.019 12.0 63.3 94.23 3 0.095 0.205 3 3 2.40 5.2 5670 25.2 0.021 13.6 71.9 107.03 3 0.114 0.244 3 3 2.90 6.2 8370 37.2 0.031 19.8 104.0 155.03 3 0.118 0.256 3 3 3.00 6.5 8910 39.6 0.033 21.3 112.0 167.03 3 0.138 0.295 3 3 3.50 7.5 12 150 54.0 0.045 29.0 153.0 228.
25、03 3 0.158 0.340 3 3 4.00 8.6 15 660 69.7 0.058 37.4 200.6 298.4TABLE 2 Yield Strength RequirementsDescription and Diameter of StrandInitial LoadMinimum Load at 1 % Extensionin. mmStress-Relieved(Normal Relaxation)Low RelaxationDescriptionNominalDiameterDescriptionNominalDiameterlbf kN lbf kN lbf kN
26、GRADE 250 (1725 MPa)2 3 0.114 0.228 2 3 2.90 5.8 500 2.2 4250 18.9 4500 20.03 3 0.089 0.189 3 3 2.25 4.8 475 2.1 4038 18.0 4275 19.03 3 0.095 0.205 3 3 2.40 5.2 525 2.3 4463 20.0 4725 21.03 3 0.114 0.244 3 3 2.90 6.2 775 3.5 6588 29.3 6975 31.03 3 0.118 0.256 3 3 3.00 6.5 825 3.7 7013 32.2 7425 33.0
27、3 3 0.138 0.295 3 3 3.50 7.5 1250 5.0 9563 42.5 10 125 45.03 3 0.158 0.340 3 3 4.00 8.5 1450 6.5 12 325 54.8 13 050 11.7GRADE 270 (1860 MPa)2 3 0.114 0.228 2 3 2.90 5.8 540 2.4 4590 20.4 4860 21.63 3 0.089 0.189 3 3 2.25 4.8 513 2.3 4360 19.4 4617 20.53 3 0.095 0.205 3 3 2.40 5.2 567 2.5 4820 21.4 5
28、103 22.73 3 0.114 0.244 3 3 2.90 6.2 837 3.7 7115 31.6 7533 33.53 3 0.118 0.256 3 3 3.00 6.5 891 4.0 7574 33.7 8019 36.03 3 0.138 0.295 3 3 3.50 7.5 125 5.4 10 328 45.9 10 125 45.03 3 0.158 0.340 3 3 4.00 8.6 566 7.0 13 311 59.2 14 094 62.7A910/A910M 1026.5 Relaxation PropertiesLow-relaxation strand
29、 shallhave relaxation losses of not more than 2.5 % when initiallyloaded to 70 % of specified minimum breaking strength or notmore than 3.5 % when loaded to 80 % of specified minimumbreaking strength of the strand after 1000 h tested underconditions listed in 6.5.1 through 6.5.7.6.5.1 If required, r
30、elaxation evidence shall be provided fromthe manufacturers records of tests on similarly dimensionedstrand of the same grade.6.5.2 The temperature of the test specimen shall be main-tained at 20 6 2C (68 6 3.5F).6.5.3 The test specimen shall not be subjected to loadingprior to the relaxation test.6.
31、5.4 The initial load shall be applied uniformly over aperiod of not less than 3 min and not more than 5 min and thegage length shall be maintained constant; load-relaxationreadings shall commence 1 min after application of the totalload.6.5.5 Overstressing of the test specimen during the loadingoper
32、ation shall not be permitted.6.5.6 The duration of the test shall be 1000 h or a shortercomputed period extrapolated to 1000 h that can be shown byrecords to provide similar relaxation values.6.5.7 The test gage length shall be at least 60 times thenominal diameter of the strand. If this gage length
33、 exceeds thecapacity of the extensometer or the testing machine, then it ispermitted to substitute a minimum gage length of 40 times thenominal diameter of the strand.7. Dimensions and Permissible Variations7.1 The size of the finished strand shall be expressed as thediameter of the strand as decima
34、l fraction of an inch.7.2 Variations in individual wire diameters shall not because for rejection provided that the other requirements of thisspecification are met.7.3 Specially-Dimensioned Strand:7.3.1 It shall be permitted to furnish, under this specifica-tion, strands with nominal diameters that
35、are different thanthose listed in Table 1 and Table 2. The breaking strength shallbe defined, and the yield strength, as defined in 6.3, shall not beless than 90 % and 85 % of the specified minimum breakingstrength for low-relaxation and stress-relieved (normal-relaxation) strand, respectively. All
36、other requirements shallapply.7.4 Permissible Variations in Diameter:7.4.1 All Grade 1725 (250) strand shall conform to a sizetolerance of 60.41 mm (60.016 in.) from the diametermeasured across the crowns of the wires (2-wire strand only).For 3-wire strand, the diameter is that diameter of a circlew
37、hich can be tangentially circumscribed around the 3 wires.This can be confirmed by comparing the individual wirediameters in the strand to those listed in Table 1 and Table 2.7.4.2 All Grade 1860 (270) strand shall conform to a sizetolerance of +0.66 mm, 0.15 mm (+0.026 in., 0.006 in.)from the nomin
38、al diameter measured across the crowns of thewires (2-wire strand only). For 3-wire strand, the nominaldiameter is that diameter of a circle which can be tangentiallycircumscribed around the 3 wires. This can be confirmed bycomparing the individual wire diameters in the strand to thoselisted in Tabl
39、e 1 and Table 2.8. Workmanship, Finish and Appearance8.1 Joints:8.1.1 There shall be no strand splices in any length of thecompleted strand.8.1.2 There shall be no wire welds made in the finishedstrands. During manufacturing of individual wires for strand-ing, welding is permitted only prior to or a
40、t the size of the lastthermal treatment (for example, patenting or control cooling).There shall be no welds in the wire after it has been drawnthrough the first die in wire drawing.8.2 The finished strand shall be uniform in diameter andshall be free of imperfections not consistent with good com-mer
41、cial stranding practice.8.3 When the strand is cut without seizings, the wire shallnot fly out of position. If any wire flies out of position and canbe replaced by hand, the strand will be considered satisfactory.8.4 The strand shall not be oiled or greased. Slight rusting,provided it is not suffici
42、ent to cause pits visible to the unaidedeye, shall not be cause for rejection.9. Sampling9.1 Test specimens cut from either end of the strand packageare permitted.10. Number of Tests10.1 One specimen for test shall be taken from each 18-Mg(20-ton) production lot of finished strand, and tested forbre
43、aking strength, yield strength, and elongation.11. Inspection11.1 If outside inspection is required, the manufacturer shallafford the inspector representing the purchaser all reasonablefacilities to satisfy that the material is being furnished inaccordance with this specification. All tests and insp
44、ectionsshall be made at the place of manufacture prior to shipment,unless otherwise agreed upon at the time of purchase, and shallbe so conducted as not to interfere unnecessarily with theoperation of the works.NOTE 3The purchaser should state at the time of order whetheroutside inspection is requir
45、ed or waived.12. Rejection and Retesting12.1 Failure of any test specimen to comply with therequirements of the specification shall constitute grounds forrejection of the lot represented by the specimen.12.2 If any specimen being tested for breaking strength,yield strength, elongation, or stress-rel
46、axation results in valuesoutside the specified limits, two additional tests shall be madeon specimens of strand from the same reel. If failure occurs ineither of these tests, the strand shall be rejected.12.3 It shall be permissable to resubmit the lot for inspec-tion by testing a specimen from each
47、 reel or pack and sortingout nonconforming material.A910/A910M 10313. Certification13.1 If outside inspection is waived, a manufacturers cer-tification that the material has been tested in accordance withand meets the requirements of this specification shall be thebasis of acceptance of the material
48、. The certification shallinclude the specification number, year-date of issue, andrevision letter, if any.13.2 The manufacturer shall, when requested in the order,furnish a representative load-elongation curve for each size andgrade of strand shipped.13.3 When the modulus of elasticity of a 2- or 3-
49、wire strandis provided, the cross-sectional area used to compute themodulus shall also be provided. The area provided in thecertification shall be the area used to calculate the modulus ofelasticity.13.4 A material test report, certification or inspection, orsimilar document printed from or used in electronic form froman electronic data interchange (EDI) transmission shall beregarded as having the same validity as a counterpart printed inthe certifiers facility. The content of the EDI transmitteddocument must meet the requirements of the invoked ASTMstandard
