1、Designation: A881/A881M 10Standard Specification forSteel Wire, Indented, Low-Relaxation for PrestressedConcrete Railroad Ties1This standard is issued under the fixed designation A881/A881M; the number immediately following the designation indicates the yearof original adoption or, in the case of re
2、vision, 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 uncoated, indented, low-relaxation steel wire for use as prestressing t
3、endons in concreterailroad ties.1.2 The values stated in either inch-pound units or SI unitsare to be regarded separately as standard. Within the text, theSI units are shown in brackets. The values stated in eachsystem may not be exact equivalents; therefore, each systemshall be used independently o
4、f the other. Combining valuesfrom the two systems may result in non-conformance with thestandard.2. Referenced Documents2.1 ASTM Standards:2A370 Test Methods and Definitions for Mechanical Testingof Steel ProductsA421/A421M Specification for Uncoated Stress-RelievedSteel Wire for Prestressed Concret
5、eA700 Practices for Packaging, Marking, and Loading Meth-ods for Steel Products for ShipmentE328 Test Methods for Stress Relaxation for Materials andStructures2.2 U.S. Military Standards:3MIL-STD-129 Marking for Shipment and Storage2.3 U.S. Federal Standard:3Fed. Std. No. 123 Marking for Shipment (C
6、ivil Agencies)3. Terminology3.1 Definitions of Terms Specific to This Standard:3.1.1 indented steel wire for railroad ties, nindented,cold-drawn, uncoated, low-relaxation wire intended for use asprestressing tendons in concrete railroad ties, the wire surfacehaving indentations that reduce longitudi
7、nal movement of thewire while also providing consistent prestress transfer length.3.1.2 low-relaxation wire, nindented cold-drawn wire,straightened, that receives a suitable continuous thermo-mechanical treatment as the last operation to produce theproperties listed.4. Ordering Information4.1 It sha
8、ll be the responsibility of the purchaser to specifyall requirements that are necessary for material ordered to thisspecification. Such requirements shall include, but are notlimited to, the following:4.1.1 Quantity (weight mass),4.1.2 Name of material (indented, low-relaxation steel wirefor prestre
9、ssed concrete railroad ties),4.1.3 Required minimum tensile strength (see Table 1),4.1.4 Nominal diameter,4.1.5 Packaging,4.1.6 ASTM designation and year of issue, and4.1.7 Special requirements (such as, indentation sidewallangle or outside inspection), if any.5. Materials and Manufacture5.1 The ste
10、el shall be made by the electric-arc furnace,basic-oxygen, or open-hearth process.5.2 The base metal shall be carbon steel of such quality thatwhen drawn to wire, indented, and then thermo-mechanicallytreated, shall have the properties and characteristics prescribedin this specification.6. Mechanica
11、l Property Requirements6.1 GeneralIndented wire shall be supplied in coils,packs, or spools to the specified mechanical properties in Table1. It shall be permissible to furnish diameters of wire not1This specification is under the jurisdiction of ASTM Committee A01 on Steel,Stainless Steel and Relat
12、ed Alloys and is the direct responsibility of SubcommitteeA01.05 on Steel Reinforcement.Current edition approved Dec. 1, 2010. Published January 2011. Originallyapproved in 1990. Last previous edition approved in 2005 as A881/A881M 05.DOI: 10.1520/A0881_A0881M-10.2For referenced ASTM standards, visi
13、t 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.3Available from Standardization Documents Order Desk, DODSSP, Bldg. 4,Section D, 700 Robbins Ave.
14、, Philadelphia, PA 19111-5098, http:/dodssp.daps.dla.mil.1*A Summary of Changes section appears at the end of this standard.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.specifically itemized in this specification, provided that the
15、strength is defined and they conform otherwise to the require-ments of this specification.6.2 Tensile StrengthThe minimum tensile strength of theindented wire shall conform to the requirements of Table 1.Other values of tensile strength and nominal diameters can bespecified if shown by test that the
16、 strength exceeds thatspecified. The tension test shall be made in accordance withTest Methods A370.6.3 Load at 1 % ExtensionThe load at 1 % extension shallbe at least 90 % of the minimum specified tensile strengthwhen tested in accordance with Test Methods A370.6.4 ElongationThe percent elongation
17、after fracture on a10-in. 250-mm gage length shall be 3.0 % minimum.6.5 Bend TestA 90 degree bend test (see Fig. 1) around apin six times the nominal diameter of the wire shall beperformed once per pack/coil for each row of indentations,with the centerline of the row of indentations located at theou
18、tside of the bend. The wire shall be bent at a uniform rate,with the duration of test to be between 10 and 30 seconds. Thebend location along the axis of the wire specimen shall berandom and three locations shall be tested along the specimen,for a total of nine bends per test. Each bend shall be ins
19、pectedafter testing to ensure no cracking or breaking occurred.6.6 RelaxationRelaxation properties shall be provided atleast annually from records of tests on finished wire.Additionalrelaxation tests shall be conducted if there is a change in rawrod supply or type. Tests to satisfy this requirement
20、shallcomply with the conditions of Supplementary Requirement S6of Specification A421/A421M. The relaxation losses are not toexceed 3.5 % after 1000 hours when tested at an initial load of80 % of minimum tensile strength.7. Requirements for Indentations7.1 IndentationsIndentations shall be in three l
21、ines spaceduniformly around the wire with one line of indentationsinclined in the opposite direction to the other two. Theindentations shall be placed in respect to the axis of the wire sothat the included angle is not less than 45, as shown in Fig. 2.Pitch and shape shall be consistent , with not m
22、ore than 10 %TABLE 1 Tensile Strength RequirementsNominalDiameterTensileStrengthNominalAreaANominal WeightMass, lb/1000 ftg/min. mm lbf kN in.2mm20.198 5.03 7230 32.2 0.0308 19.86 104.8 155.90.198 5.03 7700 34.3 0.0308 19.86 104.8 155.90.2094 5.32 9000 39.1 0.0344 22.23 117.1 174.5AThe nominal cross
23、-sectional area is based on the nominal diameter. Theactual average area in in.2mm2 may be calculated by dividing the mass (weight)per linear in. mm of the specimen in lb kg by 0.2836 (weight of 1 in.3of steel)7.850 3 106kg/mm3(mass of 1 mm3of steel). The amount of variation isdependent on the shape
24、 and character of the indentations.FIG. 1 Bend Test ConfigurationA881/A881M 102being malformed in any 2 ft 600 mm length of wire, judgedvisually. Criteria for what constitutes a malformed indentationshall be mutually agreed upon between manufacturer andpurchaser as required.7.2 TypeTwo acceptable ty
25、pes of indented wire are shownin Fig. 2(a) and (b), with dimensions in Table 2.7.3 OptionsOther types of indented wire are permitted byagreement, provided the wire is comparable with the acceptedtypes in mechanical properties and bond with concrete.7.4 Indentation Sidewall AngleThe manufacturer and
26、pur-chaser shall agree upon minimum and maximum indentationsidewall angles (as shown in Fig. 2). The manufacturer shalldemonstrate process controls to meet mutually agreed uponrequirements.NOTE 1Shallow indentation sidewall angles can impart excessiveradial forces into the concrete. Similarly, angle
27、s that are too steep canreduce transfer length to the point of creating excessive bond demand onthe concrete. Depth of indentation, concrete properties at release ofprestress, and wire surface condition are other factors to take intoconsideration when determining min/max allowable indentation sidewa
28、llangles8. Permissible Variation in Dimensions8.1 The diameter as determined by weight mass of theindented wire shall not vary from the nominal diameter bymore than 60.003 in. 60.08 mm. Diameter as determined byweight mass shall be calculated using the weight mass ofany given length of wire and dens
29、ities provided in footnote ofTable 1.8.2 The indented wire shall not be out-of-round by morethan 0.003 in. 0.08 mm. (Measured using a depth gauge byplacing the wire on a flat surface and checking maximum/minimum diameters at the same cross section. Out-of-round isthe difference between maximum and m
30、inimum diametersmeasured.)9. Workmanship, Finish, and Appearance9.1 The wire shall be free of kinks.9.2 The wire shall be furnished in firmly tied coils, packs, orspools and packaged in such a way to prevent rubbing orcollapse during shipment. Each coil, pack, or spool shall be ofone continuous leng
31、th.9.3 There shall be no welds or joints in the finished wire,unless the manufacturer and purchaser mutually agree on awelding process done on wire rod prior to any cold drawingthat results in wire properties that are consistent with theintended use.Any welds or joints made after the initial drawing
32、process shall be removed.9.4 Cast (Curvature)The curvature of the wire shall be 3in. 75 mm maximum offset on a chord 6 ft 1.8 m long.9.5 The wire shall not be oiled or greased and must beessentially free of residual wire-drawing lubricants. Slightrusting, providing it is not sufficient to cause pits
33、 visible to aperson with normal or corrected vision, shall not be cause forrejection.10. Sampling10.1 Unless otherwise agreed upon between the manufac-turer and the purchaser, test specimens shall be taken from eachcoil, pack, or spool in a lot (see Note 2) and tested to determinecompliance with 6.2
34、-6.5 and Sections 7, 8, and 9.FIG. 2 Acceptable Type of Indented WireTABLE 2 Dimensions of IndentationsNOTE 1Indentation sidewall angle shall be measured along the centerline axis of the wire through the center of indentation. Leading and trailingsidewall angles shall be calculated using measured ho
35、rizontal distances and indentation depths.NOTE 2Depth of indentation shall be the average depth of six or more random indentations measured at maximum depth.Nominal Wire Diameter, Depth, a, in. mm Nominal Length, L, Nominal Pitch, P,in. mm in. mm in. mm0.198 5.03 0.005 + 0.001, 0.0020.13 + 0.02, 0.0
36、50.138 6 0.02 3.5 6 0.5 0.217 6 0.02 5.5 6 0.50.2094 5.32 0.0045 6 0.00140.115 6 0.0350.138 6 0.02 3.5 6 0.5 0.215 6 0.011 5.46 6 0.29A881/A881M 103NOTE 2The term “lot” means all the coils, packs, or spools of wire ofthe same nominal wire diameter contained in an individual shippingrelease or shippi
37、ng order.11. Inspection11.1 The purchaser shall state, at the time of order, whetheroutside inspection is required. If outside inspection is required,the manufacturer shall afford the inspector representing thepurchaser all reasonable facilities to satisfy him that thematerial is being furnished in
38、accordance with this specifica-tion. All tests and inspections shall be made at the place ofmanufacture prior to shipment, unless otherwise agreed upon atthe time of purchase, and shall be so conducted withoutunnecessarily interfering with manufacturing operations.12. Rejection12.1 In case a test sp
39、ecimen fails to meet any requirement ofthis specification, two additional tests shall be made onsamples of wire from the same coil, pack, or spool and iffailure occurs in either of these tests, the coil/pack/spool shallbe rejected.12.2 Unless otherwise specified, any rejection based on testsmade in
40、accordance with this specification shall be reported tothe manufacturer within a reasonable length of time.13. Certification13.1 When specified in the purchase order or contract, themanufacturers certification shall be furnished to the purchaserstating that samples representing each lot have been ma
41、nufac-tured, tested, and inspected in accordance with this specifica-tion and the requirements have been met. The certification shallinclude the specification number, year-date of issue, andrevision letter, if any. A report of the test results shall befurnished.13.2 A material test report, certifica
42、te of 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
43、 the invoked ASTMstandard(s) and conform to any existing EDI agreement be-tween the purchaser and the supplier. Notwithstanding theabsence of a signature, the organization submitting the EDItransmission is responsible for the content of the report.NOTE 3The industry definition as invoked here is: ED
44、I is thecomputer-to-computer exchange of business information in a standardformat such as ANSI ASC X12.14. Packaging and Package Marking14.1 The nominal diameter of the indented wire, ASTMspecification designation, and name or mark of the manufac-turer shall be marked on a tag securely attached to e
45、ach bundleof wire.14.2 For Government Procurement OnlyWhen specifiedin the contract or order, and for direct procurement by or directshipment to the U.S. Government, material shall be preserved,packaged, and packed in accordance with the requirements ofPractices A700. Marking for shipment in additio
46、n to require-ments specified in the contract or order, shall be in accordancewith Fed. Std. No. 123 for civil agencies and MIL-STD-129for military agencies.15. Keywords15.1 concrete railroad ties; indented wire; prestressed con-crete; steel wire (tendon)SUMMARY OF CHANGESCommittee A01 has identified
47、 the location of selected changes to this standard since the last issue(A881/A881M 05) that may impact the use of this standard. (Approved Dec. 1, 2010.)(1) Revised the title, sections, tables, and figures throughout.ASTM International takes no position respecting the validity of any patent rights a
48、sserted 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 at any time
49、 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 comments 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 sho
