1、Designation: A881/A881M 10A881/A881M 15Standard 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 t
2、he case of revision, 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 p
3、restressing tendons in concrete railroadties.1.2 The values stated in either inch-pound units or SI units are to be regarded separately as standard. Within the text, the SI unitsare shown in brackets. The values stated in each system may not be exact equivalents; therefore, each system shall be used
4、independently of the other. Combining values from the two systems may result in non-conformance with the standard.2. Referenced Documents2.1 ASTM Standards:2A370 Test Methods and Definitions for Mechanical Testing of Steel ProductsA421/A421M Specification for Stress-Relieved Steel Wire for Prestress
5、ed ConcreteA700 Guide for Packaging, Marking, and Loading Methods for Steel Products for ShipmentE328 Test Methods for Stress Relaxation for Materials and Structures2.2 U.S. Military Standards:3MIL-STD-129 Marking for Shipment and Storage2.3 U.S. Federal Standard:3Fed. Std. No. 123 Marking for Shipm
6、ent (Civil 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 surface having indentations that reduce l
7、ongitudinal movement of the wirewhile also providing consistent prestress transfer length.3.1.2 low-relaxation wire, nindented cold-drawn wire, straightened, that receives a suitable continuous thermo-mechanicaltreatment as the last operation to produce the properties listed.4. Ordering Information4
8、.1 It shall be the responsibility of the purchaser to specify all requirements that are necessary for material ordered to thisspecification. Such requirements shall include, but are not limited to, the following:4.1.1 Quantity (weight mass),4.1.2 Name of material (indented, low-relaxation steel wire
9、 for prestressed 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, and1 This specification is under the jurisdiction ofASTM Committee A01 on Steel, Stainless Steel and RelatedAlloys and is th
10、e direct responsibility of Subcommittee A01.05on Steel Reinforcement.Current edition approved Dec. 1, 2010Nov. 1, 2015. Published January 2011December 2015. Originally approved in 1990. Last previous edition approved in 20052010as A881/A881M 05.A881/A881M 10. DOI: 10.1520/A0881_A0881M-10.10.1520/A08
11、81_A0881M-15.2 For referencedASTM standards, visit theASTM website, www.astm.org, or contactASTM Customer Service at serviceastm.org. For Annual Book of ASTM Standardsvolume information, refer to the standards Document Summary page on the ASTM website.3 Available from Standardization Documents Order
12、 Desk, DODSSP, Bldg. 4, Section D, 700 Robbins Ave., Philadelphia, PA 19111-5098, http:/dodssp.daps.dla.mil.This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication of what changes have been made to the previous version. Becauseit may not be te
13、chnically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current versionof the standard as published by ASTM is to be considered the official document.*A Summary of Changes section appears at the end of th
14、is standardCopyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States14.1.7 Special requirements (such as, indentation sidewall angle or outside inspection), if any.5. Materials and Manufacture5.1 The steel shall be made by the electric-arc furn
15、ace, basic-oxygen, or open-hearth any commercially accepted process.5.2 The base metal shall be carbon steel of such quality that when drawn to wire, indented, and then thermo-mechanicallytreated, shall have the properties and characteristics prescribed in this specification.6. Mechanical Property R
16、equirements6.1 GeneralIndented wire shall be supplied in coils, packs, or spools to the specified mechanical properties in Table 1. It shallbe permissible to furnish diameters of wire not specifically itemized in this specification, provided that the strength is defined andthey conform otherwise to
17、the requirements of this specification.6.2 Tensile StrengthThe minimum tensile strength of the indented wire shall conform to the requirements of Table 1. Othervalues of tensile strength and nominal diameters can be specified if shown by test that the strength exceeds that specified. Thetension test
18、 shall be made in accordance with Test Methods A370.6.3 Load at 1 % ExtensionThe load at 1 % extension shall be at least 90 % of the minimum specified tensile strength whentested in accordance with Test Methods A370.6.4 ElongationThe percent elongation after fracture on a 10-in. 250-mm gage length s
19、hall be 3.0 % minimum.6.5 Bend TestA 90 degree bend test (see Fig. 1) around a pin six times the nominal diameter of the wire shall be performedonce per pack/coil for each row of indentations, with the centerline of the row of indentations located at the outside of the bend.The wire shall be bent at
20、 a uniform rate, with the duration of test to be between 10 and 30 seconds. The bend location along theaxis of the wire specimen shall be random and three locations shall be tested along the specimen, for a total of nine bends per test.Each bend shall be inspected after testing to ensure no cracking
21、 or breaking occurred.6.6 RelaxationRelaxation properties shall be provided at least annually from records of tests on finished wire. Additionalrelaxation tests shall be conducted if there is a change in raw rod supply or type. Tests to satisfy this requirement shall complywith the conditions of Sup
22、plementary Requirement S6 of Specification A421/A421M. The relaxation losses are not to exceed3.5 % after 1000 hours when tested at an initial load of 80 % of minimum tensile strength.7. Requirements for Indentations7.1 IndentationsIndentations shall be in three lines spaced uniformly around the wir
23、e with one line of indentations inclinedin the opposite direction to the other two. The indentations shall be placed in respect to the axis of the wire so that the includedangle is not less than 45, as shown in Fig. 2. Pitch and shape shall be consistent , with not more than 10 % being malformed ina
24、ny 2 ft 600 mm length of wire, judged visually. Criteria for what constitutes a malformed indentation shall be mutually agreedupon between manufacturer and purchaser as required.7.2 TypeTwo acceptable types of indented wire are shown in Fig. 2(a) and (b), with dimensions in Table 2.7.3 OptionsOther
25、types of indented wire are permitted by agreement, provided the wire is comparable with the accepted typesin mechanical properties and bond with concrete.TABLE 1 Tensile Strength RequirementsNominalDiameterTensileStrengthNominalAreaANominal WeightMass, lb/1000 ftg/min. mm lbf kN in.2 mm20.198 5.03 7
26、230 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 22.23 117.1 174.5TABLE 1 Tensile Strength RequirementsNominalDiameterTensileStrengthNominalAreaANominal WeightMass, lb/1000 ftg/min. mm lbf kN in.2 mm20.198 5.03 7230 32.2 0.0308 19.86 104.8 15
27、5.90.198 5.03 7700 34.3 0.0308 19.86 104.8 155.90.2094 5.32 9000 39.1 0.0344 22.23 117.1 174.5A The nominal cross-sectional area is based on the nominal diameter. The actualaverage area in in.2 mm2 may be calculated by dividing the mass (weight) perlinear in. mm of the specimen in lb kg by 0.2836 (w
28、eight of 1 in.3 of steel) 7.850 106 kg/mm3 (mass of 1 mm3 of steel). The amount of variation is dependent onthe shape and character of the indentations.A881/A881M 1527.4 Indentation Sidewall AngleThe manufacturer and purchaser shall agree upon minimum and maximum indentationsidewall angles (as shown
29、 in Fig. 2). The manufacturer shall demonstrate process controls to meet mutually agreed uponrequirements.NOTE 1Shallow indentation sidewall angles can impart excessive radial forces into the concrete. Similarly, angles that are too steep can reducetransfer length to the point of creating excessive
30、bond demand on the concrete. Depth of indentation, concrete properties at release of prestress, and wiresurface condition are other factors to take into consideration when determining min/max allowable indentation sidewall angles8. Permissible Variation in Dimensions8.1 The diameter as determined by
31、 weight mass of the indented wire shall not vary from the nominal diameter by more than60.003 in. 60.08 mm. Diameter as determined by weight mass shall be calculated using the weight mass of any given lengthof wire and densities provided in footnote of Table 1.FIG. 1 Bend Test ConfigurationFIG. 2 Ac
32、ceptable Type of Indented WireA881/A881M 1538.2 The indented wire shall not be out-of-round by more than 0.003 in. 0.08 mm. (Measured using a depth gauge by placingthe wire on a flat surface and checking maximum/minimum diameters at the same cross section. Out-of-round is the differencebetween maxim
33、um and minimum diameters measured.)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, or spools and packaged in such a way to prevent rubbing or collapseduring shipment. Each coil, pack, or spool shall be of one cont
34、inuous length.9.3 There shall be no welds or joints in the finished wire, unless the manufacturer and purchaser mutually agree on a weldingprocess done on wire rod prior to any cold drawing that results in wire properties that are consistent with the intended use. Anywelds or joints made after the i
35、nitial drawing process shall be removed.9.4 Cast (Curvature)The curvature of the wire shall be 3 in. 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 be essentially free of residual wire-drawing lubricants. Slight rusting,providing it is not suffici
36、ent to cause pits visible to a person with normal or corrected vision, shall not be cause for rejection.10. Sampling10.1 Unless otherwise agreed upon between the manufacturer and the purchaser, test specimens shall be taken from each coil,pack, or spool in a lot (see Note 2) and tested to determine
37、compliance with 6.2 6.5 and Sections 7, 8, and 9.NOTE 2The term “lot” means all the coils, packs, or spools of wire of the same nominal wire diameter contained in an individual shipping releaseor shipping order.11. Inspection11.1 The purchaser shall state, at the time of order, whether outside inspe
38、ction is required. If outside inspection is required, themanufacturer shall afford the inspector representing the purchaser all reasonable facilities to satisfy him that the material is beingfurnished in accordance with this specification. All tests and inspections shall be made at the place of manu
39、facture prior toshipment, unless otherwise agreed upon at the time of purchase, and shall be so conducted without unnecessarily interfering withmanufacturing operations.12. Rejection12.1 In case a test specimen fails to meet any requirement of this specification, two additional tests shall be made o
40、n samplesof wire from the same coil, pack, or spool and if failure occurs in either of these tests, the coil/pack/spool shall be rejected.12.2 Unless otherwise specified, any rejection based on tests made in accordance with this specification shall be reported to themanufacturer within a reasonable
41、length of time.TABLE 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 horizontal distances and indentation depths.NOTE 2Depth
42、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, 0.050.138 0.02 3.5 0.5 0.217 0.02 5.5 0.50.2094 5.32 0.00
43、45 0.00140.115 0.0350.138 0.02 3.5 0.5 0.215 0.011 5.46 0.29TABLE 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 horizontal
44、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, 0.050.138 0.
45、02 3.5 0.5 0.217 0.02 5.5 0.50.2094 5.32 0.0045 0.00140.115 0.0350.138 0.02 3.5 0.5 0.215 0.011 5.46 0.29A881/A881M 15413. Certification13.1 When specified in the purchase order or contract, the manufacturers certification shall be furnished to the purchaser statingthat samples representing each lot
46、 have been manufactured, tested, and inspected in accordance with this specification and therequirements have been met. The certification shall include the specification number, year-date of issue, and revision letter, if any.A report of the test results shall be furnished.13.2 A material test repor
47、t, certificate of inspection, or similar document printed from or used in electronic form from anelectronic data interchange (EDI) transmission shall be regarded as having the same validity as a counterpart printed in thecertifiers facility. The content of the EDI transmitted document must meet the
48、requirements of the invokedASTM standard(s) andconform to any existing EDI agreement between the purchaser and the supplier. Notwithstanding the absence of a signature, theorganization submitting the EDI transmission is responsible for the content of the report.NOTE 3The industry definition as invok
49、ed here is: EDI is the computer-to-computer exchange of business information in a standard format such asANSI ASC X12.14. Packaging and Package Marking14.1 The nominal diameter of the indented wire, ASTM specification designation, and name or mark of the manufacturer shallbe marked on a tag securely attached to each bundle of wire.14.2 For Government Procurement
