ASTM A882 A882M-2004a Standard Specification for Filled Epoxy-Coated Seven-Wire Prestressing Steel Strand.pdf

1、Designation: A 882/A882M 04aStandard Specification forFilled Epoxy-Coated Seven-Wire Prestressing Steel Strand1This standard is issued under the fixed designation A 882/A882M; the number immediately following the designation indicates the yearof original adoption or, in the case of revision, the yea

2、r of last revision. A number in parentheses indicates the year of last reapproval.A superscript epsilon (e) indicates an editorial change since the last revision or reapproval.1. Scope*1.1 This specification covers ASTM Specification A 416low-relaxation Grade 250 and Grade 270 seven-wire prestress-i

3、ng steel strand with protective fusion-bonded epoxy coatingapplied by the electrostatic deposition method or other methodthat will meet the coating requirements in Section 8, and,except as allowed by 1.2, with the interstices of the seven wiresfilled with epoxy to minimize migration of corrosive med

4、ia,either by capillary action or other hydrostatic forces.NOTE 1The manufacturer as identified throughout this specification isthe coating applicator.1.2 Upon special request by the purchaser, the interstices areleft unfilled.NOTE 2Unfilled strand can corrode from the inside and its applicationfor p

5、restressing tendons in concrete or for rock and soil anchors is notrecommended.1.3 This specification is applicable for orders in eitherinch-pound units (as Specification A 882) or SI units asSpecification A 882M.1.4 The values stated in either inch-pound or SI units are tobe regarded as standard. W

6、ithin the test, the SI units are shownin brackets. The values stated in each system must be usedindependently of the other. Combining values from the twosystems may result in nonconformance with this specification.2. Referenced Documents22.1 ASTM Standards:A 370 Test Methods and Definitions for Mech

7、anical Testingof Steel ProductsA 416/A 416M Specification for Steel Strand, UncoatedSeven-Wire for Prestressed ConcreteB 117 Practice for Operating Salt Spray (Fog) ApparatusD 968 Test Methods for Abrasion Resistance of OrganicCoatings by Falling AbrasiveG 12 Test Method for Nondestructive Measureme

8、nt of FilmThickness of Pipeline Coatings on SteelG 14 Test Method for Impact Resistance of Pipeline Coat-ings (Falling Weight Test)G 20 Test Method for Chemical Resistance of PipelineCoatings2.2 Federal Highway Administration Report:FHWA-RD-74-18 Nonmetallic Coatings for Concrete Rein-forcing Bars (

9、February 1974)33. Terminology3.1 Definitions of Terms Specific to This Standard:3.1.1 disbondingloss of adhesion between the fusion-bonded epoxy coating and the steel strand wires.3.1.2 fusion-bonded epoxy coatinga product containingpigments, thermo-setting epoxy resins, cross-linking agents,and oth

10、er substances, which is applied in the form of powderonto a clean, heated metallic substrate and fuses to form acontinuous barrier coating.3.1.3 gritinert particles impregnated on the outer surfaceof the epoxy coating for improving bond with cement grout.3.1.4 holidaya discontinuity in the coating t

11、hat is notdiscernible to a person with normal or corrected vision.3.1.5 patching materiala liquid coating used to repairdamaged or uncoated areas.4. Ordering Information4.1 The purchaser should specify:4.1.1 Diameter, grade, and type of uncoated strand inaccordance with Specification A 416/A 416M (l

12、atest edition).4.1.2 Smooth or grit impregnated coating (see 7.3).4.1.3 Quantity (in feet metres).4.1.4 Requirements for certification (see Section A1.2.3).4.1.5 Requirements for material samples (see 5.3).4.1.6 Requirements for patching material (see 5.4).4.1.7 Number of pullout tests to be perform

13、ed, if any.NOTE 3A typical ordering description for epoxy-coated strand is asfollows: 84 000 feet 2560 m of grit-impregnated epoxy-coated strand,12-in. 12.7-mm diameter, Grade 270 K low-relaxation on wooden reelsto ASTM Specification A 882 A 882M .1This specification is under the jurisdiction of AST

14、M Committee A01 on Steel,Stainless Steel, and Related Alloys and is the direct responsibility of SubcommitteeA01.05 on Steel Reinforcement.Current edition approved March 1, 2004. Published April 2004. Originallyapproved in 1991. Last previous edition approved in 2004 as A 882/A 882M 04.2For referenc

15、ed 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.3Available from the National Technical Information Service, 5285 Port Roya

16、lRd., Springfield, VA 22161.1*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.5. Materials5.1 Prestressing steel strand to be coated shall meet therequirements of Specif

17、ication A 416/A 416M as specified bythe purchaser and shall be free of contaminants such as oil,grease, or paint.5.1.1 Filled epoxy-coated strand shall have relaxation lossesof not more than 6.5 % after 1,000 hours, when initially loadedto 70 % of the specified minimum breaking strength of thestrand

18、 when tested under conditions of Specification A 416 /A 416M.5.2 The coating material shall meet the requirements listedin Annex A1 of this specification. The coating material shall beof organic composition except for the pigment, or grit ifapplicable, which may be inorganic if used.5.2.1 If specifi

19、ed in the order, a written certification shall befurnished to the purchaser that properly identifies the numberof each batch of coating material used in the order, material,quantity represented, date of manufacture, name and address ofmanufacturer, a statement that the supplied coating materialmeets

20、 the requirements of Annex A1, and a statement that thecoating material used in each batch is the same material as thatwhich was qualified under the requirements of Annex A1.5.3 If specified in the order, a representative 8-oz. 0.23-kgsample of coating material shall be packaged in an airtightcontai

21、ner and identified by batch number, and supplied to thepurchaser.5.4 If specified in the order, patching material compatiblewith the coating material and inert in concrete, and meeting therequirements of Annex A1 shall be supplied to the purchaser.6. Surface Preparation6.1 The surface of the steel s

22、trand to be coated shall becleaned chemically or by another method that will impart thesame cleanliness to ensure that the coated strand meets therequirements of Section 8.7. Application of Coating7.1 The coating shall be applied to the cleaned surface assoon as possible after cleaning and before re

23、oxidation of thesurface discernible to the unaided eye occurs. However, in nocase shall application of the coating be delayed more than 10minutes after cleaning, unless otherwise permitted by thepurchaser.7.2 The coating shall be applied by the electrostatic depo-sition method, or other method that

24、will meet the coatingrequirements in Section 8, and fully cured in accordance withthe recommendations of the manufacturer of the coatingmaterial.7.3 The coating may be smooth or grit-impregnated.7.3.1 Inert particles (grit) shall be impregnated into thesurface of the coating when grit-impregnated st

25、rand is ordered.Such particles shall not cause the coating to fail the require-ments of Section 8. The particles shall be inert in concrete andnon-reactive with concrete additives and soluble salts.7.3.2 The epoxy on the surface of grit-impregnated strandshall be capable of reaching a temperature of

26、 150F 66Cwithout reducing the transfer of prestress by bond from thestrand to the surrounding concrete.NOTE 4Warning: At temperatures above 165F 74C, currentlyavailable epoxy begins to soften and lose its ability to transfer load fromstrand to concrete by bond. At 200F 93C practically all transferca

27、pacity will be lost.8. Requirements for Coated Strands8.1 Thickness of Coating:8.1.1 The coating thickness after curing shall be 15 to 45mils 380 to 1140 m.8.1.2 The thickness of the coating film shall be determinedusing a magnetic gauge or other method. The gauge shall beused and calibrated in acco

28、rdance with the manufacturersrecommendations and Section 5 of Test Method G 12, exceptthat in 5.2.1 of Test Method G 12, the foil shall be placed onthe surface of the bare strand instead of the steel plate. Thegauge shall be capable of measuring the coating thickness of acoated wire of circular cros

29、s-section with a diameter in therange of 0.1 to 0.3 in. 2.5 to 7.5 mm. The allowable error ona single measurement of the coating thickness on the coatedcrown of an outer wire of the strand shall be 65%.8.1.3 The coating thickness shall be measured on the crownof each of the six outer wires at least

30、every 2000 ft 600 m ofcontinuous strand. The average of the coating thickness mea-surements for each set of six outer wires shall be supplied tothe purchaser upon request. Records of inspection duringmanufacture shall also be made available when requested.8.2 Continuity of Coating:8.2.1 After applic

31、ation of the coating, a continuous in-lineholiday detection procedure shall be employed using anaqueous electrolyte and a holiday detector with a minimumvoltage setting of 67.5 V DC, following the procedure fur-nished by its manufacturer. The approximate location ofholidays shall be recorded using a

32、utomatic devices or markingson the strand for later patching.8.2.2 The coated strand shall only be required to meet theholiday requirements of this specification with the in-lineholiday detector, but shall not be required to pass holidayinspection performed on stationary strand for residence timesex

33、ceeding 3 seconds.8.2.3 During the continuous holiday detection procedure,coated strand containing more than two holidays per hundredfeet 30 m shall be rejected and corrective action for theepoxy-coating process shall be instituted. Coated strand withtwo holidays or less per hundred feet 30 m shall

34、be patchedin accordance with the patching material manufacturers rec-ommendation. Patching of holidays shall be performed suchthat the total of the thicknesses of the coating and the patchdoes not exceed 1.1 mm 45 mils.NOTE 5Hand-held holiday detector checks should be performedregularly to verify th

35、e accuracy of the in-line system.8.3 Adhesion of Coating:8.3.1 The adhesion and shear strength of the coating shall beevaluated by bending a sample from a finished reel of coatedstrand 180 around a mandrel diameter equal to 32 times thenominal diameter of the strand. Test specimens shall be attherma

36、l equilibrium between 68 and 86F 20 and 30C.8.3.2 No cracking or disbonding of the coating shall bevisible to the unaided eye on the outside radius of the bentstrand. Evidence of cracking or disbonding of the coating shallA 882/A882M 04a2be considered cause for rejection of the coated strand repre-s

37、ented by the bend test sample. Retests shall be conducted inaccordance with 10.1.8.3.3 Fracture of the steel wire or strand in the bend test foradhesion of coating shall not be considered as an adhesionfailure of the coating, and another specimen from the sameproduction shift may be substituted.8.3.

38、4 The adhesion of coating shall also be evaluated by atension test in accordance with Section 6 of SpecificationA 416. The coated strand shall satisfy the requirements forbreaking strength, yield strength (1 % extension), and ultimateelongation described in Specification A 416/A 416M. Nocracks visib

39、le to the unaided eye shall occur in the coating upto an elongation of 1 % (yield strength).8.3.5 Sample length for the bend test shall be at least 5 ft, 0in. long 1500 mm. Sample length for the tension test shallfollow the requirements of Test Methods and DefinitionsA 370.8.4 Bond with Concrete or

40、Grout:8.4.1 Pull-out tests shall be conducted on grit-impregnatedcoated strand to ensure proper bond properties. Pull-out speci-mens shall be cast in concrete cylinders with dimensionsshown in Table 1. The untensioned strand shall be embeddedconcentrically along the longitudinal axis of the specimen

41、. Theminimum force at 0.001 in. 0.025 mm slip shall be applied asshown in Fig. 1, by a hydraulic or mechanical jack whenconcrete reaches a compressive strength between 4000 and5000 psi 30 and 35 MPa, and measured with a calibrated loadindicator at a slip of 0.001 in. 0.025 mm. A dial gage shall beus

42、ed at the unloaded end to indicate slip. Minimum force at0.001 in. 0.025 mm slip shall be at least equal to or greaterthan the values shown in Table 1.9. Number of Tests9.1 Three pullout tests shall be performed annually as aminimum or repeated when a process change is made thatcould decrease the bo

43、nd capacity of the epoxy-coated strand.The purchaser shall have the right to request additional pullouttests to be performed on the lot of epoxy-coated strand ordered.10. Retests10.1 If the specimen for coating thickness, continuity, ad-hesion of coating, and pull-out tests fail to meet the specifie

44、drequirements, two retest samples adjacent to the first samplefrom the same reel shall be conducted for each failed test. If theresults of both retests meet the specified requirements, the reelsrepresented by the samples shall be accepted.11. Inspection11.1 The inspector representing the purchaser s

45、hall havefree entry while work on the contract of the purchaser is beingperformed. The manufacturer shall afford the inspector allreasonable facilities to satisfy him that the material is beingfurnished in accordance with this specification. All tests andinspection shall be made at the place of manu

46、facture prior toshipment, unless otherwise specified, and shall be conducted sothere is no unnecessary interference with the manufacturersoperation.12. Rejection12.1 Except as specified in 10.1, coated strand reels repre-sented by test samples that do not meet the requirements of thisspecification s

47、hall be rejected.12.2 A reel of coated strand that is rejected for thickness orcontinuity of coating shall be accepted if the non-conformingsections are removed and the remaining material meets thecoating requirements of this specification.13. Certification13.1 If outside inspection is waived, a man

48、ufacturers 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. The certification shallinclude the specification number, year-date of issue, andrevision letter, if any.13.2 The manufacture

49、r shall, when requested in the order,furnish a representative load-elongation curve for each size andgrade of strand shipped and a copy of the manufacturersquality control tests.14. Handling and Identification14.1 All strapping bands shall be padded or suitable bandingshall be used to prevent damage to the coating. All reels ofcoated strand shall be handled in such a manner as not todamage the coating on the strand.14.2 Coating damage due to handling shall be repaired inaccordance with the recommendation of the m