1、Designation: A934/A934M 16Standard Specification forEpoxy-Coated Prefabricated Steel Reinforcing Bars1This standard is issued under the fixed designation A934/A934M; the number immediately following the designation indicates the yearof original adoption or, in the case of revision, the year of last
2、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 deformed and plain steelreinforcing bars which prior to surface preparation are prefab-ricated a
3、nd then coated with a protective fusion-bonded epoxycoating by electrostatic spray or other suitable method.1.2 Prefabricated steel reinforcing bars coated with fusion-bonded epoxy powder coating in accordance with this specifi-cation are intended to be fabricated before being coated.1.3 Organic coa
4、tings other than epoxy may be used pro-vided they meet the requirements of this specification.1.4 Requirements for epoxy coatings are contained in An-nex A1.1.5 Guidelines for application process and product testprocedures of epoxy coatings for steel reinforcing bars arepresented in Appendix X1.1.6
5、Guidelines for construction practices at the job-site forcoated steel reinforcing bars are presented in Appendix X2.1.7 This specification is applicable for orders in either SI(metric) units (as Specification A934M) or inch-pound unitsas Specification A934.1.8 The values stated in either SI units or
6、 inch-pound 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.1.9 This standard does not pur
7、port to address 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:2A6
8、15/A615M Specification for Deformed and Plain Carbon-Steel Bars for Concrete ReinforcementA706/A706M Specification for Deformed and Plain Low-Alloy Steel Bars for Concrete ReinforcementA775/A775M Specification for Epoxy-Coated Steel Rein-forcing BarsA944 Test Method for Comparing Bond Strength of St
9、eelReinforcing Bars to Concrete Using Beam-End Speci-mensA996/A996M Specification for Rail-Steel and Axle-SteelDeformed Bars for Concrete ReinforcementB117 Practice for Operating Salt Spray (Fog) ApparatusD4060 Test Method for Abrasion Resistance of OrganicCoatings by the Taber AbraserG8 Test Method
10、s for Cathodic Disbonding of Pipeline Coat-ingsG14 Test Method for Impact Resistance of Pipeline Coatings(Falling Weight Test)G20 Test Method for Chemical Resistance of Pipeline Coat-ingsG42 Test Method for Cathodic Disbonding of PipelineCoatings Subjected to Elevated TemperaturesG62 Test Methods fo
11、r Holiday Detection in Pipeline Coat-ings2.2 NACE International Standard:3RP 0287 Field Measurement of Surface Profile of AbrasiveBlast Cleaned Steel Surfaces Using a Replica Tape2.3 SSPC Specifications:4SSPC-SP 10 Near-White Blast CleaningSSPC-VIS 1 Pictorial Surface Preparation Standards forPainti
12、ng Steel SurfacesSSPC-PA 2 Measurement of Dry Coating Thickness withMagnetic Gages1This 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 Mar
13、ch 1, 2016. Published March 2016. Originallyapproved in 1995. Last previous edition approved in 2013 as A934/A934M 13.DOI: 10.1520/A0934_A0934M-16.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandard
14、s volume information, refer to the standards Document Summary page onthe ASTM website.3Available from NACE International (NACE), 15835 Park Ten Pl., Houston, TX77084, http:/www.nace.org.4Available from Society for Protective Coatings (SSPC), 40 24th St., 6th Floor,Pittsburgh, PA 15222, http:/www.ssp
15、c.org.*A Summary of Changes section appears at the end of this standardCopyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States12.4 ACI Specifications:5ACI 301 Specifications for Structural ConcreteACI 315 Details and Detailing of Concrete Rei
16、nforcement2.5 CRSI Documents:6Voluntary Certification Program for Fusion-Bonded EpoxyCoating Applicator Plants3. Terminology3.1 Definitions of Terms Specific to This Standard:3.1.1 conversion coatingpreparation of the blast-cleanedmetal surface prior to coating application that is designed topretrea
17、t the metal to promote coating adhesion, reduce metalcoating reactions, improve corrosion resistance, and increaseblister resistance.3.1.2 disbondingloss of adhesion between the fusion-bonded epoxy coating and the steel reinforcing bar.3.1.3 fusion-bonded epoxy coatingproduct containingpigments, the
18、rmosetting epoxy resins, crosslinking agents, andother additives, which is applied in the form of a powder ontoa clean, heated metallic substrate and fuses to form a continu-ous barrier coating.3.1.4 holidaydiscontinuity in a coating that is not discern-ible to a person with normal or corrected visi
19、on.3.1.5 patching materialliquid two-part epoxy coatingused to repair damaged areas.3.1.6 prefabricated barssteel reinforcing bars that are cutto specified lengths and bent to the required shapes prior tocoating.3.1.7 wetting agentmaterial that lowers the surface ten-sion of water allowing it to pen
20、etrate more effectively intosmall discontinuities in the coating, giving a more accurateindication of the holiday count.4. Ordering Information4.1 It shall be the responsibility of the purchaser to specifyall requirements that are necessary for the coated steel rein-forcing bars under this specifica
21、tion. Such requirements to beconsidered include, but are not limited to, the following:4.1.1 Reinforcing bar specification and year of issue,4.1.2 Quantity and bend types of bars,4.1.3 Size and grade of bars,4.1.4 Requirements for the powder coating and provision oftest data (5.2),4.1.5 Requirements
22、 for patching material (5.3),4.1.6 Quantity of patching material,4.1.7 Coated specimens shall be provided by the manufac-turer out of the same production lot of coated reinforcementbeing furnished to the purchaser (13.1).4.1.8 Whether a report on tests performed on the coatedsteel reinforcing bars b
23、eing furnished is required (15.1),4.1.9 Method for temperature reduction of hot, freshlycoated bars (unforced air cool down or forced air/waterquench) (8.3).NOTE 1A typical ordering description is as follows: Deformed Grade420 bars to ASTM A615M _; 6000 m, No. 19; cut to specifiedlengths and fabrica
24、ted prior to coating; epoxy-coated to ASTM A934M _; including written certifications for the powder coating and coatedbars and 1 L of patching material.Deformed Grade 60 bars toASTM A615M _; 20 000 ft, No. 6;cut to specified lengths and fabricated prior to coating; epoxy-coated toASTM A934 _; includ
25、ing written certifications for the powdercoating and coated bars and 1 qt. of patching material.5. Materials5.1 Steel reinforcing bars to be coated shall meet therequirements of one of the following specifications: A615M,A706M, or A996M A615, A706, or A996 as specified by thepurchaser and shall be f
26、ree of contaminants such as oil, grease,or paint.NOTE 2Prior to coating, the steel reinforcing bars should be inspectedfor their suitability for coating. Bars with sharp edges on the deformations,rolled-in slivers, or other surface imperfections are difficult to coatproperly. The coating will flow a
27、way from the sharp edges and may resultin inadequate coating thickness at these points.5.2 The powder coating shall meet the requirements ofAnnex A1. Upon request, the purchaser shall be provided withtest data for review.5.2.1 A written certification shall be furnished to the pur-chaser that properl
28、y identifies the lot designation of the powdercoating used in the order, material quantity represented, date ofmanufacture, name and address of the powder coatingmanufacturer, and a statement that the supplied powder coatingis the same composition as that qualified according to AnnexA1 of this speci
29、fication. The powder coating shall be usedwithin the powder coating manufacturers written recom-mended shelf life.5.2.2 If specified in the order, a representative 0.2-kg 8-ozsample of the powder coating shall be supplied to the purchaserfrom each batch. The sample shall be packaged in an airtightco
30、ntainer and identified by the batch designation.5.2.3 The powder coating shall be maintained in atemperature-controlled environment following the written rec-ommendations of the powder coating manufacturer until readyfor use, at which point the powder coating shall be givensufficient time to reach a
31、pproximate plant ambient temperature.5.3 If specified in the order, patching material, compatiblewith the coating, inert in concrete, and recommended by thepowder coating manufacturer, shall be supplied to the pur-chaser.6. Prefabrication of Steel Reinforcing Bars6.1 The steel reinforcing bars to be
32、 coated shall have beenprefabricated in accordance with the purchasers requirementsor project specifications prior to surface preparation.NOTE 3Drive rolls on shear beds and backup barrels on bendersshould be protected with a suitable covering to minimize crushing orcreating rollover damage to the s
33、teel reinforcing bar deformations duringthe fabrication process.7. Surface Preparation of Steel Reinforcing Bars7.1 The surface of the steel reinforcing bars shall be cleanedby abrasive blast steel grit to near-white metal in accordancewith SSPC-SP 10.5Available from American Concrete Institute (ACI
34、), 38800 Country Club Dr.,Farmington Hills, MI 48331-3439, http:/www.concrete.org.6Available from Concrete Reinforcing Steel Institute (CRSI), 933 N. PlumGrove Rd., Schaumburg, IL 60173-4758, http:/www.crsi.org.A934/A934M 1627.1.1 The final surface condition shall be defined accordingto SSPC-VIS 1.7
35、.1.2 Average blast profile roughness depth readings of 37to 100 m 1.5 to 4.0 mils, as determined by replica tapemeasurements using RP 0287 or other methods acceptable tothe purchaser, shall be considered suitable as an anchor pattern.NOTE 4The use of a profilometer type surface measurement instru-me
36、nt that measures the peak count as well as the maximum profile depthis recommended.7.2 Asteel grit of Rockwell Hardness C50 or higher shall beused. A maximum of 5 % steel shot is allowable in the media.NOTE 5Recycled steel grit abrasive should be maintained so as tominimize contaminants such as oil,
37、 salt, and dust caused by the blastingoperation.7.3 Multidirectional, high-pressure dry air knives shall beused after blast cleaning to remove dust, grit, and other foreignmatter from the steel surface. The air knives shall not depositoil on the steel reinforcing bars.NOTE 6It is recommended that in
38、coming steel reinforcing bars andblast media be checked for salt contamination prior to use. Blast mediafound to be salt contaminated should be rejected. Steel reinforcing barsfound to be salt contaminated from exposure to deicing salts or salt sprayshould be cleaned by acid washing or other suitabl
39、e methods to removesalt contaminants from the surface prior to blast cleaning.7.4 It shall be permissible for the manufacturer to use achemical wash or conversion of the steel reinforcing barsurface, or both, to enhance coating adhesion. This pretreat-ment shall be applied after abrasive cleaning an
40、d beforecoating, in accordance with the written application instructionsspecified by the pretreatment manufacturer.8. Coating Application8.1 Cleaned, uncoated steel reinforcing bars shall behandled by personnel wearing clean gloves to prevent contami-nation of the steel surface.8.2 If pretreatment i
41、s used in the preparation of the surfacethe powder coating shall be applied to the cleaned andpretreated steel reinforcing bar surface as soon as possible aftersurface treatments have been completed, and before visibleoxidation of the surface occurs as discernible to a person withnormal or corrected
42、 vision. In no case shall application of thecoating be delayed more than 3 h after cleaning.8.3 The fusion-bonded epoxy powder coating shall beapplied in accordance with the written recommendations of themanufacturer of the powder coating for initial steel surfacetemperature range and post applicati
43、on cure requirements. Thetemperature of the surface immediately prior to coating shall bemeasured using infrared guns or temperature-indicating cray-ons at least once every 30 min during continuous operations.NOTE 7The use of infrared and temperature-indicating crayon mea-surement of the steel reinf
44、orcing bars is recommended.8.4 The powder coating shall be applied by electrostaticspray or other suitable method.9. Requirements for Coated Steel Reinforcing Bars9.1 Coating Thickness:9.1.1 The coating thickness on straight sections of bars,after curing, shall be 175 to 300 m 7 to 12 mils. The coat
45、ingthickness on bent sections of bars, after curing, shall be 175 to405 mm 7 to 16 mils. Bent sections of bars are defined as theentire radius of each bend and portions of the bar extending150 mm 6 in. beyond the beginning and ending bend pointson the bar. Bars that are bent with a radius such as Be
46、nd Type9(Fig. 1) shall have the same coating thickness requirementsas straight bars, when the “H“ dimension is equal to or less thanone-half of the “R“ dimension.NOTE 8Section 9.1.1 permits a maximum coating thickness of 405 m16 mils on bent sections of bars. Discussion of the effect of thepermissib
47、le increased coating thickness on the anchorage capacity of bentbars embedded in concrete is presented in Appendix X3.9.1.2 A single recorded steel reinforcing bar coating thick-ness measurement is the average of three individual gagereadings obtained between three consecutive deformations. Aminimum
48、 of five recorded measurements shall be taken ap-proximately evenly spaced along each side of the test specimen(a minimum of ten recorded measurements per bar).9.1.3 For acceptance purposes, the average of all recordedcoating thickness measurements shall not be less than thespecified minimum thickne
49、ss or more than the specifiedmaximum thickness. No single recorded coating thicknessmeasurement shall be less than 80 % of the specified minimumthickness or more than 120 % of the specified maximumthickness.9.1.4 Measurements shall be made in accordance withSSPC-PA 2 following the instructions for calibration and userecommended by the thickness gage manufacturer. Pull-off orfixed probe gages shall be used. Pencil-type pull-off gages thatrequire the operator to observe the readings at the instant themagnet is pulled from t
