1、Designation: A 934/A 934M 07Standard Specification forEpoxy-Coated Prefabricated Steel Reinforcing Bars1This standard is issued under the fixed designationA 934/A 934M; the number immediately following the designation indicates the yearof original adoption or, in the case of revision, the year of la
2、st 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 deformed and plain steelreinforcing bars which prior to surface preparation are prefab-ricat
3、ed and 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 formulations in accordance with this specifica-tion are not intended to be bent or rebent.NOTE 1Experience has show
4、n epoxy-coated prefabricated steel rein-forcing bars have limited capability to be successfully field bent or rebent(see 9.3.1). If the construction project requires epoxy-coated steel rein-forcing bars that must be able to sustain field bending or rebending, theuse of coated bars conforming to Spec
5、ification A 775/A 775M should beconsidered.1.3 Organic coatings 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 f
6、or steel reinforcing bars arepresented in Appendix X1.1.6 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 A 934M) or inch-pound unitsas Spe
7、cification A 934.1.8 The values stated in either SI units or 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
8、-conformancewith the standard.1.9 This standard does not purport 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 limitation
9、s prior to use.2. Referenced Documents2.1 ASTM Standards:2A 615/A 615M Specification for Deformed and PlainCarbon-Steel Bars for Concrete ReinforcementA 706/A 706M Specification for Low-Alloy Steel De-formed and Plain Bars for Concrete ReinforcementA 775/A 775M Specification for Epoxy-Coated Steel R
10、ein-forcing BarsA 944 Test Method for Comparing Bond Strength of SteelReinforcing Bars to Concrete Using Beam-End SpecimensA 996/A 996M Specification for Rail-Steel and Axle-SteelDeformed Bars for Concrete ReinforcementB117 Practice for Operating Salt Spray (Fog) ApparatusD 4060 Test Method for Abra
11、sion Resistance of OrganicCoatings by the Taber AbraserG8 Test Methods for Cathodic Disbonding of PipelineCoatingsG14 Test Method for Impact Resistance of Pipeline Coat-ings (Falling Weight Test)G20 Test Method for Chemical Resistance of PipelineCoatingsG42 Test Method for Cathodic Disbonding of Pip
12、elineCoatings Subjected to Elevated TemperaturesG62 Test Methods for 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 Society for Protective Coatings Specifications:4SS
13、PC-SP 10 Near-White Blast CleaningSSPC-VIS 1 Pictorial Surface Preparation Standards forPainting 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 d
14、irect responsibility of SubcommitteeA01.05 on Steel Reinforcement.Current edition approved Sept. 1, 2007. Published October 2007. Originallyapproved in 1995. Last previous edition approved in 2004 as A 934/A 934M04.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM
15、Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.3Available from NACE International, 1440 South Creek Dr., Houston, TX770844906.4Available from The Society for Protective Coatings, 40 24thSt., Pi
16、ttsburgh, PA152224656.1*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.2.4 American Concrete Institute Specifications:5ACI 301 Specifications for Structural ConcreteACI
17、 315 Details and Detailing of Concrete Reinforcement2.5 Concrete Reinforcing Steel Institute: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
18、 surface prior to coating application that is designed topretreat 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.
19、3.1.3 fusion-bonded epoxy coatingproduct containingpigments, thermosetting 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 th
20、at is not discern-ible to a person with normal or corrected vision.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 agentmater
21、ial that lowers the surface ten-sion of water allowing it to penetrate 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 neces
22、sary for the coated steel rein-forcing bars under this specification. 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 p
23、owder coating and provision oftest data (5.2),4.1.5 Requirements 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
24、 report on tests performed on the coatedsteel reinforcing bars being 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 2A typical ordering description is as follows: Deformed Grade420 bars to A
25、STM A 615M _; 6000 m, No. 19; cut to specifiedlengths and fabricated prior to coating; epoxy-coated to ASTM A934M _; including written certifications for the powder coating andcoated bars and 1 L of patching material.Deformed Grade 60 bars to ASTM A 615 _; 20 000 ft, No. 6;cut to specified lengths a
26、nd fabricated prior to coating; epoxy-coated toASTM A 934 _; including 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: A 615M,A 706M, or
27、A 996M A 615, A 706, or A 996 as specified bythe purchaser and shall be free of contaminants such as oil,grease, or paint.NOTE 3Prior 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 sur
28、face imperfections are difficult to coatproperly. The coating will flow away 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
29、A written certification shall be furnished to the pur-chaser that properly identifies the lot designation of the powdercoating used in the order, material quantity represented, date ofmanufacture, name and address of the powder coating manu-facturer, and a statement that the supplied powder coating
30、is thesame composition as that qualified according to Annex A1 ofthis specification. The powder coating shall be used within thepowder coating manufacturers written recommended shelflife.5.2.2 If specified in the order, a representative 0.2-kg 8-ozsample of the powder coating shall be supplied to th
31、e purchaserfrom each batch. The sample shall be packaged in an airtightcontainer 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, a
32、t which point the powder coating shall be givensufficient time to reach approximate 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. Pre
33、fabrication of Steel Reinforcing Bars6.1 The steel reinforcing bars to be coated shall have beenprefabricated in accordance with the purchasers requirementsor project specifications prior to surface preparation.NOTE 4Drive rolls on shear beds and backup barrels on bendersshould be protected with a s
34、uitable covering to minimize crushing orcreating rollover damage to the steel 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 a
35、ccordancewith SSPC-SP 10.5Available from American Concrete Institute, 38800 Country Club Dr., Farm-ington Hills, MI 48331.6Available from Concrete Reinforcing Steel Institute, 933 N. Plum Grove Rd.,Schaumburg, IL 601734758.A 934/A 934M 0727.1.1 The final surface condition shall be defined accordingt
36、o SSPC-VIS 1.7.1.2 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 5The use of a profilometer type surface measure
37、ment instru-ment 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 6Recycled steel grit abrasive should be maintained so as tominimize contaminant
38、s such as oil, 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 7It is recom
39、mended that incoming 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
40、 other suitable 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 abrasi
41、ve cleaning and 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
42、pretreatment is 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 withnorma
43、l or corrected 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
44、post application 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 8The use of infrared and temperature-indicating crayon mea-surement of t
45、he steel reinforcing 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
46、mils. The coatingthickness 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 rad
47、ius such as Bend Type9(Fig. 1) shall have the same coating thickness requirementsas straight bars, when the 9H9 dimension is equal to or less thanone-half of the 9R9 dimension.NOTE 9Section 9.1.1 permits a maximum coating thickness of 405m 16 mils on bent sections of bars. Discussion of the effect o
48、f thepermissible 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 deformat
49、ions. Aminimum 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 thickness 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 M
