1、Designation: A 775/A 775M 07aStandard Specification forEpoxy-Coated Steel Reinforcing Bars1This standard is issued under the fixed designationA 775/A 775M; the number immediately following the designation indicates the yearof original adoption or, in the case of revision, the year of last revision.
2、A number in parentheses indicates the year of last reapproval.A superscript epsilon (e) indicates an editorial change since the last revision or reapproval.This standard has been approved for use by agencies of the Department of Defense.1. Scope*1.1 This specification covers deformed and plain steel
3、reinforcing bars with protective epoxy coating applied by theelectrostatic spray method.NOTE 1The coating applicator is identified throughout this specifica-tion as the manufacturer.1.2 Other organic coatings may be used provided they meetthe requirements of this specification.1.3 Requirements for c
4、oatings are contained in Annex A1.1.4 Requirements for patching material are contained inAnnex A2.1.5 Guidelines for construction practices at the job-site arepresented in Appendix X1.1.6 This specification is applicable for orders in either SIunits (as Specification A 775M) or inch-pound units as S
5、peci-fication A 775.1.7 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
6、non-conformancewith the standard.1.8 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 limitat
7、ions 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 944 Test Method for Comparing Bond Strength of
8、 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 374 Test Methods for Thickness of Solid Electrical Insu-lationD 2967 Test Method for Corn
9、er Coverage of Powder Coat-ingsD 4060 Test Method for Abrasion 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 Pipe
10、lineCoatingsG62 Test Methods for Holiday Detection in Pipeline Coat-ings2.2 NACE International Standard:3RP-287-87 Field Measurement of Surface Profile of Abra-sive Blast-Cleaned Steel Surface Using a Replica Tape2.3 Society for Protective Coatings Specifications:4SSPC-SP 10 Near-White Blast Cleanin
11、gSSPC-VIS 1 Pictorial Surface Preparation Standards forPainting Steel SurfacesSSPC-PA 2 Measurement of Dry Coating Thickness withMagnetic Gages2.4 Concrete Reinforcing Steel Institute:5“Voluntary Certification Program for Fusion Bonded EpoxyCoating Applicator Plants”2.5 American Concrete Institute S
12、tandard:61This 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 Sept. 1, 2007. Published October 2007. Originallyapproved in 1981. Last prev
13、ious edition approved in 2007 as A 775/A 775M07.2For referenced 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 fr
14、om NACE International, 1440 South Creek, Houston, TX 77084.4Available from The Society for Protective Coatings, 40 24thSt., Pittsburgh, PA152224656.5Available from Concrete Reinforcing Steel Institute, 933 N. Plum Grove Rd.,Schaumburg, IL 601734758.6Available from American Concrete Institute, 38800
15、Country Club Dr., Farm-ington Hills, MI 48331.1*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.ACI 301 Specifications for Structural Concrete3. Terminology3.1 Definitio
16、ns of Terms Specific to This Standard:3.1.1 conversion coating, npreparation of the blast-cleaned steel surface prior to coating application that isdesigned to pretreat the metal to promote coating adhesion,reduce metal-coating reactions, improve corrosion resistance,and increase blister resistance.
17、3.1.2 disbonding, nloss of adhesion between the fusion-bonded epoxy coating and the steel reinforcing bar.3.1.3 fusion-bonded epoxy coating, nproduct containingpigments, thermosetting epoxy resins, crosslinking agents, andother additives, which is applied in the form of a powder ontoa clean, heated
18、metallic substrate and fuses to form a continu-ous barrier coating.3.1.4 holiday, ndiscontinuity in a coating that is notdiscernible to a person with normal or corrected vision.3.1.5 patching material, nliquid two-part epoxy coatingused to repair damaged or uncoated areas.3.1.6 wetting agent, nmater
19、ial that lowers the surfacetension 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 necessar
20、y 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 of bars,4.1.3 Size and grade of bars,4.1.4 Requirements for the powder coating and
21、provision oftest data (5.2 and 5.3),4.1.5 Requirements for patching material (5.4.2),4.1.6 Quantity of patching material,4.1.7 Specific requirements for test frequency (9.1),4.1.8 Whether a report on tests performed on the coatedsteel reinforcing bars being furnished is required (8.4.1 and 14)4.1.9
22、Additional specimens to be provided to the purchaserfor testing from the coated steel reinforcing bars being fur-nished (12.1), and4.1.10 Manufacturer qualification and certification require-ments (if any).NOTE 2It is recommended that the coating application procedures andprocesses be audited by an
23、independent certification program for epoxycoating applicator plants such as that provided by the Concrete Reinforc-ing Steel Institute, or equivalent.NOTE 3A typical ordering description is as follows: Deformed Grade420 bars to ASTM A 615M_; 6000 m, No. 19, 12 m long in securedlifts with sufficient
24、 spacers or padding, or both; epoxy-coated to ASTMA 775M_; including written certifications for the powder coatingand coated bars, and 1 L of patching material.Deformed Grade 60 bars to ASTM A 615_; 20 000 ft, No. 6, 40ft 0 in. long in secured lifts with sufficient spacers or padding, or both;epoxy-
25、coated to ASTM A 775_; including written certifications forthe powder coating 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 A 996M A 615, A 706, or A 996, as spec
26、ified bythe purchaser and shall be free of contaminants such as oil,grease, or paint.NOTE 4Prior 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 c
27、oatproperly and should not be coated. The coating will flow away from thesharp edges and may result in inadequate coating thickness at these points.5.2 The powder coating shall meet the requirements ofAnnex A1. Upon request, the purchaser shall be provided withthe test report for review.5.2.1 A writ
28、ten certification shall be furnished to the pur-chaser that properly identifies the number of each lot of 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 is thes
29、ame composition as that qualified according to Annex A1 ofthis specification.5.2.2 The powder coating shall be stored in a temperature-controlled environment following the written recommenda-tions of the powder coating manufacturer until ready for use.At that point, if the storage temperature is bel
30、ow the plantambient temperature, the powder coating shall be given suffi-cient time to reach approximate plant ambient temperature.The powder coating shall be used within the powder coatingmanufacturers written recommended shelf life.5.3 If specified in the order, a representative 0.2-kg 8-ozsample
31、of the powder coating shall be supplied to the purchaserfrom each batch. The sample shall be packaged in an airtightcontainer and identified by batch number.5.4 Patching material for repairing damaged coating shall becompatible with the coating, inert in concrete, and feasible forrepairs at the appl
32、icator plant or at the fabricating shop.Patching material shall be approved in accordance with AnnexA2 prior to use.5.4.1 The patching material manufacturer shall specify themetals surface preparation, and the procedures for applicationof the patching material.5.4.2 If specified in the order, patchi
33、ng material conformingto Annex A2 and recommended by the powder coating manu-facturer shall be supplied to the purchaser.6. Surface Preparation6.1 The surface of the steel reinforcing bars to be coatedshall be cleaned by abrasive blast cleaning to near-white metalin accordance with SSPC-SP 10. Addit
34、ional surface treatmentsteps may be used as indicated in A1.2. The following visualstandard of comparison may be used to define the final surfacecondition: SSPC-VIS 1.Average blast profile maximum rough-ness depth readings of 0.04 to 0.10 mm 1.5 to 4.0 mils, asdetermined by replica tape measurements
35、 using NACE RP-287-87, shall be considered suitable as an anchor pattern.NOTE 5The use of a “profilometer” type surface measurement instru-ment that measures the peak count as well as the maximum profile depthis recommended.A 775/A 775M 07a2NOTE 6Abrasive blast cleaning of steel reinforcing bars wit
36、h a highdegree ( 90 %) of grit in the cleaning media provides the most suitableanchor profile for coating adhesion. After grit has been recycled, a smallportion will take on the appearance of shot.6.2 Multidirectional, high-pressure dry air knives shall beused after blasting to remove dust, grit, an
37、d other foreignmatter from the blast-cleaned steel surface. The air knives shallnot deposit oil on the steel reinforcing bars.NOTE 7It is recommended that incoming steel reinforcing bars andblast media be checked for salt contamination prior to use. Blast mediafound to be salt contaminated should be
38、 rejected. Steel reinforcing barsfound to be salt contaminated from exposure to deicing salts or salt sprayshould be cleaned by acid washing or other suitable methods to removesalt contaminants from the surface prior to blast cleaning.6.3 It shall be permissible for the manufacturer to use achemical
39、 wash or conversion of the blast-cleaned steel rein-forcing bar surface, or both, to enhance coating adhesion. Thispretreatment shall be applied after abrasive cleaning and beforecoating, in accordance with the written application instructionsspecified by the pretreatment manufacturer.7. Coating App
40、lication7.1 If pretreatment is used in the preparation of the surface,the 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
41、person withnormal or corrected vision. In no case shall application of thecoating be delayed more than 3 h after cleaning.7.2 The fusion-bonded epoxy powder coating shall beapplied in accordance with the written recommendations of themanufacturer of the powder coating for initial steel surfacetemper
42、ature range and post application curing requirements.During continuous operations, the temperature of the surfaceimmediately prior to coating shall be measured using infraredguns or temperature indicating crayons, or both, at least onceevery 30 min.NOTE 8The use of infrared and temperature-indicatin
43、g crayon mea-surement of the steel reinforcing bars is recommended.7.3 The powder coating shall be applied by electrostaticspray or other suitable method.8. Requirements for Coated Steel Reinforcing Bars8.1 Coating Thickness:8.1.1 The coating thickness measurements after curing shallbe 175 to 300 m
44、7 to 12 mils for bars sizes Nos. 10 to 16Nos. 3 to 5 and 175 to 400 m 7 to 16 mils for bar sizesNos. 19 to 57 Nos. 6 to 18.The upper thickness limit shall notapply to repaired areas of damaged coating.8.1.2 A single recorded steel reinforcing bar coating thick-ness measurement is the average of thre
45、e individual gagereadings obtained between four consecutive deformations. Aminimum of five recorded measurements shall be taken ap-proximately evenly spaced along each side of the test speci-mens (a minimum of ten recorded measurements per bar).8.1.3 For acceptance purposes, the average of all recor
46、dedcoating 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.8.1.4 Me
47、asurements 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 gagesthat require the operator to observe the reading at the instantthe magnet is
48、pulled from the surface shall not be used.8.1.5 The coating thickness shall be measured on the bodyof a straight length of steel reinforcing bar between thedeformations.8.2 Coating Continuity:8.2.1 The manufacturers plant shall have an operationalin-line 67.5 V, 80,000 V, wet-sponge type direct-curr
49、entholiday detector or equivalent method with an automatedholiday counting system to determine the acceptability of thesteel reinforcing bars prior to shipment.NOTE 9Handheld holiday detector checks should be performed eachproduction day to verify the accuracy of the in-line system. Handheldholiday detectors offer a reliable way to correlate data obtained from thein-line holiday-detection system.8.2.2 On average, there shall not be more than 3 holidaysper meter one holiday per foot on a coated steel reinforcingbar. The aver
