ASTM A775&

Designation: A 775/A 775M – 04 Standard Specification for Epoxy-Coated Steel Reinforcing Bars1 This standard is issued under the fixed designation A 775/A 775M; the number immediately following the designation indicates the year of original adoption or, in the case of revision, the year 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. 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 reinforcing bars with protective epoxy coating applied by the electrostatic spray method. NOTE 1—The coating applicator is identified throughout this specifica- tion as the manufacturer. 1.2 Other organic coatings may be used provided they meet the requirements of this specification. 1.3 Requirements for coatings are contained in Annex A1. 1.4 Guidelines for construction practices at the job-site are presented in Appendix X1. 1.5 This specification is applicable for orders in either SI units (as Specification A 775M) or inch-pound units [as Speci- fication A 775]. 1.6 The values stated in either SI or inch-pound units are to be regarded as standard. Within the text, the inch-pound units are shown in brackets. The values stated in each system are not exact equivalents; therefore, each system must be used inde- pendently of the other, except as specifically noted in Table 1. Combining values from the two systems may result in noncon- formance with this specification. 1.7 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility 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 Documents 2.1 ASTM Standards: 2 A 615/A 615M Specification for Deformed and Plain Billet-Steel Bars for Concrete Reinforcement A 706/A 706M Specification for Low-Alloy Steel De- formed and Plain Bars for Concrete Reinforcement A 944 Test Method for Comparing Bond Strength of Steel Reinforcing Bars to Concrete Using Beam-End Specimens A 996/A 996M Specification for Rail-Steel and Axle-Steel Deformed Bars for Concrete Reinforcement B 117 Practice for Operating Salt Spray (Fog) Apparatus D 4060 Test Method for Abrasion Resistance of Organic Coatings by Taber Abrasor G 8 Test Methods for Cathodic Disbonding of Pipeline Coatings G 14 Test Method for Impact Resistance of Pipeline Coat- ings (Falling Weight Test) G 20 Test Method for Chemical Resistance of Pipeline Coatings G 62 Test Methods for Holiday Detection in Pipeline Coat- ings 2.2 NACE International Standard: RP-287-87 Field Measurement of Surface Profile of Abra- sive Blast-Cleaned Steel Surface Using a Replica Tape3 2.3 Society for Protective Coatings Specifications: SSPC-SP 10 Near-White Blast Cleaning4 1 This specification is under the jurisdiction of ASTM Committee A01 on Steel, Stainless Steel, and Related Alloys and is the direct responsibility of Subcommittee A01.05 on Steel Reinforcement. Current edition approved April 1, 2004. Published May 2004. Originally approved in 1981. Last previous edition approved in 2001 as A 775/A 775M – 01. 2 For referenced ASTM standards, visit the ASTM website, www.astm.org, or contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM Standards volume information, refer to the standard’s Document Summary page on the ASTM website. 3 Available from NACE International, 1440 South Creek, Houston, TX 77084. 4 Available from Society for Protective Coatings, 40 24th Street, Pittsburgh, PA 15222. TABLE 1 Bend Test Requirements A 615M, A 706M or A 996M A 615, A 706 or A 996M Bar No. Mandrel Diameter, mmA Bar No. Mandrel Diameter, in.A Bend Angle (After Rebound, degrees) Time to Completion max, s 10 75 3 3 180 15 13 100 4 4 180 15 16 125 5 5 180 15 19 150 6 6 180 15 22 175 7 7 180 45 25 200 8 8 180 45 29 230 9 9 180 45 32 250 10 10 180 45 36 280 11 11 180 45 43 430 14 17 90 45 57 580 18 23 90 45 AMandrel diameters specified for similar size (shown on the same line) metric and inch-pound bars may be interchanged. 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. SSPC-VIS 1 Pictorial Surface Preparation Standards for Painting Steel Surfaces4 SSPC-PA 2 Measurement of Dry Coating Thickness with Magnetic Gages4 2.4 Concrete Reinforcing Steel Institute: “Voluntary Certification Program for Fusion Bonded Epoxy Coating Applicator Plants”5 2.5 American Concrete Institute Standard: ACI 301 Specifications for Structural Concrete6 3. Terminology 3.1 Definitions of Terms Specific to This Standard: 3.1.1 conversion coating, n—a preparation of the blast- cleaned steel surface prior to coating application that is designed to pretreat the metal to promote coating adhesion, reduce metal-coating reactions, improve corrosion resistance, and increase blister resistance. 3.1.2 disbonding, n—loss of adhesion between the fusion- bonded epoxy coating and the steel reinforcing bar. 3.1.3 fusion-bonded epoxy coating, n—a product containing pigments, thermosetting epoxy resins, crosslinking agents, and other additives, which is applied in the form of a powder onto a clean, heated metallic substrate and fuses to form a continu- ous barrier coating. 3.1.4 holiday, n—a discontinuity in a coating that is not discernible to a person with normal or corrected vision. 3.1.5 patching material, n—a liquid two-part epoxy coating used to repair damaged or uncoated areas. 3.1.6 wetting agent, n—a material that lowers the surface tension of water allowing it to penetrate more effectively into small discontinuities in the coating giving a more accurate indication of the holiday count. 4. Ordering Information 4.1 It shall be the responsibility of the purchaser to specify all requirements that are necessary for the coated steel rein- forcing bars under this specification. Such requirements to be considered 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 provision of test data (5.2 and 5.3), 4.1.5 Requirements for patching material (5.4), 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 coated steel reinforcing bars being furnished is required (8.4.1 and 14) 4.1.9 Additional specimens to be provided to the purchaser for testing from the coated steel reinforcing bars being fur- nished (12.1), and 4.1.10 Manufacturer qualification and certification require- ments (if any). NOTE 2—It is recommended that the coating application procedures and processes be audited by an independent certification program for epoxy coating applicator plants such as that provided by the Concrete Reinforc- ing Steel Institute, or equivalent. NOTE 3—A typical ordering description is as follows: Deformed Grade 420 bars to ASTM A 615M_____; 6000 m, No. 19, 12 m long in secured lifts with sufficient spacers or padding, or both; epoxy-coated to ASTM A 775M–_____; including written certifications for the powder coating and coated bars, and 1 L of patching material. [Deformed Grade 60 bars to ASTM A 615 –_____; 20 000 ft, No. 6, 40 ft 0 in. long in secured lifts with sufficient spacers or padding, or both; epoxy-coated to ASTM A 775–_____; including written certifications for the powder coating and coated bars, and 1 qt of patching material.] 5. Materials 5.1 Steel reinforcing bars to be coated shall meet the requirements of one of the following specifications: A 615M, A 706M, or A 996M [A 615, A 706, or A 996], as specified by the purchaser and shall be free of contaminants such as oil, grease, or paint. NOTE 4—Prior to coating, the steel reinforcing bars should be inspected for their suitability for coating. Bars with sharp edges on the deformations, rolled-in slivers, or other surface imperfections are difficult to coat properly and should not be coated. The coating will flow away from the sharp edges and may result in inadequate coating thickness at these points. 5.2 The powder coating shall meet the requirements of Annex A1. Upon request, the purchaser shall be provided with the test report for review. 5.2.1 A written certification shall be furnished to the pur- chaser that properly identifies the number of each lot of powder coating used in the order, material quantity represented, date of manufacture, name and address of the powder coating manu- facturer, and a statement that the supplied powder coating is the same composition as that qualified according to Annex A1 of this 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 below the plant ambient 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 coating manufacturer’s written recommended shelf life. 5.3 If specified in the order, a representative 0.2-kg [8-oz] sample of the powder coating shall be supplied to the purchaser from each batch. The sample shall be packaged in an airtight container and identified by batch number. 5.4 If specified in the order, patching material, compatible with the coating, inert in concrete, and recommended by the powder coating manufacturer, shall be supplied to the pur- chaser. 6. Surface Preparation 6.1 The surface of the steel reinforcing bars to be coated shall be cleaned by abrasive blast cleaning to near-white metal in accordance with SSPC-SP10. Additional surface treatment steps may be used as indicated in A1.2. The following visual standard of comparison may be used to define the final surface condition: SSPC-VIS 1. Average blast profile maximum rough- ness depth readings of 0.04 to 0.10 mm [1.5 to 4.0 mils], as 5 Available from Concrete Reinforcing Steel Institute, 933 N. Plum Grove Road, Schaumburg, IL 60173. 6 Available from American Concrete Institute, 38800 International Way, P.O. Box 9094, Farmington Hills, MI 48333–9094. A 775/A 775M – 04 2 ???? & ???? & E??? & ???? QQ?As a reader（74398380）?? ?? ?? determined by replica tape measurements using NACE RP- 287-87, shall be considered suitable as an anchor pattern. NOTE 5—The use of a “profilometer” type surface measurement instru- ment that measures the peak count as well as the maximum profile depth is recommended. NOTE 6—Abrasive blast cleaning of steel reinforcing bars with a high degree (> 90 %) of grit in the cleaning media provides the most suitable anchor profile for coating adhesion. After grit has been recycled, a small portion will take on the appearance of shot. 6.2 Multidirectional, high-pressure dry air knives shall be used after blasting to remove dust, grit, and other foreign matter from the blast-cleaned steel surface. The air knives shall not deposit oil on the steel reinforcing bars. NOTE 7—It is recommended that incoming steel reinforcing bars and blast media be checked for salt contamination prior to use. Blast media found to be salt contaminated should be rejected. Steel reinforcing bars found to be salt contaminated from exposure to deicing salts or salt spray should be cleaned by acid washing or other suitable methods to remove salt contaminants from the surface prior to blast cleaning. 6.3 It shall be permissible for the manufacturer to use a chemical wash or conversion of the blast-cleaned steel rein- forcing bar surface, or both, to enhance coating adhesion. This pretreatment shall be applied after abrasive cleaning and before coating, in accordance with the written application instructions specified by the pretreatment manufacturer. 7. Coating Application 7.1 If pretreatment is used in the preparation of the surface, the powder coating shall be applied to the cleaned and pretreated steel reinforcing bar surface as soon as possible after surface treatments have been completed, and before visible oxidation of the surface occurs as discernible to a person with normal or corrected vision. In no case shall application of the coating be delayed more than 3 h after cleaning. 7.2 The fusion-bonded epoxy powder coating shall be applied in accordance with the written recommendations of the manufacturer of the powder coating for initial steel surface temperature range and post application curing requirements. During continuous operations, the temperature of the surface immediately prior to coating shall be measured using infrared guns or temperature indicating crayons, or both, at least once every 30 min. NOTE 8—The use of infrared and temperature-indicating crayon mea- surement of the steel reinforcing bars is recommended. 7.3 The powder coating shall be applied by electrostatic spray or other suitable method. 8. Requirements for Coated Steel Reinforcing Bars 8.1 Coating Thickness: 8.1.1 For acceptance purposes, at least 90 % of all coating thickness measurements after curing shall be 175 to 300 µm [7 to 12 mils] for bars sizes Nos. 10 to 16 [Nos. 3 to 5] and 175 to 400 µm [7 to 16 mils] for bar sizes Nos. 19 to 57 [Nos. 6 to 18]. A finding that more than 5 % of the coating thickness measurements are below 125 µm [5 mils] shall be considered cause for rejection. The upper thickness limit shall not apply to repaired areas of damaged coating. 8.1.2 A minimum of fifteen coated steel reinforceing bar thickness measurements shall be taken approximately evenly spaced along each side of the test bar. 8.1.2.1 Measurements shall be made in accordance with Test Method G 12, following the instructions for calibration and use recommended by the thickness gage manufacturer. Pull-off or fixed probe gages shall be used. “Pencil-type’’ pull-off gages that require the operator to observe the reading at the instant the magnet is pulled from the surface shall not be used. 8.1.3 The coating thickness shall be measured on the body of a straight length of steel reinforcing bar between the deformations. 8.1.4 The coating thickness shall be measured on the body of a straight length of steel reinforcing bar between the deformations. 8.2 Coating Continuity: 8.2.1 The manufacturer’s plant shall have an operational in-line 67.5 V, 80,000 V, wet-sponge type direct-current holiday detector or equivalent method with an automated holiday counting system to determine the acceptability of the steel reinforcing bars prior to shipment. NOTE 9—Hand-held holiday detector checks should be performed each production day to verify the accuracy of the in-line system. Hand-held holiday detectors offer a reliable way to correlate data obtained from the in-line holiday-detection system. 8.2.2 On average, there shall not be more than 3 holidays per meter [one holiday per foot] on a coated steel reinforcing bar. The average applies to the full production length of a bar. 8.2.3 A wetting agent shall be used per Test Methods G 62 in the inspection for holidays on the coated steel reinforcing bars. 8.3 Coating Flexibility: 8.3.1 The coating flexibility shall be evaluated by bending production coated steel reinforcing bars at a uniform rate around a mandrel of specified size within a maximum specified time period as prescribed in Table 1. The two longitudinal ribs shall be placed in a plane perpendicular to the mandrel radius. The test specimens shall be between 20 and 30°C [68 and 86°F]. 8.3.2 Cracking or disbonding of the coating on the outside radius of the bent bar visible to a person with normal or corrected vision shall be considered cause for rejection of the coated steel reinforcing bars represented by the bend test sample. NOTE 10—The qualification requirements for coating flexibility (see A1.3.5.1) prescribe bending a No. 19 [No. 6] deformed bar around a 150-mm [6-in.] diameter mandrel. The bend test requirements in Table 1 for evaluating the coating flexibility of production-coated steel reinforcing bars, for bar sizes Nos. 10 to 25 [Nos. 3 to 8], are not compatible with fabrication bending practices. Finished bend diameters for bar sizes Nos. 10 to 25 [Nos. 3 to 8] used in actual construction are smaller than the mandrel diameters in Table 1. Thus, the finished bends of production- coated bars, particularly the smaller bar sizes used for stirrups and ties, should be examined closely for hairline cracking on the outside radius of the bent bar. If hairline cracking is present, it should be repaired with patching material. A 775/A 775M – 04 3 8.3.3 A test in which fracture or partial failure of the steel reinforcing bar, or cracking or disbonding caused by imperfec- tions in the bar surface visible after performing the bend test occurs, shall be considered an invalid test and the test shall be repeated on a new specimen. 8.4 Coating Adhesion: 8.4.1 Coating adhesion shall be evaluated by testing pro- duction coated steel reinforcing bars according to the cathodic disbondment procedure described in Annex A1.3.2.1. Data from testing pertaining to the coated steel reinforcing bars being furnished shall be made available to the purchaser upon request. NOTE 11—It is recommended that the manufacturer retain test speci- mens for 30 days of production and use a 30–day rolling average of coating disbondment test data as a basis for its statistical process control program for the steel reinforcing bar coating operation. 8.5 The requirements for coated steel reinforcing bars shall be met at the manufacturer’s plant prior to shipment. 9. Number of Tests 9.1 The purchaser shall have the option to specify the sampling and test schedule for the number and frequency of tests for coating thickness, continuity, flexibility and adhesion. 9.2 If the number and frequency of tests are not specified by the purchaser the following apply: 9.2.1 Tests for coating thickness shall be made on a mini- mum of two bars of each size every two production hours, 9.2.2 Bend tests for coating flexibility shall be conducted on at least one bar of each size every four production hours, and 9.2.3 Random tests shall be made for coating continuity. 9.3 Coating adhesion as measured by cathodic disbondment testing shall be conducted on at least one bar every eight production hours. NOTE 12—The coated steel reinforcing bars to be tested for coating adhesion should be selected from the bar sizes being coated and from positions on the production line so as to be representative of the overall coating process. 10. Retests 10.1 If the specimen for coating thickness or flexibility fails to meet the specified requirements, two retests on random samples shall be conducted for each failed test. If the results of both retests meet the specified requirements, the coated steel reinforcing bars represented by the samples shall be accepted. 11. Permissible Amount of Damaged Coating and Repair of Damaged Coating 11.1 The maximum amount of repaired damaged coating shall not exceed 1 % of the total surface area in each 0.3 m [1–ft] of the bar. This limit on repaired damaged coating shall not include sheared or cut ends that are coated with patching material (see 11.4). 11.2 All damaged coating due to fabrication or handling (to the point of shipment) shall be repaired with patching material. NOTE 13—If the amount of repaired damaged coating in any 0.3–m [1–ft] length of a coated bar, exceeds 1 %, that section should be removed from the coated steel reinforcing bar and discarded. In patching damaged coating , care should be taken not to apply the patching material over an