ASTM A1055/A1055M-22

This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication of what changes have been made to the previous version. Because
it may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current version
of the standard as published by ASTM is to be considered the official document.
Designation: A1055/A1055M − 16 A1055/A1055M − 22
Standard Specification for
Zinc and Epoxy Dual-Coated Steel Reinforcing Bars
This standard is issued under the fixed designation A1055/A1055M; 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 (´) indicates an editorial change since the last revision or reapproval.
1. Scope*
1.1 This specification covers deformed and plain steel reinforcing bars with a dual coating of zinc-alloy followed by an epoxy
coating applied by the electrostatic spray method.
1.2 The zinc-alloy coating is produced as one of two types: zinc-alloy applied by the thermal spray method (Type I) or zinc-alloy
applied in accordance with Specification A1094/A1094M (Type II).
NOTE 1—The coating applicator is identified throughout this specification as the manufacturer.
1.3 Requirements for the zinc coating are contained in Table 1.
1.4 Requirements for epoxy powder coatings are contained in Annex A1.
1.5 Guidelines for construction practices at the job-site are presented in Appendix X1.
1.6 The text of this specification references notes and footnotes which provide explanatory material. These notes and footnotes
(excluding those in tables and figures) shall not be considered as requirements of the specification.
1.7 This specification is applicable for orders in either inch-pound units [as Specification A1055] or SI units [as Specification
A1055M].
1.8 The values stated in either inch-pound units or SI units are to be regarded as standard. Within the text, the SI units are shown
in brackets. The values stated in each system may not be exact equivalents; therefore, each system must be used independently
of the other, except as specifically noted in Table 2. Combining values from the two systems may result in non-conformance with
this specification.
1.9 This specification 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 specification to establish appropriate safety, health, and environmental practices and determine the applicability
of regulatory limitations prior to use.
1.10 This international standard was developed in accordance with internationally recognized principles on standardization
established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued
by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
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 Dec. 1, 2016Sept. 1, 2022. Published March 2017November 2022. Originally approved in 2008. Last previous edition approved in 20102016
ε1
as A1055 – 10A1055/A1055M – 16. . DOI: 10.1520/A1055_A1055M-16.10.1520/A1055_A1055M-22.
*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
A1055/A1055M − 22
TABLE 1 Chemical Composition Requirements for Zinc and Zinc-Alloy Wires
Al,
Common
max Cd, Cu, Fe, Pb, Sn, Sb, Ag, Bi, As, Ni, Mg, Mo, Ti, Zn, Other,
Name
unless max max max max max max max max max max max max max min Total max
A
(UNS)
noted
B
99.99 Zinc
C D
0.002 0.003 0.005 0.003 0.003 0.001 { { { { { { { { 99.99 {
(Z13005)
B
99.99 Zinc 0.10 total
0.01 0.02 0.02 0.02 0.03 { { { { { { { { { 99.9
(Z15005)
non-Zn
99.995 Zinc
0.001 0.003 0.001 0.002 0.003 0.003 { { { { { { { { 99.995 0.005
E
({)
99.95 Zinc
0.01 0.02 0.001 0.02 0.03 0.001 { { { { { { { { 99.95 0.050
({)
99.95 Zinc
0.01 0.005 0.7 0.01 0.005 0.001 { { { { { 0.01 0.01 0.18 99 1.0
({)
98Zn/2Al
1.5-2.5 0.005 0.005 0.02 0.005 0.003 0.10 0.015 0.02 0.002 0.005 0.02 { { remainder {
(Z30402)
A
UNS designations were established in accordance with Practice E527.
B
In accordance with ANSI/AWS A5.33.
C
The following applies to all specified limits in this table. For the purposes of determining conformance with this specification, an observed value obtained from analysis
shall be rounded off to the nearest unit in the last right-hand place of figures used in expressing the limiting value, in accordance with the rounding method of Practice E29.
D
{ indicates that the element is not applicable.
E
({) indicates no Unified Numbering System (UNS) designation for this option.
TABLE 2 Bend Test Requirements
A615, A706, A615M, A706M,
Bend Angle Time
or A996 or A996M
(After to
Pin Pin
Rebound, Completion
Bar Bar
Diameter Diameter
degrees) max, s
No. No.
A A
in. mm
3 3 10 75 180 15
4 4 13 100 180 15
5 5 16 125 180 15
6 6 19 150 180 15
7 7 22 175 180 45
8 8 25 200 180 45
B B
9 9 29 230 180 45
B B
10 10 32 250 180 45
B B
11 11 36 280 180 45
B B
14 17 43 430 90 45
B B
18 23 57 580 90 45
A
Pin diameters specified for similar size (shown on the same line) inch-pound bars
and metric may be interchanged.
B
Bar designation Nos. 9, 10, 11, 14, and 18 [29, 32, 36, 43, and 57] are not
covered by Specification A996/A996M.
2. Referenced Documents
2.1 ASTM Standards:
A615/A615M Specification for Deformed and Plain Carbon-Steel Bars for Concrete Reinforcement
A706/A706M Specification for Deformed and Plain Low-Alloy Steel Bars for Concrete Reinforcement
A775/A775M Specification for Epoxy-Coated Steel Reinforcing Bars
A944 Test Method for Comparing Bond Strength of Steel Reinforcing Bars to Concrete Using Beam-End Specimens
A996/A996M Specification for Rail-Steel and Axle-Steel Deformed Bars for Concrete Reinforcement
A1035/A1035M Specification for Deformed and Plain, Low-Carbon, Chromium, Steel Bars for Concrete Reinforcement
A1094/A1094M Specification for Continuous Hot-Dip Galvanized Steel Bars for Concrete Reinforcement
B117 Practice for Operating Salt Spray (Fog) Apparatus
B833 Specification for Zinc and Zinc Alloy Wire for Thermal Spraying (Metallizing) for the Corrosion Protection of Steel
D4060 Test Method for Abrasion Resistance of Organic Coatings by the Taber Abraser
D4417 Test Methods for Field Measurement of Surface Profile of Blast Cleaned Steel
E29 Practice for Using Significant Digits in Test Data to Determine Conformance with Specifications
E527 Practice for Numbering Metals and Alloys in the Unified Numbering System (UNS)
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.
A1055/A1055M − 22
G14 Test Method for Impact Resistance of Pipeline Coatings (Falling Weight Test)
G20 Test Method for Chemical Resistance of Pipeline Coatings
G62 Test Methods for Holiday Detection in Pipeline Coatings
2.2 American Welding Society:
ANSI/AWS A5.33 Specification for Solid and Ceramic Wires and Ceramic Rods for Thermal Spraying
AWS C2.23M ⁄C2.23 Specification for the Application of Thermal Spray Coatings (Metallizing) of Aluminum, Zinc, and Their
Alloys and Composites for the Corrosion Protection for Steel
AWS C2.25 ⁄C2.25M Specification for Thermal Spray Feedstock—Solid and Composite Wire and Ceramic Rods
2.3 Society for Protective Coatings Specifications:
SSPC-PA 2 Measurement of Dry Coating Thickness with Magnetic Gages
SSPC-SP 10 Near-White Blast Cleaning
SSPC-VIS 1 Pictorial Surface Preparation Standards for Painting Steel Surfaces
2.4 Concrete Reinforcing Steel Institute:
Voluntary Certification Program for Fusion Bonded Epoxy Coating Applicator Plants
2.5 American Concrete Institute Standard:
ACI 301 Specifications for Structural Concrete
3. Terminology
3.1 Definitions of Terms Specific to This Specification:
3.1.1 batch, n—epoxy powder or patching material contained in an individual shipping release or shipping order.
3.1.2 damaged coating, n—area surrounded by coating where steel surface is visible to a person with normal or corrected vision.
3.1.3 disbonding, n—loss of adhesion between the fusion-bonded epoxy coating and the zinc-coated steel reinforcing bar.
3.1.4 fusion-bonded epoxy coating, n—a product containing pigments, thermosetting resins, cross-linking agents, and other
additives, which is applied in the form of a powder onto a clean, heated metallic substrate and fused to form a continuous barrier
coating.
3.1.5 holiday, n—a discontinuity in a coating that is not visible to a person with normal or corrected vision.
3.1.6 lot, n—bars of one size and pattern of deformations contained in an individual shipping release or shipping order.
3.1.7 patching material, n—a liquid two-part, epoxy coating used to repair damaged coating and to coat or uncoated areas on the
surface of a coated bar, or to coat cut ends of a coated bar.
3.1.8 thermal spray coating (metallizing), n—a zinc and zinc alloy, or both, wire used in depositing a metallized layer of zinc by
thermal spraying (metallizing) using oxy-fuel or electric-arc thermal spraying which is applied onto a clean, heated metallic
substrate to form a continuous coating.
3.1.9 wetting agent, n—a material that decreases 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 Orders for zinc-alloy and epoxy dual-coated steel reinforcing bars under this specification shall contain the following
information:
4.1.1 Specification for reinforcing bars to be coated (ASTM designation and year of issue) (5.1),
Available from American Welding Society (AWS), 8669 NW 36 St., #130, Miami, FL 33166-6672, http://www.aws.org.
Available from Society for Protective Coatings (SSPC), 800 Trumbull Dr., Pittsburgh, PA 15205, http://www.sspc.org.
Available from Concrete Reinforcing Steel Institute (CRSI), 933 N. Plum Grove Rd., Schaumburg, IL 60173-4758, http://www.crsi.org.
Available from American Concrete Institute (ACI), 38800 Country Club Dr., Farmington Hills, MI 48331-3439, http://www.concrete.org.
A1055/A1055M − 22
4.1.2 Quantity of bars,
4.1.3 Size designation and grade of bars,
4.1.4 Requirements for the zinc-alloy coating, Type I or Type II (5.2 and 5.3), and that Type II product be chemically treated by
the galvanizer,
4.1.5 Requirements for the epoxy powder coating (5.4),
4.1.6 Quantity of patching material, and
4.1.7 ASTM designation A1055 [A1055M] and year of issue.
4.2 The purchaser shall have the option to specify additional requirements, including, but not limited to the following:
4.2.1 Requirements for providing powder coating samples from each batch (5.4),
4.2.2 Approval from the coating manufacturer that the patching material supplied is compatible (5.5),
4.2.3 Specific requirements for sampling and test frequency for thickness, continuity, flexibility, and adhesion (9.1),
4.2.4 Whether a report on tests performed on the coated steel reinforcing bars being furnished is required (8.4.1 and Section 14),
4.2.5 Requirements for inspection (12.1),
4.2.6 Manufacturer qualification and certification requirements (if any), and
4.2.7 Other special requirements, if any.
NOTE 2—It is recommended that the coating application procedures and processes be audited by an independent certification program for coating
applicator plants such as that provided by the Voluntary Certification Program or equivalent.
5. Materials
5.1 Steel Reinforcing Bars for Type I Zinc-Alloy Coated Bars:
5.1.1 Steel reinforcing bars to be coated shall meet the requirements of one of the following specifications: A615, A706, A996,
or A996A1035 [A615M, A706M, A996M, or A996M]A1035M] as specified by the purchaser and shall be free of contaminants
such as oil, grease, or paint when received at the manufacturer’s plant and prior to cleaning and coating.
NOTE 3—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 those points.
A1055/A1055M − 22
5.2 Zinc-Alloy Wire for Type I Zinc-Alloy Coated Bars:
5.2.1 The thermal spray coating feedstock material shall be specified according to Specification B833 or to AWS C2.25 ⁄C2.25M.
5.2.2 The wire shall conform to one of the chemical composition requirements prescribed in Table 1.
5.2.3 The wire shall be clean and free of corrosion, adhering foreign material, scale, seams, nicks, burrs, and other defects which
would interfere with the operation of thermal spraying equipment. The wire shall uncoil readily and be free of bends or kinks that
would prevent its passage through the thermal spray gun.
5.2.4 The wire shall be a continuous length per spool, coil, or drum. Splices or welds are permitted, provided that they do not
interfere with the thermal spray equipment or coating process.
5.2.5 The starting end of each coil shall be tagged to indicate winding direction and to be readily identifiable with ASTM
designation.
5.3 Type II Zinc-Alloy Coated Bars:
5.3.1 The product to be epoxy coated shall conform to the requirements of Specification A1094/A1094M.
5.4 Epoxy Powder Coating:
5.4.1 The epoxy powder coating shall conform to the requirements of Annex A1. Upon request, the purchaser shall be provided
with data confirming the epoxy powder coating conforms to the requirements of Annex A1.
5.4.2 A written certification shall be furnished to the purchaser that properly identifies the number of each batch of epoxy powder
coating used in the purchase order, material quantity represented, date of manufacture, name and address of the epoxy powder
coating manufacturer, and a statement that the supplied epoxy powder coating is the same composition as that qualified in
accordance with Annex A1 of this specification.
5.4.3 The epoxy powder coating shall be transported and stored in a temperature-controlled environment in accordance with the
documented recommendations of the manufacturer of the epoxy powder coating until ready for use. At that point, if the storage
temperature is below the plant ambient temperature, the epoxy powder coating shall be given sufficient time to reach a temperature
that is within 65°F [62°C]65 °F [62 °C] of the plant ambient temperature.
5.4.4 The epoxy powder coating shall be used within the epoxy powder coating manufacturer’s written recommended shelf life.
5.5 If specified in the purchase order or contract, a representative 8-oz [0.2-kg] sample of the epoxy powder coating shall be
supplied to the purchaser from each lot. The sample shall be packaged in an airtight container and identified by lot number.
5.6 Patching material for repairing damaged epoxy coating shall conform to the requirements of Annex A2 in Specification
A775/A775M.
5.6.1 The manufacturer of the patching material shall specify the metal surface preparation, the coating thickness, and the
procedures for application of the patching material.
5.6.2 If specified in the purchase order or contract, patching material shall be supplied to the purchaser.
6. Surface Preparation
6.1 Type I:
6.1.1 Blast media found to be contaminated with soluble salts shall be rejected.
NOTE 4—It is recommended that incoming steel reinforcing bars and blast media be checked for soluble salt contamination prior to use. Steel reinforcing
bars found to be soluble salt contaminated from exposure to deicing salts or salt spray should be cleaned by acid washing or other suitable methods to
A1055/A1055M − 22
remove soluble salt contaminants from the surface prior to abrasive blast cleaning.
6.1.2 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-SP 10. The final surface condition shall be defined according to SSPC-VIS 1.
6.1.3 Average blast profile roughness depth readings shall be 1.5 to 4.0 mils [40 to 100 μm]. Measurements shall be determined
by either:
6.1.3.1 A “Profilometer” type surface instrument that measures the peak count as well as the maximum profile depth, used in
accordance with the written instructions of the manufacturer of the instrument and Test Methods D4417, Method B, or
6.1.3.2 Replica tape measurements using Test Methods D4417, Method C.
NOTE 5—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 of it will take on the appearance of shot.
6.1.4 Multidirectional, high-pressure dry air knives shall be used after blasting abrasive blast cleaning to remove dust, grit, and
other foreign matter from the abrasive blast-cleaned steel surface. The air knives shall not deposit oil on the steel reinforcing bars.
6.2 Type II:
6.2.1 Prior to epoxy coating, the surface of Type II zinc-alloy coated bars produced to Specification A1094/A1094M shall be
visually inspected to ensure freedom from surface contaminants such as dirt, dust, and oils. Any such contaminants shall be
removed prior to epoxy coating.
7. Zinc-Alloy Coating Application
7.1 Type I:
7.1.1 A thin zinc-alloy layer shall be applied by a thermal arc spray (metallization) system directly after the abrasive blast cleaning
and before application of the epoxy powder coating in accordance with AWS C2.23M ⁄C2.23 and the written specification of the
zinc alloy supplier.
7.1.1.1 Thermal spray equipment shall be set up, calibrated, and operated in accordance with the manufacturer’s instructions and
technical manuals, or the Thermal Coating Spray applicator’s recommendation.
7.1.2 The zinc-alloy coating shall be applied to the cleaned steel reinforcing bar surface as soon as possible after the bar has been
cleaned and before visible oxidation of the surface occurs as visible to a person with normal or corrected vision. In no case shall
application of the coating be delayed more than 30 minutes after cleaning.
7.1.3 The epoxy powder coating shall be applied by electrostatic spray or other suitable method.
7.1.4 The fusion-bonded epoxy powder coating shall be applied in accordance with the written recommendations of the
manufacturer of the epoxy powder coating for initial steel surface temperature range and post-application curing requirements.
During continuous operations, the temperature of the metal surface immediately prior to coating shall be measured using infrared
guns or temperature-indicating crayons, or both, at least once every 30 minutes. At no time shall the temperature of the metal
surface exceed 700°F [334°C].700 °F [334 °C].
NOTE 6—The use of both infrared and temperature-indicating crayon measurement of the surface temperature of steel reinforcing bars is recommended.
7.2 Type II:
7.2.1 The zinc-alloy coating shall be applied in conformance to the requirements of Specification A1094/A1094M. Except in the
case of continuous galvanizing followed by immediate in-line application of epoxy coating, the product shall be chemically treated
by the galvanizer to provide a surface suitable for application of epoxy coating at another location.
A1055/A1055M − 22
8. Requirements for Coated Steel Reinforcing Bars
8.1 Coating Thickness:
8.1.1 The coating thickness of the zinc-alloy layer shall be a minimum of 1.4 mils [35 μm] for Type I and a minimum of 2.0 mils
[50 μm] for Type II.
8.1.2 The total coating thickness measurements of the combined zinc-alloy layer and the epoxy coating layer after curing shall
be 77 mils to 12 mils [175[175 μm to 300 μm] for bars sizes Nos. 3 to 5 [10 to 16] and 77 mils to 16 mils [175[175 μm to 400
μm] for bar sizes Nos. 6 to 18 [19 to 57]. The upper thickness limit shall not apply to repaired areas of damaged coating.
8.1.3 Coating thicknesses shall be measured and recorded for both zinc-alloy and epoxy thickness. A single-recorded steel
reinforcing bar coating thickness measurement is the average of three individual gage readings obtained between four consecutive
deformations. A minimum of five recorded measurements shall be taken approximately evenly spaced along each side of the test
specimens (a minimum of ten recorded measurements per bar).
NOTE 7—The zinc-alloy thickness will be measured by either using a bar that has only the zinc-alloy coating applied or by use of a duplex measuring
device capable of reading the zinc-alloy and epoxy coatings simultaneously.
8.1.4 For acceptance purposes, the average of all recorded coating thickness measurements shall not be less than the specified
minimum thickness or more than the specified maximum thickness. No single-recorded coating thickness measurement shall be
less than 80 % of the specified minimum thickness or more than 120 % of the specified maximum thickness.
8.1.5 Thickness measurements shall be made in accordance with SSPC-PA 2 and in accordance with the manufacturer’s
instructions for the measuring device, following the instructions for calibration and use recommended by the thickness gauge
manufacturer. “Pencil-type” pull-off gauges that require the operator to observe the reading at the instant the magnet is pulled from
the surface shall not be used.
8.1.6 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 zinc-alloy coating shall be uniform without blisters, cracks, loose particles, or exposed steel as examined with 10×
magnification.
8.2.2 The manufacturer’s plant shall have an operational in-line 67.5 V, 80 000 Ω wet-sponge type direct-current in-line holiday
detector or equivalent holiday-detection system with an automated holiday counting system to determine the epoxy coating
acceptability of the coated steel reinforcing bars prior to shipment. A wetting agent is not required during the inspection for
holidays.
8.2.3 Hand-held holiday detector checks shall be performed during each production day to verify the accuracy of the in-line
holiday detection system.
8.2.4 On average, there shall not be more than one holiday per foot [three holidays per metre] on a coated steel reinforcing bar.
The average applies to the full production length of a bar.
8.3 Epoxy Coating Flexibility:
8.3.1 The epoxy coating flexibility for Type I and Type II shall be evaluated by bending production-coated steel reinforcing bars
(with both the zinc-alloy and the powder coating applied) at a uniform rate around a pin of specified size within a maximum
specified time period as prescribed in Table 2. The two longitudinal ribs of the coated bar shall be placed in a plane perpendicular
to the radius of the pin. The temperature of the test specimens for Type I shall be between 158158 °F and 176°F [70176 °F [70 °C
and 80°C].80 °C]. The temperature of the test specimens for Type II shall be between 6868 °F and 86°F [2086 °F [20 °C and
30°C].30 °C].
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 specimen.
A1055/A1055M − 22
NOTE 8—The qualification requirements for coating flexibility (see A1.3.4.1) prescribe bending a No. 6 [19] deformed bar around a 6-in. [150-mm]
diameter pin. The bend test requirements in Table 2 for evaluating the coating flexibility of production-coated steel reinforcing bars, for bar sizes Nos.
3 to 8 [10 to 25], are not compatible with fabrication bending practices. Finished bend diameters for bar sizes Nos. 3 to 8 [10 to 25] used in actual
construction are smaller than the pin diameters in Table 2. 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. To minimize the potential for damaging the coating, bending should be performed within the prescribed temperature range of
158158 °F and 176°F [70176 °F [70 °C and 80°C]80 °C] for Type I product and 6868 °F and 86°F [2086 °F [20 °C and 30°C]30 °C] for Type II product.
8.3.3 A bend test in which fracture or partial failure of the steel reinforcing bar, or cracking or disbonding of the coating caused
by imperfections 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 The requirements for coated steel reinforcing bars shall be satisfied 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 shall apply:
9.2.1 Tests for the zinc-alloy and epoxy coating thickness shall be performed on a minimum of two bars of each size every two
production hours
...