ASTM A934/A934M-22

Standard Specification for Epoxy-Coated Prefabricated Steel Reinforcing Bars

ABSTRACT
This specification covers deformed and plain steel reinforcing bars. Steel samples shall be blast cleaned and shall be coated with a protective fusion-bonded epoxy coating by electrostatic spray or other suitable method. The steel specimens shall undergo deformation test, holiday checks, bending tests, and cathodic disbondment test. The steels materials shall conform to the required values of coating thickness, continuity, flexibility, adhesion.
SCOPE
1.1 This specification covers deformed and plain steel reinforcing bars which prior to surface preparation are prefabricated and then coated with a protective fusion-bonded epoxy coating by electrostatic spray or other suitable method.  
1.2 Prefabricated steel reinforcing bars coated with fusion-bonded epoxy powder coating in accordance with this specification are intended to be fabricated before being coated.  
1.3 Organic coatings other than epoxy may be used provided they meet the requirements of this specification.  
1.4 Requirements for epoxy coatings are contained in Annex A1.  
1.5 Requirements for patching material are contained in Annex A2 in Specification A775/A775M.  
1.6 Guidelines for application process and product test procedures of epoxy coatings for steel reinforcing bars are presented in Appendix X1.  
1.7 Guidelines for construction practices at the job-site for coated steel reinforcing bars are presented in Appendix X2.  
1.8 This specification is applicable for orders in either inch-pound units (as Specification A934) or SI [metric] units [as Specification A934M].  
1.9 The values stated in either inch-pound units or SI units are to be regarded separately as standard. The values stated in each system may not be exact equivalents; therefore, each system shall be used independently of the other. Combining values from the two systems may result in non-conformance with the standard.  
1.10 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 appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use.  
1.11 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.

General Information

• Status: Published
• Publication Date: 31-Aug-2022
• ICS: 77.140.15 - Steels for reinforcement of concrete
• Technical Committee: A01 - Steel, Stainless Steel and Related Alloys
• Drafting Committee: A01.05 - Steel Reinforcement

Relations

• Refers: ASTM G8-24 - Standard Test Methods for Cathodic Disbonding of Coated Steel
• Effective Date: 01-Feb-2024
• Refers: ASTM A1035/A1035M-23a - Standard Specification for Deformed and Plain, Low-Carbon, Chromium, Steel Bars for Concrete Reinforcement
• Effective Date: 01-Nov-2023
• Refers: ASTM G62-23 - Standard Test Methods for Holiday Detection of Coatings used to Protect Pipelines
• Effective Date: 01-Oct-2023
• Refers: ASTM G20-10(2019) - Standard Test Method for Chemical Resistance of Pipeline Coatings
• Effective Date: 01-Oct-2019
• Refers: ASTM A1035/A1035M-19 - Standard Specification for Deformed and Plain, Low-Carbon, Chromium, Steel Bars for Concrete Reinforcement
• Effective Date: 01-Sep-2019
• Refers: ASTM A1035/A1035M-16b - Standard Specification for Deformed and Plain, Low-Carbon, Chromium, Steel Bars for Concrete Reinforcement
• Effective Date: 15-Oct-2016
• Refers: ASTM A1035/A1035M-16a - Standard Specification for Deformed and Plain, Low-Carbon, Chromium, Steel Bars for Concrete Reinforcement
• Effective Date: 01-Mar-2016
• Refers: ASTM A1035/A1035M-16 - Standard Specification for Deformed and Plain, Low-Carbon, Chromium, Steel Bars for Concrete Reinforcement
• Effective Date: 15-Jan-2016
• Refers: ASTM A996/A996M-15 - Standard Specification for Rail-Steel and Axle-Steel Deformed Bars for Concrete Reinforcement
• Effective Date: 01-Jul-2015
• Refers: ASTM A1035/A1035M-15 - Standard Specification for Deformed and Plain, Low-Carbon, Chromium, Steel Bars for Concrete Reinforcement
• Effective Date: 01-Jul-2015
• Refers: ASTM A615/A615M-15 - Standard Specification for Deformed and Plain Carbon-Steel Bars for Concrete Reinforcement
• Effective Date: 01-Apr-2015
• Refers: ASTM A996/A996M-14a - Standard Specification for Rail-Steel and Axle-Steel Deformed Bars for Concrete Reinforcement
• Effective Date: 01-Oct-2014
• Refers: ASTM A615/A615M-14 - Standard Specification for Deformed and Plain Carbon-Steel Bars for Concrete Reinforcement
• Effective Date: 01-Apr-2014
• Refers: ASTM A1035/A1035M-14 - Standard Specification for Deformed and Plain, Low-Carbon, Chromium, Steel Bars for Concrete Reinforcement
• Effective Date: 01-Mar-2014
• Refers: ASTM A996/A996M-14 - Standard Specification for Rail-Steel and Axle-Steel Deformed Bars for Concrete Reinforcement
• Effective Date: 01-Mar-2014

Overview

ASTM A934/A934M-22: Standard Specification for Epoxy-Coated Prefabricated Steel Reinforcing Bars provides comprehensive requirements for the manufacture, testing, and use of prefabricated steel reinforcing bars coated with a fusion-bonded epoxy. Developed by ASTM International, this specification addresses both deformed and plain steel bars that are cut and bent to shape prior to having a protective epoxy layer applied, ensuring long-term corrosion resistance in reinforced concrete applications.

The standard ensures consistent quality by covering aspects such as material requirements, coating thickness, continuity, flexibility, and adhesion. It also allows for the use of organic coatings other than epoxy, provided they meet all specified requirements. ASTM A934/A934M-22 is recognized internationally and is suitable for use with both inch-pound and metric units.

Key Topics

• Prefabricated Steel Reinforcing Bars: The specification applies to steel bars that are fabricated to required shapes and sizes prior to surface preparation and coating.
• Fusion-Bonded Epoxy Coating: Bars are coated using electrostatic spray or an equivalent method, forming a protective barrier to prevent corrosion.
• Material Requirements:
  • Bars must comply with referenced ASTM steel specifications (such as A615, A706, A996, or A1035).
  • Coating materials must meet criteria for thickness, flexibility, continuity (free from holidays), and strong adhesion.
• Testing Procedures:
  • Deformation and bending tests to verify structural conformance.
  • Holiday checks (detecting coating discontinuities) using specific detectors.
  • Cathodic disbondment tests to evaluate coating adhesion under electrical stress conditions.
• Coating Repair:
  • Damaged coating, if detected, must be repaired using specified patching materials.
  • Limits on the allowable area of repair ensure the integrity and performance of the protective layer.
• Inspection and Certification:
  • Inspection routines and documentation requirements are outlined for quality assurance.
  • Electronic and printed certification of compliance is required for shipments.

Applications

ASTM A934/A934M-22 is widely used for concrete reinforcement in environments where corrosion resistance is critical, such as:

• Bridges: Reinforcing bars exposed to de-icing salts or marine environments.
• Parking Structures: Where exposure to chlorides accelerates corrosion.
• Marine and Coastal Construction: Piers, seawalls, and docks requiring durable reinforcement.
• Transportation Infrastructure: Tunnels, subways, and highways susceptible to moisture and chemical attack.
• Industrial Facilities: Structures exposed to harsh chemicals or wet environments.

Use of epoxy-coated prefabricated steel reinforcing bars extends service life, reduces maintenance costs, and improves structural durability by mitigating corrosion risks.

Related Standards

For effective implementation and compliance, ASTM A934/A934M-22 is often used in conjunction with the following standards:

• ASTM A615/A615M: Standard Specification for Deformed and Plain Carbon-Steel Bars for Concrete Reinforcement
• ASTM A775/A775M: Standard Specification for Epoxy-Coated Steel Reinforcing Bars (applies to bars coated after fabrication)
• ASTM A706/A706M: Standard Specification for Deformed and Plain Low-Alloy Steel Bars for Concrete Reinforcement
• SSPC-SP 10: Near-White Blast Cleaning - surface preparation prior to coating
• NACE RP 0287: Measurement of surface profile after blast cleaning
• ACI 301/315: Related concrete structures and detailing specifications

By adhering to ASTM A934/A934M-22 and related standards, project stakeholders ensure the highest level of quality and performance for reinforced concrete structures in corrosive environments, contributing to safe and sustainable infrastructure.

Standards Content (Sample)

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.
Designation: A934/A934M −22
Standard Specification for
Epoxy-Coated Prefabricated Steel Reinforcing Bars
This standard is issued under the fixed designationA934/A934M; the number immediately following the designation indicates the year
of original adoption or, in the case of revision, the year of last revision.Anumber in parentheses indicates the year of last reapproval.
A superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope* 1.11 This international standard was developed in accor-
dance with internationally recognized principles on standard-
1.1 This specification covers deformed and plain steel
ization established in the Decision on Principles for the
reinforcing bars which prior to surface preparation are prefab-
Development of International Standards, Guides and Recom-
ricated and then coated with a protective fusion-bonded epoxy
mendations issued by the World Trade Organization Technical
coating by electrostatic spray or other suitable method.
Barriers to Trade (TBT) Committee.
1.2 Prefabricated steel reinforcing bars coated with fusion-
2. Referenced Documents
bonded epoxy powder coating in accordance with this specifi-
cation are intended to be fabricated before being coated.
2.1 ASTM Standards:
A615/A615MSpecificationforDeformedandPlainCarbon-
1.3 Organic coatings other than epoxy may be used pro-
Steel Bars for Concrete Reinforcement
vided they meet the requirements of this specification.
A706/A706MSpecification for Deformed and Plain Low-
1.4 Requirements for epoxy coatings are contained in An-
Alloy Steel Bars for Concrete Reinforcement
nex A1.
A775/A775MSpecification for Epoxy-Coated Steel Rein-
1.5 Requirements for patching material are contained in
forcing Bars
Annex A2 in Specification A775/A775M.
A944Test Method for Comparing Bond Strength of Steel
Reinforcing Bars to Concrete Using Beam-End Speci-
1.6 Guidelines for application process and product test
mens
procedures of epoxy coatings for steel reinforcing bars are
A996/A996MSpecification for Rail-Steel and Axle-Steel
presented in Appendix X1.
Deformed Bars for Concrete Reinforcement
1.7 Guidelines for construction practices at the job-site for
A1035/A1035M Specification for Deformed and Plain,
coated steel reinforcing bars are presented in Appendix X2.
Low-Carbon, Chromium, Steel Bars for Concrete Rein-
1.8 This specification is applicable for orders in either
forcement
inch-pound units (as Specification A934) or SI [metric] units
B117Practice for Operating Salt Spray (Fog) Apparatus
[as Specification A934M].
D4060Test Method for Abrasion Resistance of Organic
Coatings by the Taber Abraser
1.9 The values stated in either inch-pound units or SI units
E2937Guide for Using Infrared Spectroscopy in Forensic
are to be regarded separately as standard. The values stated in
Paint Examinations
each system may not be exact equivalents; therefore, each
G8Test Methods for Cathodic Disbonding of Pipeline Coat-
system shall be used independently of the other. Combining
ings
values from the two systems may result in non-conformance
G14TestMethodforImpactResistanceofPipelineCoatings
with the standard.
(Falling Weight Test)
1.10 This standard does not purport to address all of the
G20Test Method for Chemical Resistance of Pipeline Coat-
safety concerns, if any, associated with its use. It is the
ings
responsibility of the user of this standard to establish appro-
G42Test Method for Cathodic Disbonding of Pipeline
priate safety, health, and environmental practices and deter-
Coatings Subjected to Elevated Temperatures
mine the applicability of regulatory limitations prior to use.
G62Test Methods for Holiday Detection in Pipeline Coat-
ings
This specification is under the jurisdiction ofASTM Committee A01 on Steel,
Stainless Steel and RelatedAlloys and is the direct responsibility of Subcommittee
A01.05 on Steel Reinforcement. For referenced ASTM standards, visit the ASTM website, www.astm.org, or
Current edition approved Sept. 1, 2022. Published November 2022. Originally contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM
approved in 1995. Last previous edition approved in 2019 as A934/A934M – 19. Standards volume information, refer to the standard’s Document Summary page on
DOI: 10.1520/A0934_A0934M-22. the ASTM website.
*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
A934/A934M − 22
2.2 NACE International Standard: 4.1.2 Quantity of bars,
RP0287Field Measurement of Surface Profile of Abrasive
4.1.3 Size and grade of bars, and
Blast Cleaned Steel Surfaces Using a Replica Tape
4.1.4 ASTM designation and year of issue.
2.3 SSPC Specifications:
4.2 Thepurchasershallhavetheoptiontospecifyadditional
SSPC-SP10Near-White Blast Cleaning
requirements, including but not limited to the following:
SSPC-VIS1Pictorial Surface Preparation Standards for
4.2.1 Requirements for review of test data to demonstrate
Painting Steel Surfaces
that the powder coating meets Annex A1 (5.2),
SSPC-PA2Measurement of Dry Coating Thickness with
4.2.2 Representative sample of epoxy powder coating
Magnetic Gages
5 (5.2.2),
2.4 ACI Specifications:
4.2.3 Quantity of patching material (5.3.3),
ACI301Specifications for Structural Concrete
4.2.4 Additional requirements for test frequency (Section
ACI315Details and Detailing of Concrete Reinforcement
6 10),
2.5 CRSI Documents:
4.2.5 Coated specimens shall be provided by the manufac-
Voluntary Certification Programfor Fusion-Bonded Epoxy
turer out of the same production lot of coated reinforcement
Coating Applicator Plants
being furnished to the purchaser (13.1).
3. Terminology
4.2.6 Requirements for inspection (13.1),
4.2.7 Manufacturer qualification and certification require-
3.1 Definitions of Terms Specific to This Standard:
ments (if any),
3.1.1 conversion coating, n—preparation of the blast-
4.2.8 A report of the results of the tests performed on the
cleaned metal surface prior to coating application that is
coated steel reinforcing bars (Section 15),
designed to pretreat the metal to promote coating adhesion,
4.2.9 Requirements for patching material to be sent to
reduce metal coating reactions, improve corrosion resistance,
purchaser (5.3),
and increase blister resistance.
4.2.10 Special packing, bar or bundle marking, loading or
3.1.2 disbonding, n—loss of adhesion between the fusion-
storage requirements, and
bonded epoxy coating and the steel reinforcing bar.
4.2.11 Other special requirements, if any.
3.1.3 fusion-bonded epoxy coating, n—product containing
pigments, thermosetting epoxy resins, crosslinking agents, and NOTE 1—A typical ordering description is as follows:
Deformed Grade 60 bars to ASTM A615–______; 20000 ft, No. 6;
other additives, which is applied in the form of a powder onto
cut to specified lengths and fabricated prior to coating; epoxy-coated to
a clean, heated metallic substrate and fuses to form a continu-
ASTM A934 –____; including written certifications for the powder
ous barrier coating.
coating and coated bars and 1 qt. of patching material.
[Deformed Grade 420 bars toASTMA615M–____; 6000 m, No. 19;
3.1.4 holiday, n—discontinuity in a coating that is not
cut to specified lengths and fabricated prior to coating; epoxy-coated to
discernible to a person with normal or corrected vision.
ASTM A934M –____; including written certifications for the powder
3.1.5 patching material, n—liquid two-part epoxy coating coating and coated bars and 1 L of patching material.]
used to repair damaged coating and to coat uncoated areas on
the surface of a coated bar. 5. Materials
3.1.6 prefabricated bars, n—steel reinforcing bars that are
5.1 Steel reinforcing bars to be coated shall meet the
cut to specified lengths and bent to the required shapes prior to
requirements of one of the following specifications: A615,
coating.
A706,A996,orA1035[A615M,A706M,A996M,orA1035M]
as specified by the purchaser and shall be free of contaminants
3.1.7 wetting agent, n—material that lowers the surface
such as oil, grease, or paint.
tension of water allowing it to penetrate more effectively into
small discontinuities in the coating, giving a more accurate
NOTE2—Priortocoating,thesteelreinforcingbarsshouldbeinspected
indication of the holiday count.
fortheirsuitabilityforcoating.Barswithsharpedgesonthedeformations,
rolled-in slivers, or other surface imperfections are difficult to coat
4. Ordering Information
properly.The coating will flow away from the sharp edges and may result
in inadequate coating thickness at these points.
4.1 Orders for epoxy-coated prefabricated steel reinforcing
5.2 The powder coating shall meet the requirements of
bars under this specification shall contain the following infor-
AnnexA1. Upon request, the purchaser shall be provided with
mation:
test data for review.
4.1.1 Specificationandyearofissueforthereinforcingbars
5.2.1 A written certification shall be furnished to the pur-
to be coated (5.1),
chaserthatproperlyidentifiesthelotdesignationofthepowder
coatingusedintheorder,materialquantityrepresented,dateof
AvailablefromNACEInternational(NACE),15835ParkTenPl.,Houston,TX
manufacture, name and address of the powder coating
77084, http://www.nace.org.
manufacturer,andastatementthatthesuppliedpowdercoating
Available from Society for Protective Coatings (SSPC), 800 Trumbull Drive,
Pittsburgh, PA 15205, https://www.sspc.org.
is the same composition as that qualified according to Annex
Available from American Concrete Institute (ACI), 38800 Country Club Dr.,
A1 of this specification. The powder coating shall be used
Farmington Hills, MI 48331-3439, http://www.concrete.org.
within the powder coating manufacturer’s written recom-
Available from Concrete Reinforcing Steel Institute (CRSI), 933 N. Plum
Grove Rd., Schaumburg, IL 60173-4758, http://www.crsi.org. mended shelf life.
A934/A934M − 22
5.2.2 If specified in the order, a representative 8-oz [0.2-kg]
sampleofthepowdercoatingshallbesuppliedtothepurchaser
from each batch. The sample shall be packaged in an airtight
container and identified by the batch designation.
5.2.3 The powder coating shall be maintained in a
temperature-controlled environment following the written rec-
ommendations of the powder coating manufacturer until ready
for use, at which point the powder coating shall be given
FIG. 1 Bend Type 9 (ACI 315)
sufficienttimetoreachapproximateplantambienttemperature.
5.3 Patching material for repairing damaged coating and
uncoated areas of coated bars shall be inert in concrete and
7.4 It shall be permissible for the manufacturer to use a
feasible for repairs at the applicator plant.
chemical wash or conversion of the steel reinforcing bar
5.3.1 The powder coating manufacturer shall specify the
surface, or both, to enhance coating adhesion. This pretreat-
approved patching material to be used with their powder.
ment shall be applied after abrasive cleaning and before
5.3.2 Patching material shall be approved in accordance
coating,inaccordancewiththewrittenapplicationinstructions
with Annex A2 in Specification A775/A775M prior to use.
specified by the pretreatment manufacturer.
5.3.3 If specified in the order, patching material shall be
supplied to the purchaser.
8. Coating Application
8.1 If pretreatment is used in the preparation of the surface
6. Prefabrication of Steel Reinforcing Bars
the powder coating shall be applied to the cleaned and
6.1 The steel reinforcing bars to be coated shall have been
pretreatedsteelreinforcingbarsurfaceassoonaspossibleafter
prefabricated in accordance with the purchaser’s requirements
surface treatments have been completed, and before visible
or project specifications prior to surface preparation.
oxidation of the surface occurs as discernible to a person with
normal or corrected vision. In no case shall application of the
NOTE 3—Drive rolls on shear beds and backup barrels on benders
should be protected with a suitable covering to minimize crushing or
coating be delayed more than 3 h after cleaning.
creating rollover damage to the steel reinforcing bar deformations during
8.2 The fusion-bonded epoxy powder coating shall be
the fabrication process.
appliedinaccordancewiththewrittenrecommendationsofthe
manufacturer of the powder coating for initial steel surface
7. Surface Preparation of Steel Reinforcing Bars
temperature range and post application cure requirements.The
7.1 Thesurfaceofthesteelreinforcingbarsshallbecleaned
temperatureofthesurfaceimmediatelypriortocoatingshallbe
by abrasive blast steel grit to near-white metal in accordance
measured using infrared guns or temperature-indicating cray-
with SSPC-SP10.
ons at least once every 30 min during continuous operations.
7.1.1 The final surface condition shall be defined according
NOTE 7—The use of infrared and temperature-indicating crayon mea-
to SSPC-VIS1.
surement of the steel reinforcing bars is recommended.
7.1.2 Average blast profile roughness depth readings of
8.3 The powder coating shall be applied by electrostatic
1.5mils to 4.0 mils [37µm to 100 µm], as determined by
spray or other suitable method.
replica tape measurements using RP0287 or other methods
acceptable to the purchaser, shall be considered suitable as an
8.4 Cleaned, uncoated steel reinforcing bars shall be
anchor pattern.
handledbypersonnelwearingcleanglovestopreventcontami-
nation of the steel surface.
NOTE 4—The use of a profilometer type surface measurement instru-
ment that measures the peak count as well as the maximum profile depth
is recommended.
9. Requirements for Coated Steel Reinforcing Bars
7.2 AsteelgritofRockwellHardnessC50orhighershallbe
9.1 Coating Thickness:
used.Amaximum of 5% steel shot is allowable in the media.
9.1.1 Thecoatingthicknessonstraightsectionsofbarsafter
curing shall be 7mils to 12 mils [175µm to 300 µm]. The
NOTE 5—Recycled steel grit abrasive should be maintained so as to
coating thickness on bent sections of bars after curing shall be
minimize contaminants such as oil, salt, and dust caused by the blasting
operation. 7mils to 16 mils [175µm to 405 mm]. Bent sections of bars
aredefinedastheentireradiusofeachbendandportionsofthe
7.3 Multidirectional, high-pressure dry air knives shall be
barextending6in.[150mm]beyondthebeginningandending
usedafterblastcleaningtoremovedust,grit,andotherforeign
bend points on the bar. Bars that are bent with a radius such as
matter from the steel surface. The air knives shall not deposit
Bend Type 9 (Fig. 1) shall have the same coating thickness
oil on the steel reinforcing bars.
requirementsasstraightbars,whenthe "H"dimensionisequal
NOTE 6—It is recommended that incoming steel reinforcing bars and
to or less than one-half of the "R" dimension.
blast media be checked for salt contamination prior to use. Blast media
found to be salt contaminated should be rejected. Steel reinforcing bars NOTE8—Section9.1.1permitsamaximumcoatingthicknessof16mils
found to be salt contaminated from exposure to deicing salts or salt spray [405 µm] on bent sections of bars. Discussion of the effect of the
should be cleaned by acid washing or other suitable methods to remove permissible increased coating thickness on the anchorage capacity of bent
salt contaminants from the surface prior to blast cleaning. bars embedded in concrete is presented in Appendix X3.
A934/A934M − 22
9.1.2 A single recorded steel reinforcing bar coating thick- perpendiculartothemandrelradius.Thetemperatureofthetest
ness measurement is the average of three individual gauge specimensshallbebetween68°Fand86°F[20°Cand30°C].
readings obtained between three consecutive deformations. A 9.3.2 Cracking or disbonding of the coating on the outside
minimum of five recorded measurements shall be taken ap- radius of the bent bar discernible to a person with normal or
proximatelyevenlyspacedalongeachsideofthetestspecimen corrected vision shall be considered cause for rejection of the
(a minimum of ten recorded measurements per bar). coated steel reinforcing bars represented by the bend test
sample.
9.1.3 For acceptance purposes, the average of all recorded
coating thickness measurements shall not be less than the
9.4 Coating Adhesion:
specified minimum thickness or more than the specified
9.4.1 Coating adhesion shall be evaluated by cathodic
maximum thickness. No single recorded coating thickness
disbondment testing of production-coated steel reinforcing
measurementshallbelessthan80%ofthespecifiedminimum
bars. Test Method G42 shall be followed except, (1) the
thickness or more than 120% of the specified maximum
cathodeshallbea8-in.[200-mm]longcoatedsteelreinforcing
thickness.
bar; (2) the anode shall be a 6-in. [150-mm] long solid
9.1.4 Measurements shall be made in accordance with
platinum electrode (0.06-in. [1.6-mm] nominal diameter) or
SSPC-PA2 following the instructions for calibration and use
platinized wire (0.12-in. [3-mm] nominal diameter); (3)a
recommendedbythethicknessgaugemanufacturer.Pull-offor
calomel reference electrode shall be used; (4) the electrolyte
fixed probe gauges shall be used. Pencil-type pull-off gauges
solution shall be 3% NaCl by mass dissolved in distilled
that require the operator to observe the readings at the instant
water; (5) the electrolyte solution temperature shall be 150°F
the magnet is pulled from the surface shall not be used.
63.6°F[65°C 62°C];(6)thedrilledcoatingdefectshallbe
9.1.5 Approximately equal numbers of straight and bent 0.12 in. [3 mm] in diameter; (7) a potential of –3 V measured
sections of coated steel reinforcing bars shall be evaluated. On
against the calomel reference electrode shall be applied and a
the bent sections, approximately half of these measurements 10-ohm shunt resistor used, and; (8) the test duration shall be
shall be made on the inside radius and half on the outside
24 h.
radius. 9.4.2 Following the 24-h exposure and prior to coating
evaluation, the coated steel reinforcing bar shall be given a
9.2 Coating Continuity:
minimum of a 1-h cooling-off period to allow the bar to reach
9.2.1 Holiday checks to determine the acceptability of the
68°F to 86°F [20°C to 30°C].
coatedsteelreinforcingbarspriortoshipmentshallbemadeat
9.4.3 Measurements of the cathodic disbondment radius
the manufacturer’s plant with a handheld 67.5-V, 80000-Ω,
shallbeobtainedat0°,90°,180°,and270°.Theaverageofthe
wet-sponge-type dc holiday detector.
four values shall not exceed 0.24 in. [6 mm] when measured
9.2.2 Thereshallnotbeonaveragemorethanthreeholidays
from the edge of the intentional coating defect.
per metre [one holiday per linear foot] on the coated steel
9.4.4 Approximately even numbers of straight and bent
reinforcing bars. The average applies to the full production
sections of coated steel reinforcing bars shall be evaluated
length of a bar. For coated bars less than 1 ft [0.3 m] in length,
(approximately half of these tests shall be made on the inside
the maximum shall be one holiday.
radius and half on the outside radius on the bent bar sections).
9.2.3 Awetting agent shall be used in accordance with Test
Methods G62 in the inspection for holidays on the coated steel
10. Frequency of Tests
reinforcing bars.
10.1 Tests for coating thickness shall be made on a mini-
9.2.4 The coated steel reinforcing bars shall be inspected at
mum of two bars of straight section and two bars of bent
a maximum rate of 0.2 ft/s [0.05 m/s], wiping one side of the
section of each size from each production hour.
coated bar and then the other with the wetted sponge or an
10.2 Tests for coating continuity shall be conducted on a
equivalent method.
minimum of two bars of each size from each production hour.
NOTE 9—Care should be taken that contact of the sponge along the
10.3 Tests for coating flexibility shall be made on a mini-
entire steel surface being tested is maintained in order to obtain an
mum of one bar of each bar size from each four production
accurate holiday count.
hours.
9.3 Coating Flexibility:
10.4 Tests for coating adhesion shall be made on a mini-
9.3.1 Coating flexibility shall be evaluated by bending
mum of two bars from each 8-h production shift: one straight
production-coated steel reinforcing bars around a mandrel
bar section and one bent bar section. If there are no bent bars
eighttimesthenominaldiameter(d)ofthebaratauniformrate
being coated during the production period, a second straight
and within 5 s. The exception to the 8d mandrel requirement
bar section shall be substituted for the test.
shall be Nos. 14 and 18 [Nos. 43 and 57] bars. A 17-in.
[430-mm] mandrel (9.71d) shall be used when evaluating No.
11. Retests
14 [No. 43] bar, and a 23-in. [580-mm] mandrel (10.22d) shall
be used with No. 18 [No. 57] bar. For Nos. 3 to 5 [Nos. 10 to 11.1 If any test specimen for coating thickness, continuity,
16] coated steel reinforcing bars, the bend angle after rebound flexibility,oradhesionfailstomeetthespecifiedrequirements,
shall be 9°. For Nos. 6 to 18 [Nos. 19 to 57] coated steel the bar from which the test specimen was taken shall be
reinforcing bars, the bend angle after rebound shall be 6°. The rejected and two further coated steel reinforcing bars from the
two longitudinal deformations shall be placed in a plane same lot shall be subjected to the test or tests in which the
A934/A934M − 22
original bar failed. If both additional coated steel reinforcing affectedlotshallbereplacedor,alternately,strippedofcoating,
barspasstheretest,thelotfromwhichtheyweretakenshallbe recleaned, recoated, and resubmitted for acceptance testing in
deemed to meet the requirements of this specification. If either accordance with the requirements of this specification.
of them fails, the lot shall be deemed not to comply with this
NOTE 12—If the coating is not to be stripped from the rejected steel
specification.
reinforcing bars, the bars should be scrapped.
11.2 If the lot does not comply with this specification, two
15. Certification
coated steel reinforcing bars shall be selected from the lot
15.1 The purchaser shall be furnished, at the time of
immediately preceding and immediately following the non-
compliant lot and subjected to the test or tests in which the shipment, written certification that samples representing each
lot of coated steel reinforcing bars have been either tested or
original bars failed. If all bars pass the retests, then the lots
shall be deemed to meet the requirements of this specification. inspected as directed in this specification and the requirements
have been met. When specified in the purchase order or
Ifanybarfailsaretest,thelotfromwhichitoriginatedshallbe
deemed not to comply with this specification. contract, a report of the test results shall be furnished.
11.3 In the case of a second noncompliant lot, the untested 15.2 A Material Test Report, Certificate of Inspection, or
lot immediately next to it, which may be preceding or similar document printed from or used in electronic form from
following, shall be subjected to retest. This procedure shall be an electronic data interchange (EDI) transmission shall be
repeated until a compliant lot is tested. regardedashavingthesamevalidityasacounterpartprintedin
the certifier’s facility. The content of the EDI-transmitted
NOTE10—IntheuseoftheRetestprovisionofthisspecification,a“lot”
document must meet the requirements of the invoked ASTM
is defined as the coated steel reinforcing bars that are represented by the
standard(s) and conform to any EDI agreements between the
samplewhichhasbeentested.Acertainnumberofcoatedsteelreinforcing
barswillhavebeenproducedsincethelastacceptancetestwasperformed purchaser and the supplier. Notwithstanding the absence of a
and accepted. The steel reinforcing bars that have been coated since that
signature, the organization submitting the EDI transmission is
lasttestshouldbedividedintofourequaltimeperiodgroupsaccordingto
responsible for the content of the report.
whentheywereproduced.Eachlotshouldthenbefurtherdefinedasthose
coated steel reinforcing bars that have been produced in a given time
NOTE13—Theindustrydefinitioninvokedhereis:EDIisthecomputer-
period since the last accepted test.
to-computer exchange of business information in a standard format such
as ANSI ASC X12.
12. Permissible Amount of Damaged Coating and Repair
of Damaged Coating 16. Handling and Identification
12.1 Damaged coating discernible to a person with normal 16.1 Coated steel reinforcing bars shall be transported and
or corrected vision shall be repaired with patching material handled with care. All systems for handling coated steel
meetingtherequirementsof5.3inaccordancewiththewritten
reinforcing bars shall have padded contact areas.All bundling
recommendations of the patching material manufacturer. Any bands shall be padded, or suitable banding used to prevent
rust shall be removed by suitable means before application of
damage to the coating. All bundles of coated steel reinforcing
the patching material. bars shall be lifted with a strong back, spreader bar, multiple
supports, or a platform bridge to prevent bar-to-bar abrasion
12.2 The maximum amount of repaired damaged coating
from sags in the bundles. The coated steel reinforcing bars or
shall not exceed 1% of the total surface area in each 1-ft
bundles shall not be dropped or dragged.
[0.3-m] length.
16.2 Smaller pieces of coated steel reinforcing bars, such as
NOTE 11—If the amount of repaired damaged coating in any 1-ft
stirrups and ties, shall be packaged in such a way as to
[0.3-m] length of a coated bar exceeds 1%, that section should be
minimize damage to the coating during shipping and handling.
removed from the coated steel reinforcing bar and discarded. In patching
damaged coating, care should be taken not to apply the patching material
16.3 If circumstances require storing coated steel reinforc-
over an excessive area of the intact coating during the repair process.Too
ingbarsoutdoorsformorethantwomonths,protectivestorage
large an area of thick patching material, especially on smaller-size
measures shall be implemented to protect the material from
reinforcing bars, is likely to cause a reduction in bond strength of the bars
to concrete.
sunlight, salt spray, and weather exposure. If the manufacturer
stores coated steel reinforcing bars outdoors without cover, the
12.3 Repaired areas shall have a minimum thickness of 7
date on which the coated bars are placed outdoor shall be
mils [175 µm].
recorded on the identification tag of the bundled steel. Coated
13. Inspection
steel reinforcing bars stored in severe corrosive environments
will require protection sooner. Coated steel reinforcing bars or
13.1 Inspection of the epoxy-coated steel reinforcing bars
bundles shall be covered with opaque polyethylene sheeting or
shall be agreed upon between the purchaser and the manufac-
other suitable opaque protective material. For stacked bundles,
turer as part of the purchase order or contract.
theprotectivecoveringshallbedrapedaroundtheperimeterof
14. Rejection the stack. The covering shall be secured adequately, and allow
for air circulation around the bars to minimize condensation
14.1 Coated steel reinforcing bars represented by test speci-
under the covering.
mens that do not meet the requirements of this specification
shall be rejected and marked with a contrasting color paint or 16.4 All coated steel reinforcing bars or bundles shall be
other suitable identification. At the manufacturer’s option, the stored off the ground on protective cribbing.
A934/A934M − 22
16.5 The identification of all steel reinforcing bars shall be coating, the powder coating lot designation and the quality
maintained throughout the fabrication and coating process to assurance testing performed.
the point of shipment.
17. Keywords
16.6 Quality assurance codes that certify compliance to this
specification shall be placed on all identification tags of the
17.1 concrete reinforcement; corrosion resistance; epoxy
coated steel reinforcing bars or bundles. These codes shall
coating; prefabrication; steel reinforcing bars
include references to the date of fabrication, the date of
ANNEX
(Mandatory Information)
A1. REQUIREMENTS FOR FUSION-BONDED EPOXY POWDER COATINGS FOR PREFABRICATED
STEEL REINFORCING BARS
A1.1 Epoxy Powder Coatings (6)Ten coated No. 6 [No. 19] steel reinforcing bars, 8-in.
[0.20-m] long, with a coating thickness of 7mils to 12 mils
A1.1.1 This annex covers qualification requirements for
[175µm to 300 µm]. The coated bars shall have their ends
fusion-bonded epoxy powder coatings for protecting steel
sealed with a minimum of 10 mils [250 µm] of patching
reinforcing bars from corrosion.
material.
A1.1.2 Other organic coatings may be used provided they
A1.2.3.2 Steel reinforcing bars with a nominal diameter
meet the requirements of this specification.
within 60.04 in. [61 mm] of No. 6 [No. 19] bars shall be
acceptable for qualification testing.
A1.2 Test Materials
A1.2.3.3 The coating on the bars and films tested shall be
A1.2.1 A 1-lb [0.5-kg] sample of the powder coating with
freeofholes,voids,contamination,cracks,anddamagedareas.
its generic description and its infrared spectrum shall be
The coated bars shall be checked for holidays using a 67.5-V,
submitted to the testing agency.The infrared spectrum shall be
80000-Ω, wet-sponge-type dc holiday detector in accordance
obtainedwithFourierTransformInfraredSpectroscopy(FTIR)
with Test Methods G62. The total number of coating holidays
usingGuideE2937.Thespectrumandgenericdescriptionshall
found on the bar specimens tested shall be reported.
become an integral part of the qualification test report.
A1.2.3.4 Thepowdercoatingmanufacturershallspecifythe
NOTE A1.1—The infrared spectrum uniquely identifies the powder
method and grade of metal surface preparation and the coating
sample.
application procedures for the test specimens and for contract
A1.2.2 Asample of patching material shall be submitted to
production of coated steel reinforcing bars. These procedures
the testing agency. The product name and a description of the
shall be listed in the test report. Note that production-coated
patching material shall be given in the test report.
steel reinforcing bars shall be required to be manufactured in
the same manner as the qualification bars. Therefore, it is
A1.2.3 Test Specimens:
necessary that the qualification coated steel reinforcing bars be
A1.2.3.1 The following specimens shall be submitted as a
prepared in the same manner proposed for production. Varia-
minimum for testing:
tions in the critical preparation, thermal treatment, coating
(1)Fourteen 4-ft [1.2-m] long No. 6 [No. 19], Grade 60
procedures and cure methods known to be allowable without a
[Grade 420] deformed steel reinforcing bars, with a coating
compromiseinqualityshallalsobedetailedinthequalification
thickness of 7mils to 12 mils [175µm to 300 µm].
report.
(2)Six uncoated and uncleaned No. 6 [No. 19] steel
reinforcingbars,4ft[1.2m]long,fromthesamelotofsteelas
A1.3 Coating Requirements
the coated bars.
(3)Four 4in. by 4in. by 0.05-in. [100mm by 100mm by A1.3.1 Infrared Spectroscopy (IR)—Variations in the gel
1.3-mm] thick steel plates with center holes for Taber abrasers and cure time of the powder coatings shall be permitted, if the
with a coating thickness of 10mils 6 2 mils [250µm 6 50 resulting powder spectrum is comparable to the reference
µm]. spectrum of the original powder that was submitted for initial
(4)Four 4in. by 4-in. [100mm by 100-mm] free films of qualification. Differences between powders are indicated by
coatingmaterialwithathicknessof7milsto9mils[175µmto the presence or absence of one or more absorption peaks or
225 µm]. significant differences in shape or position (frequency) of the
(5)Twelve coated No. 6 [No. 19] steel reinforcing bars, bands in the spectra. The reference and sample spectra are
10-in. [0.25-m] long, with a coating thickness of 7mils to 12 considered to represent the same material when the position of
mils[175µmto300µm].Thecoatedbarsshallhavetheirends corre
...

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: A934/A934M − 19 A934/A934M − 22
Standard Specification for
Epoxy-Coated Prefabricated Steel Reinforcing Bars
This standard is issued under the fixed designation A934/A934M; 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 which prior to surface preparation are prefabricated and
then coated with a protective fusion-bonded epoxy coating by electrostatic spray or other suitable method.
1.2 Prefabricated steel reinforcing bars coated with fusion-bonded epoxy powder coating in accordance with this specification are
intended to be fabricated before being coated.
1.3 Organic coatings other than epoxy may be used provided they meet the requirements of this specification.
1.4 Requirements for epoxy coatings are contained in Annex A1.
1.5 Requirements for patching material are contained in Annex A2 in Specification A775/A775M.
1.6 Guidelines for application process and product test procedures of epoxy coatings for steel reinforcing bars are presented in
Appendix X1.
1.7 Guidelines for construction practices at the job-site for coated steel reinforcing bars are presented in Appendix X2.
1.8 This specification is applicable for orders in either inch-pound units (as Specification A934) or SI [metric] units [as
Specification A934M].
1.9 The values stated in either inch-pound units or SI units are to be regarded separately as standard. The values stated in each
system may not be exact equivalents; therefore, each system shall be used independently of the other. Combining values from the
two systems may result in non-conformance with the standard.
1.10 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 appropriate safety, health, and environmental practices and determine the applicability of
regulatory limitations prior to use.
1.11 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 June 1, 2019Sept. 1, 2022. Published June 2019November 2022. Originally approved in 1995. Last previous edition approved in 20162019 as
A934/A934M – 16.19. DOI: 10.1520/A0934_A0934M-19.10.1520/A0934_A0934M-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
A934/A934M − 22
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
B117 Practice for Operating Salt Spray (Fog) Apparatus
D4060 Test Method for Abrasion Resistance of Organic Coatings by the Taber Abraser
E2937 Guide for Using Infrared Spectroscopy in Forensic Paint Examinations
G8 Test Methods for Cathodic Disbonding of Pipeline Coatings
G14 Test Method for Impact Resistance of Pipeline Coatings (Falling Weight Test)
G20 Test Method for Chemical Resistance of Pipeline Coatings
G42 Test Method for Cathodic Disbonding of Pipeline Coatings Subjected to Elevated Temperatures
G62 Test Methods for Holiday Detection in Pipeline Coatings
2.2 NACE International Standard:
RP 0287 Field Measurement of Surface Profile of Abrasive Blast Cleaned Steel Surfaces Using a Replica Tape
2.3 SSPC Specifications:
SSPC-SP 10 Near-White Blast Cleaning
SSPC-VIS 1 Pictorial Surface Preparation Standards for Painting Steel Surfaces
SSPC-PA 2 Measurement of Dry Coating Thickness with Magnetic Gages
2.4 ACI Specifications:
ACI 301 Specifications for Structural Concrete
ACI 315 Details and Detailing of Concrete Reinforcement
2.5 CRSI Documents:
Voluntary Certification Program for Fusion-Bonded Epoxy Coating Applicator Plants
3. Terminology
3.1 Definitions of Terms Specific to This Standard:
3.1.1 conversion coating, n—preparation of the blast-cleaned metal 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—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 continuous barrier
coating.
3.1.4 holiday, n—discontinuity in a coating that is not discernible to a person with normal or corrected vision.
3.1.5 patching material, n—liquid two-part epoxy coating used to repair damaged areas.coating and to coat uncoated areas on the
surface of a coated bar.
3.1.6 prefabricated bars, n—steel reinforcing bars that are cut to specified lengths and bent to the required shapes prior to coating.
3.1.7 wetting agent, n—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.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM Standards
volume information, refer to the standard’s Document Summary page on the ASTM website.
Available from NACE International (NACE), 15835 Park Ten Pl., Houston, TX 77084, http://www.nace.org.
Available from Society for Protective Coatings (SSPC), 800 Trumbull Drive, Pittsburgh, PA 15205, https://www.sspc.org.
Available from American Concrete Institute (ACI), 38800 Country Club Dr., Farmington Hills, MI 48331-3439, http://www.concrete.org.
Available from Concrete Reinforcing Steel Institute (CRSI), 933 N. Plum Grove Rd., Schaumburg, IL 60173-4758, http://www.crsi.org.
A934/A934M − 22
4. Ordering Information
4.1 Orders for epoxy-coated prefabricated steel reinforcing bars under this specification shall contain the following information:
4.1.1 Specification and year of issue for the reinforcing bars to be coated (5.1),
4.1.2 Quantity of bars,
4.1.3 Size and grade of bars, and
4.1.4 ASTM designation 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 review of test data to demonstrate that the powder coating meets Annex A1 (5.2),
4.2.2 Representative sample of epoxy powder coating (5.2.2),
4.2.3 Quantity of patch material,patching material (5.3.3),
4.2.4 Additional requirements for test frequency (Section 10),
4.2.5 Coated specimens shall be provided by the manufacturer out of the same production lot of coated reinforcement being
furnished to the purchaser (13.1).
4.2.6 Requirements for inspection (13.1),
4.2.7 Manufacturer qualification and certification requirements (if any),
4.2.8 A report of the results of the tests performed on the coated steel reinforcing bars (Section 15),
4.2.9 Requirements for patching material to be sent to purchaser (5.3),
4.2.10 Special packing, bar or bundle marking, loading or storage requirements, and
4.2.11 Other special requirements, if any.
NOTE 1—A typical ordering description is as follows:
Deformed Grade 60 bars to ASTM A615 – ______; 20 000 ft, No. 6; cut to specified lengths and fabricated prior to coating; epoxy-coated to ASTM
A934 – ____; including written certifications for the powder coating and coated bars and 1 qt. of patching material.
[Deformed Grade 420 bars to ASTM A615M – ____; 6000 m, No. 19; cut to specified lengths and fabricated prior to coating; epoxy-coated to ASTM
A934M – ____; including written certifications for the powder coating and coated bars and 1 L of patching material.]
5. Materials
5.1 Steel reinforcing bars to be coated shall meet the requirements of one of the following specifications: A615, A706, A996, or
A1035 [A615M, A706M, A996M, or A1035M] as specified by the purchaser and shall be free of contaminants such as oil, grease,
or paint.
NOTE 2—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. 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 test data
for review.
5.2.1 A written certification shall be furnished to the purchaser that properly identifies the lot designation of the powder coating
used in the order, material quantity represented, date of manufacture, name and address of the powder coating manufacturer, and
A934/A934M − 22
a statement that the supplied powder coating is the same composition as that qualified according to Annex A1 of this specification.
The powder coating shall be used within the powder coating manufacturer’s written recommended shelf life.
5.2.2 If specified in the order, a representative 8-oz [0.2-kg] 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 the batch designation.
5.2.3 The powder coating shall be maintained in a temperature-controlled environment following the written recommendations of
the powder coating manufacturer until ready for use, at which point the powder coating shall be given sufficient time to reach
approximate plant ambient temperature.
5.3 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 purchaser.Patching material for repairing damaged coating and uncoated areas of
coated bars shall be inert in concrete and feasible for repairs at the applicator plant.
5.3.1 The powder coating manufacturer shall specify the approved patching material to be used with their powder.
5.3.2 Patching material shall be approved in accordance with Annex A2 in Specification A775/A775M prior to use.
5.3.3 If specified in the order, patching material shall be supplied to the purchaser.
6. Prefabrication of Steel Reinforcing Bars
6.1 The steel reinforcing bars to be coated shall have been prefabricated in accordance with the purchaser’s requirements or project
specifications prior to surface preparation.
NOTE 3—Drive rolls on shear beds and backup barrels on benders should be protected with a suitable covering to minimize crushing or creating rollover
damage to the steel reinforcing bar deformations during the fabrication process.
7. Surface Preparation of Steel Reinforcing Bars
7.1 The surface of the steel reinforcing bars shall be cleaned by abrasive blast steel grit to near-white metal in accordance with
SSPC-SP 10.
7.1.1 The final surface condition shall be defined according to SSPC-VIS 1.
7.1.2 Average blast profile roughness depth readings of 1.51.5 mils to 4.0 mils [37[37 μm to 100 μm], as determined by replica
tape measurements using RP 0287 or other methods acceptable to the purchaser, shall be considered suitable as an anchor pattern.
NOTE 4—The use of a profilometer type surface measurement instrument that measures the peak count as well as the maximum profile depth is
recommended.
7.2 A steel grit of Rockwell Hardness C50 or higher shall be used. A maximum of 5 % steel shot is allowable in the media.
NOTE 5—Recycled steel grit abrasive should be maintained so as to minimize contaminants such as oil, salt, and dust caused by the blasting operation.
7.3 Multidirectional, high-pressure dry air knives shall be used after blast cleaning to remove dust, grit, and other foreign matter
from the steel surface. The air knives shall not deposit oil on the steel reinforcing bars.
NOTE 6—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.
7.4 It shall be permissible for the manufacturer to use a chemical wash or conversion of the steel reinforcing 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.
A934/A934M − 22
FIG. 1 Bend Type 9 (ACI 315)
8. Coating Application
8.1 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.
8.2 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 cure requirements. The
temperature of the surface immediately prior to coating shall be measured using infrared guns or temperature-indicating crayons
at least once every 30 min during continuous operations.
NOTE 7—The use of infrared and temperature-indicating crayon measurement of the steel reinforcing bars is recommended.
8.3 The powder coating shall be applied by electrostatic spray or other suitable method.
8.4 Cleaned, uncoated steel reinforcing bars shall be handled by personnel wearing clean gloves to prevent contamination of the
steel surface.
9. Requirements for Coated Steel Reinforcing Bars
9.1 Coating Thickness:
9.1.1 The coating thickness on straight sections of bars after curing shall be 77 mils to 12 mils [175[175 μm to 300 μm]. The
coating thickness on bent sections of bars after curing shall be 77 mils to 16 mils [175[175 μm to 405 mm]. Bent sections of bars
are defined as the entire radius of each bend and portions of the bar extending 6 in. [150 mm] beyond the beginning and ending
bend points on the bar. Bars that are bent with a radius such as Bend Type 9 (Fig. 1) shall have the same coating thickness
requirements as straight bars, when the "H" dimension is equal to or less than one-half of the "R" dimension.
NOTE 8—Section 9.1.1 permits a maximum coating thickness of 16 mils [405 μm] on bent sections of bars. Discussion of the effect of the permissible
increased coating thickness on the anchorage capacity of bent bars embedded in concrete is presented in Appendix X3.
9.1.2 A single recorded steel reinforcing bar coating thickness measurement is the average of three individual gagegauge readings
obtained between three consecutive deformations. A minimum of five recorded measurements shall be taken approximately 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 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.
9.1.4 Measurements shall be made in accordance with SSPC-PA 2 following the instructions for calibration and use recommended
by the thickness gagegauge manufacturer. Pull-off or fixed probe gagesgauges shall be used. Pencil-type pull-off gagesgauges that
require the operator to observe the readings at the instant the magnet is pulled from the surface shall not be used.
9.1.5 Approximately equal numbers of straight and bent sections of coated steel reinforcing bars shall be evaluated. On the bent
sections, approximately half of these measurements shall be made on the inside radius and half on the outside radius.
A934/A934M − 22
9.2 Coating Continuity:
9.2.1 Holiday checks to determine the acceptability of the coated steel reinforcing bars prior to shipment shall be made at the
manufacturer’s plant with a handheld 67.5-V, 80 000-Ω, wet-sponge-type dc holiday detector.
9.2.2 There shall not be on average more than three holidays per metre [one holiday per linear foot] on the coated steel reinforcing
bars. The average applies to the full production length of a bar. For coated bars less than 1 ft [0.3 m] in length, the maximum shall
be one holiday.
9.2.3 A wetting agent shall be used in accordance with Test Methods G62 in the inspection for holidays on the coated steel
reinforcing bars.
9.2.4 The coated steel reinforcing bars shall be inspected at a maximum rate of 0.2 ft/s [0.05 m/s], wiping one side of the coated
bar and then the other with the wetted sponge or an equivalent method.
NOTE 9—Care should be taken that contact of the sponge along the entire steel surface being tested is maintained in order to obtain an accurate holiday
count.
9.3 Coating Flexibility:
9.3.1 Coating flexibility shall be evaluated by bending production-coated steel reinforcing bars around a mandrel eight times the
nominal diameter (d) of the bar at a uniform rate and within 5 s. The exception to the 8d mandrel requirement shall be Nos. 14
and 18 [Nos. 43 and 57] bars. A 17-in. [430-mm] mandrel (9.71d) shall be used when evaluating No. 14 [No. 43] bar, and a 23-in.
[580-mm] mandrel (10.22d) shall be used with No. 18 [No. 57] bar. For Nos. 3 to 5 [Nos. 10 to 16] coated steel reinforcing bars,
the bend angle after rebound shall be 9°. For Nos. 6 to 18 [Nos. 19 to 57] coated steel reinforcing bars, the bend angle after rebound
shall be 6°. The two longitudinal deformations shall be placed in a plane perpendicular to the mandrel radius. The temperature of
the test specimens shall be between 6868 °F and 86°F [2086 °F [20 °C and 30°C].30 °C].
9.3.2 Cracking or disbonding of the coating on the outside radius of the bent bar discernible 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.
9.4 Coating Adhesion:
9.4.1 Coating adhesion shall be evaluated by cathodic disbondment testing of production-coated steel reinforcing bars. Test
Method G42 shall be followed except, (1) the cathode shall be a 8-in. [200-mm] long coated steel reinforcing bar; (2) the anode
shall be a 6-in. [150-mm] long solid platinum electrode (0.06-in. [1.6-mm] nominal diameter) or platinized wire (0.12-in. [3-mm]
nominal diameter); (3) a calomel reference electrode shall be used; (4) the electrolyte solution shall be 3 % NaCl by mass dissolved
in distilled water; (5) the electrolyte solution temperature shall be 150150 °F 6 3.6°F [653.6 °F [65 °C 6 2°C];2 °C]; (6) the
drilled coating defect shall be 0.12 in. [3 mm] in diameter; (7) a potential of –3 V measured against the calomel reference electrode
shall be applied and a 10-ohm shunt resistor used, and; (8) the test duration shall be 24 h.
9.4.2 Following the 24-h exposure and prior to coating evaluation, the coated steel reinforcing bar shall be given a minimum of
a 1-h cooling-off period to allow the bar to reach 6868 °F to 86°F [2086 °F [20 °C to 30°C].30 °C].
9.4.3 Measurements of the cathodic disbondment radius shall be obtained at 0°, 90°, 180°, and 270°. The average of the four
values shall not exceed 0.24 in. [6 mm] when measured from the edge of the intentional coating defect.
9.4.4 Approximately even numbers of straight and bent sections of coated steel reinforcing bars shall be evaluated (approximately
half of these tests shall be made on the inside radius and half on the outside radius on the bent bar sections).
10. Frequency of Tests
10.1 Tests for coating thickness shall be made on a minimum of two bars of straight section and two bars of bent section of each
size from each production hour.
10.2 Tests for coating continuity shall be conducted on a minimum of two bars of each size from each production hour.
A934/A934M − 22
10.3 Tests for coating flexibility shall be made on a minimum of one bar of each bar size from each four production hours.
10.4 Tests for coating adhesion shall be made on a minimum of two bars from each 8-h production shift: one straight bar section
and one bent bar section. If there are no bent bars being coated during the production period, a second straight bar section shall
be substituted for the test.
11. Retests
11.1 If any test specimen for coating thickness, continuity, flexibility, or adhesion fails to meet the specified requirements, the bar
from which the test specimen was taken shall be rejected and two further coated steel reinforcing bars from the same lot shall be
subjected to the test or tests in which the original bar failed. If both additional coated steel reinforcing bars pass the retest, the lot
from which they were taken shall be deemed to meet the requirements of this specification. If either of them fails, the lot shall be
deemed not to comply with this specification.
11.2 If the lot does not comply with this specification, two coated steel reinforcing bars shall be selected from the lot immediately
preceding and immediately following the non-compliant lot and subjected to the test or tests in which the original bars failed. If
all bars pass the retests, then the lots shall be deemed to meet the requirements of this specification. If any bar fails a retest, the
lot from which it originated shall be deemed not to comply with this specification.
11.3 In the case of a second noncompliant lot, the untested lot immediately next to it, which may be preceding or following, shall
be subjected to retest. This procedure shall be repeated until a compliant lot is tested.
NOTE 10—In the use of the Retest provision of this specification, a “lot” is defined as the coated steel reinforcing bars that are represented by the sample
which has been tested. A certain number of coated steel reinforcing bars will have been produced since the last acceptance test was performed and
accepted. The steel reinforcing bars that have been coated since that last test should be divided into four equal time period groups according to when they
were produced. Each lot should then be further defined as those coated steel reinforcing bars that have been produced in a given time period since the
last accepted test.
12. Permissible Amount of Damaged Coating and Repair of Damaged Coating
12.1 Damaged coating discernible to a person with normal or corrected vision shall be repaired with patching material meeting
the requirements of 5.3 in accordance with the written recommendations of the patching material manufacturer. Any rust shall be
removed by suitable means before application of the patching material.
12.2 The maximum amount of repaired damaged coating shall not exceed 1 % of the total surface area in each 1-ft [0.3-m] length.
NOTE 11—If the amount of repaired damaged coating in any 1-ft [0.3-m] 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 excessive area
of the intact coating during the repair process. Too large an area of thick patching material, especially on smaller-size reinforcing bars, is likely to cause
a reduction in bond strength of the bars to concrete.
12.3 Repaired areas shall have a minimum thickness of 7 mils [175 μm].
13. Inspection
13.1 Inspection of the epoxy-coated steel reinforcing bars shall be agreed upon between the purchaser and the manufacturer as
part of the purchase order or contract.
14. Rejection
14.1 Coated steel reinforcing bars represented by test specimens that do not meet the requirements of this specification shall be
rejected and marked with a contrasting color paint or other suitable identification. At the manufacturer’s option, the affected lot
shall be replaced or, alternately, stripped of coating, recleaned, recoated, and resubmitted for acceptance testing in accordance with
the requirements of this specification.
NOTE 12—If the coating is not to be stripped from the rejected steel reinforcing bars, the bars should be scrapped.
A934/A934M − 22
15. Certification
15.1 The purchaser shall be furnished, at the time of shipment, written certification that samples representing each lot of coated
steel reinforcing bars have been either tested or inspected as directed in this specification and the requirements have been met.
When specified in the purchase order or contract, a report of the test results shall be furnished.
15.2 A Material Test Report, Certificate of Inspection, or similar document printed from or used in electronic form from an
electronic data interchange (EDI) transmission shall be regarded as having the same validity as a counterpart printed in the
certifier’s facility. The content of the EDI-transmitted document must meet the requirements of the invoked ASTM standard(s) and
conform to any EDI agreements between the purchaser and the supplier. Notwithstanding the absence of a signature, the
organization submitting the EDI transmission is responsible for the content of the report.
NOTE 13—The industry definition invoked here is: EDI is the computer-to-computer exchange of business information in a standard format such as ANSI
ASC X12.
16. Handling and Identification
16.1 Coated steel reinforcing bars shall be transported and handled with care. All systems for handling coated steel reinforcing
bars shall have padded contact areas. All bundling bands shall be padded, or suitable banding used to prevent damage to the
coating. All bundles of coated steel reinforcing bars shall be lifted with a strong back, spreader bar, multiple supports, or a platform
bridge to prevent bar-to-bar abrasion from sags in the bundles. The coated steel reinforcing bars or bundles shall not be dropped
or dragged.
16.2 Smaller pieces of coated steel reinforcing bars, such as stirrups and ties, shall be packaged in such a way as to minimize
damage to the coating during shipping and handling.
16.3 If circumstances require storing coated steel reinforcing bars outdoors for more than two months, protective storage measures
shall be implemented to protect the material from sunlight, salt spray, and weather exposure. If the manufacturer stores coated steel
reinforcing bars outdoors without cover, the date on which the coated bars are placed outdoor shall be recorded on the identification
tag of the bundled steel. Coated steel reinforcing bars stored in severe corrosive environments will require protection sooner.
Coated steel reinforcing bars or bundles shall be covered with opaque polyethylene sheeting or other suitable opaque protective
material. For stacked bundles, the protective covering shall be draped around the perimeter of the stack. The covering shall be
secured adequately, and allow for air circulation around the bars to minimize condensation under the covering.
16.4 All coated steel reinforcing bars or bundles shall be stored off the ground on protective cribbing.
16.5 The identification of all steel reinforcing bars shall be maintained throughout the fabrication and coating process to the point
of shipment.
16.6 Quality assurance codes that certify compliance to this specification shall be placed on all identification tags of the coated
steel reinforcing bars or bundles. These codes shall include references to the date of fabrication, the date of coating, the powder
coating lot designation and the quality assurance testing performed.
17. Keywords
17.1 concrete reinforcement; corrosion resistance; epoxy coating; prefabrication; steel reinforcing bars
A934/A934M − 22
ANNEX
(Mandatory Information)
A1. REQUIREMENTS FOR FUSION-BONDED EPOXY POWDER COATINGS FOR PREFABRICATED
STEEL REINFORCING BARS
A1.1 Epoxy Powder Coatings
A1.1.1 This annex covers qualification requirements for fusion-bonded epoxy powder coatings for protecting steel reinforcing bars
from corrosion.
A1.1.2 Other organic coatings may be used provided they meet the requirements of this specification.
A1.2 Test Materials
A1.2.1 A 1-lb [0.5-kg] sample of the powder coating with its generic description and its infrared spectrum shall be submitted to
the testing agency. The infrared spectrum shall be obtained with Fourier Transform Infrared Spectroscopy (FTIR) using Guide
E2937. The spectrum and generic description shall become an integral part of the qualification test report.
NOTE A1.1—The infrared spectrum uniquely identifies the powder sample.
A1.2.2 A sample of patching material shall be submitted to the testing agency. The product name and a description of the patching
material shall be given in the test report.
A1.2.3 Test Specimens:
A1.2.3.1 The following specimens shall be submitted as a minimum for testing:
(1) Fourteen 4-ft [1.2-m] long No. 6 [No. 19], Grade 60 [Grade 420] deformed steel reinforcing bars, with a coating thickness
of 77 mils to 12 mils [175[175 μm to 300 μm].
(2) Six uncoated and uncleaned No. 6 [No. 19] steel reinforcing bars, 4 ft [1.2 m] long, from the same lot of steel as the coated
bars.
(3) Four 44 in. by 44 in. by 0.05-in. [100[100 mm by 100100 mm by 1.3-mm] thick steel plates with center holes for Taber
abrasers with a coating thickness of 1010 mils 6 2 mils [250[250 μm 6 50 μm].
(4) Four 44 in. by 4-in. [100[100 mm by 100-mm] free films of coating material with a thickness of 77 mils to 9 mils
[175[175 μm to 225 μm].
(5) Twelve coated No. 6 [No. 19] steel reinforcing bars, 10-in. [0.25-m] long, with a coating thickness of 77 mils to 12 mils
[175[175 μm to 300 μm]. The coated bars shall have their ends sealed with a minimum of 10 mils [250 μm] of patching material.
(6) Ten coated No. 6 [No. 19] steel reinforcing bars, 8-in. [0.20-m] long, with a coating thickness of 77 mils to 12 mils
[175[175 μm to 300 μm]. The coated bars shall have their ends sealed with a minimum of 10 mils [250 μm] of patching material.
A1.2.3.2 Steel reinforcing bars with a nominal diameter within 60.04 in. [61 mm] of No. 6 [No. 19] bars shall be acceptable for
qualification testing.
A934/A934M − 22
A1.2.3.3 The coating on the bars and films tested shall be free of holes, voids, contamination, cracks, and damaged areas. The
coated bars shall be checked for holidays using a 67.5-V, 80 000-Ω, wet-sponge-type dc holiday detector in accordance with Test
Methods G62. The total number of coating holidays found on the bar specimens tested shall be reported.
A1.2.3.4 The powder coating manufacturer shall specify the method and grade of metal surface preparation and the coating
application procedures for the test specimens and for contract production of coated steel reinforcing bars. These procedures shall
be listed in the test report. Note that production-coated steel reinforcing bars shall be required to be manufactured in the same
manner as the qualification bars. Therefore, it is necessary that the qualification coated steel reinforcing bars be prepared in the
same manner proposed for production. Variations in the critical preparation, thermal treatment, coating procedures and cure
methods known to be allowable without a compromise in quality shall also be detailed in the qualification report.
A1.3 Coating Requirements
A1.3.1 Infrared Spectroscopy (IR)—Variations in the gel and cure time of the powder coatings shall be permitted, if the resulting
powder spectrum is comparable to the reference spectrum of the original powder that was submitted for initial qualification.
Differences between powders are indicated by the presence or absence of one or more absorption peaks or significant differences
in shape or position (frequency) of the bands in the spectra. The reference and sample spectra are considered to represent the same
-1
material when the position of corresponding peaks in the two spectra are within plus/minus 5 cm . The IR test shall be performed
-1 -1
using the FTIR. The spectral range should cover at least 4000 cm to 650 cm . Samples being compared shall be prepared in the
same manner (for example, KBr, cast film, ATR) as the reference material and the IR scans shall be obtained using equivalent
parameters. Spectral differences associated with sample concentration (the overall level of transmittance or absorbance across the
entire spectrum of the sample or other effects unrelated to the composition such as incidental presence of atmospheric peaks) shall
not be considered as non-conforming differences when making the comparison.
A1.3.2 Chemical Resistance—The chemical resistance of the coating shall be evaluated in accordance with Test Method G20 by
immersing coated steel reinforcing bars in each of the following: distilled water, a 3-M aqueous solution of CaCl , a 3-M aqueous
solution of NaOH, and a solution saturated with Ca(OH) . Specimens without holidays and specimens with an intentional 0.25-in.
[6-mm] diameter hole drilled through the coating shall be tested. The temperature of the test solutions shall be 7575 °F 6 3.6°F
[243.6 °F [24 °C 6 2°C].2 °C]. The immersion shall last 45 days. The coating must not blister, soften, lose bond, or develop
holidays during this period. The coating surrounding the intentionally made hole shall exhibit no undercutting during the 45-day
period.
A1.3.3 Cathodic Disbondment—The effects of electrical and electrochemical stresses on the bond of the coating to steel and on
the film integrity shall be assessed in elevated and ambient temperature cathodic disbondment tests. Fig. A1.1 presents the
recommended equipment configuration for performing cathodic disbondment testing on steel reinforcing bars. The intentional
coating defect shall be placed approximately 2 in. [50 mm] from the sealed end of the test bar centered between the longitudinal
and transverse ribs. It shall be drilled just deep enough to expose a full 0.12-in. [3-mm] diameter in the steel. The test bar shall
be inserted with the sealed end of the bar resting on the bottom of the test vessel and electrolyte added until 4 in. [100 mm] of
the bar length is submerged.
A1.3.3.1 Test A—Test Method G42 shall be followed except, (1) the cathode shall be a 8-in. [200-mm] long coated steel
reinforcing bar; (2) the anode shall be a 6-in. [150-mm] long solid platinum electrode (0.06-in. [1.6-mm] nominal diameter) or
platinized wire (0.12-in. [3-mm] nominal diameter); (3) a calomel reference electrode shall be used; (4) the electrolyte solution
shall be 3 % NaCl by mass dissolved in distilled water; (5) the electrolyte solution temperature shall be 150150 °F 6 3.6°F
[653.6 °F [65 °C 6 2°C];2 °C]; (6) the drilled coating defect shall be 0.12 in. [3 mm] in diameter; (7) a potential of −3 V measured
against the calomel reference electrode shall be applied and a 10-ohm shunt resistor used; and (8) the test duration shall be 24 h.
The tested bars shall be allowed to cool for approximately 11 h 6 0.25 h prior to evaluation. Four measurements shall be taken,
at 0°, 90°, 180°, and 270°, and the values averaged. The average coating disbondment radius of three coated steel reinforcing bars
shall not exceed 0.24 in. [6 mm] when measured from the edge of the intentional coating defect.
A934/A934M − 22
FIG. A1.1 Cathodic Disbondment Test Equipment Configuration
A1.3.3.2 Test B—Test Methods G8 shall be followed except, (1) the cathode shall be a 8-in. [200-mm] long coated steel reinforcing
bar; (2) the anode shall be a 6-in. [150-mm] long solid platinum electrode (0.06-in. [1.6-mm] nominal diameter) or platinized wire
(0.12-in. [3-mm] nominal diameter); (3) a calomel reference electrode shall be used; (4) the electrolyte solution shall be 3 % NaCl
by mass dissolved in distilled water; (5) the electrolyte solution temperature shall be 7474 °F 6 3.6°F [233.6 °F [23 °C 6
2°C];2 °C]; (6) the drilled coating defect shall be 0.12 in. [3 mm] in diameter; (7) a potential of −1.5 V measured against the
calomel reference electrode shall be applied and a 10-ohm shunt resistor used; and (8) the test duration shall be 168 h. The tested
bars shall be allowed to cool for approximately 11 h 6 0.25 h prior to evaluation. Four measurements shall be taken, at 0°, 90°,
180°, and 270°, and the values averaged. The average coating disbondment radius of three coated steel reinforcing bars shall not
exceed 0.08 in. [2 mm] when measured from the edge of the intentional coating defect.
A1.3.4 Salt Spray Resistance—The resistance of the coating to a hot, wet corrosive environment shall be evaluated in accordance
with Practice B117 by exposing 8-in. [200-mm] long coated steel reinforcing bars containing intentional defects to 9595 °F 6
3.6°F [353.6 °F [35 °C 6 2°C]2 °C] salt spray comprised of 5 % NaCl by mass dissolved in distilled water for 800800 h 6 20 h.
Three intentional 0.12-in. [3-mm] diameter defects shall be drilled through the coating of each test bar approximately evenly
spaced along one side of the bar with the holes centered between deformations. The coated steel reinforcing bars shall be placed
horizontally in the cabinet with the damage sites facing the side (90°). The tested bars shall be allowed to cool for approximately
11 h 6 0.25 h prior to evaluation. Four measurements shall be taken, at 0°, 90°, 180°, and 270°, and the values averaged. The
average coating disbondment radius of nine test sites on three coated steel reinforcing bars shall not exceed 0.12 in. [3 mm] when
measured from the edge of the intentional coating defect.
A934/A934M − 22
FIG. A1.2 Chloride Permeability Test Equipment Configuration
A1.3.5 Chloride Permeability—The chloride permeability characteristics of the cured coating having a thickness of 77 mils to 9
mils [175[175 μm to 225 μm] shall be measured on two test films and a control film at 7575 °F 6 3.6°F [243.6 °F [24 °C 6
2°C]2 °C] for 45 days. The permeability cells shall be of the type shown in Fig. A1.2. Films selected for testing shall be carefully
handled and examined for any defects prior to installation in the cell. The cell shall consist of two glass compartments separated
by a coating film sandwiched between two glass plates, each having a centered 1-in. [25-mm] hole. One compartment shall contain
5.3 oz [175 mL] of 3M NaCl and the other 3.5 oz [115 mL] of distilled water. The activity of chloride ions passing through the
film shall be measured using a specific ion meter equipped with a chloride electrode and a double junction reference electrode.
Activity measurements shall be converted into concentration values of mole per M [L] with a conversion diagram, constructed by
plotting measured chloride ion activities versus known chloride ion concentrations. The cumulative concentration of chloride ions
-4
permeating through the film shall be less than 1 × 10 M.
A1.3.6 Coating Flexibility—The coating shall be evaluated by bending three No. 6 [No. 19] coated steel reinforcing bars 6° (after
rebound) around a 6-in. [150-mm] diameter mandrel. The bend shall be made at a uniform rate and completed within 5 s. The two
longitudinal deformations shall be placed in a plane perpendicular to the mandrel radius. The specimens shall be between 6868 °F
and 86°F [2086 °F [20 °C and 30°C].30 °C]. No cracking of the coating shall be discernible to a person with normal or corrected
vision on the outside radius of any of the three bent bars.
A1.3.7 Relative Bond Strength in Concrete—The relative bond strength of the steel reinforcing bars to concrete shall be
determined with beam-end specimens by the method described in Test Method A944 using No. 6 [No. 19] steel reinforcing bars
with a relative rib area (ratio of projected rib area normal to the bar axis to the product of the nominal bar perimeter and the
center-to-center rib spacing) between 0.075 and 0.085. The bars shall be bottom-cast and shall have a cover of 1.51.5 in. 6 0.06
in. [40[40 mm 6 2 mm], a lead length of 0.50.5 in. 6 0.12 in. [13[13 mm 6 3 mm], and a bonded length of 1010 in. 6 0.25 in.
[250[250 mm 6 5 mm]. Test bars shall be oriented so that the longitudinal deformations and direction of rolling, relative to the
direction of the applied tension, are the same for coated and uncoated bars. The test bars must be pulled in the same direction with
respect to the direction of rolling. Three to six coated bar specimens and three to six uncoated bar specimens shall be tested. All
A934/A934M − 22
steel reinforcing bars in a test group shall be from the same steel heat. The uncoated bars shall be cleaned only by lightly wiping
with acetone or other suitable solvent. The mean bond strength of the coated bars shall not be less than 85 % of the mean bond
strength of the uncoated bars.
A1.3.8 Abrasion Resistance—The resistance of the coating on each of three steel panels to abrasion by a Taber abraser (Test
Method D4060) or its equivalent, using CS-10 wheels and a 2.2-lb [1-kg] load per wheel, shall be such that the weight loss shall
not exceed 0.0035 oz [100 mg] after 1000 cycles.
A1.3.9 Impact Test—The resistance of the coating to mechanical damage shall be assessed by the falling weight test. A test
apparatus similar to that described in Test Method G14 shall be used along with a 0.63-in. [16-mm] tup. Impact shall occur on the
low-lying areas on the coated bars, that is, between deformations or ribs. The test shall be performed at 7575 °F 6 3.6°F [243.6 °F
[24 °C 6 2°C].2 °C]. With an impact of 40 in.-lb [4.5 Nm], no shattering, cracking, or bond loss of the coating shall occur except
at the impact area, that is, the area permanently deformed by the tup.
A1.4 Qualification Testing
A1.4.1 Testing Agency—Qualification tests shall be performed by an agency acceptable to the purchaser.
A1.5 Certification
A1.5.1 A report summarizing the results of all tests and bearing the signature of the testing laboratory shall be furnished to the
manufacturer.
APPENDIXES
(Nonmandatory Information)
X1. APPLICATION PROCESS AND PRODUCT TEST PROCEDURES OF EPOXY COATINGS
FOR STEEL REINFORCING BARS
X1.1 Scope
X1.1.1 This appendix includes recommended process and product test procedures to be included as part of a manufacturer’s
Quality Assurance Program for fusion-bonded epoxy coating of prefabricated steel reinforcing bars.
X1.1.2 Alternative procedures may be used provided they are acceptable to the purchaser.
X1.1.3 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 Reinforcing Steel Institute, or equivalent.
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