ASTM A820/A820M-22

Standard Specification for Steel Fibers for Fiber-Reinforced Concrete

ABSTRACT
This specification covers steel fibers intended for use in fiber-reinforced concrete. The fibers shall be straight or deformed and of Types I (cold-drawn wire), II (cut sheet), III (melt-extracted), IV (mill cut), and V ( modified cold-drawn wire). Tensile and bend tests of randomly-selected finished fibers shall be performed. Measurement of dimensions shall be performed and values should conform to permissible variations of length, nominal length, diameter, equivalent diameter, aspect ratio, and nominal aspect ratio. Guidelines for inspection, rejection, rehearing, certification, and packaging are also given.
SCOPE
1.1 This specification covers minimum requirements for steel fibers intended for use in fiber-reinforced concrete. Five types of steel fibers for this purpose are defined as pieces of smooth or deformed cold-drawn wire; smooth or deformed cut sheet; melt-extracted fibers; mill-cut or modified cold-drawn wire steel fibers that are sufficiently small to be dispersed at random in a concrete mixture.  
1.2 This specification provides for measurement of dimensions, tolerances from specified dimensions, and required minimum physical properties, and prescribes testing procedures to establish conformance to these requirements.  
1.3 In the case of conflict between a requirement of a product specification and a requirement of this specification, the product specification shall prevail. In the case of a conflict between a requirement of the product specification or a requirement of this specification and a more stringent requirement of the purchase order, the purchase order shall prevail. The purchase order requirements shall not take precedence if they, in any way, violate the requirements of the product specification or this specification; for example, by the waiving of a test requirement or by making a test requirement less stringent.  
1.4 The values stated in either SI units or inch-pound 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.  
1.5 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 A370-24 - Standard Test Methods and Definitions for Mechanical Testing of Steel Products
• Effective Date: 01-Mar-2024
• Refers: ASTM A700-14(2019) - Standard Guide for Packaging, Marking, and Loading Methods for Steel Products for Shipment
• Effective Date: 01-Nov-2019
• Refers: ASTM A370-19 - Standard Test Methods and Definitions for Mechanical Testing of Steel Products
• Effective Date: 01-Jul-2019
• Refers: ASTM A370-17a - Standard Test Methods and Definitions for Mechanical Testing of Steel Products
• Effective Date: 15-Nov-2017
• Refers: ASTM A370-17 - Standard Test Methods and Definitions for Mechanical Testing of Steel Products
• Effective Date: 01-Jan-2017
• Refers: ASTM A370-15 - Standard Test Methods and Definitions for Mechanical Testing of Steel Products
• Effective Date: 01-Nov-2015
• Refers: ASTM A700-14 - Standard Guide for Packaging, Marking, and Loading Methods for Steel Products for Shipment
• Effective Date: 01-Nov-2014
• Refers: ASTM A370-14 - Standard Test Methods and Definitions for Mechanical Testing of Steel Products
• Effective Date: 15-May-2014
• Refers: ASTM A370-13 - Standard Test Methods and Definitions for Mechanical Testing of Steel Products
• Effective Date: 15-Nov-2013
• Refers: ASTM A370-12a - Standard Test Methods and Definitions for Mechanical Testing of Steel Products
• Effective Date: 15-Oct-2012
• Refers: ASTM A370-12 - Standard Test Methods and Definitions for Mechanical Testing of Steel Products
• Effective Date: 15-Mar-2012
• Refers: ASTM A370-11a - Standard Test Methods and Definitions for Mechanical Testing of Steel Products
• Effective Date: 15-Nov-2011
• Refers: ASTM C1116/C1116M-10a - Standard Specification for Fiber-Reinforced Concrete
• Effective Date: 01-Dec-2010
• Refers: ASTM C1116/C1116M-10 - Standard Specification for Fiber-Reinforced Concrete
• Effective Date: 01-Jul-2010
• Refers: ASTM A370-10 - Standard Test Methods and Definitions for Mechanical Testing of Steel Products
• Effective Date: 15-Jun-2010

Overview

ASTM A820/A820M-22: Standard Specification for Steel Fibers for Fiber-Reinforced Concrete defines the minimum requirements for steel fibers used to reinforce concrete. These steel fibers are engineered to enhance the mechanical properties of concrete, improving its toughness, impact resistance, and crack control. The specification covers five primary types of steel fibers: cold-drawn wire, cut sheet, melt-extracted, mill cut, and modified cold-drawn wire. Both straight and deformed fibers are included, and the standard outlines requirements for fiber dimensions, physical properties, testing procedures, packaging, and certification.

Key Topics

• Types of Steel Fibers

  • Type I: Cold-drawn wire
  • Type II: Cut sheet
  • Type III: Melt-extracted
  • Type IV: Mill cut
  • Type V: Modified cold-drawn wire

• Testing and Compliance

  • Tensile and bend tests on randomly selected fibers
  • Dimensional measurement: length, diameter, equivalent diameter, and aspect ratio
  • Tolerances for physical dimensions and mechanical properties

• Quality Assurance

  • Guidelines for inspection, rejection, and retesting
  • Certification and test reporting procedures
  • Packaging and marking requirements for shipment

• Standardization Principles

  • Harmonization with international standardization practices
  • Use of both SI and inch-pound units, to be applied independently

Applications

Steel fibers meeting ASTM A820/A820M-22 are broadly specified in both precast and cast-in-place fiber-reinforced concrete applications, such as:

• Industrial and Commercial Flooring
  • Enhanced durability, reduced cracking, and improved load distribution
• Shotcrete for Tunnel Linings and Mining
  • Increased ductility and toughness in sprayed concrete applications
• Precast Concrete Products
  • Improved impact resistance in pipes, panels, and beams
• Pavements, Overlays, and Repairs
  • Superior crack control, reduced maintenance, and extended service life
• Infrastructure Projects
  • Bridges, airports, and transportation structures employ fiber-reinforced concrete for enhanced structural performance

Steel fibers conforming to ASTM A820/A820M-22 are selected and specified by engineers, architects, and contractors seeking to optimize fiber-reinforced concrete performance through reliable, tested reinforcement materials.

Related Standards

Steel fibers for concrete reinforcement are commonly used with or referenced by the following standards and guidelines:

• ASTM C1116/C1116M: Specification for Fiber-Reinforced Concrete
• ASTM A370: Test Methods and Definitions for Mechanical Testing of Steel Products
• ASTM A700: Packaging, Marking, and Loading Methods for Steel Products for Shipment
• ACI 506.1: Guide to Fiber-Reinforced Shotcrete
• ACI 544.1R: Committee Report on Fiber-Reinforced Concrete
• Fed. Std. No. 123: Marking for Shipment (Civil Agencies)
• MIL-STD-129: Marking for Shipment and Storage (Military)

These documents are frequently referenced to ensure that steel fiber products are specified, tested, and delivered in line with recognized industry practices and international requirements.

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Key SEO terms: ASTM A820, steel fibers, fiber-reinforced concrete, concrete reinforcement, ASTM standards, mechanical properties, tensile strength, aspect ratio, industrial concrete, shotcrete, precast concrete, packaging, certification.

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: A820/A820M −22
Standard Specification for
Steel Fibers for Fiber-Reinforced Concrete
This standard is issued under the fixed designationA820/A820M; 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* 2. Referenced Documents
1.1 This specification covers minimum requirements for 2.1 The following documents, of the issue in effect on the
date of material purchase, form a part of this specification to
steel fibers intended for use in fiber-reinforced concrete. Five
the extent referenced herein.
types of steel fibers for this purpose are defined as pieces of
smooth or deformed cold-drawn wire; smooth or deformed cut
2.2 ASTM Standards:
sheet; melt-extracted fibers; mill-cut or modified cold-drawn
A370Test Methods and Definitions for Mechanical Testing
wire steel fibers that are sufficiently small to be dispersed at
of Steel Products
random in a concrete mixture.
A700Guide for Packaging, Marking, and Loading Methods
for Steel Products for Shipment
1.2 This specification provides for measurement of
C1116/C1116MSpecification for Fiber-Reinforced Concrete
dimensions, tolerances from specified dimensions, and re-
quired minimum physical properties, and prescribes testing 2.3 ACI Documents:
procedures to establish conformance to these requirements. ACI 506.1Guide to Fiber-Reinforced Shotcrete
ACI 544.1RCommittee Report on Fiber-Reinforced Con-
1.3 In the case of conflict between a requirement of a
crete
product specification and a requirement of this specification,
2.4 U.S. Federal Standards:
the product specification shall prevail. In the case of a conflict
Fed. Std. No. 123Marking for Shipment (Civil Agencies)
between a requirement of the product specification or a
2.5 U.S. Military Standards:
requirement of this specification and a more stringent require-
MIL-STD-129Marking for Shipment and Storage
ment of the purchase order, the purchase order shall prevail.
The purchase order requirements shall not take precedence if
3. Terminology
they, in any way, violate the requirements of the product
specification or this specification; for example, by the waiving 3.1 Definitions of Terms Specific to This Standard:
of a test requirement or by making a test requirement less 3.1.1 deformed fiber, n—a fiber that is bent, flattened, or
stringent. roughened to improve mechanical bond to the concrete matrix.
3.1.2 modified fiber, n—a cold-drawn wire fiber whose
1.4 The values stated in either SI units or inch-pound units
cross-section has been changed from circular by shaving the
are to be regarded separately as standard. The values stated in
wire.
each system may not be exact equivalents; therefore, each
system shall be used independently of the other. Combining 3.1.3 nominal length, n—the length of a deformed fiber,
values from the two systems may result in non-conformance
out-to-out, after being deformed.
with the standard.
3.1.4 range of equivalent diameter, d ,n—a set of limits
e-r
1.5 This international standard was developed in accor- placed on the equivalent diameter by the specifier. See 8.1.6
and Note 3.
dance with internationally recognized principles on standard-
ization established in the Decision on Principles for the
3.2 Symbols—The following symbols used in this specifi-
Development of International Standards, Guides and Recom-
cation are defined as follows:
mendations issued by the World Trade Organization Technical
Barriers to Trade (TBT) Committee.
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
This specification is under the jurisdiction ofASTM Committee A01 on Steel, the ASTM website.
Stainless Steel and RelatedAlloys and is the direct responsibility of Subcommittee Available from American Concrete Institute (ACI), 38800 Country Club Dr.,
A01.05 on Steel Reinforcement. Farmington Hills, MI 48331-3439, http://www.concrete.org.
Current edition approved Sept. 1, 2022. Published September 2022. Originally Available from Standardization Documents Order Desk, DODSSP, Bldg. 4,
approved in 1985. Last previous edition approved in 2016 as A820/A820M–16. Section D, 700 Robbins Ave., Philadelphia, PA 19111-5098, http://
DOI: 10.1520/A0820_A0820M-22. dodssp.daps.dla.mil.
*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
A820/A820M − 22
2 2
A=cross-sectional area, in. [mm ] 7.1.2 The cross-sectional area used to compute f shall be
u
d=diameter, in. [mm] carried out to five decimal places, in units of square inches
f =ultimate tensile strength, psi [MPa] [square millimetres], and shall be: (1) for drawn wire fibers,
u
l=length, in. [mm] Type I, the area calculated from the actual diameter of the
λ= l/ d=aspect ratio parent source material or finished fiber; (2) for cut sheet fibers,
3.2.1 The subscript n on dimensional units indicates “nomi- Type II,theareacalculatedfromtheactualthicknessandwidth
nal” and the subscript e indicates “equivalent.” “Nominal” and of the parent source material specimen, or if fibers are tested,
“equivalent” dimensions are calculated from other measurable the area of each individual fiber calculated from measured
dimensions or average weight [mass]. length and weight [mass] of the fiber. See 8.1.5. (3) for
melt-extracted fibers, Type III, or mill-cut fibers, Type IV,
4. Classification specified by equivalent diameter, the area calculated from the
equivalent diameter of the fibers. See 8.1.5; and (4) for
4.1 Five general types of steel fibers are identified in this
modified cold drawn wire fibers, Type V, specified by a range of
specification based upon the product or process used as a
equivalent diameters, the area of each individual fiber calcu-
source of the steel fiber material.
lated from the measured length and weight [mass] of the fiber.
4.1.1 Type I, cold-drawn wire.
See 8.1.6. The ultimate tensile load in pounds-force [newtons]
4.1.2 Type II, cut sheet.
for individual fibers shall be measured to at least three
4.1.3 Type III, melt-extracted.
significant figures. Testing shall be in accordance with Test
4.1.4 Type IV, mill cut.
Methods and Definitions A370, where applicable.
4.1.5 Type V, modified cold-drawn wire.
7.2 Bending Requirements:
4.2 Fibers shall be straight or deformed.
7.2.1 Fibers shall withstand being bent around a 0.125 in.
[3.2 mm] diameter pin to an angle of 90° at temperatures not
5. Ordering Information
less than 60°F [16°C] without breaking.
5.1 Orders for steel fibers under this specification shall
NOTE 2—The bending requirements of this specification provide a
contain the following information:
general indication of fiber ductility, as may be important in resisting
5.1.1 Quantity in pounds or tons [kilograms],
breakage during handling and mixing operations. Ductility measures of
5.1.2 Type or types permissible (4.1),
fiber-reinforced concrete are outside the scope of this specification; see
5.1.3 Diameter or equivalent diameter (8.1.4), or range of
ACI 544.1R.
equivalent diameters (8.1.6),
7.2.2 Bend tests shall be conducted on ten randomly se-
5.1.4 Length or nominal length (3.1.3),
lected specimens of finished fibers. It shall be permissible to
5.1.5 Deformations, if required,
perform bend tests manually.At least one test consisting of ten
5.1.6 Whether certification by the manufacturer is required
specimensshallbemadeforeach5tons[4500kg]ofmaterial.
including whether a report is to be furnished (Section 11), and
At least 90% of the specimens shall pass the test.
5.1.7 ASTM designation and year of issue
8. Dimensions and Permissible Variations
NOTE 1—For information on satisfactory sizes and aspect ratios, see
ACI 544.1R and ACI 506.1, and contact the manufacturers regarding
8.1 Dimensions:
availability.
8.1.1 Straight cold-drawn wire (Type I) fibers are specified
by diameter (d) or equivalent (d ) and length (l), that establish
6. Materials and Manufacture e
a specified aspect ratio, (λ), or (λ ), as (l / d)or(l / d ).
e e
6.1 The materials and manufacturing methods used shall be
8.1.2 Deformed cold-drawn wire (Type I) fibers are speci-
such that the fibers produced conform to the requirements in
fied by the diameter (d) or equivalent diameter (d ) and
e
this specification.
nominal length after bending (l ). Nominal aspect ratio (λ)is
n n
established as (l / d)or(l / d ).
n n e
7. Mechanical Properties
8.1.3 Cutsheet(TypeII)fibersarespecifiedb
...

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: A820/A820M − 16 A820/A820M − 22
Standard Specification for
Steel Fibers for Fiber-Reinforced Concrete
This standard is issued under the fixed designation A820/A820M; 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 minimum requirements for steel fibers intended for use in fiber-reinforced concrete. Five types of
steel fibers for this purpose are defined as pieces of smooth or deformed cold-drawn wire; smooth or deformed cut sheet;
melt-extracted fibers; mill-cut or modified cold-drawn wire steel fibers that are sufficiently small to be dispersed at random in a
concrete mixture.
1.2 This specification provides for measurement of dimensions, tolerances from specified dimensions, and required minimum
physical properties, and prescribes testing procedures to establish conformance to these requirements.
1.3 In the case of conflict between a requirement of a product specification and a requirement of this specification, the product
specification shall prevail. In the case of a conflict between a requirement of the product specification or a requirement of this
specification and a more stringent requirement of the purchase order, the purchase order shall prevail. The purchase order
requirements shall not take precedence if they, in any way, violate the requirements of the product specification or this
specification; for example, by the waiving of a test requirement or by making a test requirement less stringent.
1.4 The values stated in either SI units or inch-pound 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.
1.5 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.
2. Referenced Documents
2.1 The following documents, of the issue in effect on the date of material purchase, form a part of this specification to the extent
referenced herein.
2.2 ASTM Standards:
A370 Test Methods and Definitions for Mechanical Testing of Steel Products
A700 Guide for Packaging, Marking, and Loading Methods for Steel Products for Shipment
C1116/C1116M Specification for Fiber-Reinforced Concrete
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, 2016Sept. 1, 2022. Published June 2016September 2022. Originally approved in 1985. Last previous edition approved in 20152016 as
A820/A820M – 15.A820/A820M – 16. DOI: 10.1520/A0820_A0820M-16.10.1520/A0820_A0820M-22.
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.
*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
A820/A820M − 22
2.3 ACI Documents:
ACI 506.1 Guide to Fiber-Reinforced Shotcrete
ACI 544.1R Committee Report on Fiber-Reinforced Concrete
2.4 U.S. Federal Standards:
Fed. Std. No. 123 Marking for Shipment (Civil Agencies)
2.5 U.S. Military Standards:
MIL-STD-129 Marking for Shipment and Storage
3. Terminology
3.1 Definitions of Terms Specific to This Standard:
3.1.1 deformed fiber, n—a fiber that is bent, flattened, or roughened to improve mechanical bond to the concrete matrix.
3.1.2 modified fiber, n—a cold-drawn wire fiber whose cross-section has been changed from circular by shaving the wire.
3.1.3 nominal length, n—the length of a deformed fiber, out-to-out, after being deformed.
3.1.4 range of equivalent diameter, d , n—a set of limits placed on the equivalent diameter by the specifier. See 8.1.6 and Note
e-r
3.
3.2 Symbols—The following symbols used in this specification are defined as follows:
2 2
A = cross-sectional area, in. [mm ]
d = diameter, in. [mm]
f = ultimate tensile strength, psi [MPa]
u
l = length, in. [mm]
λ = l/ d = aspect ratio
3.2.1 The subscript n on dimensional units indicates “nominal” and the subscript e indicates “equivalent.” “Nominal” and
“equivalent” dimensions are calculated from other measurable dimensions or average weight [mass].
4. Classification
4.1 Five general types of steel fibers are identified in this specification based upon the product or process used as a source of the
steel fiber material.
4.1.1 Type I, cold-drawn wire.
4.1.2 Type II, cut sheet.
4.1.3 Type III, melt-extracted.
4.1.4 Type IV, mill cut.
4.1.5 Type V, modified cold-drawn wire.
4.2 Fibers shall be straight or deformed.
5. Ordering Information
5.1 Orders for steel fibers under this specification shall contain the following information:
5.1.1 Quantity in pounds or tons [kilograms],
5.1.2 Type or types permissible (4.1),
Available from American Concrete Institute (ACI), P.O. Box 9094, 38800 Country Club Dr., Farmington Hills, MI 48333-9094,48331-3439, http://www.concrete.org.
Available from Standardization Documents Order Desk, DODSSP, Bldg. 4, Section D, 700 Robbins Ave., Philadelphia, PA 19111-5098, http://dodssp.daps.dla.mil.
A820/A820M − 22
5.1.3 Diameter or equivalent diameter (8.1.4), or range of equivalent diameters (8.1.6),
5.1.4 Length or nominal length (3.1.3),
5.1.5 Deformations, if required,
5.1.6 Whether certification by the manufacturer is required including whether a report is to be furnished (Section 11), and
5.1.7 ASTM designation and year of issue
NOTE 1—For information on satisfactory sizes and aspect ratios, see ACI 544.1R and ACI 506.1, and contact the manufacturers regarding availability.
6. Materials and Manufacture
6.1 The materials and manufacturing methods used shall be such that the fibers produced conform to the requirements in this
specification.
7. Mechanical Properties
7.1 Tensile Requirements:
7.1.1 At least ten individual tensile tests of randomly selected finished fibers shall be performed for each 5 tons [4 500 kg] of
product. This is an approximate distribution of one fiber tensile test per every 0.5 ton [450 kg] of finished product. The average
tensile strength, f , of each fiber shall not be less than 50 000 psi [345 MPa]. The tensile strength of any one of the ten specimens
u
shall not be less than 45 000 psi [310 MPa]. Where the parent source material consists of sheet or wire, tensile tests by the
manufacturer may be performed on larger samples of source material. One sample of each different source material used shall then
be tested for each 5 tons [4 500 kg] of material. The tensile strength of a single sample of source material shall not be less than
50 000 psi [345 MPa].
7.1.2 The cross-sectional area used to compute f shall be carried out to five decimal places, in units of square inches [square
u
millimetres], and shall be: (1) for drawn wire fibers, Type I, the area calculated from the actual diameter of the parent source
material or finished fiber; (2) for cut sheet fibers, Type II, the area calculated from the actual thickness and width of the parent
source material specimen, or if fibers are tested, the area of each individual fiber calculated from measured length and weight
[mass] of the fiber. See 8.1.5. (3) for melt-extracted fibers, Type III,or mill-cut fibers, Type IV, specified by equivalent diameter,
the area calculated from the equivalent diameter of the fibers. See 8.1.5; and (4) for modified cold drawn wire fibers, Type V,
specified by a range of equivalent diameters, the area of each individual fiber calculated from the measured length and weight
[mass] of the fiber. See 8.1.6. The ultimate tensile load in pounds-force [newtons] for individual fibers shall be measured to at least
three significant figures. Testing shall be in accordance with Test Methods and Definitions A370, where applicable.
7.2 Bending Requirements:
7.2.1 Fibers shall withstand being bent around a 0.125 in. [3.2 mm] diameter pin to an angle of 90° at temperatures not less than
60°F [16°C]60 °F [16 °C] without breaking.
NOTE 2—The bending requirements of this specification provide a general indication of fiber ductility, as may be important in resisting breakage during
handling and mixing operations. Ductility measures of fiber-reinforced concrete are outside the scope of this specification; see ACI 544.1R.
7.2.2 Bend tests shall be conducted on ten randomly
...