ASTM C1731-21

Standard Specification for Concrete Floor Tile

ABSTRACT
This specification establishes the product criteria and minimum performance requirements for concrete floor tile (CFT) used as interior and exterior flooring. The units described by this specification are manufactured from cementitious materials, mineral aggregates (normal weight, lightweight, or both), water, and additives that are cast into various textures and shapes, often simulating natural stone, brick, terracotta, saltillo, and others. The standard addresses materials and their manufacture, physical properties, sampling, packaging and package marking, and certification.
SCOPE
1.1 This specification covers concrete floor tile (CFT) for application as interior and exterior flooring. The units described by this specification are manufactured from cementitious materials, mineral aggregates (normal weight, lightweight, or both), water, and additives that are cast into various textures and shapes, often simulating natural stone, brick, terracotta, saltillo, and others.  
1.2 This specification is limited to requirements for the physical attributes for the CFT units.  
1.3 The use of results from testing installed CFT units that have been removed from use for determining conformance or nonconformance to the requirements of this specification is beyond the scope of this specification.  
1.4 The values stated in inch-pound units are to be regarded as standard. The values given in parentheses are mathematical conversions to SI units that are provided for information only and are not considered standard.  
1.5 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 and health practices and determine the applicability of regulatory limitations prior to use.  
1.6 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-May-2021
• ICS: 91.060.30 - Ceilings. Floors. Stairs
• ICS: 91.100.30 - Concrete and concrete products
• Technical Committee: C15 - Masonry – Manufactured Masonry Units, Mortars and Grouts
• Drafting Committee: C15.03 - Concrete Masonry Units and Related Units

Relations

• Refers: ASTM C31/C31M-24a - Standard Practice for Making and Curing Concrete Test Specimens in the Field
• Effective Date: 01-Apr-2024
• Refers: ASTM C989/C989M-24 - Standard Specification for Slag Cement for Use in Concrete and Mortars
• Effective Date: 01-Feb-2024
• Refers: ASTM C31/C31M-24 - Standard Practice for Making and Curing Concrete Test Specimens in the Field
• Effective Date: 01-Jan-2024
• Refers: ASTM C1232-23 - Standard Terminology for Masonry
• Effective Date: 15-Dec-2023
• Refers: ASTM C140/C140M-23a - Standard Test Methods for Sampling and Testing Concrete Masonry Units and Related Units
• Effective Date: 01-Dec-2023
• Refers: ASTM C39/C39M-23 - Standard Test Method for Compressive Strength of Cylindrical Concrete Specimens
• Effective Date: 01-Dec-2023
• Refers: ASTM C482-20 - Standard Test Method for Bond Strength of Ceramic Tile to Portland Cement Paste
• Effective Date: 01-Apr-2020
• Refers: ASTM C1353/C1353M-20 - Standard Test Method for Abrasion Resistance of Dimension Stone Subjected to Foot Traffic Using a Rotary Platform Abraser
• Effective Date: 01-Apr-2020
• Refers: ASTM C1353/C1353M-20e1 - Standard Test Method for Abrasion Resistance of Dimension Stone Subjected to Foot Traffic Using a Rotary Platform Abraser
• Effective Date: 01-Apr-2020
• Refers: ASTM C150/C150M-19 - Standard Specification for Portland Cement
• Effective Date: 01-Apr-2019
• Refers: ASTM C1600/C1600M-18 - Standard Specification for Rapid Hardening Hydraulic Cement
• Effective Date: 15-Dec-2018
• Refers: ASTM C140/C140M-18 - Standard Test Methods for Sampling and Testing Concrete Masonry Units and Related Units
• Effective Date: 15-Jul-2018
• Refers: ASTM C31/C31M-18 - Standard Practice for Making and Curing Concrete Test Specimens in the Field
• Effective Date: 01-Jan-2018
• Refers: ASTM C140/C140M-17b - Standard Test Methods for Sampling and Testing Concrete Masonry Units and Related Units
• Effective Date: 15-Dec-2017
• Refers: ASTM C618-17 - Standard Specification for Coal Fly Ash and Raw or Calcined Natural Pozzolan for Use in Concrete
• Effective Date: 01-Oct-2017

Overview

ASTM C1731-21: Standard Specification for Concrete Floor Tile establishes the minimum product criteria and performance requirements for concrete floor tile (CFT) manufactured for both interior and exterior flooring applications. Developed by ASTM Committee C15, this standard provides essential guidance on the materials, manufacturing processes, physical properties, testing, sampling, packaging, and certification requirements for CFT units. Concrete floor tiles covered by this standard are produced using cementitious materials, mineral aggregates (normal weight, lightweight, or both), water, and various additives. These tiles are often designed to replicate the appearance of natural stone, brick, terracotta, saltillo, and other surfaces.

Key Topics

• Material Requirements:

  • Cementitious materials (Portland, blended, hydraulic, and rapid hardening cements)
  • Normal and lightweight aggregates
  • Air-entraining and chemical admixtures
  • Pigments and reinforcing fibers
  • Water and other suitable constituents

• Physical Properties:

  • Minimum and maximum dimensional requirements
  • Compressive strength: sets baseline strength for durability
  • Shear bond strength: ensures adhesion to mortar substrates
  • Resistance to freeze-thaw cycles: crucial for exterior applications
  • Water absorption limits: controls moisture-related issues
  • Flexural load: addresses load-bearing capability
  • Length change: measures dimensional stability
  • Abrasion resistance: key for high-traffic areas
  • Dynamic coefficient of friction: ensures safety in wet conditions

• Sampling & Testing:

  • Specifies sampling frequency and procedures for selection of test samples
  • Outlines accredited testing methods and laboratory requirements

• Packaging, Marking, & Certification:

  • Mandates product identification and conformance declarations on packaging
  • Manufacturer must provide test and certification reports upon request

Applications

Using the ASTM C1731-21 specification ensures that concrete floor tiles meet performance expectations for:

• Interior Flooring:

  • Residential, commercial, and retail settings where appearance, strength, and durability are essential
  • Suitable for simulating high-value materials like stone or brick at reduced costs

• Exterior Flooring:

  • Patios, walkways, and entrances exposed to weather, requiring resistance to freeze-thaw cycling, deicing salts, and surface abrasion

• High-Traffic Zones:

  • Public transit areas, corridors, and shopping centers where abrasion resistance and slip safety are critical

Architects, manufacturers, designers, and contractors benefit from this standard by ensuring consistent quality, long-term performance, and regulatory compliance for concrete floor tile installations in a wide range of construction projects.

Related Standards

ASTM C1731-21 references and builds upon several other important materials and testing standards, including:

• ASTM C33/C33M - Specification for Concrete Aggregates
• ASTM C150/C150M - Specification for Portland Cement
• ASTM C494/C494M - Specification for Chemical Admixtures for Concrete
• ASTM C140/C140M - Test Methods for Sampling and Testing Concrete Masonry Units and Related Units
• ASTM C1645/C1645M - Freeze-thaw and De-icing Salt Durability Test
• ASTM C1353/C1353M - Abrasion Resistance of Dimension Stone
• ANSI A326.3 - Test Method for Measuring Dynamic Coefficient of Friction of Hard Surface Flooring Materials

By following ASTM C1731-21 and the associated referenced standards, professionals ensure the use of high-quality, robust concrete floor tiles that are well-suited for demanding indoor and outdoor flooring environments. This specification contributes to higher safety, lower maintenance needs, and improved building longevity.

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: C1731 − 21
Standard Specification for
Concrete Floor Tile
This standard is issued under the fixed designation C1731; 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.
INTRODUCTION
The purpose of this specification is to establish the product specifications and minimum
performance requirements of concrete floor tile.
1. Scope* 2. Referenced Documents
2.1 ASTM Standards:
1.1 This specification covers concrete floor tile (CFT) for
C31/C31M Practice for Making and Curing Concrete Test
application as interior and exterior flooring. The units de-
Specimens in the Field
scribed by this specification are manufactured from cementi-
C33/C33M Specification for Concrete Aggregates
tious materials, mineral aggregates (normal weight,
C39/C39M Test Method for Compressive Strength of Cylin-
lightweight, or both), water, and additives that are cast into
drical Concrete Specimens
various textures and shapes, often simulating natural stone,
C140/C140M Test Methods for Sampling and Testing Con-
brick, terracotta, saltillo, and others.
crete Masonry Units and Related Units
1.2 This specification is limited to requirements for the
C150/C150M Specification for Portland Cement
physical attributes for the CFT units.
C157/C157M Test Method for Length Change of Hardened
Hydraulic-Cement Mortar and Concrete
1.3 The use of results from testing installed CFT units that
C172/C172M Practice for Sampling Freshly Mixed Con-
have been removed from use for determining conformance or
crete
nonconformance to the requirements of this specification is
C260/C260M Specification for Air-Entraining Admixtures
beyond the scope of this specification.
for Concrete
1.4 The values stated in inch-pound units are to be regarded C331/C331M Specification for Lightweight Aggregates for
as standard. The values given in parentheses are mathematical Concrete Masonry Units
conversions to SI units that are provided for information only C482 Test Method for Bond Strength of Ceramic Tile to
and are not considered standard. Portland Cement Paste
C494/C494M Specification for Chemical Admixtures for
1.5 This standard does not purport to address all of the
Concrete
safety concerns, if any, associated with its use. It is the
C595/C595M Specification for Blended Hydraulic Cements
responsibility of the user of this standard to establish appro-
C618 Specification for Coal Ash and Raw or Calcined
priate safety, health, and environmental practices and deter-
Natural Pozzolan for Use in Concrete
mine the applicability of regulatory limitations prior to use.
C979/C979M Specification for Pigments for Integrally Col-
1.6 This international standard was developed in accor-
ored Concrete
dance with internationally recognized principles on standard-
C989/C989M Specification for Slag Cement for Use in
ization established in the Decision on Principles for the
Concrete and Mortars
Development of International Standards, Guides and Recom-
C1093 Practice for Accreditation of Testing Agencies for
mendations issued by the World Trade Organization Technical
Masonry
Barriers to Trade (TBT) Committee.
C1116/C1116M Specification for Fiber-Reinforced Concrete
C1157/C1157M Performance Specification for Hydraulic
Cement
This specification is under the jurisdiction of ASTM Committee C15 on
Manufactured Masonry Units and is the direct responsibility of Subcommittee
C15.03 on Concrete Masonry Units and Related Units. For referenced ASTM standards, visit the ASTM website, www.astm.org, or
Current edition approved June 1, 2021. Published June 2021. Originally contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM
approved in 2013. Last previous edition approved in 2016 as C1731 – 16. DOI: Standards volume information, refer to the standard’s Document Summary page on
10.1520/C1731–21. 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
C1731 − 21
C1232 Terminology for Masonry 4.4 Reinforcing Fibers—Specification C1116/C1116M.
C1353/C1353M Test Method for Abrasion Resistance of
4.5 Water—Specification C1602/C1602M.
Dimension Stone Subjected to Foot Traffic Using a Rotary
4.6 Other Constituents—Integral water repellents and other
Platform Abraser
materials shall be previously established as suitable for use in
C1600/C1600M Specification for Rapid Hardening Hydrau-
concrete floor tile or shall be shown by test or experience not
lic Cement
to be detrimental to concrete floor tile or any material custom-
C1602/C1602M Specification for Mixing Water Used in the
arily used in concrete floor tile construction.
Production of Hydraulic Cement Concrete
C1645/C1645M Test Method for Freeze-thaw and De-icing
5. Physical Properties
Salt Durability of Solid Concrete Interlocking Paving
Units
5.1 Dimensions:
5.1.1 CFT units shall have a minimum thickness of ⁄4 in.
NOTE 1—An installation guide for concrete floor tile (CFT) is being
(6.4 mm) and a maximum thickness of 1.2 in. (30 mm).
developed concurrently in Subcommittee C15.05 Masonry Assemblies.
5.1.2 CFT units shall not exceed 36 in. (914 mm) in any
2.2 ANSI Standards:
face dimension.
A326.3 American National Standard Test Method for Mea-
5.1.3 Dimensional Tolerances:
suring Dynamic Coefficient of Friction of Hard Surface
5.1.3.1 Standard Units—For standard units, no overall di-
Flooring Materials
mension (width, height, and length) shall differ by more than
6 ⁄8 in. (3.2 mm) from the specified dimensions.
3. Terminology
5.1.3.2 Irregular Units—For irregular units that feature
3.1 Terminology defined in Terminology C1232 shall apply
deliberate dimensional variations more than 6 ⁄8 in. (3.2 mm),
for this section.
the CFT manufacturer shall be consulted as to specific dimen-
3.2 Definitions of Terms Specific to This Standard: sional tolerances.
NOTE 2—Dimensional tolerances for irregular units may vary due to the
3.2.1 concrete floor tile (CFT), n—manufactured masonry
wide variety of CFT shapes and styles including tumbled, flagstone, and
unit that is a blend of cementitious material, aggregates,
other rustic appearances.
pigments, chemical admixtures, and water that is designed to
5.2 Compressive Strength:
be applied via masonry mortar to a horizontal substrate.
5.2.1 The average compressive strength shall equal or
3.2.2 back pattern, n—grooves or other textures included on
exceed 4000 psi (27.6 MPa) with no individual specimen less
the back of the CFT unit.
than 3600 psi (24.8 MPa).
5.2.2 For wet-cast products sample concrete from regular
4. Materials and Manufacture
production in accordance with Practice C172/C172M and
4.1 Cementitious Materials shall conform to the following
prepare three cylinders in accordance with Practice C31/
applicable specifications:
C31M. Test compressive strength of the concrete mix in
4.1.1 Portland Cement—Specification C150/C150M.
accordance with Test Method C39/C39M.
4.1.2 Blended Cement—Specification C595/C595M.
5.2.3 For dry-cast products sample a minimum of three
4.1.3 Hydraulic Cement—Specification C1157/C1157M.
specimens from regular production in accordance with Test
4.1.4 Rapid Hardening Hydraulic Cements—Specification
Method C140/C140M. Test compressive strength in accor-
C1600/C1600M.
dance with Annex A4 of Test Method C140/C140M.
4.1.5 Pozzolans and Fly Ash—Specification C618.
5.3 Shear Bond Strength:
4.1.6 Ground Granulated Blast-Furnace Slag—
5.3.1 Units shall develop a shear bond strength with the
Specification C989/C989M.
mortar substrate of at least 50 psi (0.34 MPa) when tested in
4.2 Aggregates shall conform to the following applicable
accordance with Test Method C482 with the following modi-
specifications, except that grading requirements shall not
fications (listed in 5.3.1.1 through 5.3.1.4):
necessarily apply:
5.3.1.1 Five units shall be tested.
4.2.1 Normal Weight—Specification C33/C33M.
5.3.1.2 The mortar substrate shall be that specified for
4.2.2 Lightweight—Specification C331/C331M.
testing of non-vitreous tile in Test Method C482.
...

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: C1731 − 16 C1731 − 21
Standard Specification for
Concrete Floor Tile
This standard is issued under the fixed designation C1731; 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.
INTRODUCTION
The purpose of this specification is to establish the product specifications and minimum
performance requirements of concrete floor tile.
1. Scope*
1.1 This specification covers concrete floor tile (CFT) for application as interior and exterior flooring. The units described by this
specification are manufactured from cementitious materials, mineral aggregates (normal weight, lightweight, or both), water, and
additives that are cast into various textures and shapes, often simulating natural stone, brick, terracotta, saltillo, and others.
1.2 This specification is limited to requirements for the physical attributes for the CFT units.
1.3 The use of results from testing installed CFT units that have been removed from use for determining conformance or
nonconformance to the requirements of this specification is beyond the scope of this specification.
1.4 The values stated in inch-pound units are to be regarded as standard. The values given in parentheses are mathematical
conversions to SI units that are provided for information only and are not considered standard.
1.5 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 and health practices and determine the applicability of regulatory
limitations prior to use.
1.6 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 ASTM Standards:
C31/C31M Practice for Making and Curing Concrete Test Specimens in the Field
C33/C33M Specification for Concrete Aggregates
C39/C39M Test Method for Compressive Strength of Cylindrical Concrete Specimens
This specification is under the jurisdiction of ASTM Committee C15 on Manufactured Masonry Units and is the direct responsibility of Subcommittee C15.03 on
Concrete Masonry Units and Related Units.
Current edition approved June 1, 2016June 1, 2021. Published July 2016June 2021. Originally approved in 2013. Last previous edition approved in 20152016 as C1731
– 15.16. DOI: 10.1520/C1731–16.10.1520/C1731–21.
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
C1731 − 21
C140/C140M Test Methods for Sampling and Testing Concrete Masonry Units and Related Units
C150/C150M Specification for Portland Cement
C157/C157M Test Method for Length Change of Hardened Hydraulic-Cement Mortar and Concrete
C172/C172M Practice for Sampling Freshly Mixed Concrete
C260/C260M Specification for Air-Entraining Admixtures for Concrete
C331/C331M Specification for Lightweight Aggregates for Concrete Masonry Units
C482 Test Method for Bond Strength of Ceramic Tile to Portland Cement Paste
C494/C494M Specification for Chemical Admixtures for Concrete
C595/C595M Specification for Blended Hydraulic Cements
C618 Specification for Coal Fly Ash and Raw or Calcined Natural Pozzolan for Use in Concrete
C979/C979M Specification for Pigments for Integrally Colored Concrete
C989/C989M Specification for Slag Cement for Use in Concrete and Mortars
C1093 Practice for Accreditation of Testing Agencies for Masonry
C1116/C1116M Specification for Fiber-Reinforced Concrete
C1157/C1157M Performance Specification for Hydraulic Cement
C1232 Terminology for Masonry
C1353/C1353M Test Method for Abrasion Resistance of Dimension Stone Subjected to Foot Traffic Using a Rotary Platform
Abraser
C1600/C1600M Specification for Rapid Hardening Hydraulic Cement
C1602/C1602M Specification for Mixing Water Used in the Production of Hydraulic Cement Concrete
C1645/C1645M Test Method for Freeze-thaw and De-icing Salt Durability of Solid Concrete Interlocking Paving Units
NOTE 1—An installation guide for concrete floor tile (CFT) is being developed concurrently in Subcommittee C15.05 Masonry Assemblies.
2.2 ANSI Standards:
A137.1-2012A326.3 American National Standard Specification for Ceramic TileTest Method for Measuring Dynamic
Coefficient of Friction of Hard Surface Flooring Materials
3. Terminology
3.1 Terminology defined in Terminology C1232 shall apply for this section.
3.2 Definitions of Terms Specific to This Standard:
3.2.1 concrete floor tile (CFT), n—manufactured masonry unit that is a blend of cementitious material, aggregates, pigments,
chemical admixtures, and water that is designed to be applied via masonry mortar to a horizontal substrate.
3.2.2 back pattern, n—grooves or other textures included on the back of the CFT unit.
4. Materials and Manufacture
4.1 Cementitious Materials shall conform to the following applicable specifications:
4.1.1 Portland Cement—Specification C150/C150M.
4.1.2 Blended Cement—Specification C595/C595M.
4.1.3 Hydraulic Cement—Specification C1157/C1157M.
4.1.4 Rapid Hardening Hydraulic Cements—Specification C1600/C1600M.
4.1.5 Pozzolans and Fly Ash—Specification C618.
4.1.6 Ground Granulated Blast-Furnace Slag—Specification C989/C989M.
4.2 Aggregates shall conform to the following applicable specifications, except that grading requirements shall not necessarily
apply:
Available from Available from Tile Council of North America, https://www.tcnatile.com.
C1731 − 21
4.2.1 Normal Weight—Specification C33/C33M.
4.2.2 Lightweight—Specification C331/C331M.
4.3 Chemical Admixtures shall conform to the following applicable specifications:
4.3.1 Air-Entraining Admixtures—Specification C260/C260M.
4.3.2 Water-Reducing, Retarding, and Accelerating Admixtures—Specification C494/C494M.
4.3.3 Pigments for Integrally Colored Concrete—Specification C979/C979M.
4.4 Reinforcing Fibers—Specification C1116/C1116M.
4.5 Water—Specification C1602/C1602M.
4.6 Other Constituents—Integral water repellents and other materials shall be previously established as suitable for use in concrete
floor tile or shall be shown by test or experience not to be detrimental to concrete floor tile or any material customarily used in
concrete floor tile construction.
5. Physical Properties
5.1 Dimensions:
5.1.1 CFT units shall have a minimum thickness of ⁄4 in. (6.4 mm) and a maximum thickness of 1.2 in. (30 mm).
5.1.2 CFT units shall not exceed 36 in. (914 mm) in any face dimension.
5.1.3 Dimensional Tolerances:
5.1.3.1 Standard Units—For standard units, no overall dimension (width, height, and length) shall differ by more than 6 ⁄8 in. (3.2
mm) from the specified dimensions.
5.1.3.2 Irregular Units—For irregular units that feature deliberate dimensional variations more than 6 ⁄8 in. (3.2 mm), the CFT
manufacturer shall be consulted as to specific dimensional tolerances.
NOTE 2—Dimensional tolerances for irregular units may vary due to the wide variety of CFT shapes and styles including tumbled, flagstone, and other
rustic appearances.
5.2 Compressive Strength:
5.2.1 The average compressive strength shall equal or exceed 4000 psi (27.6 MPa) with no individual specimen less than 3600
psi (24.8 MPa).
5.2.2 For wet-cast products sample concrete from regular production in accordance with Practice C172/C172M and prepare three
cylinders in accordance with Practice C31/C31M. Test compressive strength of the concrete mix in accordance with Test Method
C39/C39M.
5.2.3 For dry-cast products sample a minimum of three specimens from regular production in accordance with Test Method
C140/C140M. Test compressive strength in accordance with Annex A4 of Test Method C140/C140M.
5.3 Shear Bond Strength:
5.3.1 Units shall develop a shear bond strength with the mortar substrate of at least 50 psi (0.34 MPa) when tested i
...