ASTM D6575/D6575M-22

Standard Test Method for Determining Stiffness of Geosynthetics Used as Turf Reinforcement Mats (TRMs)

SIGNIFICANCE AND USE
4.1 In general this test method is adapted from tests developed for woven fabrics (previously designated as Test Method D1388).  
4.2 The cantilever test method may not be suitable for testing products that are very limp or have a marked tendency to curl or twist at a cut edge.
SCOPE
1.1 This test method covers the determination of the stiffness of geosynthetics used as turf reinforcement mats (TRMs).  
1.2 The method is applicable to TRMs of any fiber content and any number of components.  
1.3 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 nonconformance with the standard.  
1.4 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.  
1.5 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: 30-Jun-2022
• ICS: 65.020.20 - Plant growing
• Technical Committee: D35 - Geosynthetics
• Drafting Committee: D35.05 - Geosynthetic Erosion Control

Relations

• Refers: ASTM D4439-24 - Standard Terminology for Geosynthetics
• Effective Date: 01-Feb-2024
• Refers: ASTM D4354-12(2020) - Standard Practice for Sampling of Geosynthetics and Rolled Erosion Control Products (RECPs) for Testing
• Effective Date: 01-May-2020
• Refers: ASTM D1776/D1776M-20 - Standard Practice for Conditioning and Testing Textiles
• Effective Date: 01-Feb-2020
• Refers: ASTM D4439-18 - Standard Terminology for Geosynthetics
• Effective Date: 15-Apr-2018
• Refers: ASTM D4439-17 - Standard Terminology for Geosynthetics
• Effective Date: 01-Aug-2017
• Refers: ASTM D123-17 - Standard Terminology Relating to Textiles
• Effective Date: 01-Mar-2017
• Refers: ASTM D6566-17 - Standard Test Method for Measuring Mass per Unit Area of Turf Reinforcement Mats
• Effective Date: 01-Jan-2017
• Refers: ASTM D1776/D1776M-16 - Standard Practice for Conditioning and Testing Textiles
• Effective Date: 01-Jan-2016
• Refers: ASTM D123-15b - Standard Terminology Relating to Textiles
• Effective Date: 15-Sep-2015
• Refers: ASTM D123-15a - Standard Terminology Relating to Textiles
• Effective Date: 01-Sep-2015
• Refers: ASTM D4439-15a - Standard Terminology for Geosynthetics
• Effective Date: 01-Sep-2015
• Refers: ASTM D4439-15 - Standard Terminology for Geosynthetics
• Effective Date: 01-Jul-2015
• Refers: ASTM D123-15 - Standard Terminology Relating to Textiles
• Effective Date: 01-Apr-2015
• Refers: ASTM D1776/D1776M-15 - Standard Practice for Conditioning and Testing Textiles
• Effective Date: 01-Feb-2015
• Refers: ASTM D1388-14 - Standard Test Method for Stiffness of Fabrics
• Effective Date: 01-Jul-2014

Overview

ASTM D6575/D6575M-22 is a standard test method developed by ASTM International for determining the stiffness of geosynthetics used as turf reinforcement mats (TRMs). This method is essential for evaluating the mechanical properties of TRMs, which play a critical role in erosion control and vegetation establishment in various civil engineering and landscaping applications. The test evaluates the geosynthetic's resistance to bending, providing essential data for manufacturers, engineers, and regulators to ensure product quality and performance in the field.

Key highlights of this standard include:

• Applicability to TRMs of any fiber content and construction
• Adaptation from fabric stiffness testing, specifically the cantilever method
• Flexibility in performing tests using either SI or inch-pound units, but not mixed

Key Topics

• Stiffness and Flexural Rigidity: The test determines a geosynthetic’s stiffness, which is its resistance to bending. Flexural rigidity is calculated as the cube of the bending length multiplied by the mass per unit area.
• Bending Length: Measured by the cantilever method, this reflects how a TRM bends under its own weight and is critical for performance assessment in the field.
• Test Procedure: The standard outlines conditioning, specimen selection, and measurement approaches, emphasizing repeatability and reproducibility.
• Limitations: The cantilever method is not suitable for TRMs that are extremely limp or exhibit excessive curling or twisting at cut edges.
• Reporting: Results must be reported with precision, specifying measurements in both machine and cross-machine directions for comprehensive analysis.
• Safety and Compliance: Users are responsible for ensuring appropriate safety, health, and environmental practices and compliance with regulatory requirements.

Applications

This standard is widely used in:

• Product Development and Quality Control: Manufacturers use this test method to verify the stiffness properties of turf reinforcement mats prior to market release. Consistency in stiffness helps ensure the mechanical integrity necessary for erosion control applications.
• Civil Engineering Projects: Engineers specify TRMs based on stiffness to meet site-specific slope stability and erosion resistance needs. The ASTM D6575/D6575M-22 test data assist in product selection and design.
• Regulatory Compliance: Municipalities and regulatory bodies may require certified stiffness results when approving TRMs for use in public works, infrastructure, and landscaping projects.
• Research and Comparative Analysis: Testing allows comparative assessment of various TRM products, aiding in material selection and innovation.

Related Standards

Several ASTM and federal standards are referenced or related to the test procedures in ASTM D6575/D6575M-22. Notable examples include:

• ASTM D1388: Standard Test Method for Stiffness of Fabrics, the basis of the current method
• ASTM D6566: Test Method for Measuring Mass Per Unit Area of Turf Reinforcement Mats, used for calculating flexural rigidity
• ASTM D4354: Practice for Sampling of Geosynthetics and Rolled Erosion Control Products for Testing
• ASTM D1776/D1776M: Practice for Conditioning and Testing Textiles
• ASTM D123, D4439: Terminology standards related to textiles and geosynthetics
• Federal CCC-T-191b: Textile Test Methods, referenced for terminology and conversion factors

By following ASTM D6575/D6575M-22, stakeholders can consistently measure and compare geosynthetic stiffness in TRMs, promoting effective application in soil erosion control and vegetative reinforcement projects while adhering to international quality standards.

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: D6575/D6575M − 22
Standard Test Method for
Determining Stiffness of Geosynthetics Used as Turf
Reinforcement Mats (TRMs)
This standard is issued under the fixed designation D6575/D6575M; 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 D6566Test Method for Measuring Mass Per Unit Area of
Turf Reinforcement Mats
1.1 This test method covers the determination of the stiff-
E177Practice for Use of the Terms Precision and Bias in
ness of geosynthetics used as turf reinforcement mats (TRMs).
ASTM Test Methods
1.2 The method is applicable to TRMs of any fiber content
E691Practice for Conducting an Interlaboratory Study to
and any number of components.
Determine the Precision of a Test Method
1.3 The values stated in either SI units or inch-pound units 3
2.2 Federal Standards:
are to be regarded separately as standard. The values stated in
CCC-T-191bTextile Test Methods No. 5206.2
each system may not be exact equivalents; therefore, each
system shall be used independently of the other. Combining
3. Terminology
values from the two systems may result in nonconformance
3.1 Definitions of Terms Specific to This Standard:
with the standard.
3.1.1 bending length (general), n—a measure of the inter-
1.4 This standard does not purport to address all of the
action between geosynthetic weight and geosynthetic stiffness
safety concerns, if any, associated with its use. It is the
as shown by the way in which a geosynthetic bends under its
responsibility of the user of this standard to establish appro-
ownweight.Itreflectsthestiffnessofageosyntheticwhenbent
priate safety, health, and environmental practices and deter-
in one plane under the force of gravity, and is one component
mine the applicability of regulatory limitations prior to use.
of drape.
1.5 This international standard was developed in accor-
3.1.1.1 Discussion—Bending length is called “drape stiff-
dance with internationally recognized principles on standard-
ness” in Federal Specification CCC-T-191b.
ization established in the Decision on Principles for the
3.1.2 bending length (specific), n—the cube root of the ratio
Development of International Standards, Guides and Recom-
of the flexural rigidity to the mass per unit area.
mendations issued by the World Trade Organization Technical
Barriers to Trade (TBT) Committee.
3.1.3 flexural rigidity (general), n—resistance to bending.
3.1.3.1 Discussion—Resistance to bending or flexural rigid-
2. Referenced Documents
ity is called “flex stiffness” in Federal Specification CCC-T-
2.1 ASTM Standards:
191b.
D123Terminology Relating to Textiles
3.1.4 flexural rigidity (specific), n—the couple on either end
D1388Test Method for Stiffness of Fabrics
ofasampleofunitwidthbentintounitcurvatureintheabsence
D1776/D1776MPractice for Conditioning and Testing Tex-
of any tension.
tiles
3.1.4.1 Discussion—The methods measure the bending
D4354Practice for Sampling of Geosynthetics and Rolled
length. Flexural rigidity is calculated directly by multiplying
Erosion Control Products (RECPs) for Testing
the cube of the bending length by the weight per unit area (see
D4439Terminology for Geosynthetics
3.1.2).
3.1.5 stiffness, n—resistance to bending.
This test method is under the jurisdiction of ASTM Committee D35 on
Geosynthetics and is the direct responsibility of Subcommittee D35.05 on Geosyn-
3.2 Definitions—For definitions of other textile or geosyn-
thetic Erosion Control.
thetic terms used in this test method, refer to Terminologies
CurrenteditionapprovedJuly1,2022.PublishedJuly2022.Originallyapproved
D123 and D4439.
in 2000. Last previous edition approved in 2016 as D6575/D6575M–16. DOI:
10.1520/D6575_D6575M-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 Available from U.S. Government Publishing Office, 732 N. Capitol St., NW,
the ASTM website. Washington, DC 20401-0001, http://www.gpo.gov.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
D6575/D6575M − 22
4. Significance and Use the machine direction tests and cut the cross-machine direction
specimens so that separate cross-machine direction yarns/
4.1 In general this test method is adapted from tests devel-
filaments are contained in each. Avoid selvages, end pieces,
oped for woven fabrics (previously designated as Test Method
andcreasedorfoldedplaces,andhandlethespecimensaslittle
D1388).
as possible.
4.2 The cantilever test method may not be suitable for
NOTE 1—Some TRMs are constructed from several component mate-
testing products that are very limp or have a marked tendency
rials and sample preparation must be performed in such a way as to
to curl or twist at a cut edge.
maintain the structural integrity of the product. Procedures found to be
successful for cutting test specimens from TRMs include the use of hot
Cantilever Method
knives to seal the edges and the use of bags and slip covers to keep all
components together during sample preparation. The method of cutting
5. Summary of Method
the specimen should be included in the report.
5.1 Aspecimen of the TRM is slid in a direction parallel to
9. Procedure
its long dimension, so that its end projects from the edge of a
9.1 Make tests on conditioned specimens in the standard
horizontal surface. The length of overhang is measured when
atmosphere for testing.
the tip of the test specimen is depressed under its own weight
to the point where the line joining the tip to the edge of the
9.2 Set the tester on a table or bench so that the horizontal
platform makes an angle of 41.5° with the horizontal. One half
platform and inclined reference lines are at eye level. Adjust
of this length is the bending length of the specimen. The cube
the platform so that it is horizontal as indicated by the leveling
of this quantity multiplied by the weight per unit area of the
bubble.
geosynthetic is the flexural rigidity.
9.3 Placeaspecimenontheplatformwiththeweightontop
5.2 This test method is known also as the Single Cantilever
of it so that the leading edges coincide. Holding the weight in
Test.
a horizontal plane, slide the specimen and weight slowly and
steadily until the leading edges project beyond the edge of the
6. Apparatus
platform. Take the measurement of the overhang where the
6.1 Stiffness Tester, having the following parts:
center of the leading edge of the specimen touches the incline.
6.1.1 Horizontal Platform, with a minimum area of 18 by
At least 6 in. [152.4 mm] of the specimen should remain under
12in. [457.2 by 304.8 mm] and having a smooth low-friction,
the sliding plate at the point the leading edge touches the
flatsurfacesuchaspolishedmetalorplastic.Alevelingbubble
measurement incline. Do not measure specimens that twist
shall be incorporated in the platform, or be available for
more than 45°. Read the length of overhang from the scale to
verification that the horizontal platform is level.
the nearest 1 mm.
6.1.2 Indicator,inclinedatanangleof41.5°belowtheplane
9.4 Take four readings from each specimen, with each side
of the platform surface.
up, first at one end and then the other.
6.1.3 Weight, consisting of a metal bar not less than 4 by
1 9.5 Determine the mass per unit area according to Test
18in. [101.6 by 457.2 mm] by about ⁄8 in. [3 mm] thick.
Method D6566.
6.1.4 Scale and Pointer, to measure the length of the
overhang.
10. Calculation
7. Conditioning
10.1 Unless otherwise specified, average the four readings
obta
...

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: D6575/D6575M − 16 D6575/D6575M − 22
Standard Test Method for
Determining Stiffness of Geosynthetics Used as Turf
Reinforcement Mats (TRMs)
This standard is issued under the fixed designation D6575/D6575M; 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 test method covers the determination of the stiffness of geosynthetics used as Turf Reinforcement Mats (TRM).turf
reinforcement mats (TRMs).
1.2 The method is applicable to TRMs of any fiber content and any number of components.
1.3 The values stated in either SI units or inch-pound units are to be regarded separately as standard. The values stated in each
system aremay not necessarilybe exact equivalents; therefore, to ensure conformance with the standard, each system shall be used
independently of the other, andother. Combining values from the two systems shall not be combined.may result in nonconformance
with the standard.
1.4 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 safety, health, and healthenvironmental practices and determine the
applicability of regulatory limitations prior to use.
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 ASTM Standards:
D123 Terminology Relating to Textiles
D1388 Test Method for Stiffness of Fabrics
D1776/D1776M Practice for Conditioning and Testing Textiles
D4354 Practice for Sampling of Geosynthetics and Rolled Erosion Control Products (RECPs) for Testing
D4439 Terminology for Geosynthetics
D6566 Test Method for Measuring Mass Per Unit Area of Turf Reinforcement Mats
E177 Practice for Use of the Terms Precision and Bias in ASTM Test Methods
E691 Practice for Conducting an Interlaboratory Study to Determine the Precision of a Test Method
2.2 Federal Standards:
CCC-T-191b Textile Test Methods No. 5206.2
This test method is under the jurisdiction of ASTM Committee D35 on Geosynthetics and is the direct responsibility of Subcommittee D35.05 on Geosynthetic Erosion
Control.
Current edition approved July 1, 2016July 1, 2022. Published July 2016July 2022. Originally approved in 2000. Last previous edition approved in 20142016 as
D6575D6575/D6575M – 16. –14a. DOI: 10.1520/D6575_D6575M-16.10.1520/D6575_D6575M-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.
Available from U.S. Government Publishing Office, 732 N. Capitol St., NW, Washington, DC 20401-0001, http://www.gpo.gov.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
D6575/D6575M − 22
3. Terminology
3.1 Definitions of Terms Specific to This Standard:
3.1.1 bending length, n:
3.1.1.1 general, adj—a measure of the interaction between geosynthetic weight and geosynthetic stiffness as shown by the way
in which a geosynthetic bends under its own weight. It reflects the stiffness of a geosynthetic when bent in one plane under the
force of gravity, and is one component of drape.
3.1.1.2 Discussion—Bending length is called drape stiffness in Federal Specification CCC-T-191b.
3.1.1.3 specific, adj—the cube root of the ratio of the flexural rigidity to the mass per unit area.
3.1.1 bending length (general), n—a measure of the interaction between geosynthetic weight and geosynthetic stiffness as shown
by the way in which a geosynthetic bends under its own weight. It reflects the stiffness of a geosynthetic when bent in one plane
under the force of gravity, and is one component of drape.
3.1.1.1 Discussion—
Bending length is called “drape stiffness” in Federal Specification CCC-T-191b.
3.1.2 flexural rigidity, n:
3.1.2.1 general, adj—resistance to bending.
3.1.2.2 Discussion—Resistance to bending or “flexural rigidity” is called flex stiffness in Federal Specification CCC-T-191b.
3.1.2.3 specific, adj—the couple on either end of a sample of unit width bent into unit curvature in the absence of any tension.
3.1.2.4 Discussion—The methods measure the bending length. Flexural rigidity is calculated directly by multiplying the cube of
the bending length by the weight per unit area (see 3.1.1.3).
3.1.2 bending length (specific), n—the cube root of the ratio of the flexural rigidity to the mass per unit area.
3.1.3 stiffness, n—resistance to bending.
3.1.3 flexural rigidity (general), n—resistance to bending.
3.1.3.1 Discussion—
Resistance to bending or flexural rigidity is called “flex stiffness” in Federal Specification CCC-T-191b.
3.1.4 flexural rigidity (specific), n—the couple on either end of a sample of unit width bent into unit curvature in the absence of
any tension.
3.1.4.1 Discussion—
The methods measure the bending length. Flexural rigidity is calculated directly by multiplying the cube of the bending length by
the weight per unit area (see 3.1.2).
3.1.5 stiffness, n—resistance to bending.
3.2 Definitions—For definitions of other textile or geosynthetic terms used in this test method, refer to Terminologies D123 and
D4439.
4. Significance and Use
4.1 In general this test method is adapted from tests developed for woven fabrics (previously designated as Test Method D1388).
4.2 The cantilever test method may not be suitable for testing products that are very limp or have a marked tendency to curl or
twist at a cut edge.
D6575/D6575M − 22
Cantilever Method
5. Summary of Method
5.1 A specimen of the TRM is slid in a direction parallel to its long dimension, so that its end projects from the edge of a horizontal
surface. The length of overhang is measured when the tip of the test specimen is depressed under its own weight to the point where
the line joining the tip to the edge of the platform makes an angle of 41.5° with the horizontal. One half of this length is the bending
length of the specimen. The cube of this quantity multiplied by the weight per unit area of the geosynthetic is the flexural rigidity.
5.2 This test method is known also as the Single Cantilever Test.
6. Apparatus
6.1 Stiffness Tester, having the following parts:
6.1.1 Horizontal Platform, with a minimum area of 18 by 12 in. [457.2 by 304.8 mm] and having a smooth low-friction, flat
surface such as polished metal or plastic. A leveling bubble shall be incorporated in the platform, or be available for verification
that the horizontal platform is level.
6.1.2 Indicator, inclined at an angle of 41.5° below the plane of the platform surface.
6.1.3 Weight, consisting of a metal bar not less than 4 by 18 in. [101.6 by 457.2 mm] by about ⁄8 in. [3 mm] thick.
6.1.4 Scale and Pointer, to measure the length of the overhang.
7. Conditioning
7.1 For tests made as directed in 9.1 – 9.5, bring the specimenssample to a moisture equilibrium in the atmosphere for testing
TRMs, that is, a temperature of 70 6 4°F4 °F [21 6 2°C]2 °C] and relative humidity of 60 6 10 %. See Practice D1776/D1776M.
7.2 Additional conditioning may be needed to remove curl from rolled geosynthetics. See Practice D4354.
8. Selection and Preparation of Specimens
8.1 Cut test specimens 4 in. wide by a minimum of 18 in. long [101.6 by 457.2 mm]; longer specimens may be needed to obtain
a measurement. At least 6 in. [152.4 mm] of the specimen should remain under the sliding plate at the point of measurement. Cut
four specimens with the long direction parallel to the machine direction and four with the long direction parallel to the transverse
(or cross-machine) direction. If the geosynthetic is not uniform or a higher degree of precision is required, more may be tested.
Vary cutting the specimens in such a way that the machine direction specimens do not contain the same machine direction
yarns/filaments for the machine direction tests and cut the cross-machine direction specimens so that separate cross-machine
direction yarns/filaments are contained in each. Avoid selvages, end pieces, and creased or folded places, and ha
...