ASTM D7735-17(2022)

Standard Test Method for Type A Durometer Hardness Testing of Thermoplastic Pavement Marking at Elevated Temperatures

SIGNIFICANCE AND USE
5.1 This method is based on the penetration of a specific type of indentor when forced into the material under specified conditions. The indentation hardness is inversely related to the penetration and is dependent on the elastic modulus, viscoelastic behavior of the material, geometry of the indentor, the applied force and temperature at test. This test method is empirical and therefore primarily for control purposes. No simple relationship exists between indentation hardness determined by this test method and any fundamental property of the material tested.
SCOPE
1.1 This test method covers Type A Durometer hardness of thermoplastic pavement marking material at elevated temperatures.  
1.2 This test method is similar to Test Method D2240 for hardness with special attention given to keeping the temperature of the test sample and instrument constant. Within the highway materials community, it is sometimes known as “indentation resistance.”  
1.3 All materials, instruments or equipment used for the determination of temperature, hardness and time shall be traceable to National Institute of Standards and Technology or other internationally recognized organizations parallel in nature.  
1.4 The values stated in SI units are to be regarded as standard. The values given in parentheses are for information only.  
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, health, and environmental 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: 30-Nov-2022
• ICS: 93.080.30 - Road equipment and installations
• Technical Committee: D01 - Paint and Related Coatings, Materials, and Applications
• Drafting Committee: D01.44 - Traffic Coatings

Relations

• Refers: ASTM D16-24 - Standard Terminology for Paint, Related Coatings, Materials, and Applications
• Effective Date: 01-Jan-2024
• Refers: ASTM D16-16 - Standard Terminology for Paint, Related Coatings, Materials, and Applications
• Effective Date: 01-Jul-2016
• Refers: ASTM D16-14 - Standard Terminology for Paint, Related Coatings, Materials, and Applications
• Effective Date: 01-Dec-2014
• Refers: ASTM E177-14 - Standard Practice for Use of the Terms Precision and Bias in ASTM Test Methods
• Effective Date: 01-May-2014
• Refers: ASTM E177-13 - Standard Practice for Use of the Terms Precision and Bias in ASTM Test Methods
• Effective Date: 01-May-2013
• Refers: ASTM E691-13 - Standard Practice for Conducting an Interlaboratory Study to Determine the Precision of a Test Method
• Effective Date: 01-May-2013
• Refers: ASTM D16-12 - Standard Terminology for Paint, Related Coatings, Materials, and Applications
• Effective Date: 01-Aug-2012
• Refers: ASTM D7308-07(2012) - Standard Practice for Sample Preparation of Thermoplastic Traffic Marking Materials
• Effective Date: 01-Jun-2012
• Refers: ASTM E691-11 - Standard Practice for Conducting an Interlaboratory Study to Determine the Precision of a Test Method
• Effective Date: 01-Nov-2011
• Refers: ASTM D16-11a - Standard Terminology for Paint, Related Coatings, Materials, and Applications
• Effective Date: 01-Jun-2011
• Refers: ASTM D16-11 - Standard Terminology for Paint, Related Coatings, Materials, and Applications
• Effective Date: 01-Jan-2011
• Refers: ASTM E177-10 - Standard Practice for Use of the Terms Precision and Bias in ASTM Test Methods
• Effective Date: 01-Oct-2010
• Refers: ASTM D16-10 - Standard Terminology for Paint, Related Coatings, Materials, and Applications
• Effective Date: 01-Feb-2010
• Refers: ASTM E177-08 - Standard Practice for Use of the Terms Precision and Bias in ASTM Test Methods
• Effective Date: 01-Oct-2008
• Refers: ASTM E691-08 - Standard Practice for Conducting an Interlaboratory Study to Determine the Precision of a Test Method
• Effective Date: 01-Oct-2008

Overview

ASTM D7735-17(2022): Standard Test Method for Type A Durometer Hardness Testing of Thermoplastic Pavement Marking at Elevated Temperatures is a crucial industry standard developed by ASTM International. This test method specifies procedures to determine the hardness, or indentation resistance, of thermoplastic pavement marking materials at elevated temperatures. The test ensures that measurements are repeatable and reliable for quality control and comparative analysis across different laboratories.

The method involves using a Type A Durometer to measure the hardness of pavement marking materials, focusing on precise temperature control of both the sample and the instrument. The goal is to provide a reproducible empirical indication of indentation hardness for control purposes in pavement marking applications.

Key Topics

• Indentation Hardness Measurement: The standard is based on the penetration depth of a specific indentor into the thermoplastic material under controlled conditions. The measured resistance provides an indication of material hardness.
• Temperature Control: Strict regulation of sample and instrument temperature is enforced, typically at 46°C (115°F), to ensure accuracy and consistency. The test may be conducted in a water bath or oven.
• Reproducibility and Repeatability: By maintaining environmental stability during testing, ASTM D7735 enhances the reliability and comparability of results across laboratories.
• Empirical Method: The resulting hardness value is a practical assessment for quality control and does not directly correlate to fundamental material properties such as elastic modulus or viscoelastic characteristics.
• Traceability and Calibration: All measurement tools and equipment must be traceable to the National Institute of Standards and Technology (NIST) or equivalent internationally recognized organizations.
• Safety and Compliance: Users are responsible for following appropriate safety, health, and environmental protocols when using this standard.

Applications

ASTM D7735-17(2022) is widely utilized within the highway materials and traffic coatings industries for the following key applications:

• Quality Control of Pavement Markings: Ensures thermoplastic pavement markings meet specified hardness criteria for durability and long-term road surface delineation.
• Performance Specification Compliance: Supports manufacturers and agencies in verifying that products conform to contractual or regulatory performance standards at elevated temperatures where markings must remain effective.
• Material Comparison: Provides a standardized approach for comparing different formulations of thermoplastic pavement materials, ensuring objective assessment and selection.
• Research and Development: Facilitates laboratory studies and the development of new pavement marking materials by providing a consistent method for measuring indentation resistance.

Related Standards

ASTM D7735 references several important related standards that further support the quality and reliability of traffic coating materials:

• ASTM D2240 - Standard Test Method for Rubber Property-Durometer Hardness; provides the foundational procedure for durometer hardness testing.
• ASTM D7307 - Practice for Sampling of Thermoplastic Pavement Marking Materials; outlines sampling methods for representative testing.
• ASTM D7308 - Practice for Sample Preparation of Thermoplastic Pavement Marking Materials; details procedures for preparing samples before testing.
• ASTM E177 - Practice for Use of the Terms Precision and Bias in ASTM Test Methods; supports understanding of test result variability.
• ASTM E691 - Practice for Conducting an Interlaboratory Study to Determine the Precision of a Test Method; provides guidelines for method validation and reproducibility.

Practical Value

Adopting ASTM D7735-17(2022) ensures high levels of consistency, repeatability, and reliability in the hardness testing of thermoplastic pavement markings. By using a standardized approach, organizations can improve product quality, meet regulatory requirements, and enhance roadway safety through durable, effective pavement marking systems optimized for elevated temperature conditions. This standard is essential for manufacturers, quality assurance teams, researchers, and regulatory agencies involved in traffic coatings and road safety 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: D7735 − 17 (Reapproved 2022)
Standard Test Method for
Type A Durometer Hardness Testing of Thermoplastic
Pavement Marking at Elevated Temperatures
This standard is issued under the fixed designation D7735; 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 D16 TerminologyforPaint,RelatedCoatings,Materials,and
Applications
1.1 This test method covers Type A Durometer hardness of
D2240 Test Method for Rubber Property—Durometer Hard-
thermoplastic pavement marking material at elevated tempera-
ness
tures.
D7307 Practice for Sampling of Thermoplastic Pavement
1.2 This test method is similar to Test Method D2240 for
Marking Materials
hardness with special attention given to keeping the tempera-
D7308 Practice for Sample Preparation of Thermoplastic
ture of the test sample and instrument constant. Within the
Pavement Marking Materials
highway materials community, it is sometimes known as
E177 Practice for Use of the Terms Precision and Bias in
“indentation resistance.”
ASTM Test Methods
1.3 All materials, instruments or equipment used for the E691 Practice for Conducting an Interlaboratory Study to
Determine the Precision of a Test Method
determination of temperature, hardness and time shall be
traceable to National Institute of Standards and Technology or
other internationally recognized organizations parallel in na- 3. Terminology
ture.
3.1 Definitions:
1.4 The values stated in SI units are to be regarded as
3.1.1 The terms and definitions in Terminology D16 apply
standard. The values given in parentheses are for information
to this method.
only.
3.1.2 hardness, adv—the value of resistance of a small
1.5 This standard does not purport to address all of the penetrating device. In the case of the Type A Durometer in
accordance with Test Method D2240, the presser foot/indentor
safety concerns, if any, associated with its use. It is the
responsibility of the user of this standard to establish appro- (spherical to 0.79 mm 6 0.03 mm or 0.03 in. 6 0.001 in.) is
priate safety, health, and environmental practices and deter- connected to a spring loaded to a total of 0.075 N/Durometer
mine the applicability of regulatory limitations prior to use. units at full deflection. For reading of Type A hardness the
1.6 This international standard was developed in accor- instruments scale reads from 0 to 100. Minimal deflection is 0
dance with internationally recognized principles on standard- (softest) and maximum is 100 (hardest).
ization established in the Decision on Principles for the
3.1.3 thermoplastic, n—pavement marking (same as 3.1.4).
Development of International Standards, Guides and Recom-
3.1.4 thermoplastic pavement marking—a highly filled
mendations issued by the World Trade Organization Technical
100 % total solids highway marking system that when heated
Barriers to Trade (TBT) Committee.
toamoltenstatecanbeextrudedorsprayedontoaroadsurface
and when cooled forms a solid durable delineator or thermo-
2. Referenced Documents
plastic pavement marking usually melted to 220 °C (425 °F).
2.1 ASTM Standards:
4. Summary of Test Method
This test method is under the jurisdiction of ASTM Committee D01 on Paint
4.1 This method was developed to enable the testing of
and Related Coatings, Materials, andApplications and is the direct responsibility of
hardness or indentation resistance of thermoplastic pavement
Subcommittee D01.44 on Traffic Coatings.
marking material at ambient roadway/highway temperatures.
Current edition approved Dec. 1, 2022. Published December 2022. Originally
Due to the speed at which basic thermoplastic pavement
approved in 2011. Last previous edition approved in 2017 as D7735 – 17. DOI:
10.1520/7735-17R22.
marking cools, testing its hardness at elevated temperatures is
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
difficult, even at a relatively low 46 °C (115 °F). Existing
contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM
non-standardmethodsarenotconsistentbecausetheyallowthe
Standards volume information, refer to the standard’s Document Summary page on
the ASTM website. samples to change temperature during testing. By keeping both
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
D7735 − 17 (2022)
the test samples and the hardness tester in a regulated environ- 9. Procedure
ment before and during testing, the results are much more
9.1 Sample the thermoplastic pavement marking in accor-
repeatable within a laboratory. The goal for this method is to
dance with Practice D7307 then begin preparation of samples
allow results from this test to be more reproducible from
in accordance with Practice D7308.
laboratory to laboratory.
9.2 Pour thermoplastic that has been heated to 425 °F (or
4.2 The methodology involves measuring the hardness of
per manufacturer’s recommendation) into a 20 mL aluminum
thermoplastic pavement marking by keeping the test sample in
pan, or larger, to approximately half full, and then allow
the elevated temperature environment (a water bath) during the
cooling to room temperature.
testing process and using a Durometer that can be placed in the
water bath and function. This method could be performed in a
9.3 Turn on heater on water bath and oscillator or stirrer and
glove box/oven if the door was not opened before or during the
allow the temperature to stabilize to 46 °C 6 1.0 °C (115 °F 6
testing.
3.0 °F) or as agreed upon by the involved parties
9.4 Turnonovensetto46 °C 61.0 °C(115 °F 63.0 °F)or
5. Significance and Use
as mutually agreed upon by the involved parties and place the
5.1 This method is based on the penetration of a specific
Type A Durometer inside
type of indentor when forced into the material under specified
conditions. The indentation hardness is inversely related to the NOTE 1—A bath or oven operated outside the recommended tempera-
ture control may result in greater result variability.
penetration and is dependent on the elastic modulus, viscoelas-
tic behavior of the material, geometry of the indentor, the
9.4.1 Other temperatures can be used when agreed upon
applied force and temperature at test. This test method is
between the parties involved.
empirical and therefore primarily for control purposes. No
9.5 Place cooled thermoplastic pavement marking hardness
simple relationship exists between indentation hardness deter-
sample in water bath.
mined by this test method and any fundamental property of the
material tested.
9.6 Samples should be allowed to equilibrate to the required
temperature for at least one hour before being tested.
6. Apparatus
9.6.1 Samples should be tested within three hours of being
6.1 Safety Glasses.
placed into the water.
6.2 Aluminum Pans(20mL)oradequatesizefortesterbase.
9.7 Before testing sample, remove lid from water bath.
Quickly place hardness tester from oven in the water bath
6.3 A Hardness Tester Type A Needle-type Durometer in
making sure that the needle point and bottom of weight is
accordance with Test Method D2240.
below the waterline. This will ensure that tester is exactly the
6.4 Constant 1000 g Load Weight for Type A Durometer.
same temperature as sample.
6.5 Optional—Test Block Kit containing Type A Durometer
NOTE 2—If the tester is removed from the water during the testing
samples with values traceable to an accredited calibration
process, its temperature will change and cause variations in results.
laboratory. Sample(s)canbetestedmultipletimesaslongassampleandtesterbottom
ar
...