ASTM D6307-19

Standard Test Method for Asphalt Content of Asphalt Mixture by Ignition Method

SIGNIFICANCE AND USE
4.1 This test method can be used for quantitative determination of asphalt content in asphalt mixture and pavement samples for quality control, specification acceptance, and mixture evaluation studies. This test method does not require the use of solvents. Aggregate obtained by this test method may be used for gradation analysis according to Test Method D5444.
SCOPE
1.1 This test method covers the determination of asphalt content of asphalt mixture and asphalt pavement samples by removing the asphalt cement in an ignition furnace. The means of sample heating may be the convection method or direct irradiation method.
Note 1: Aggregate obtained by this test method may be used for sieve analysis. Particle size degradation may occur with some aggregates.  
1.2 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.  
1.3 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.  
1.4 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-Dec-2018
• ICS: 93.080.20 - Road construction materials
• Technical Committee: D04 - Road and Paving Materials
• Drafting Committee: D04.25 - Analysis of Asphalt Mixtures

Relations

• Replaces: ASTM D6307-16 - Standard Test Method for Asphalt Content of Asphalt Mixture by Ignition Method
• Effective Date: 01-Jan-2019
• Refers: ASTM C670-24a - Standard Practice for Preparing Precision and Bias Statements for Test Methods for Construction Materials
• Effective Date: 01-Feb-2024
• Refers: ASTM D4753-24 - Standard Guide for Evaluating, Selecting, and Specifying Balances and Standard Masses for Use in Soil, Rock, and Construction Materials Testing
• Effective Date: 01-Feb-2024
• Refers: ASTM C670-24 - Standard Practice for Preparing Precision and Bias Statements for Test Methods for Construction Materials
• Effective Date: 01-Jan-2024
• Refers: ASTM D140/D140M-16(2023) - Standard Practice for Sampling Asphalt Materials
• Effective Date: 01-Dec-2023
• Refers: ASTM D75/D75M-19 - Standard Practice for Sampling Aggregates
• Effective Date: 01-Nov-2019
• Refers: ASTM D140/D140M-16 - Standard Practice for Sampling Asphalt Materials
• Effective Date: 01-Jun-2016
• Refers: ASTM D140/D140M-15 - Standard Practice for Sampling Bituminous Materials
• Effective Date: 01-Jun-2015
• Refers: ASTM D4753-15 - Standard Guide for Evaluating, Selecting, and Specifying Balances and Standard Masses for Use in Soil, Rock, and Construction Materials Testing
• Effective Date: 01-May-2015
• Refers: ASTM D140/D140M-14 - Standard Practice for Sampling Bituminous Materials
• Effective Date: 01-Jun-2014
• Refers: ASTM D75/D75M-13 - Standard Practice for Sampling Aggregates
• Effective Date: 15-Dec-2013
• Refers: ASTM C670-13 - Standard Practice for Preparing Precision and Bias Statements for Test Methods for Construction Materials
• Effective Date: 01-Jul-2013
• Refers: ASTM D979/D979M-12 - Standard Practice for Sampling Bituminous Paving Mixtures
• Effective Date: 01-Feb-2012
• Refers: ASTM D1461-11 - Standard Test Method for Moisture or Volatile Distillates in Bituminous Paving Mixtures
• Effective Date: 15-Dec-2011
• Refers: ASTM D979/D979M-11 - Standard Practice for Sampling Bituminous Paving Mixtures
• Effective Date: 15-Jun-2011

Overview

ASTM D6307-19: Standard Test Method for Asphalt Content of Asphalt Mixture by Ignition Method is an internationally recognized method developed by ASTM International. This standard specifies the procedure for determining the asphalt content of asphalt mixtures and pavement samples using an ignition furnace. The test method offers a quantitative approach that eliminates the need for solvents, promoting safer and more efficient laboratory practices. Designed for use in quality control, specification acceptance, and evaluation studies, this standard facilitates accurate measurement of asphalt binder content, which is essential for optimal pavement performance.

Key Topics

• Ignition Furnace Method: This method uses either convection or direct irradiation heating to burn off the asphalt binder, leaving behind aggregate for precise measurement. The difference in mass before and after burning determines the asphalt content.
• Sample Preparation and Handling: Procedural details include proper sampling of asphalt mixtures and aggregates, oven-drying, and the importance of calibration using mix-specific samples.
• Calibration and Correction: To ensure accuracy, a calibration factor is determined for each mix type, accounting for potential mass loss from certain aggregate types or additives during ignition.
• Safety Considerations: Emphasizes compliance with safety, health, and environmental practices due to high ignition temperatures and the need for proper equipment handling.
• Data Collection and Reporting: Specifies requirements for automated data collection, calculation of results, and comprehensive reporting, including identification of mix and aggregate details, test conditions, and measured results.
• Aggregates for Further Analysis: Aggregate recovered after the ignition method can be used for gradation analysis, supporting further quality assessment.

Applications

• Quality Control in Asphalt Production: Ensures that asphalt mixtures contain the correct proportion of asphalt binder, a key factor for durability and performance in road construction.
• Acceptance Testing for Road Construction Projects: Provides reliable data for engineers and contractors to verify that asphalt mixes meet project specifications and regulatory requirements.
• Mixture Evaluation and Forensic Studies: Used to evaluate the consistency of asphalt mixtures in existing pavements, aiding in maintenance decisions and forensic analysis of pavement failures.
• Aggregate Gradation Analysis: The extracted aggregate can be reutilized for mechanical size analysis, enabling comprehensive assessment without requiring new samples.
• Laboratory and On-Site Testing: Adaptable for use in laboratory conditions and field quality assurance, with detailed guidance on equipment and procedures.

Related Standards

• ASTM D5444: Test Method for Mechanical Size Analysis of Extracted Aggregate, used for further analysis of aggregates obtained from the ignition method.
• ASTM D979/D979M: Practice for Sampling Bituminous Paving Mixtures for reliable sample collection.
• ASTM D75/D75M: Practice for Sampling Aggregates, ensuring representative aggregate samples.
• ASTM D140/D140M: Practice for Sampling Asphalt Materials.
• ASTM D1461: Test Method for Moisture or Volatile Distillates in Asphalt Mixtures, which can complement asphalt content analysis.
• ASTM D4753: Guide for evaluating balances and weighing equipment used in this and related methods.
• AASHTO R47: Standard Practice for Reducing Samples of Hot Mix Asphalt to Testing Size.

Keywords: asphalt content, ignition method, asphalt mixture, pavement testing, quality control, aggregate gradation, ASTM D6307, asphalt binder, road construction testing, standard test method

This standard is essential for laboratories, contractors, and agencies involved in the production and testing of asphalt mixtures, ensuring consistent and reliable pavement construction outcomes.

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: D6307 − 19
Standard Test Method for
Asphalt Content of Asphalt Mixture by Ignition Method
This standard is issued under the fixed designation D6307; 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 D4753 Guide for Evaluating, Selecting, and Specifying Bal-
ances and Standard Masses for Use in Soil, Rock, and
1.1 This test method covers the determination of asphalt
Construction Materials Testing
content of asphalt mixture and asphalt pavement samples by
D5444 Test Method for Mechanical Size Analysis of Ex-
removing the asphalt cement in an ignition furnace.The means
tracted Aggregate
of sample heating may be the convection method or direct
2.2 AASHTO Standard:
irradiation method.
R47 Standard Practice for Reducing Samples of Hot Mix
NOTE 1—Aggregate obtained by this test method may be used for sieve
Asphalt (HMA) to Testing Size
analysis. Particle size degradation may occur with some aggregates.
1.2 The values stated in SI units are to be regarded as
3. Summary of Test Methods
standard. No other units of measurement are included in this
3.1 The asphalt cement in the paving mixture is ignited
standard.
using the furnace equipment applicable to the particular
1.3 This standard does not purport to address all of the
method. The asphalt content is calculated by difference from
safety concerns, if any, associated with its use. It is the
the mass of the residual aggregate and moisture content. The
responsibility of the user of this standard to establish appro-
asphalt content is expressed as mass percent of moisture-free
priate safety, health, and environmental practices and deter-
mixtures. Test Method A is intended for furnaces with an
mine the applicability of regulatory limitations prior to use.
internal automated weighing system. Test Method B is in-
1.4 This international standard was developed in accor-
tended for furnaces without an internal weighing system.
dance with internationally recognized principles on standard-
ization established in the Decision on Principles for the
4. Significance and Use
Development of International Standards, Guides and Recom-
4.1 This test method can be used for quantitative determi-
mendations issued by the World Trade Organization Technical
nation of asphalt content in asphalt mixture and pavement
Barriers to Trade (TBT) Committee.
samples for quality control, specification acceptance, and
mixture evaluation studies. This test method does not require
2. Referenced Documents
the use of solvents. Aggregate obtained by this test method
2.1 ASTM Standards:
may be used for gradation analysis according to Test Method
C670 Practice for Preparing Precision and Bias Statements
D5444.
for Test Methods for Construction Materials
D75/D75M Practice for Sampling Aggregates
5. Apparatus
D140/D140M Practice for Sampling Asphalt Materials
5.1 Balance,readableto0.1g,andcapableofmeasuringthe
D979/D979M Practice for Sampling Bituminous Paving
mass of sample, sample trays, and catch pan.The balance shall
Mixtures
be in accordance with Guide D4753, Class GP2.
D1461 Test Method for Moisture or Volatile Distillates in
5.2 Sample Tray(s), of appropriate size that allows the
Asphalt Mixtures
samples to be spread thinly and allows air to flow up through
and around the sample particles. The sample shall be enclosed
This test method is under the jurisdiction of ASTM Committee D04 on Road
completely with screen mesh, perforated stainless steel plate,
and Paving Materials and is the direct responsibility of Subcommittee D04.25 on
or other suitable material.
Analysis of Asphalt Mixtures.
Current edition approved Jan. 1, 2019. Published February 2019. Originally
NOTE 2—Screen mesh or other suitable material with maximum and
approved in 1998. Last previous edition approved in 2016 as D6307 – 16. DOI:
10.1520/D6307-19.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM Available from American Association of State Highway and Transportation
Standards volume information, refer to the standard’s Document Summary page on Officials (AASHTO), 444 N. Capitol St., NW, Suite 249, Washington, DC 20001,
the ASTM website. http://www.transportation.org.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
D6307 − 19
minimum openings of 3.35 mm and 600 µm, respectively, has been found the equipment used (for a particular method), the test specimen may be
to perform well. divided into suitable increments, tested, and the results combined for
calculationofasphaltcontentbasedontheweightedaverageofthemasses
5.3 Catch Pan, of appropriate size to hold the sample trays
used in the increments.
so that aggregate particles and melting asphalt binder falling
7.4 Obtain samples of asphalt cement in accordance with
through the screen mesh are caught.
Practice D140/D140M.
5.4 CatchPan/SampleTray(s)HandlingApparatus,suitable
for inserting catch pan and sample tray(s) into furnace and
TEST METHOD A
removing hot catch pan and sample tray(s) from furnace.
5.5 Assorted Spatulas, Pans, Bowls, and Wire Brushes, for
8. Apparatus
preparing asphalt mixtures and removing aggregate from
sample tray(s) and catch pan.
8.1 In addition to the apparatus listed in Section 5, the
following apparatus is required for Test Method A.
5.6 Protective Gloves, well insulated and capable of with-
8.1.1 Ignition Furnace—A forced-air ignition furnace that
standing 580 °C.
heats the sample by either convection method or direct
5.7 Ovens—Mechanical ovens, convection or forced draft,
irradiation method. The convection-type furnace must have a
shall be provided for drying aggregates and asphalt mixtures,
minimum temperature capability of 580 °C. The furnace shall
and for preheating asphalt mixtures prior to ignition testing.
have an internal weighing system capable of measuring the
5.8 Ignition Furnace, as described in 8.1.1 or 11.1.1.
mass of sample sizes of at least 2500 g. The furnace chamber
shall be of sufficient size to accommodate sample sizes of at
6. Hazards
least 2500 g.Adata collection system also shall be included so
6.1 The temperature of the furnace, sample, sample tray(s), that the sample mass loss can be determined automatically to
andcatchpanafterremovalfromthefurnaceisextremelyhigh. an accuracy of 0.1 g and displayed during a test. The test is
Caution, therefore, must be exercised at all times when deemed complete when the difference between consecutive
handling these items, as failure to do so could result in serious measuredmasslossdoesnotexceed0.01 %ofthesamplemass
injury, severe burns, or fire. The sample, sample tray(s), and for three consecutive 1-min intervals. The equipment shall
catch pan should be placed inside a safety cage and should not provide a printout of the test results. A system capable of
be allowed to cool near any materials that are subject to reducing furnace emissions to an acceptable level also shall be
ignition at the high temperatures used in this procedure. The incorporated in the furnace. The furnace shall be vented into a
furnace manufacturer’s instruction manual must be followed to hood or to the outside and, when set up properly, will have no
take all necessary precautions. noticeable odors escaping into the laboratory. The furnace will
have a fan with the capability to pull air through the furnace to
7. Sampling
expedite the test and to reduce escape of smoke into the
laboratory. The furnace shall be equipped so that the door
7.1 ObtainsamplesofaggregateinaccordancewithPractice
cannot be opened during the ignition test.
D75/D75M.
8.1.2 Filters,ifrequired,ofthetypespecifiedbythefurnace
7.2 Obtain samples of asphalt mixture in accordance with
manufacturer.
Practice D979/D979M and AASHTO R47.
7.3 Preparation of Test Specimens:
9. Calibration
7.3.1 If the mixture is not soft enough to separate with a
9.1 The type of aggregate in the mixture may affect the
spatula or trowel, place it in a large, flat pan and warm in an
results of this test method because different aggregates lose
oven set at 110 6 5 °C until it can be separated or mixed. Split
mass on ignition to varying degrees. The results also may be
or quarter the material in accordance withAASHTO R47 until
affected by the presence of additives and modifiers in the
the mass of material required for the test is obtained.
asphalt mixture sample. Accordingly, to optimize accuracy, a
7.3.2 The size of the test sample shall be governed by the
calibration factor shall be established by testing three calibra-
nominal maximum aggregate size of the mixture and shall
tion samples for each mix type. The calibration shall be
conform to the mass requirement shown in Table 1 (see Note
performed on a prepared sample of asphalt mixture, which also
3).
shall include additives and modifiers, if any, to be used.
NOTE 3—When the mass of the test specimen exceeds the capacity of
9.2 Obtain samples of blended aggregate to be used in the
asphalt mixture in accordance with 7.1. The sample should be
TABLE 1 Size of Sample
approximately the same mass and gradation as that to be used
for the asphalt mixture test sample (10.1).
Nominal Maximum Aggregate Size
Minimum Mass of Sample, kg
Standard, mm
9.3 Obtain samples of asphalt cement to be used in the
4.75 0.5
9.5 1
asphalt mixture in accordance with 7.4.
12.5 1.5
19.0 2
9.4 Oven dry the aggregate samples to a constant mass.
25.0 3
9.4.1 For the convection-type furnace, set the furnace tem-
37.5 4
perature to 540 6 5 °C for calibration using mixtures.
D6307 − 19
9.4.2 For the direct irradiation-type furnace, set the burn designed for samples that may not burn completely using the
profile to the DEFAULT mode. DEFAULT burn profile.
9.16 The temperature or burn profile for testing asphalt
9.5 Heat the aggregates and asphalt cement to approxi-
mixture samples in 10.3 shall be the same temperature or burn
mately 150 °C. Heat all mixing bowls and tools to approxi-
profile selected for testing mixture calibration samples.
mately 150 °C.
10. Procedure
9.6 Prior to the mixing of calibration samples, an initial or
“butter” mix is required to condition the mixing equipment.
10.1 Obtain an asphalt mixture sample in accordance with
Remove and discard the “butter” mix from the bowl by
Section 7. The sample mass should be approximately the same
scraping, leaving a uniform coating of asphalt mix residue.
as that used for calibration (9.2).
10.2 Oven dry the asphalt mixture sample to constant mass
NOTE 4—The “butter” mix prevents calibration samples from being
biased by residual asphalt mix retained in the mixing bowl.
at a temperature of 110 6 5 °C or determine the moisture
content of samples in accordance with Test Method D1461,so
9.7 Prepare three calibration samples at the design asphalt
that the measured mass loss can be corrected for moisture.
cement content (P). Incorporate additives and modifiers, if any,
to be used. 10.3 Set the furnace temperature or burn profile in accor-
dance with Section 9. Samples can be placed in the furnace at
9.8 Determineandrecordthemassofthesampletray(s)and
significantly lower temperatures, since the furnace will quickly
catch pan to the nearest 0.1 g.
heat to the desired temperature once the sample begins to burn.
9.9 Evenly distribute the sample in the sample tray(s).
The furnace temperature is likely to increase during the
ignition phase of the test.
9.10 Determine the mass of the sample, sample tray(s), and
10.4 Determine and record the mass of the sample tray(s)
catch pan to the nearest 0.1 g. Calculate and record the initial
and catch pan to the nearest 0.1 g.
mass of the sample (M ).
I
10.5 Evenly distribute the sample in the sample tray(s).
9.11 Heat the calibration sample in the convection-type
furnace at 540 6 5 °C; or in the direct irradiation-type furnace 10.6 Determine the mass of the sample, sample tray(s), and
using the DEFAULT mode until
...

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: D6307 − 16 D6307 − 19
Standard Test Method for
Asphalt Content of Asphalt Mixture by Ignition Method
This standard is issued under the fixed designation D6307; 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 asphalt content of asphalt mixture and asphalt pavement samples by removing
the asphalt cement in an ignition furnace. The means of sample heating may be the convection method or direct irradiation method.
NOTE 1—Aggregate obtained by this test method may be used for sieve analysis. Particle size degradation may occur with some aggregates.
1.2 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.
1.3 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 limitationlimitations prior to use.
1.4 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:
C670 Practice for Preparing Precision and Bias Statements for Test Methods for Construction Materials
C702 Practice for Reducing Samples of Aggregate to Testing Size
D75D75/D75M Practice for Sampling Aggregates
D140D140/D140M Practice for Sampling Asphalt Materials
D979D979/D979M Practice for Sampling Bituminous Paving Mixtures
D1461 Test Method for Moisture or Volatile Distillates in Asphalt Mixtures
D4753 Guide for Evaluating, Selecting, and Specifying Balances and Standard Masses for Use in Soil, Rock, and Construction
Materials Testing
D5444 Test Method for Mechanical Size Analysis of Extracted Aggregate
2.2 AASHTO Standards:Standard:
R47 Standard Practice for Reducing Samples of Hot Mix Asphalt (HMA) to Testing Size
3. Summary of Test Methods
3.1 The asphalt cement in the paving mixture is ignited using the furnace equipment applicable to the particular method. The
asphalt content is calculated by difference from the mass of the residual aggregate and moisture content. The asphalt content is
expressed as mass percent of moisture-free mixtures. Test Method A is intended for furnaces with an internal,internal automated
weighing system. Test Method B is intended for furnaces without an internal weighing system.
4. Significance and Use
4.1 This test method can be used for quantitative determination of asphalt content in asphalt mixture and pavement samples for
quality control, specification acceptance, and mixture evaluation studies. This test method does not require the use of solvents.
Aggregate obtained by this test method may be used for gradation analysis according to Test Method D5444.
This test method is under the jurisdiction of ASTM Committee D04 on Road and Paving Materials and is the direct responsibility of Subcommittee D04.25 on Analysis
of Asphalt Mixtures.
Current edition approved May 1, 2016Jan. 1, 2019. Published July 2016February 2019. Originally approved in 1998. Last previous edition approved in 20102016 as
D6307 – 10.D6307 – 16. DOI: 10.1520/D6307-16.10.1520/D6307-19.
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 American Association of State Highway and Transportation Officials (AASHTO), 444 N. Capitol St., NW, Suite 249, Washington, DC 20001,
http://www.transportation.org.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
D6307 − 19
5. Apparatus
5.1 Balance, readable to 0.1 g, and capable of measuring the mass of sample, sample trays, and catch pan. The balance shall
be in accordance with Guide D4753, Class GP2.
5.2 Sample Tray(s), of appropriate size that allows the samples to be spread thinly and allows air to flow up through and around
the sample particles. The sample shall be enclosed completely with screen mesh, perforated stainless steel plate, or other suitable
material.
NOTE 2—Screen mesh or other suitable material with maximum and minimum openings of 3.35 mm and 600 μm, respectively, has been found to
perform well.
5.3 Catch Pan, of appropriate size to hold the sample trays so that aggregate particles and melting asphalt binder falling through
the screen mesh are caught.
5.4 Catch Pan/Sample Tray(s) Handling Apparatus, suitable for inserting catch pan and sample tray(s) into furnace and
removing hot catch pan and sample tray(s) from furnace.
5.5 Assorted Spatulas, Pans, Bowls, and Wire Brushes, for preparing asphalt mixtures and removing aggregate from sample
tray(s) and catch pan.
5.6 Protective Gloves, well insulated and capable of withstanding 580°C.580 °C.
5.7 Ovens—Mechanical ovens, convection or forced draft, shall be provided for drying aggregates and asphalt mixtures, and for
preheating asphalt mixtures prior to ignition testing.
5.8 Ignition Furnace, as described in 8.1.1 or 11.1.1.
6. Hazards
6.1 The temperature of the furnace, sample, sample tray(s), and catch pan after removal from the furnace is extremely high.
Caution, therefore, must be exercised at all times when handling these items, as failure to do so could result in serious injury, severe
burns, or fire. The sample, sample tray(s), and catch pan should be placed inside a safety cage and should not be allowed to cool
near any materials that are subject to ignition at the high temperatures used in this procedure. The furnace manufacturer’s
instruction manual must be followed to take all necessary precautions.
7. Sampling
7.1 Obtain samples of aggregate in accordance with Practice D75D75/D75M.
7.2 Obtain samples of asphalt mixture in accordance with Practice D979D979/D979M and AASHTO R47.
7.3 Preparation of Test Specimens:
7.3.1 If the mixture is not soft enough to separate with a spatula or trowel, place it in a large, flat pan and warm in an oven set
at 110 6 5°C5 °C until it can be separated or mixed. Split or quarter the material in accordance with PracticeAASHTO C702R47
until the mass of material required for the test is obtained.
7.3.2 The size of the test sample shall be governed by the nominal maximum aggregate size of the mixture and shall conform
to the mass requirement shown in Table 1 (see Note 3).
NOTE 3—When the mass of the test specimen exceeds the capacity of the equipment used (for a particular method), the test specimen may be divided
into suitable increments, tested, and the results combined for calculation of asphalt content based on the weighted average of the masses used in the
increments.
7.4 Obtain samples of asphalt cement in accordance with Practice D140D140/D140M.
TEST METHOD A
8. Apparatus
8.1 In addition to the apparatus listed in Section 5, the following apparatus is required for Test Method A.
TABLE 1 Size of Sample
Nominal Maximum Aggregate Size
Minimum Mass of Sample, kg
Standard, mm
4.75 0.5
9.5 1
12.5 1.5
19.0 2
25.0 3
37.5 4
D6307 − 19
8.1.1 Ignition Furnace—A forced air forced-air ignition furnace that heats the sample by either convection method or
direct-irradiation direct irradiation method. The convection-type furnace must have a minimum temperature capability of
580°C.580 °C. The furnace shall have an internal weighing system capable of measuring the mass of sample sizes of at least 2500
g. The furnace chamber shall be of sufficient size to accommodate sample sizes of at least 2500 g. A data collection system also
shall be included so that the sample mass loss can be determined automatically to an accuracy of 0.1 g and displayed during a test.
The test is deemed complete when the difference between consecutive measured mass loss does not exceed 0.01 % of the sample
mass for three consecutive 1-min intervals. The equipment shall provide a printout of the test results. A system capable of reducing
furnace emissions to an acceptable level also shall be incorporated in the furnace. The furnace shall be vented into a hood or to
the outside and, when set up properly, will have no noticeable odors escaping into the laboratory. The furnace will have a fan with
the capability to pull air through the furnace to expedite the test and to reduce escape of smoke into the laboratory. The furnace
shall be equipped so that the door cannot be opened during the ignition test.
8.1.2 Filters, if required, of the type specified by the furnace manufacturer.
9. Calibration
9.1 The type of aggregate in the mixture may affect the results of this test method because different aggregates lose mass on
ignition to varying degrees. The results also may be affected by the presence of additives and modifiers in the asphalt mixture
sample. Accordingly, to optimize accuracy, a calibration factor shall be established by testing three calibration samples for each
mix type. The calibration shall be performed on a prepared sample of asphalt mixture, which also shall include additives and
modifiers, if any, to be used.
9.2 Obtain samples of blended aggregate to be used in the asphalt mixture in accordance with 7.1. The sample should be
approximately the same mass and gradation as that to be used for the asphalt mixture test sample (10.1).
9.3 Obtain samples of asphalt cement to be used in the asphalt mixture in accordance with 7.4.
9.4 Oven-dry Oven dry the aggregate samples to a constant mass.
9.4.1 For the convection-type furnace, set the furnace temperature to 540 6 5°C5 °C for calibration using mixtures.
9.4.2 For the direct-irradiation-type direct irradiation-type furnace, set the burn profile to the DEFAULT mode.
9.5 Heat the aggregates and asphalt cement to approximately 150°C.150 °C. Heat all mixing bowls and tools to approximately
150°C.150 °C.
9.6 Prior to the mixing of calibration samples, an initial or “butter” mix is required to condition the mixing equipment. Remove
and discard the “butter” mix from the bowl by scraping, leaving a uniform coating of asphalt mix residue.
NOTE 4—The “butter” mix prevents calibration samples from being biased by residual asphalt mix retained in the mixing bowl.
9.7 Prepare three calibration samples at the design asphalt cement content (P). Incorporate additives and modifiers, if any, to
be used.
9.8 Determine and record the mass of the sample tray(s) and catch pan to the nearest 0.1 g.
9.9 Evenly distribute the sample in the sample tray(s).
9.10 Determine the mass of the sample, sample tray(s), and catch pan to the nearest 0.1 g. Calculate and record the initial mass
of the sample (M ).
I
9.11 Heat the calibration sample in the convection-type furnace at 540 6 5°C;5 °C; or in the direct irradiation type
irradiation-type furnace using the DEFAULT mode until the change in mass of the sample during three consecutive 1-min intervals
does not exceed 0.01 % of the sample mass (M ).
I
9.12 Measure and record the mass (M ) of the sample after ignition to the nearest 0.1 g. The mass can be obtained immediately
L
upon completion of the test from the printout or display.
9.13 Calculate the calibration factor (C ) as follows:
F
M 2 M
I L
C 5 3100 2 P (1)
S D
F
M
I
where:
M = total mass of the mixture calibration sample prior to ignition,
I
M = total mass of the mixture calibration sample after ignition, and
L
P = percentage of actual asphalt cement in the mix by mass of the total mix expressed as a percentage.
9.14 Repeat steps 9.8 – 9.13 for two additional calibration samples. Calculate the average calibration factor (C ) by averaging
F
the three C values.
F
9.15 Calibration Temperature Adjustments—Adjustments:
D6307 − 19
9.15.1 For the convection-type furnace, if the calibration factor exceeds 1.0 %, lower the test temperature to 482 6 5°C5 °C
and repeat steps 9.2 – 9.14 . Use the ca
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