ASTM D6857/D6857M-23

Standard Test Method for Maximum Specific Gravity and Density of Asphalt Mixtures Using Automatic Vacuum Sealing Method

SIGNIFICANCE AND USE
5.1 The maximum specific gravities and densities of asphalt mixtures are intrinsic properties whose values are influenced by the composition of the mixture in terms of types and amounts of aggregates and asphalt materials.  
5.1.1 They are used to calculate values for percent air voids in compacted asphalt mixtures.  
5.1.2 They provide target values for the compaction of asphalt mixtures.  
5.1.3 They are essential when calculating the amount of asphalt binder absorbed by the internal porosity of the individual aggregate particles in an asphalt mixture.
Note 2: The quality of the results produced by this standard are dependent on the competence of the personnel performing the procedure and the capability, calibration, and maintenance of the equipment used. Agencies that meet the criteria of Specification D3666 are generally considered capable of competent and objective testing, sampling, inspection, etc. Users of this standard are cautioned that compliance with Specification D3666 alone does not completely ensure reliable results. Reliable results depend on many factors; following the suggestions of Specification D3666 or some similar acceptable guideline provides a means of evaluating and controlling some of those factors.
SCOPE
1.1 This test method covers the determination of maximum specific gravity and density of uncompacted asphalt mixtures at 25 °C [77 °F].  
1.2 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.  
1.3 The text of this standard references notes and footnotes which provide explanatory material. These notes and footnotes (excluding those in tables and figures) shall not be considered as requirements of 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: 31-Oct-2023
• ICS: 91.100.50 - Binders. Sealing materials
• Technical Committee: D04 - Road and Paving Materials
• Drafting Committee: D04.21 - Specific Gravity and Density of Asphalt Mixtures

Relations

• Replaces: ASTM D6857/D6857M-18 - Standard Test Method for Maximum Specific Gravity and Density of Asphalt Mixtures Using Automatic Vacuum Sealing Method
• Effective Date: 01-Nov-2023
• 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 D979/D979M-22 - Standard Practice for Sampling Asphalt Mixtures
• Effective Date: 01-Nov-2022
• 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
• Referred By: ASTM D6925-15 - Standard Test Method for Preparation and Determination of the Relative Density of Asphalt Mix Specimens by Means of the Superpave Gyratory Compactor
• Effective Date: 01-Nov-2023
• Referred By: ASTM D8044-23 - Standard Test Method for Evaluation of Asphalt Mixture Cracking Resistance Using the Semi-Circular Bend Test (SCB) at Intermediate Temperatures
• Effective Date: 01-Nov-2023
• Referred By: ASTM D6995-21 - Standard Test Method for Determining Field VMA Based on the Maximum Specific Gravity of an Asphalt Mixture (G<inf>mm</inf>)
• Effective Date: 01-Nov-2023
• Referred By: ASTM D7981-20 - Standard Practice for Compaction of Prismatic Asphalt Specimens by Means of the Shear Box Compactor
• Effective Date: 01-Nov-2023
• Referred By: ASTM D7064/D7064M-21 - Standard Practice for Open-Graded Friction Course (OGFC) Asphalt Mixture Design
• Effective Date: 01-Nov-2023
• Referred By: ASTM D3203-22 - Standard Test Method for Percent Air Voids in Compacted Asphalt Mixtures
• Effective Date: 01-Nov-2023
• Referred By: ASTM D8259/D8259M-21 - Standard Test Method for Rotary Wheel Testing (RWT) of Compacted Asphalt Mixtures
• Effective Date: 01-Nov-2023
• Referred By: ASTM D8292-20 - Standard Test Method for Permanent Deformation Behavior and Rutting Resistance of Compacted Asphalt Mix in the Modified Loaded Wheel Tracker Test Utilizing Controlled Confining Pressure
• Effective Date: 01-Nov-2023
• Referred By: ASTM D7552-22 - Standard Test Method for Determining the Complex Shear Modulus (G*) of Asphalt Mixtures Using Dynamic Shear Rheometer
• Effective Date: 01-Nov-2023
• Referred By: ASTM D8079-23 - Standard Practice for Preparation of Compacted Slab Asphalt Mix Samples Using a Segmented Rolling Compactor
• Effective Date: 01-Nov-2023
• Referred By: ASTM D8303-20 - Standard Test Method for Determining Thermal Cracking Properties of Asphalt Mixtures Through Measurement of Thermally Induced Stress and Strain
• Effective Date: 01-Nov-2023

Overview

ASTM D6857/D6857M-23 is the international standard test method for determining the maximum specific gravity and density of asphalt mixtures using the automatic vacuum sealing method. Developed by ASTM International, this standard offers an efficient laboratory procedure for evaluating uncompacted asphalt mixtures at 25 °C (77 °F). These fundamental measurements are critical in asphalt mix design, quality control, and pavement performance analysis. The use of automatic vacuum sealing reduces sample handling and minimizes water exposure, improving accuracy and efficiency in determining mixture properties.

Key Topics

• Maximum Specific Gravity and Density
  The standard describes the process for measuring the mass and volume of oven-dried, loose asphalt mixture samples using an automatic vacuum sealing apparatus and underwater weighing. Maximum specific gravity is a key property used to:

  • Calculate percent air voids in compacted asphalt mixtures
  • Establish compaction targets for quality assurance
  • Determine asphalt binder absorption by aggregates

• Sample Preparation and Testing Conditions

  • Ensures samples are oven-dried and properly separated without fracturing aggregates
  • Samples are tested at a controlled temperature of 25 °C (77 °F) for consistency

• Apparatus and Equipment

  • Specifies requirements for balances, vacuum chambers, sealing bags, water baths, and gauges
  • Emphasizes calibration and maintenance of equipment for reliable results

• Precision and Reliability

  • Provides guidance on acceptable ranges of results based on single-operator and multi-laboratory precision
  • Stresses personnel competence and compliance with related ASTM specifications (such as ASTM D3666) for quality assurance

• Safety and Compliance

  • Users must establish appropriate safety, health, and environmental practices relevant to their laboratory
  • Adherence to international standardization principles, supporting global trade and technical harmonization

Applications

ASTM D6857/D6857M-23 has significant practical applications in the construction and maintenance of flexible pavements. Key uses include:

• Asphalt Mix Design and Verification
  Determining the maximum specific gravity and density enables accurate calculation of air void content, an essential factor in mix optimization for durability, stability, and performance.

• Quality Control and Assurance
  Ensures that asphalt mixtures produced in plants or on-site meet specified design parameters by providing target values for compaction and consistency of material properties.

• Binder Absorption Calculations
  Helps in evaluating the amount of asphalt binder absorbed by aggregates, impacting both economic efficiency and long-term pavement behavior.

• Research and Development
  Facilitates the comparison of new materials, additives, and production techniques to improve pavement life and performance.

Related Standards

Several ASTM standards are referenced and work in conjunction with ASTM D6857/D6857M-23:

• ASTM D2041/D2041M – Theoretical Maximum Specific Gravity and Density of Asphalt Mixtures
• ASTM D979/D979M – Sampling Asphalt Mixtures
• ASTM D3666 – Minimum Requirements for Agencies Testing and Inspecting Road and Paving Materials
• ASTM D4753 – Evaluating, Selecting, and Specifying Balances and Standard Masses
• ASTM E691 – Conducting Interlaboratory Studies for Test Method Precision
• ASTM E1547 – Terminology Relating to Industrial and Specialty Chemicals

Summary

ASTM D6857/D6857M-23 provides a standardized, efficient procedure for evaluating asphalt mixture properties vital for pavement engineering. Its adoption ensures consistency in laboratory testing, supports robust quality control, and aligns with international best practices in asphalt technology and materials testing. Use of this standard is essential for organizations aiming to produce high-quality, durable pavements and to comply with industry-wide quality and performance benchmarks.

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: D6857/D6857M − 23
Standard Test Method for
Maximum Specific Gravity and Density of Asphalt Mixtures
Using Automatic Vacuum Sealing Method
This standard is issued under the fixed designation D6857/D6857M; 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 D3666 Specification for Minimum Requirements for Agen-
cies Testing and Inspecting Road and Paving Materials
1.1 This test method covers the determination of maximum
D4753 Guide for Evaluating, Selecting, and Specifying Bal-
specific gravity and density of uncompacted asphalt mixtures at
ances and Standard Masses for Use in Soil, Rock, and
25 °C [77 °F].
Construction Materials Testing
1.2 The values stated in either SI units or inch-pound units
E691 Practice for Conducting an Interlaboratory Study to
are to be regarded separately as standard. The values stated in
Determine the Precision of a Test Method
each system may not be exact equivalents; therefore, each
E1547 Terminology Relating to Industrial and Specialty
system shall be used independently of the other. Combining
Chemicals
values from the two systems may result in nonconformance
with the standard.
3. Terminology
1.3 The text of this standard references notes and footnotes
3.1 The terms ‘specific gravity’ and ‘density’ used in this
which provide explanatory material. These notes and footnotes
test method are in accordance with the Terminology E1547.
(excluding those in tables and figures) shall not be considered
3.2 Definitions:
as requirements of the standard.
3.2.1 density—as determined by this test method, the mass
1.4 This standard does not purport to address all of the
of a cubic meter of the material at 25 °C in SI units, or the mass
safety concerns, if any, associated with its use. It is the
of a cubic foot of the material at 77 °F in inch-pound units.
responsibility of the user of this standard to establish appro-
3.2.2 residual pressure—as employed by this test method,
priate safety, health, and environmental practices and deter-
the pressure in a vacuum chamber when vacuum is applied.
mine the applicability of regulatory limitations prior to use.
1.5 This international standard was developed in accor-
3.2.3 specific gravity—as determined by this test method,
dance with internationally recognized principles on standard-
the ratio of a given mass of material at 25 °C [77 °F] to the
ization established in the Decision on Principles for the
mass of an equal volume of water at the same temperature.
Development of International Standards, Guides and Recom-
mendations issued by the World Trade Organization Technical
4. Summary of Test Method
Barriers to Trade (TBT) Committee.
4.1 A weighed sample of oven-dried asphalt mixture in the
loose condition at room temperature is placed inside a specially
2. Referenced Documents
designed channel bag. The bag containing the sample is placed
2.1 ASTM Standards:
inside another bag and placed inside a vacuum chamber. Air is
D979/D979M Practice for Sampling Asphalt Mixtures
evacuated from the sample to an absolute pressure of 6.0 mm
D2041/D2041M Test Method for Theoretical Maximum
Hg [6 Torr] and is automatically sealed. The bags containing
Specific Gravity and Density of Asphalt Mixtures
the sample are removed from the vacuum chamber and placed
inside a large water tank equipped with scales for weighing the
sample underwater. While completely submerged, the bag is
This test method is under the jurisdiction of ASTM Committee D04 on Road
cut open by scissors to allow the water to enter the bag. Since
and Paving Materials and is the direct responsibility of Subcommittee D04.21 on
the sample is under complete vacuum, water will be forced
Specific Gravity and Density of Asphalt Mixtures.
around all the accessible areas of the sample. The difference in
Current edition approved Nov. 1, 2023. Published December 2023. Originally
weight in air and suspended weight in water will provide the
approved in 2003. Last previous edition approved in 2018 as D6857/D6857M – 18.
DOI: 10.1520/D6857_D6857M-23.
sample volume after correcting for the bag influence. The dry
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
weight and the volume can be used to calculate the maximum
contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM
specific gravity of the sample. This method is a rapid technique
Standards volume information, refer to the standard’s Document Summary page on
the ASTM website. for determination of maximum specific gravity that minimizes
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
D6857/D6857M − 23
the exposure of asphalt mixture samples to water during testing 6.3 Vacuum Chamber, with a 0.93 kW [1.25 hp] pump,
and reduces the chance of water absorption. capable of evacuating a sealed and enclosed chamber to
5.6 mm Hg [6 Torr]. The chamber shall be large enough to seal
NOTE 1—For porous aggregates, if water absorption correction is not
samples as large as 2200 g [4.85 lb]. The device shall
performed on the maximum specific gravities obtained using this test
automatically seal the plastic bag and exhaust air back into the
method, the results may be higher than the results obtained by Test
chamber in a controlled manner to ensure proper conformance
Method D2041/D2041M. Without aggregate water absorption correction,
air voids calculated based on these results may be higher. of the plastic to the asphalt mixture. The air exhaust and
vacuum operation time should be calibrated at the factory prior
5. Significance and Use to initial use. The air exhaust system should be calibrated to
bring the chamber to atmospheric pressure in 80 to 150 s after
5.1 The maximum specific gravities and densities of asphalt
the completion of the vacuum operation. The vacuum system
mixtures are intrinsic properties whose values are influenced
should be provided with a latch to control the chamber door
by the composition of the mixture in terms of types and
opening.
amounts of aggregates and asphalt materials.
6.4 Absolute Vacuum Measurement Gauge, independent of
5.1.1 They are used to calculate values for percent air voids
the vacuum sealing device, that may be placed directly inside
in compacted asphalt mixtures.
the chamber to verify vacuum performance and the chamber
5.1.2 They provide target values for the compaction of
door sealing condition of the unit. The gauge shall be capable
asphalt mixtures.
of reading pressure to 3 mm Hg [3 Torr].
5.1.3 They are essential when calculating the amount of
6.5 Plastic Bags, consisting of inner plastic bag (internal
asphalt binder absorbed by the internal porosity of the indi-
bag) having channels built into one side of the bag, with
vidual aggregate particles in an asphalt mixture.
minimum and maximum bag opening sizes of 280 mm [11 in.]
NOTE 2—The quality of the results produced by this standard are and 340 mm [13.5 in.], respectively, and outer plastic bag
dependent on the competence of the personnel performing the procedure
(external bag) with minimum and maximum opening sizes of
and the capability, calibration, and maintenance of the equipment used.
368 mm [14.50 in.] and 394 mm [15.5 in.], respectively. The
Agencies that meet the criteria of Specification D3666 are generally
bags shall be of plastic material that will not adhere to asphalt
considered capable of competent and objective testing, sampling,
film, is puncture resistant, and is impermeable to water. Each
inspection, etc. Users of this standard are cautioned that compliance with
Specification D3666 alone does not completely ensure reliable results. bag shall have a minimum thickness of 0.127 mm [0.005 in.]
Reliable results depend on many factors; following the suggestions of
and maximum thickness of 0.178 mm [0.007 in.]. The com-
Specification D3666 or some similar acceptable guideline provides a
bined apparent specific gravity of the two bags shall be
means of evaluating and controlling some of those factors.
provided by the manufacturer.
6. Apparatus NOTE 5—Protect the plastic bags during storage. Rough handling,
storing in close proximity to sharp objects, near aggregates, or inside
6.1 Balance, with ample capacity and sufficient sensitivity
drawers will damage the plastic bags. Refer to the manufacturer’s
procedures for safe handling and storage of bags.
to enable maximum specific gravity of specimens to be
calculated to at least four significant figures, that is, to at least
6.6 Holder, for water displacement of the sample, having no
three decimal places. It shall be equipped with a suitable
sharp edges.
apparatus to permit weighing the specimen while it is sus-
6.7 Filler Plates, to position the sample and the bags in the
pended in water. The suspension wire attached to the scales
same plane as the sealing bar.
should break the surface of the water at a single point and
6.8 Bag-Cutting Knife, or scissors.
should have a maximum diameter of 3 mm [0.125 in.]. The
balance shall conform to Guide D4753 as a class GP2 balance.
6.9 Thermometric Device, a temperature measuring device
readable to 0.5 °C [1 °F] and accurate to 0.3 °C [0.5 °F] for
NOTE 3—Since there are no more significant figures in the quotient
monitoring the temperature of the water bath.
(maximum specific gravity) than appear in either the dividend (the mass
of the specimen in air) or in the divisor (the volume of the specimen
6.10 Laboratory Oven, capable of heating the asphalt
obtained from the difference in mass of the specimen in air and in water),
sample to 110 6 5 °C [230 6 9 °F].
this means that the balance must have a sensitivity capable of providing
both mass and volume values to at least four figures. For example, a
7. Sampling
sensitivity of 0.1 g [0.00022 lb] would provide four significant figures for
the determination of a mass in the range from 130.0 to 999.9 g [0.29 to 7.1 Obtain the sample in accordance with Practice D979/
2.20 lb] when the specific gravity is 2.300.
D979M.
6.2 Water Bath, with minimum dimensions (length × width
7.2 The size of the sample shall conform to the following
× depth) of 610 by 460 by 460 mm [24 by 18 by 18 in.] or a requirements. Samples larger than 2200 g [4.85 lb] m
...

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: D6857/D6857M − 18 D6857/D6857M − 23
Standard Test Method for
Maximum Specific Gravity and Density of Asphalt Mixtures
Using Automatic Vacuum Sealing Method
This standard is issued under the fixed designation D6857/D6857M; 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 maximum specific gravity and density of uncompacted asphalt mixtures at 25 °C
[77 °F].
1.2 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.
1.3 The text of this standard references notes and footnotes which provide explanatory material. These notes and footnotes
(excluding those in tables and figures) shall not be considered as requirements of 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.
2. Referenced Documents
2.1 ASTM Standards:
C670 Practice for Preparing Precision and Bias Statements for Test Methods for Construction Materials
D979/D979M Practice for Sampling Asphalt Mixtures
D2041/D2041M Test Method for Theoretical Maximum Specific Gravity and Density of Asphalt Mixtures
D3666 Specification for Minimum Requirements for Agencies Testing and Inspecting Road and Paving Materials
D4753 Guide for Evaluating, Selecting, and Specifying Balances and Standard Masses for Use in Soil, Rock, and Construction
Materials Testing
E691 Practice for Conducting an Interlaboratory Study to Determine the Precision of a Test Method
E1547 Terminology Relating to Industrial and Specialty Chemicals
This test method is under the jurisdiction of ASTM Committee D04 on Road and Paving Materials and is the direct responsibility of Subcommittee D04.21 on Specific
Gravity and Density of Asphalt Mixtures.
Current edition approved Aug. 15, 2018Nov. 1, 2023. Published August 2018December 2023. Originally approved in 2003. Last previous edition approved in 20172018
as D6857/D6857M – 17.D6857/D6857M – 18. DOI: 10.1520/D6857_D6857M-18.10.1520/D6857_D6857M-23.
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.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
D6857/D6857M − 23
3. Terminology
3.1 The terms ‘specific gravity’ and ‘density’ used in this test method are in accordance with the Terminology E1547.
3.2 Definitions:
3.2.1 density—as determined by this test method, the mass of a cubic meter of the material at 25 °C in SI units, or the mass of
a cubic foot of the material at 77 °F in inch-pound units.
3.2.2 residual pressure—as employed by this test method, the pressure in a vacuum chamber when vacuum is applied.
3.2.3 specific gravity—as determined by this test method, the ratio of a given mass of material at 25 °C [77 °F] to the mass of an
equal volume of water at the same temperature.
4. Summary of Test Method
4.1 A weighed sample of oven-dried asphalt mixture in the loose condition at room temperature is placed inside a specially
designed channel bag. The bag containing the sample is placed inside another bag and placed inside a vacuum chamber. Air is
evacuated from the sample to an absolute pressure of 6.0 mm Hg [6 Torr] and is automatically sealed. The bags containing the
sample are removed from the vacuum chamber and placed inside a large water tank equipped with scales for weighing the sample
underwater. While completely submerged, the bag is cut open by scissors to allow the water to enter the bag. Since the sample is
under complete vacuum, water will be forced around all the accessible areas of the sample. The difference in weight in air and
suspended weight in water will provide the sample volume after correcting for the bag influence. The dry weight and the volume
can be used to calculate the maximum specific gravity of the sample. This method is a rapid technique for determination of
maximum specific gravity that minimizes the exposure of asphalt mixture samples to water during testing and reduces the chance
of water absorption.
NOTE 1—For porous aggregates, if water absorption correction is not performed on the maximum specific gravities obtained using this test method, the
results may be higher than the results obtained by Test Method D2041/D2041M. Without aggregate water absorption correction, air voids calculated based
on these results may be higher.
5. Significance and Use
5.1 The maximum specific gravities and densities of asphalt mixtures are intrinsic properties whose values are influenced by the
composition of the mixture in terms of types and amounts of aggregates and asphalt materials.
5.1.1 They are used to calculate values for percent air voids in compacted asphalt mixtures.
5.1.2 They provide target values for the compaction of asphalt mixtures.
5.1.3 They are essential when calculating the amount of asphalt binder absorbed by the internal porosity of the individual
aggregate particles in an asphalt mixture.
NOTE 2—The quality of the results produced by this standard are dependent on the competence of the personnel performing the procedure and the
capability, calibration, and maintenance of the equipment used. Agencies that meet the criteria of Specification D3666 are generally considered capable
of competent and objective testing, sampling, inspection, etc. Users of this standard are cautioned that compliance with Specification D3666 alone does
not completely ensure reliable results. Reliable results depend on many factors; following the suggestions of Specification D3666 or some similar
acceptable guideline provides a means of evaluating and controlling some of those factors.
6. Apparatus
6.1 Balance, with ample capacity,capacity and with sufficient sensitivity to enable maximum specific gravity of specimens to be
calculated to at least four significant figures, that is, to at least three decimal places. It shall be equipped with a suitable apparatus
to permit weighing the specimen while it is suspended in water. The suspension wire attached to the scales should break the surface
of the water at a single point and should have a maximum diameter of 3 mm [0.125 in.]. The balance shall conform to Guide D4753
as a class GP2 balance.
NOTE 3—Since there are no more significant figures in the quotient (maximum specific gravity) than appear in either the dividend (the mass of the
D6857/D6857M − 23
specimen in air) or in the divisor (the volume of the specimen,specimen obtained from the difference in mass of the specimen in air and in water), this
means that the balance must have a sensitivity capable of providing both mass and volume values to at least four figures. For example, a sensitivity of
0.1 g [0.00022 lb] would provide four significant figures for the determination of a mass in the range from 130.0 to 999.9 g [0.29 to 2.20 lb] when the
specific gravity is 2.300.
6.2 Water Bath, with minimum dimensions (length × width × depth) of 610 by 460 by 460 mm [24 by 18 by 18 in.] or a cylindrical
container with a minimum diameter of 460 mm [18 in.] and minimum depth of 460 mm [18 in.], for completely submerging the
specimen in water while suspended.
NOTE 4—Setting the water tank at waist level will enable the user to conduct this test while standing and will significantly simplify the weighing
operations.
6.3 Vacuum Chamber, with a 0.93-kW [1.25-hp] pump 0.93 kW [1.25 hp] pump, capable of evacuating a sealed and enclosed
chamber to 5.6 mm Hg [6 Torr]. The chamber shall be large enough to seal samples as large as 2200 g [4.85 lb]. The device shall
automatically seal the plastic bag and exhaust air back into the chamber in a controlled manner to ensure proper conformance of
the plastic to the asphalt mixture. The air exhaust and vacuum operation time should be calibrated at the factory prior to initial
use. The air exhaust system should be calibrated to bring the chamber to atmospheric pressure in 80 to 150 s,s after the completion
of the vacuum operation. The vacuum system should be provided with a latch to control the chamber door opening.
6.4 Absolute Vacuum Measurement Gauge, independent of the vacuum sealing device, that may be placed directly inside the
chamber to verify vacuum performance and the chamber door sealing condition of the unit. The gauge shall be capable of reading
pressure to 3 mm Hg [3 Torr].
6.5 Plastic Bags, consisting of inner plastic bag (internal bag) having random channels built into one side of the bag, with
minimum and maximum bag opening sizes of 305 mm [12 in.]280 mm [11 in.] and 340 mm [13.5 in.], respectively, and outer
plastic bag (external bag) with minimum and maximum opening sizes of 368 mm [14.50 in.] and 394 mm [15.5 in.], respectively.
The bags shall be of plastic material that will not adhere to asphalt film, is puncture resistant, and is impermeable to air.water. Each
bag shall have a minimum thickness of 0.127 mm [0.005 in.] and maximum thickness of 0.178 mm [0.007 in.]. The combined
apparent specific gravity of the two bags shall be provided by the manufacturer.
NOTE 5—Protect the plastic bags during storage. Rough handling, storing in close proximity to sharp objects, near aggregates, or inside drawers will
damage the plastic bags. Refer to the manufacturer’s procedures for safe handling and storage of bags.
6.6 Holder, for water displacement of the sample, having no sharp edges.
6.7 Filler Plates, to position the sample and the bags in the same plane as the sealing bar.
6.8 Bag-Cutting Knife, or scissors.
6.9 Thermometric Device, a temperature measuring device readable to 0.5 °C [1 °F] and accurate to 0.3 °C [0.5 °F] for monitoring
the temperature of the water bath.
6.10 Laboratory Oven, capable of heating the asphalt sample to 110 6
...