ASTM D2726/D2726M-21

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Designation: D2726/D2726M − 19 D2726/D2726M − 21
Standard Test Method for
Bulk Specific Gravity and Density of Non-Absorptive
Compacted Asphalt Mixtures
This standard is issued under the fixed designation D2726/D2726M; 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.
This standard has been approved for use by agencies of the U.S. Department of Defense.
1. Scope*
1.1 This test method covers the determination of bulk specific gravity and density of specimens of compacted asphalt mixtures.
1.2 This test method should not be used with samples that contain open or interconnecting voids or absorb more than 2.0 % of
water by volume, or both, as determined in 11.3.
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 are not necessarily exact equivalents; therefore, to ensure conformance with the standard, each system shall be used
independently of the other, and values from the two systems shall not be combined.
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:
D979/D979M Practice for Sampling Bituminous Paving Mixtures
D1188 Test Method for Bulk Specific Gravity and Density of Compacted Bituminous Mixtures Using Coated Samples
D3203/D3203M Test Method for Percent Air Voids in Compacted 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
D5361/D5361M Practice for Sampling Compacted Asphalt Mixtures for Laboratory Testing
D6752/D6752M Test Method for Bulk Specific Gravity and Density of Compacted Asphalt Mixtures Using Automatic Vacuum
Sealing Method
D7227/D7227M Practice for Rapid Drying of Compacted Asphalt Mixture Specimens Using Vacuum Drying Apparatus
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 March 1, 2019May 1, 2021. Published March 2019May 2021. Originally approved in 1968. Last previous edition approved in 20172019 as
D2726/D2726M – 17.D2726/D2726M – 19. DOI: 10.1520/D2726_D2726M-19.10.1520/D2726_D2726M-21.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM Standards
volume information, refer to the standard’s Document Summary page on the ASTM website.
*A Summary of Changes section appears at the end of this standard
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D2726/D2726M − 21
E1 Specification for ASTM Liquid-in-Glass Thermometers
E77 Test Method for Inspection and Verification of Thermometers
E563 Practice for Preparation and Use of an Ice-Point Bath as a Reference Temperature
E644 Test Methods for Testing Industrial Resistance Thermometers
E1137/E1137M Specification for Industrial Platinum Resistance Thermometers
E2251 Specification for Liquid-in-Glass ASTM Thermometers with Low-Hazard Precision Liquids
3. Terminology
3.1 Definitions of Terms Specific to This Standard:
3.1.1 bulk density—as determined by this test method, the mass of a metre cubed (or foot cubed) of the material at 25 °C [77 °F].
3.1.2 bulk specific gravity—as determined by this test method, the ratio of the mass of a given volume 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 The specimen is immersed in a water bath at 25 °C [77 °F]. The mass under water is recorded, and the specimen is taken out
of the water, blotted quickly with a damp cloth towel, and weighed in air. The difference between the two masses is used to measure
the mass of an equal volume of water at 25 °C [77 °F].
4.2 This test method provides guidance for determination of the oven dry oven-dry or thoroughly dry mass of the specimen. The
bulk specific gravity is calculated from these masses. Then the density is obtained by multiplying the specific gravity of the
specimen by the density of the water.
5. Significance and Use
5.1 The results obtained from this test method can be used to determine the unit weight of compacted dense asphalt mixtures and
in conjunction with Test Method D3203/D3203M, to obtain percent air voids. These values in turn may be used in determining
the relative degree of compaction.
5.2 Since specific gravity has no units, it must be converted to density in order to do calculations that require units. This conversion
is made by multiplying the specific gravity at a given temperature by the density of water at the same temperature.
NOTE 1—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, and with sufficient sensitivity to enable bulk specific gravities of the 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 suspended in water. To avoid erroneous readings by undue displacement of water, use wire or fish
line of the smallest practical size to suspend the specimen and holder. Do not use chains, strings, or sash cords. The balance shall
conform to Guide D4753 as a Class GP2 balance.
NOTE 2—Since there are no more significant figures in the quotient (bulk specific gravity) than appear in either the dividend (the mass of the specimen
in air) or in the divisor (the mass of the volume of water equal to the volume of the specimen, obtained from the difference in weight of the saturated
surface-dry specimen in air and in water), this means that the balance must have a sensitivity capable of providing both mass values to at least four figures.
For example, a sensitivity of 0.1 g [0.0002 lb] would provide four significant figures for mass in the range from 100.1 to 999.9 g [0.221 to 2.204 lb].
6.2 Water Bath, capable of maintaining a temperature of 25 6 1 °C [77 6 1.8 °F] for immersing the specimen in water while
suspended, equipped with an overflow outlet for maintaining a constant water level. The use of an overflow outlet is mandatory.
NOTE 3—The water bath does not need to be a sophisticated device. Any method that maintains 25 6 1 °C [77 6 1.8 °F] can be used including tempering,
aquarium heaters, stirrers, or other devices.
D2726/D2726M − 21
6.3 Drying Oven, capable of maintaining a temperature of 110 6 5 °C [230 6 9 °F].
6.4 Thermometer—The thermometer shall be one of the following:
6.4.1 A liquid-in-glass partial or total immersion thermometer of suitable range with subdivisions and maximum scale error of
0.5 °C [1.0 °F] which conforms to the requirements of Specification E1. Calibrate the thermometer in accordance with one of the
methods in Test Method E77 or verify its original calibration at the ice point (Notes 4 and 5).
NOTE 4—Practice E563 provides instructions on the preparation and use of an ice-point bath as a reference temperature.
NOTE 5—If the thermometer does not read 0.0 6 0.5 °C [32.0 6 1.0 °F] at the ice point, then the thermometer should be recalibrated.
6.4.2 A liquid-in-glass partial or total immersion thermometer of suitable range with subdivisions and maximum scale error of
0.5 °C [1.0 °F] which conforms to the requirements of Specification E2251. Calibrate the thermometer in accordance with one the
methods in Test Method E77 or verify its original calibration at the ice point (Notes 4 and 5).
6.4.3 A platinum resistance thermometer (PRT) with a probe which conforms to the requirements of Specification E1137/E1137M.
The PRT shall have a three- or four-wire connection configuration and the overall sheath length shall be at least 50 mm [2 in.]
greater than the immersion depth. Calibrate the PRT system (probe and readout) in accordance with Test Methods E644 or verify
its original calibration at the ice point (Notes 4 and 5). Corrections shall be applied to ensure accurate measurements within 0.5 °C
[1.0 °F
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