ASTM D6752-02

NOTICE: This standard has either been superseded and replaced by a new version or discontinued.
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Designation: D 6752 – 02
Standard Test Method for
Bulk Specific Gravity and Density of Compacted Bituminous
Mixtures Using Automatic Vacuum Sealing Method
This standard is issued under the fixed designation D 6752; 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 (e) indicates an editorial change since the last revision or reapproval.
1. Scope conversion is made by multiplying the specific gravity at a
given temperature by the density of water at the same tempera-
1.1 This test method covers the determination of maximum
ture.
specific gravity of loose bituminous mixtures by the vacuum
3.3 This method can be used for 100 mm and 150 mm
sealing method.
diameter cylindrical as well as cubical asphalt specimens to
1.2 This method can be used for compacted cylindrical and
correct for absorptive and open graded mixes. Mixes such as
cubical bituminous laboratory and field specimens.
Stone Matrix Asphalt (SMA), porous friction coarse, and
1.3 The bulk specific gravity of the compacted bituminous
Superpave coarse graded mixes with significant surface texture
mixtures may be used in calculating the unit weight of the
and interconnected voids should be sealed for accurate bulk
mixture.
specific density results. Follow manufacturer recommendation
1.4 This standard does not purport to address all of the
for appropriate bag sizes to be utilized with cubical and
safety concerns, if any, associated with its use. It is the
abnormally shaped samples.
responsibility of the user of this standard to establish appro-
priate safety and health practices and determine the applica-
4. Apparatus
bility of regulatory requirements prior to use.
4.1 Balance, with ample capacity, and with sufficient sensi-
2. Referenced Documents tivity to enable bulk specific gravity of specimens to be
calculated to at least four significant figures, that is to at least
2.1 ASTM Standards:
2 three decimal places. It shall be equipped with a suitable
D 979 Practice for Sampling Bituminous Paving Mixtures
apparatus to permit weighing the specimen while it is sus-
D 1461 Test Method for Moisture or Volatile Distillates in
pended in water. The balance shall conform to Specification
Bituminous Paving Mixtures
D 4753 as a class GP2 balance.
D 2726 Test Method for Bulk Specific Gravity and Density
of Non-Absorptive Compacted Bituminous Mixtures
NOTE 1—Since there are no more significant figures in the quotient
D 3203 Test Method for Percent Air Voids in Compacted (bulk specific gravity) than appear in either the dividend (the mass of the
specimen in air) or in the divisor (the volume of the specimen, obtained
Dense and Open Bituminous Paving Mixtures
from the difference in mass of the specimen in air and in water), this
D 4753 Specification for Evaluating, Selecting and Speci-
means that the balance must have a sensitivity capable of providing both
fying Balances and Scales for Use in Soil, Rock, and
mass and volume values to at least four figures. For example, a sensitivity
Construction Materials Testing
of 0.1 g would provide four significant figures for the determination of a
mass in the range from 130.0 to 999.9 g when the specific gravity is 2.300.
3. Significance and Use
4.2 Water Bath, with minimum dimensions (Length 3
3.1 The results obtained from this method can be used to
Width 3 Depth) of 610 3 460 3 460 mm (24 3 18 3 18 in.)
determine the unit weight of compacted bituminous mixtures
or a large cylindrical container, for completely submerging the
and in conjunction with Test Method D 3203, to obtain percent
specimen in water while suspended, equipped with an overflow
air voids. These values in turn may be used in determining the
outlet for maintaining a constant water level.
relative degree of compaction.
3.2 Since specific gravity has no units, it must be converted NOTE 2—It is preferable to keep the water temperature constant by
using a temperature controlled heater. Also, to reduce the chance for the
to density in order to do calculations that require units. This
1 4
This test method is under the jurisdiction of ASTM Committee D04 on Road Bulk specific gravity determined by this method may be lower than the results
and Paving Materials and is the direct responsibility of Subcommittee D04.21 on obtained by Test Method D 2726. As a result, air voids determined from these bulk
Specific Gravity and Density of Bituminous Mixtures. specific gravity values may be higher than the air voids values determined using Test
Current edition approved Jan. 10, 2002. Published March 2002. Originally Method D 2726. These differences may be more pronounced for coarse aggregate
published as PS 131–01. Last previous edition PS 131–01. mixtures. Users of this method are cautioned to evaluate any alteration in percent
Annual Book of ASTM Standards, Vol 04.03. asphalt content or aggregate gradations for mix designs with a known positive
Annual Book of ASTM Standards, Vol 04.08. performance history.
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NOTICE: This standard has either been superseded and replaced by a new version or discontinued.
Contact ASTM International (www.astm.org) for the latest information.
D 6752
bag to touch the sides of the water tank, it is preferable to elevate the water
6. Test Specimens
tank to a level at which the sample can be placed on the weighing
6.1 It is recommended, (1) that the diameter of cylindrically
mechanism while standing up, and the placement of the sample and the
molded or cored specimens, or the length of the sides of sawed
bag in the water tank can easily be inspected.
specimens be at least equal to four times the maximum size of
4.3 Cushioned holder, for water displacement of the sample,
the aggregate; and (2) that the thickness of specimens be at
having no sharp edges.
least one and one half times the maximum size of the
aggregate. Pavement specimens are to be taken by such means
NOTE 3—To avoid accidental puncture of the plastic bags in the water
bath, plastic coated cushioned holders have been found to work well for
as coring, sawing of blocks, and so forth.
this test method.
6.2 Take care to avoid distortion, bending, or cracking of
specimens during and after removal from pavement or mold.
4.4 Vacuum Chamber, with a 0.93 kW (1.25 hp) pump
Store specimens in a safe, cool place.
capable of evacuating a sealed and enclosed chamber to 100
6.3 Specimens shall be free of foreign materials, such as
kPa vacuum (29.5 in. Hg vacuum) in less than 60 s, when at sea
sealcoat, tack coat, foundation material, soil, paper, or foil.
level. The chamber shall be large enough to seal samples of
When any of these materials are visually evident, they shall be
150 mm wide by 350 mm long by 150 mm thick. The device
removed. Sealcoat or tackcoat, or both, may be removed by
shall automatically seal the plastic bag and exhaust air back
sawing the bottom or the top faces, or both, of the sample.
into the chamber in a controlled manner to ensure proper
6.4 If desired, specimens may be separated from other
conformance of the plastic to the asphalt specimen. The air
pavement layers by sawing or other suitable means.
exhaust and vacuum operation time should be calibrated at the
factory prior to initial use. The air exhaust system should be
7. Procedure
calibrated to bring the chamber to atmospheric pressure in 80
to 120 s, after the completion of the vacuum operation. The 7.1 This procedure can be used for compacted field and
vacuum system should be provided with a latch to control the laboratory specimens. Specifically, use this procedure, if the
chamber door opening. mix is absorptive as determined by Test Method D 2726 or if
4.5 A Vacuum Measurement Gage, independent of the the mix is classified as an open graded mixture by the local
vacuum sealing device that could be placed directly inside the mixture specifications. Follow the procedure outlined in this
chamber to verify vacuum performance and the chamber door section for determination of bulk specific gravity.
sealing condition of the unit. The gage shall be capable of
7.2 Mass of Unsealed Specimen:
reading to 3 TORR (29.8 in. Hg) of vacuum.
7.2.1 Laboratory Prepared Specimens—Determine the
4.6 Plastic Bags, used with the vacuum device shall be one
mass of the specimen after it has cooled to room temperature.
of the two following sizes. The smaller bags shall have a Designate this mass as A.
minimum opening of 235 mm (9.25 in.) and maximum opening
7.2.2 Cores and Specimens Containing Moisture—Dry the
of 260 mm (10.25 in.) and the larger bags shall have a
specimen to constant mass. Designate this mass as A. Constant
minimum of 375 mm (14.75 in.) and a maximum opening of
mass is defined as less than 0.05 % change in mass between
394 mm (15.5 in.). The bags shall be of plastic material that
consecutive 15 minute drying intervals.
will not adhere to asphalt film, is puncture resi
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