ASTM D7227/D7227M-11e1
(Practice)Standard Practice for Rapid Drying of Compacted Asphalt Specimens Using Vacuum Drying Apparatus
Standard Practice for Rapid Drying of Compacted Asphalt Specimens Using Vacuum Drying Apparatus
SIGNIFICANCE AND USE
3.1 Specimen dry weight is a critical measure in determination of accurate density and many other tests in the construction and raw materials industries. Drying specimens at room temperature is required for some tests and provides an advantage for other tests to ensure the integrity and to preserve the characteristics of specimens.
FIG. 1 Water Removal Plate and Sample Holder Installed in Sample Chamber
3.2 This practice covers drying compacted asphalt specimens in a vacuum chamber that is capable of keeping the specimen at close to room temperature. A vacuum pump reduces the pressure inside the chamber, thus allowing water to evaporate at low temperature. Since the specimen naturally cools during the evaporation process, making water harder to evaporate, it is important to have proper temperature controls in the chamber to ensure specimen remains at close to room temperature. Automatic controls within the unit allow the specimen to remain at close to room temperature by periodically allowing a flow of warm air to enter the vacuum chamber. Cycling between vacuum and airflow conditions allows the specimen to dry in a short period of time. Completely saturated specimens with over 30 g [0.07 lb] of retained water can be dried in about 30 minutes. For most field cores that are not completely saturated the drying time is generally less than 15 minutes. Note 1—Cycle time (period) can depend on the material composition. Each cycle involves an alternating period of 30 to 180 seconds of vacuum operation and 30 to 120 seconds of air flow.
3.3 This method can be used for 100 mm [4 in.] diameter, 150 mm [6 in.] diameter cylindrical, and cubical compacted bituminous specimens.
3.4 This method can also be used for drying loose asphalt mixtures, aggregate samples and other solid specimens. Follow manufacturers recommended procedures for drying specimens other than compacted bituminous specimens.
3.5 This method can be used to determine moisture content and amount ...
SCOPE
1.1 This practice covers the process of drying compacted asphalt specimens using vacuum drying apparatus.
1.2 The specimens dried by this practice remain at room temperature, which helps in maintaining specimen integrity during the drying process.
1.3 This practice can be used for compacted cylindrical and cubical bituminous laboratory and field specimens
1.4 This practice can also be used for drying other construction materials such as concrete, soils, aggregates and loose asphalt mixtures. Use manufacturers recommendations for drying other construction materials.
1.5 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 equivalent; therefore, each system shall be used independently of the other. Combining values from the two systems may result in non-conformance with the standard.
1.6 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 and health practices and determine the applicability of regulatory requirements prior to use.
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Designation: D7227/D7227M − 11
Standard Practice for
Rapid Drying of Compacted Asphalt Specimens Using
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Vacuum Drying Apparatus
This standard is issued under the fixed designation D7227/D7227M; 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.
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ε NOTE—This Practice was editorially corrected in September 2012.
1. Scope 3. Significance and Use
1.1 This practice covers the process of drying compacted
3.1 Specimen dry weight is a critical measure in determi-
asphalt specimens using vacuum drying apparatus.
nation of accurate density and many other tests in the construc-
tion and raw materials industries. Drying specimens at room
1.2 The specimens dried by this practice remain at room
temperature is required for some tests and provides an advan-
temperature, which helps in maintaining specimen integrity
tage for other tests to ensure the integrity and to preserve the
during the drying process.
characteristics of specimens.
1.3 This practice can be used for compacted cylindrical and
3.2 This practice covers drying compacted asphalt speci-
cubical bituminous laboratory and field specimens
mens in a vacuum chamber that is capable of keeping the
1.4 This practice can also be used for drying other construc-
specimen at close to room temperature. A vacuum pump
tion materials such as concrete, soils, aggregates and loose
reduces the pressure inside the chamber, thus allowing water to
asphalt mixtures. Use manufacturers recommendations for
evaporate at low temperature. Since the specimen naturally
drying other construction materials.
cools during the evaporation process, making water harder to
1.5 The values stated in either SI units or inch-pound units
evaporate, it is important to have proper temperature controls
are to be regarded separately as standard. The values stated in
in the chamber to ensure specimen remains at close to room
each system may not be exact equivalent; therefore, each
temperature. Automatic controls within the unit allow the
system shall be used independently of the other. Combining
specimen to remain at close to room temperature by periodi-
values from the two systems may result in non-conformance
callyallowingaflowofwarmairtoenterthevacuumchamber.
with the standard.
Cycling between vacuum and airflow conditions allows the
specimen to dry in a short period of time. Completely saturated
1.6 This standard does not purport to address all of the
specimens with over 30 g [0.07 lb] of retained water can be
safety concerns, if any, associated with its use. It is the
dried in about 30 minutes. For most field cores that are not
responsibility of the user of this standard to establish appro-
completely saturated the drying time is generally less than 15
priate safety and health practices and determine the applica-
minutes.
bility of regulatory requirements prior to use.
NOTE 1—Cycle time (period) can depend on the material composition.
Each cycle involves an alternating period of 30 to 180 seconds of vacuum
2. Referenced Documents
operation and 30 to 120 seconds of air flow.
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2.1 ASTM Standards:
3.3 This method can be used for 100 mm [4 in.] diameter,
D5361 Practice for Sampling Compacted Bituminous Mix-
150 mm [6 in.] diameter cylindrical, and cubical compacted
tures for Laboratory Testing
bituminous specimens.
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3.4 This method can also be used for drying loose asphalt
This practice is under the jurisdiction of ASTM Committee D04 on Road and
Paving Materials and is the direct responsibility of Subcommittee D04.21 on
mixtures, aggregate samples and other solid specimens. Follow
Specific Gravity and Density of Bituminous Mixtures.
manufacturers recommended procedures for drying specimens
Current edition approved June 1, 2011. Published July 2011. DOI: 10.1520/
other than compacted bituminous specimens.
D7227_D7227M-11.
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For referenced ASTM standards, visit the ASTM website, www.astm.org, or
3.5 This method can be used to determine moisture content
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
and amount of water loss during drying by weighing the
Standards volume information, refer to the standard’s Document Summary page on
the ASTM website. sample before and after the drying operations.
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D7227/D7227M − 11
FIG. 1 Water Removal Plate and Sample Holder Installed in Sample Chamber
4. Apparatus 5. Sampling
4.1 Absorptive cloth or paper towels, for drying water from 5.1 Test specimens may be molded f
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