ASTM D6995-05
(Test Method)Standard Test Method for Determining Field VMA based on the Maximum Specific Gravity of the Mix (Gmm)
Standard Test Method for Determining Field VMA based on the Maximum Specific Gravity of the Mix (G<inf>mm</inf>)
SIGNIFICANCE AND USE
Various users desire indication of compliance with VMA specifications for hot mix asphalt (HMA) during production.
The standard practice for determining VMA requires that the bulk specific gravity of the aggregate components be determined. This is a very time consuming test, which is not suitable for routine QC procedures.
When an aggregate source used in the mix has a highly variable bulk specific gravity and a reference average bulk specific gravity (Gsb) (for example, as established in the mix design) is used to calculate VMA during HMA production, erroneous values may occur.
The test for maximum specific gravity of the mix (Gmm) is a routine QC test at HMA plants. The effective specific gravity of the aggregate components (Gse) can be easily calculated from this test. However the Gse does not take into account the amount of asphalt absorbed, which is required for accurate VMA determination. This method provides a means to correct the Gse to account for the average absorbed asphalt. This procedure should not be used if the percent water absorption of the total (combined) aggregates varies between four tests, randomly obtained over a 30 day period, by more than 0.4 %.
SCOPE
1.1 This test method is intended to be used for a rapid field determination of voids in mineral aggregate (VMA) of hot mix asphalt (HMA). It provides equations for calculating the VMA based on the asphalt content of the mix and its maximum specific gravity (Gmm). It is intended that this should be used for the rapid "field" determination of VMA during Quality Control (QC) operations at HMA plants, particularly where the specific gravity of the aggregate is highly variable.
1.2 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 limitations prior to use.
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Standards Content (Sample)
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Designation:D6995 −05
StandardTest Method for
Determining Field VMA based on the Maximum Specific
Gravity of the Mix (G )
mm
This standard is issued under the fixed designation D6995; 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 3. Summary of Test Method
1.1 This test method is intended to be used for a rapid field 3.1 The percent of (field)VMAin the mix can be calculated
determination of voids in mineral aggregate (VMA) of hot mix by means of equations in which measured values for the
asphalt (HMA). It provides equations for calculating the VMA theoretical maximum specific gravity, the asphalt content, the
based on the asphalt content of the mix and its maximum specific gravity of the asphalt, and the average bulk specific
specific gravity (G ). It is intended that this should be used gravity of the total aggregate and the compacted mix are
mm
for the rapid “field” determination of VMA during Quality known.
Control (QC) operations at HMAplants, particularly where the
4. Significance and Use
specific gravity of the aggregate is highly variable.
4.1 Various users desire indication of compliance with
1.2 This standard does not purport to address all of the
VMA specifications for hot mix asphalt (HMA) during pro-
safety concerns, if any, associated with its use. It is the
duction.
responsibility of the user of this standard to establish appro-
priate safety and health practices and determine the applica-
4.2 The standard practice for determining VMA requires
bility of regulatory limitations prior to use.
that the bulk specific gravity of the aggregate components be
determined. This is a very time consuming test, which is not
2. Referenced Documents
suitable for routine QC procedures.
2.1 ASTM Standards:
4.3 When an aggregate source used in the mix has a highly
C127 Test Method for Density, Relative Density (Specific
variable bulk specific gravity and a reference average bulk
Gravity), and Absorption of Coarse Aggregate
specific gravity (G ) (for example, as established in the mix
sb
C128 Test Method for Density, Relative Density (Specific
design) is used to calculate VMA during HMA production,
Gravity), and Absorption of Fine Aggregate
erroneous values may occur.
D70 Test Method for Density of Semi-Solid Bituminous
4.4 The test for maximum specific gravity of the mix (G )
mm
Materials (Pycnometer Method)
is a routine QC test at HMA plants. The effective specific
D854 Test Methods for Specific Gravity of Soil Solids by
gravity of the aggregate components (G ) can be easily
se
Water Pycnometer
calculated from this test. However the G does not take into
se
D2041 Test Method for Theoretical Maximum Specific
account the amount of asphalt absorbed, which is required for
Gravity and Density of Bituminous Paving Mixtures
accurateVMAdetermination.Thismethodprovidesameansto
D2172 Test Methods for Quantitative Extraction of Bitumen
correct the G to account for the average absorbed asphalt.
se
From Bituminous Paving Mixtures
This procedure should not be used if the percent water
D2726 Test Method for Bulk Specific Gravity and Density
absorption of the total (combined) aggregates varies between
of Non-Absorptive Compacted Bituminous Mixtures
four tests, randomly obtained over a 30 day period, by more
D6307 Test Method forAsphalt Content of Hot-MixAsphalt
than 0.4 %.
by Ignition Method
5. Procedure
5.1 DeterminethepercentoffieldVMAinacompactedmix
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
sample by first obtaining the following information and then
Specific Gravity and Density of Bituminous Mixtures.
calculating the value.
Current edition approved Sept. 15, 2005. Published October 2005. DOI:
10.1520/D6995-05.
5.2 Tests Run During the HMA Mix Design Procedure
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
5.2.1 Test Method C127, C128, and D854—Determine the
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
average bulk specific gravity (G ) of the fine and coarse
Standards volume information, refer to the standard’s Document Summary page on sb
the ASTM website. aggregates, and mineral filler if applicable. Once this value is
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D6995−05
determineditshouldbeusedinthecalculationsinsection6.1.1 6.1.1 Determine the average bulk specific gravity of the
until a change in the plant produced mix occurs. combined aggregate (G ) as follows:
sb
NOTE 1—It is recommended that a minimum of three sets of tests (one
G comb 5 (1)
for each aggregate) should be averaged to establish this bulk specific s d
sb
% ofaggregate#1 % ofaggregate#2
gravity. 1 1…
bulkspecificgravity G bulkspecificgravity G
s d s d
sb1 sb2
5.2.2 Use the percent by weight of each aggregate estab-
6.1.2 Determine the effective specific gravity (G )ofthe
se
lished in the mix design in the calculation in section 6.1.1.If
aggregate in the mix as follows:
the percent of individual aggregates in the mix is changed
100.0 2 % asphalt binder
during production a new G (comb) should be calculated per
sb
G 5 (2)
se
100.0 % as
...
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