ASTM D7370-08
(Test Method)Standard Test Method for Determination of Relative Density and Absorption of Fine, Coarse and Blended Aggregate Using Combined Vacuum Saturation and Rapid Submersion
Standard Test Method for Determination of Relative Density and Absorption of Fine, Coarse and Blended Aggregate Using Combined Vacuum Saturation and Rapid Submersion
SIGNIFICANCE AND USE
Relative density (specific gravity) is the characteristic generally used for calculation of the volume occupied by the aggregate in various mixtures containing aggregate, including Portland cement concrete, bituminous concrete, and other mixtures that are proportioned or analyzed on an absolute volume basis. Relative density (specific gravity) is also used in the computation of voids in aggregate in Test Method C 29/C 29M. Relative density (specific gravity) saturated surface dry (SSD) is used if the aggregate is at SSD, that is, if its absorption has been satisfied. Conversely, the relative density (specific gravity) oven-dry (OD) is used for computations when the aggregate is dry or assumed to be dry.
Apparent density and apparent relative density (apparent specific gravity) pertain to the solid material making up the constituent particles not including the pore space within the particles which is accessible to water.
Absorption values are used to calculate the change in the mass of an aggregate due to water absorbed in the pore spaces within the constituent particles, when it is deemed that the aggregate has been in contact with water long enough to satisfy the absorption potential. The laboratory standard for absorption is that obtained after submerging dry aggregate for a prescribed period of time.
Note 1—There are other test methods that have been used and continue to be used to determine these aggregate properties: C 127 and C 128. This test method may result in values for these properties that are close to or divergent from values from other test methods.
Note 2—The quality of the results produced by this standard are dependant upon the competence of the personnel performing the procedure and the capability, calibration, and the maintenance of the equipment used. Agencies that meet the criteria of Practice D 3666 are generally considered capable of competent and objective testing / sampling / inspection / etc. Users of this standard are cautioned t...
SCOPE
1.1 This standard covers the determination of relative density and absorption of fine aggregates by Method A and coarse and blended aggregates by Method B.
1.2 The values are stated in SI units and are regarded as the standard units.
1.3 A multi-laboratory precision and bias statement for coarse and combined aggregate tests in this standard has not been developed at this time. Therefore, this standard should not be used for acceptance or rejection of coarse and combined aggregate materials for purchasing purposes.
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 and health practices and determine the applicability of regulatory limitations prior to use.
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Designation:D7370–08
Standard Test Method for
Determination of Relative Density and Absorption of Fine,
Coarse and Blended Aggregate Using Combined Vacuum
Saturation and Rapid Submersion
This standard is issued under the fixed designation D 7370; 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 C 702 Practice for Reducing Samples of Aggregate to
Testing Size
1.1 This standard covers the determination of relative den-
D75 Practice for Sampling Aggregates
sity and absorption of fine aggregates by MethodAand coarse
D 4753 Guide for Evaluating, Selecting, and Specifying
and blended aggregates by Method B.
Balances and Standard Masses for Use in Soil, Rock, and
1.2 The values are stated in SI units and are regarded as the
Construction Materials Testing
standard units.
D 3666 SpecificationforMinimumRequirementsforAgen-
1.3 A multi-laboratory precision and bias statement for
cies Testing and Inspecting Road and Paving Materials
coarse and combined aggregate tests in this standard has not
E 691 Practice for Conducting an Interlaboratory Study to
beendevelopedatthistime.Therefore,thisstandardshouldnot
Determine the Precision of a Test Method
be used for acceptance or rejection of coarse and combined
aggregate materials for purchasing purposes.
3. Summary of Test Method
1.4 This standard does not purport to address all of the
3.1 Sufficient aggregate sample is dried to constant mass.
safety concerns, if any, associated with its use. It is the
For each test two representative dry aggregate samples of the
responsibility of the user of this standard to establish appro-
same material are selected for testing. One sample is evacuated
priate safety and health practices and determine the applica-
in a vacuum chamber inside a plastic bag and opened under
bility of regulatory limitations prior to use.
water for rapid saturation of the aggregate. The dry mass and
2. Referenced Documents submerged mass of the sample is used for calculation of
apparent relative density. The second sample of the same
2.1 ASTM Standards:
aggregate is tested in a known volume metal pycnometer. The
C 29/C 29M Test Method for Bulk Density (“Unit Weight”)
known mass of the pycnometer with water, mass of the dry
and Voids in Aggregate
aggregate and mass of the aggregate and pycnometer filled
C 127 Test Method for Density, Relative Density (Specific
with water is used for calculation of unsaturated density. The
Gravity), and Absorption of Coarse Aggregate
results from the two samples tested are then used to calculate
C 128 Test Method for Density, Relative Density (Specific
absorption, and relative density (OD).
Gravity), and Absorption of Fine Aggregate
3.2 This test can be completed in less than 30 minutes and
C 136 Test Method for Sieve Analysis of Fine and Coarse
can be used for rapid determination of aggregate properties in
Aggregates
construction testing laboratories.
C 670 Practice for Preparing Precision and Bias Statements
3.3 This test can be performed on fine, coarse and blended
for Test Methods for Construction Materials
(combined) aggregates by using appropriate plastic bag and
pycnometer sizes.
This test method is under the jurisdiction of ASTM Committee D04 on Road
4. Significance and Use
and Paving Materials and is the direct responsibility of Subcommittee D04.51 on
4.1 Relative density (specific gravity) is the characteristic
Aggregate Tests.
Current edition approved July 15, 2008. Published August 2008.
generally used for calculation of the volume occupied by the
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
aggregate in various mixtures containing aggregate, including
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
Portland cement concrete, bituminous concrete, and other
Standards volume information, refer to the standard’s Document Summary page on
the ASTM website. mixtures that are proportioned or analyzed on an absolute
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
D7370–08
volume basis. Relative density (specific gravity) is also used in The air exhaust and vacuum operation time shall be set at the
the computation of voids in aggregate in Test Method C 29/ factory so that the chamber is brought to atmospheric pressure
C 29M.Relativedensity(specificgravity)saturatedsurfacedry in 80 to 125 seconds, after the completion of the vacuum
(SSD) is used if the aggregate is at SSD, that is, if its operations.
absorption has been satisfied. Conversely, the relative density
5.5 Vacuum Measurement Gauge, independent of the
(specific gravity) oven-dry (OD) is used for computations
vacuum sealing device that could be placed directly inside the
when the aggregate is dry or assumed to be dry.
chamber to verify vacuum performance and the chamber door
4.2 Apparentdensityandapparentrelativedensity(apparent
sealing condition of the unit. The gauge shall be capable of
specific gravity) pertain to the solid material making up the
reading down to 3 mm Hg and readable to 61mmHg.
constituent particles not including the pore space within the
5.6 Plastic Bags, used with the vacuum device shall be one
particles which is accessible to water.
of the two following sizes. The smaller bags shall have a
4.3 Absorptionvaluesareusedtocalculatethechangeinthe
minimumopeningof235mm(9.25in.)andmaximumopening
mass of an aggregate due to water absorbed in the pore spaces
of 260 mm (10.25 in.) and the larger bags shall have a
within the constituent particles, when it is deemed that the
minimum opening of 375 mm (14.75 in.) and a maximum
aggregatehasbeenincontactwithwaterlongenoughtosatisfy
opening of 394 mm (15.5 in.). The bags shall be of plastic
theabsorptionpotential.Thelaboratorystandardforabsorption
material, shall be puncture resistant, and shall be impermeable
isthatobtainedaftersubmergingdryaggregateforaprescribed
to water. The bags shall have a minimum thickness of 0.127
period of time.
mm (0.005 in.).The apparent specific gravity for the bags shall
be provided by the manufacturer.
NOTE 1—Thereareothertestmethodsthathavebeenusedandcontinue
to be used to determine these aggregate properties: C 127 and C 128.This
5.7 Small Metal Pycnometer, with 137 6 0.2 mm (5.375 6
test method may result in values for these properties that are close to or
0.008 in.) ID and 89 6 0.40 mm (3.5 6 0.016 in.) height, for
divergent from values from other test methods.
testing fine aggregates. The pycnometer shall be machined to
NOTE 2—The quality of the results produced by this standard are
be smooth on all surfaces. The inside of the lid shall be
dependant upon the competence of the personnel performing the proce-
machined at a 5° angle to create an inverted conical surface.
dure and the capability, calibration, and the maintenance of the equipment
The pycnometer shall be equipped with a temperature strip to
used. Agencies that meet the criteria of Practice D 3666 are generally
allow the user to monitor temperature during testing.
considered capable of competent and objective testing / sampling /
inspection / etc. Users of this standard are cautioned that compliance with
5.8 Large Metal Pycnometer, with 198 6 0.2 mm (7.776 6
PracticeD 3666alonedoesnotcompletelyassurereliableresults.Reliable
0.008 in.) ID and 114 6 0.8 mm (4.5 6 0.03 in.) height, for
results depend on many factors: following the suggestions of Practice
testing coarse and blended aggregate. The pycnometer shall be
D 3666orsimilaracceptableguidelineprovidesameansofevaluatingand
machined to be smooth on all surfaces. The inside of the lid
controlling some of those factors.
shall be machined at a 5° angle to create an inverted conical
5. Apparatus surface. The pycnometer shall be equipped with a temperature
strip to allow the user to monitor temperature during testing.
5.1 Balance, a balance that conforms to Guide D 4753. The
5.9 Fine Aggregate Fixture, for holding and securing the lid
balance shall be sensitive, readable and accurate to 0.1 g. The
on the small metal pycnometer from lifting during fine aggre-
balance shall be equipped with suitable apparatus for suspend-
gate tests. The fixture shall be provided with a level indicator.
ing the sample in water.
5.2 Water Bath, with minimum dimensions (Length by 5.10 Accessories—Bag cutting knife or scissors, spray
WidthbyDepth)of610by460by460mm(24by18by18in.) bottle filled with isopropyl alcohol, a bucket large enough to
or a large cylindrical container with a minimum diameter of allow the pycnometer to be fully submerged in water, water
460 mm and depth of 460 mm (18 by 18 in.), for completely containers to dispense water into pycnometer during testing,
submerging the sample in water while suspended, equipped syringe with a needle no larger in diameter than 3 mm (0.125
with an overflow outlet for maintaining a constant water level in.), small paint brush and 25 65mm(1 6 0.2 in.) wide metal
and means to maintain the water temperature at 25 6 1°C (77 spatula.
6 2°F).
5.11 Rubber Sheets, for protecting the plastic bags against
punctures caused by sharp edges on coarse and blended
NOTE 3—It is preferable to keep the water temperature constant by
aggregate samples.The apparent specific gravity for the rubber
using a temperature controlled heater. Also, to reduce the chance for the
bagtotouchthesidesofthewatertank,itispreferabletoelevatethewater sheets shall be provided by the manufacturer.
tank to a level at which the sample can be placed on the weighing
5.12 PC computer,withappropriatesoftwareforcalculation
mechanism while the operator is standing up (waist height), and the
of the results.
placement of the sample and the bag in the water tank can easily be
inspected.
6. Verification
5.3 Sample Holder, for water displacement of the sample,
6.1 System Verification:
having no sharp edges.
6.1.1 The vacuum settings of the vacuum chamber shall be
5.4 Vacuum Chamber, with a pump capable of evacuating a
verified once every 12 months and after major repairs and after
sealed and enclosed chamber to a pressure of 6 mm Hg, when
each shipment or relocation.
at sea level. The device shall automatically seal the plastic bag
and exhaust air back into the chamber in a controlled manner 6.1.2 Placethegaugeinsidethevacuumchamberandrecord
to ensure proper conformance of the plastic to the specimen. the setting, while the vacuum unit is operating. The gauge
D7370–08
should indicate a pressure of 6 mm Hg (6 TORR) or less. The 6.3.4 Gently place the lid on the pycnometer. Using a
unit shall not be used if the gauge reading is above 6 mm Hg syringe filled with 25 6 1°C (77 6 2°F) water, slowly fill the
(6 TORR). pycnometer through the large fill hole on the lid post. Make
surethesyringetipisfarenoughinthepycnometertobebelow
6.1.3 Vacuum gauge used for verification shall be verified
the water level. Gentle application in this step prevents
for accuracy once every three years.
formation of air bubbles inside the pycnometer. Fill the
NOTE 4—In line vacuum gauges, while capable of indicating vacuum
pycnometeruntilwatercomesoutthe3mm( ⁄8in.)holeonthe
performance of the pump, are not suitable for use in enclosed vacuum
surface of the lid.
chambers and cannot accurately measure vacuum levels.
6.3.5 Wipe any remaining water from the top of the lid and
NOTE 5—The worksheet in the appendix is provided as an optional tool
sides with a towel. Place the pycnometer on the scale and
to the user for recording of masses obtained during this test method. Users
record the mass.
may develop their own worksheet or a computer program for this purpose.
6.3.6 Clean the pycnometer and repeat steps 6.3.2 to 6.3.5
6.2 Calibration of the Small Pycnometer:
two more times and average the calibration masses obtained in
6.2.1 Prior to testing, condition the pycnometer at 25 6 1°C
6.3.5.
(77 6 2°F) by placing it inside a bucket of water that is
6.3.7 If the range for the 3 calibration masses is larger than
maintainedat25 61°C(77 62°F).Usealevelindicatororthe
1 g, then the test is not being run correctly. Check to see if the
provided level to level the fixture.
fixture is level. Make certain the water injection with the
6.2.2 Remove the pycnometer from the water bucket and
syringe is done below the pycnometer water surface and is
dry it with a towel. Place the pycnometer in the fixture and
applied gently. Check the water temperature. Check the pyc-
push it back until it makes contact with the stops.
nometer temperature. Repeat the above procedure until you
6.2.3 Fill the pycnometer with 25 6 1°C (77 6 2°F) water
have three masses that are within 1 g range.
to approximately 10 mm (0.375 in.) from the top. Using the
6.3.8 Re-calibrate the pycnometer for each day of use.
alcohol spray bottle, spray the surface of the water to remove
bubbles.
7. Sampling
6.2.4 Gently place the lid on the pycnometer and close the
7.1 Fine Aggregate Samples (Method A):
clamps on the fixture.
7.1.1 Sampling shall be done in accordance with Practice
6.2.5 Using a syringe filled with 25 6 1°C (77 6 2°F)
D75.Forfineaggregatetestingthoroughlymixthesampleand
water, slowly fill the pycnometer through the large fill hole on
reduce it to obtain one 1000 6 5 g sample for apparent density
the lid post. Make sure the syringe tip is far enough in the
and two 500 6 3 g samples for determination of apparent bulk
pycnometer to be below the water level. Gentle application in
density.Foraggregatereductionusetheappropriateprocedures
this step prevents formation of air bubbles inside the pycnom-
described in Practice C 702.
eter. Fill the pycnometer until water comes out the 3 mm ( ⁄8
7.2 Coarse Aggregate Samples (Method B):
in.) hole on the surface of the lid.
7.2.1 Sample the aggregate in accordance with Practice
6.2.6 Wipe any remaining water from the top of the lid with
D75.
a towel.
7.2.2 Dry the aggregate to constant mass and thoroughly
6.2.7 Place the entire fixture with the pycnometer on the
mix the sample of aggregate and reduce it to one 2000 6 10 g
scale and record the mass.
sample for determination of apparent density and two 1000 6
6.2.8 Clean the pycnometer and repeat steps 6.2.1 to 6.2.7
10 g samples for determination of apparent bulk density. For
two more times and average the calibration masses obtained in
reduction of the aggregate samples, use the appropriate proce-
6.2.7.
dures in Practice C 702.
6.2.9 If the range for the 3 calibration masses is larger than
7.2.3 If the sample is tested in two or more size fractions,
0.5g,thenthe
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