1、Designation: D 7370 09Standard Test Method forDetermination of Relative Density and Absorption of Fine,Coarse and Blended Aggregate Using Combined VacuumSaturation and Rapid Submersion1This standard is issued under the fixed designation D 7370; the number immediately following the designation indica
2、tes the year oforiginal adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.1. Scope1.1 This test method covers the determination of
3、 relativedensity and absorption of fine aggregates by Method A andcoarse and blended aggregates by Method B.1.2 The values are stated in SI units and are regarded as thestandard units.1.3 A multi-laboratory precision and bias statement forcoarse and combined aggregate tests in this standard has notb
4、een developed at this time. Therefore, this standard should notbe used for acceptance or rejection of coarse and combinedaggregate materials for purchasing purposes.1.4 This standard does not purport to address all of thesafety concerns, if any, associated with its use. It is theresponsibility of th
5、e user of this standard to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:2C 29/C 29M Test Method for Bulk Density (“Unit Weight”)and Voids in AggregateC 127 Test Method for Density,
6、 Relative Density (SpecificGravity), and Absorption of Coarse AggregateC 128 Test Method for Density, Relative Density (SpecificGravity), and Absorption of Fine AggregateC 136 Test Method for Sieve Analysis of Fine and CoarseAggregatesC 670 Practice for Preparing Precision and Bias Statementsfor Tes
7、t Methods for Construction MaterialsC 702 Practice for Reducing Samples of Aggregate toTesting SizeD75 Practice for Sampling AggregatesD 4753 Guide for Evaluating, Selecting, and SpecifyingBalances and Standard Masses for Use in Soil, Rock, andConstruction Materials TestingD 3666 Specification for M
8、inimum Requirements forAgen-cies Testing and Inspecting Road and Paving MaterialsE 691 Practice for Conducting an Interlaboratory Study toDetermine the Precision of a Test Method3. Summary of Test Method3.1 Sufficient aggregate sample is dried to constant mass.For each test two representative dry ag
9、gregate samples of thesame material are selected for testing. One sample is evacuatedin a vacuum chamber inside a plastic bag and opened underwater for rapid saturation of the aggregate. The dry mass andsubmerged mass of the sample is used for calculation ofapparent relative density. The second samp
10、le of the sameaggregate is tested in a known volume metal pycnometer. Theknown mass of the pycnometer with water, mass of the dryaggregate and mass of the aggregate and pycnometer filledwith water is used for calculation of unsaturated density. Theresults from the two samples tested are then used to
11、 calculateabsorption, and relative density (OD).3.2 This test can be completed in less than 30 minutes andcan be used for rapid determination of aggregate properties inconstruction testing laboratories.3.3 This test can be performed on fine, coarse and blended(combined) aggregates by using appropria
12、te plastic bag andpycnometer sizes.4. Significance and Use4.1 Relative density (specific gravity) is the characteristicgenerally used for calculation of the volume occupied by theaggregate in various mixtures containing aggregate, includingPortland cement concrete, bituminous concrete, and othermixt
13、ures that are proportioned or analyzed on an absolutevolume basis. Relative density (specific gravity) is also used in1This test method is under the jurisdiction of ASTM Committee D04 on Roadand Paving Materials and is the direct responsibility of Subcommittee D04.51 onAggregate Tests.Current editio
14、n approved June 1, 2009. Published July 2009. Originally approvedin 2008. Last previous edition approved in 2008 as D 7370 08.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information,
15、 refer to the standards Document Summary page onthe ASTM website.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.the computation of voids in aggregate in Test Method C 29/C 29M. Relative density (specific gravity) saturated surface d
16、ry(SSD) is used if the aggregate is at SSD, that is, if itsabsorption has been satisfied. Conversely, the relative density(specific gravity) oven-dry (OD) is used for computationswhen the aggregate is dry or assumed to be dry.4.2 Apparent density and apparent relative density (apparentspecific gravi
17、ty) pertain to the solid material making up theconstituent particles not including the pore space within theparticles which is accessible to water.4.3 Absorption values are used to calculate the change in themass of an aggregate due to water absorbed in the pore spaceswithin the constituent particle
18、s, when it is deemed that theaggregate has been in contact with water long enough to satisfythe absorption potential. The laboratory standard for absorptionis that obtained after submerging dry aggregate for a prescribedperiod of time.NOTE 1There are other test methods that have been used and contin
19、ueto be used to determine these aggregate properties: C 127 and C 128. Thistest method may result in values for these properties that are close to ordivergent from values from other test methods.NOTE 2The quality of the results produced by this standard aredependant upon the competence of the person
20、nel performing the proce-dure and the capability, calibration, and the maintenance of the equipmentused. Agencies that meet the criteria of Practice D 3666 are generallyconsidered capable of competent and objective testing/sampling/inspection/etc. Users of this standard are cautioned that compliance
21、 withPractice D 3666 alone does not completely assure reliable results. Reliableresults depend on many factors: following the suggestions of PracticeD 3666 or similar acceptable guideline provides a means of evaluating andcontrolling some of those factors.5. Apparatus5.1 Balance, a balance that conf
22、orms to Guide D 4753. Thebalance shall be sensitive, readable and accurate to 0.1 g. Thebalance shall be equipped with suitable apparatus for suspend-ing the sample in water.5.2 Water Bath, with minimum dimensions (length by widthby depth) of 610 by 460 by 460 mm (24 by 18 by 18 in.) or alarge cylin
23、drical container with a minimum diameter of 460mm and depth of 460 mm (18 by 18 in.), for completelysubmerging the sample in water while suspended, equippedwith an overflow outlet for maintaining a constant water leveland means to maintain the water temperature at 25 6 1C (776 2F).NOTE 3It is prefer
24、able to keep the water temperature constant byusing a temperature controlled heater. Also, to reduce the chance for thebag to touch the sides of the water tank, it is preferable to elevate the watertank to a level at which the sample can be placed on the weighingmechanism while the operator is stand
25、ing up (waist height), and theplacement of the sample and the bag in the water tank can easily beinspected.5.3 Sample Holder, for water displacement of the sample,having no sharp edges.5.4 Vacuum Chamber, with a pump capable of evacuating asealed and enclosed chamber to a pressure of 6 mm Hg, whenat
26、 sea level. The device shall automatically seal the plastic bagand exhaust air back into the chamber in a controlled mannerto ensure proper conformance of the plastic to the specimen.The air exhaust and vacuum operation time shall be set at thefactory so that the chamber is brought to atmospheric pr
27、essurein 80 to 125 seconds, after the completion of the vacuumoperations.5.5 Vacuum Measurement Gauge, independent of thevacuum sealing device that could be placed directly inside thechamber to verify vacuum performance and the chamber doorsealing condition of the unit. The gauge shall be capable of
28、reading down to 3 mm Hg and readable to 61mmHg.5.6 Plastic Bags, used with the vacuum device shall be oneof the two following sizes. The smaller bags shall have aminimum opening of 235 mm (9.25 in.) and maximum openingof 260 mm (10.25 in.) and the larger bags shall have aminimum opening of 375 mm (1
29、4.75 in.) and a maximumopening of 394 mm (15.5 in.). The bags shall be of plasticmaterial, shall be puncture resistant, and shall be impermeableto water. The bags shall have a minimum thickness of 0.127mm (0.005 in.). The apparent specific gravity for the bags shallbe provided by the manufacturer.5.
30、7 Small Metal Pycnometer, with 137 6 0.2 mm (5.375 60.008 in.) ID and 89 6 0.40 mm (3.5 6 0.016 in.) height, fortesting fine aggregates. The pycnometer shall be machined tobe smooth on all surfaces. The inside of the lid shall bemachined at a 5 angle to create an inverted conical surface.The pycnome
31、ter shall be equipped with a graduated tempera-ture strip to allow the user to visually monitor temperatureduring testing.5.8 Large Metal Pycnometer, with 198 6 0.2 mm (7.776 60.008 in.) ID and 114 6 0.8 mm (4.5 6 0.03 in.) height, fortesting coarse and blended aggregate. The pycnometer shall bemach
32、ined to be smooth on all surfaces. The inside of the lidshall be machined at a 5 angle to create an inverted conicalsurface. The pycnometer shall be equipped with a graduatedtemperature strip to allow the user to visually monitor tem-perature during testing.5.9 Fine Aggregate Fixture, for holding an
33、d securing the lidon the small metal pycnometer from lifting during fine aggre-gate tests. The fixture shall be provided with a level indicator.5.10 AccessoriesBag cutting knife or scissors, spraybottle filled with isopropyl alcohol, a bucket large enough toallow the pycnometer to be fully submerged
34、 in water, watercontainers to dispense water into pycnometer during testing,syringe with a needle no larger in diameter than 3 mm (0.125in.), small paint brush and 25 6 5mm(16 0.2 in.) wide metalspatula.5.11 Rubber Sheets, for protecting the plastic bags againstpunctures caused by sharp edges on coa
35、rse and blendedaggregate samples. The apparent specific gravity for the rubbersheets shall be provided by the manufacturer.5.12 Thermometric device for monitoring the temperatureto within 61C (61.8 F).6. Verification6.1 System Verification:6.1.1 The vacuum settings of the vacuum chamber shall beveri
36、fied once every 12 months and after major repairs and aftereach shipment or relocation.6.1.2 Place the gauge inside the vacuum chamber and recordthe setting, while the vacuum unit is operating. The gaugeD7370092should indicate a pressure of 6 mm Hg (6 TORR) or less. Theunit shall not be used if the
37、gauge reading is above 6 mm Hg(6 TORR).6.1.3 Vacuum gauge used for verification shall be standard-ized for accuracy on annual basis.NOTE 4In line vacuum gauges, while capable of indicating vacuumperformance of the pump, are not suitable for use in enclosed vacuumchambers and cannot accurately measur
38、e vacuum levels.NOTE 5The worksheet in the appendix is provided as an optional toolto the user for recording of masses obtained during this test method. Usersmay develop their own worksheet or a computer program for this purpose.6.2 Calibration of the Small Pycnometer:6.2.1 Prior to testing, conditi
39、on the pycnometer at 25 6 1C(77 6 2F) by placing it inside a bucket of water that ismaintained at 25 6 1C (77 6 2F). Use a level indicator or theprovided level to level the fixture.6.2.2 Remove the pycnometer from the water bucket anddry it with a towel. Place the pycnometer in the fixture andpush i
40、t back until it makes contact with the stops.6.2.3 Fill the pycnometer with 25 6 1C (77 6 2F) waterto approximately 10 mm (0.375 in.) from the top. Using thealcohol spray bottle, spray the surface of the water to removebubbles.6.2.4 Gently place the lid on the pycnometer and close theclamps on the f
41、ixture.6.2.5 Using a syringe filled with 25 6 1C (77 6 2F)water, slowly fill the pycnometer through the large fill hole onthe lid post. Make sure the syringe tip is far enough in thepycnometer to be below the water level. Gentle application inthis step prevents formation of air bubbles inside the py
42、cnom-eter. Fill the pycnometer until water comes out the 3 mm (18in.) hole on the surface of the lid.6.2.6 Wipe any remaining water from the top of the lid witha towel.6.2.7 Place the entire fixture with the pycnometer on thescale and record the mass to the nearest 0.1 g.6.2.8 Clean the pycnometer a
43、nd repeat steps 6.2.1 to 6.2.7two more times and average the calibration masses obtained in6.2.7.6.2.9 If the range for the 3 calibration masses is larger than0.5 g, then the test is not being run correctly. Check to see if thefixture is level. Make certain the water injection with thesyringe is don
44、e below the pycnometer water surface and isapplied gently. Check the water temperature. Check the pyc-nometer temperature. Repeat the above procedure until youhave three masses that are within 0.5 g range.6.2.10 Re-calibrate the pycnometer for each day of use.6.3 Calibration of the Large Pycnometer:
45、6.3.1 Prior to testing, condition the pycnometer at 25 6 1C(77 6 2F) by placing it inside a bucket of water that ismaintained at 25 6 1C (77 6 2F).6.3.2 Remove the pycnometer from the water bucket anddry it with a towel. Set the pycnometer on a level surface.6.3.3 Fill the pycnometer with 25 6 1C (7
46、7 6 2F) waterto approximately 10 mm (0.375 in.) from the top. Using thealcohol spray bottle, spray the surface of the water to removeany air bubbles.6.3.4 Gently place the lid on the pycnometer. Using asyringe filled with 25 6 1C (77 6 2F) water, slowly fill thepycnometer through the large fill hole
47、 on the lid post. Makesure the syringe tip is far enough in the pycnometer to be belowthe water level. Gentle application in this step preventsformation of air bubbles inside the pycnometer. Fill thepycnometer until water comes out the 3 mm (18 in.) hole on thesurface of the lid.6.3.5 Wipe any remai
48、ning water from the top of the lid andsides with a towel. Place the pycnometer on the scale andrecord the mass to the nearest 0.1 g.6.3.6 Clean the pycnometer and repeat steps 6.3.2 to 6.3.5two more times and average the calibration masses obtained in6.3.5.6.3.7 If the range for the 3 calibration ma
49、sses is larger than1 g, then the test is not being run correctly. Check to see if thefixture is level. Make certain the water injection with thesyringe is done below the pycnometer water surface and isapplied gently. Check the water temperature. Check the pyc-nometer temperature. Repeat the above procedure until youhave three masses that are within 1 g range.6.3.8 Re-calibrate the pycnometer for each day of use.7. Sampling7.1 Fine Aggregate Samples (Method A):7.1.1 Sampling shall be done in accordance with PracticeD75. For fine aggregate testing thorough
