1、Designation: D7370 09D7370/D7370M 14Standard 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 D7370;D7370/D7370M; the number immediately follow
2、ing the designation indicatesthe year of original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of lastreapproval. A superscript epsilon () indicates an editorial change since the last revision or reapproval.1. Scope1.1 This test method c
3、overs the determination of relative density and absorption of fine aggregates by MethodAand coarse andblended aggregates by Method B.1.2 The values are stated in SI units and are regarded as the standard units.1.2 A multi-laboratory precision and bias statement for coarse and combined aggregate test
4、s in this standard has not beendeveloped at this time. Therefore, this standard should not be used for acceptance or rejection of coarse and combined aggregatematerials for purchasing purposes.1.3 The values stated in either SI units or inch-pound units are to be regarded separately as standard. The
5、 values stated in eachsystem may not be exact equivalents; therefore, each system shall be used independently of the other. Combining values from thetwo systems may result in non-conformance with the standard. Some values have only SI units because inch-pound equivalentsare not used in practice.1.4
6、This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibilityof the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatorylimitations prior to use.2. Referenced Documen
7、ts2.1 ASTM Standards:2C29/C29M Test Method for Bulk Density (“Unit Weight”) and Voids in AggregateC127 Test Method for Density, Relative Density (Specific Gravity), and Absorption of Coarse AggregateC128 Test Method for Density, Relative Density (Specific Gravity), and Absorption of Fine AggregateC1
8、36 Test Method for Sieve Analysis of Fine and Coarse AggregatesC670 Practice for Preparing Precision and Bias Statements for Test Methods for Construction MaterialsC702 Practice for Reducing Samples of Aggregate to Testing SizeD75 Practice for Sampling AggregatesD4753 Guide for Evaluating, Selecting
9、, and Specifying Balances and Standard Masses for Use in Soil, Rock, and ConstructionMaterials TestingD3666 Specification for Minimum Requirements for Agencies Testing and Inspecting Road and Paving MaterialsE691 Practice for Conducting an Interlaboratory Study to Determine the Precision of a Test M
10、ethod3. Summary of Test Method3.1 Sufficient aggregate sample is dried to constant mass. For each test two representative dry aggregate samples of the samematerial are selected for testing. One sample is evacuated in a vacuum chamber inside a plastic bag and opened under water forrapid saturation of
11、 the aggregate. The dry mass and submerged mass of the sample is used for calculation of apparent relativedensity. The second sample of the same aggregate is tested in a known volume metal pycnometer. The known mass of the1 This test method is under the jurisdiction ofASTM Committee D04 on Road and
12、Paving Materials and is the direct responsibility of Subcommittee D04.51 on AggregateTests.Current edition approved June 1, 2009June 1, 2014. Published July 2009February 2015. Originally approved in 2008. Last previous edition approved in 20082009 asD7370 08.D7370 09. DOI: 10.1520/D7370-09.10.1520/D
13、7370_D7370M-14.2 For referencedASTM standards, visit theASTM website, www.astm.org, or contactASTM Customer Service at serviceastm.org. For Annual Book of ASTM Standardsvolume information, refer to the standards Document Summary page on the ASTM website.This document is not an ASTM standard and is i
14、ntended only to provide the user of an ASTM standard an indication of what changes have been made to the previous version. Becauseit may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the cu
15、rrent versionof the standard as published by ASTM is to be considered the official document.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States1pycnometer with water, mass of the dry aggregate and mass of the aggregate and pycnometer fill
16、ed with water is used forcalculation of unsaturated density. The results from the two samples tested are then used to calculate absorption, and relativedensity (OD).3.2 This test can be completed in less than 30 minutesmin and can be used for rapid determination of aggregate properties inconstructio
17、n testing laboratories.3.3 This test can be performed on fine, coarse and blended (combined) aggregates by using appropriate plastic bag andpycnometer sizes.4. Significance and Use4.1 Relative density (specific gravity) is the characteristic generally used for calculation of the volume occupied by t
18、heaggregate in various mixtures containing aggregate, including Portland cement concrete, bituminous concrete, and other mixturesthat are proportioned or analyzed on an absolute volume basis. Relative density (specific gravity) is also used in the computationof voids in aggregate in Test Method C29/
19、C29M. Relative density (specific gravity) saturated surface dry (SSD) is used if theaggregate 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.4.2 Apparen
20、t density and apparent relative density (apparent specific gravity) pertain to the solid material making up theconstituent particles not including the pore space within the particles which is accessible to water.4.3 Absorption values are used to calculate the change in the mass of an aggregate due t
21、o water absorbed in the pore spaceswithin the constituent particles, when it is deemed that the aggregate has been in contact with water long enough to satisfy theabsorption potential. The laboratory standard for absorption is that obtained after submerging dry aggregate for a prescribed periodof ti
22、me.NOTE 1There are other test methods that have been used and continue to be used to determine these aggregate properties: C127 and C128. This testmethod may result in values for these properties that are close to or divergent from values from other test methods.NOTE 2The quality of the results prod
23、uced by this standard are dependantdependent upon the competence of the personnel performing the procedureand the capability, calibration, and the maintenance of the equipment used. Agencies that meet the criteria of Practice D3666 are generally consideredcapable of competent and objective testing/s
24、ampling/inspection/etc. Users of this standard are cautioned that compliance with Practice D3666 alone doesnot completely assure reliable results. Reliable results depend on many factors: following the suggestions of Practice D3666 or similar acceptableguideline provides a means of evaluating and co
25、ntrolling some of those factors.5. Apparatus5.1 Balance, a balance that conforms to Guide D4753. The balance shall be sensitive, readable and accurate to 0.1 g. Thebalance shall be equipped with suitable apparatus for suspending the sample in water.5.2 Water Bath, with minimum dimensions (length by
26、width by depth) of 610 by 460 by 460 mm (2424 by 18 by 18 in.)in.or a large cylindrical container with a minimum diameter of 460 mm and depth of 460 mm (1818 by 18 in.),in., for completelysubmerging the sample in water while suspended, equipped with an overflow outlet for maintaining a constant wate
27、r level andmeans to maintain the water temperature at 25 6 1C (7777 6 2F).2F.NOTE 3It is preferable to keep the water temperature constant by using a temperature controlled heater.Also, to reduce the chance for the bag to touchthe sides of the water tank, it is preferable to elevate the water tank t
28、o a level at which the sample can be placed on the weighing mechanism while theoperator is standing up (waist height), and the placement of the sample and the bag in the water tank can easily be inspected.5.3 Sample Holder, for water displacement of the sample, having no sharp edges.5.4 Vacuum Chamb
29、er, with a pump capable of evacuating a sealed and enclosed chamber to a pressure of 6 mm Hg, Hg 6 Torr,when at sea level. The device shall automatically seal the plastic bag and exhaust air back into the chamber in a controlled mannerto ensure proper conformance of the plastic to the specimen. The
30、air exhaust and vacuum operation time shall be set at the factoryso that the chamber is brought to atmospheric pressure in 80 to 125 seconds, 125 s, after the completion of the vacuum operations.5.5 Vacuum Measurement Gauge, independent of the vacuum sealing device that could be placed directly insi
31、de the chamberto verify vacuum performance and the chamber door sealing condition of the unit. The gauge shall be capable of reading downto 3 mm Hg 3 Torr and readable to 61 mm Hg.Hg 61 Torr.5.6 Plastic Bags, used with the vacuum device shall be one of the two following sizes. The smaller bags shall
32、 have a minimumopening of 235 mm (9.25 in.)9.25 in. and maximum opening of 260 mm (10.25 in.)10.25 in. and the larger bags shall have aminimum opening of 375 mm (14.75 in.)14.75 in. and a maximum opening of 394 mm (15.5 in.).15.5 in. The bags shall beof plastic material, shall be puncture resistant,
33、 and shall be impermeable to water. The bags shall have a minimum thickness of0.127 mm (0.005 in.).0.005 in. The apparent specific gravity for the bags shall be provided by the manufacturer.5.7 Small Metal Pycnometer, with 137 6 0.2 mm (5.3755.375 6 0.008 in.)0.01 in. ID and 89 6 0.40 mm (3.53.5 6 0
34、.016in.)0.02 in. height, for testing fine aggregates. The pycnometer shall be machined to be smooth on all surfaces. The inside of thelid shall be machined at a 5 angle to create an inverted conical surface. The pycnometer shall be equipped with a graduatedtemperature strip to allow the user to visu
35、ally monitor temperature during testing.D7370/D7370M 1425.8 Large Metal Pycnometer, with 198 6 0.2 mm (7.7767.776 6 0.008 in.)0.01 in. ID and 114 6 0.8 mm (4.54.5 6 0.03in.)in. height, for testing coarse and blended aggregate. The pycnometer shall be machined to be smooth on all surfaces. The inside
36、of the lid shall be machined at a 5 angle to create an inverted conical surface. The pycnometer shall be equipped with a graduatedtemperature strip to allow the user to visually monitor temperature during testing.5.9 Fine Aggregate Fixture, for holding and securing the lid on the small metal pycnome
37、ter from lifting during fine aggregatetests. The fixture shall be provided with a level indicator.5.10 AccessoriesBag cutting knife or scissors, spray bottle filled with isopropyl alcohol, a bucket large enough to allow thepycnometer to be fully submerged in water, water containers to dispense water
38、 into pycnometer during testing, syringe with aneedle no larger in diameter than 3 mm (0.125 in.),0.125 in., small paint brush and 25 6 5 mm (11 6 0.2 in.)in. wide metalspatula.5.11 Rubber Sheets, for protecting the plastic bags against punctures caused by sharp edges on coarse and blended aggregate
39、samples. The apparent specific gravity for the rubber sheets shall be provided by the manufacturer.5.12 Thermometric device for monitoring the temperature to within 61C (61.8 F).61C 62F.6. Verification6.1 System Verification:6.1.1 The vacuum settings of the vacuum chamber shall be verified once ever
40、y 12 months and after major repairs and after eachshipment or relocation.6.1.2 Place the gauge inside the vacuum chamber and record the setting, while the vacuum unit is operating. The gauge shouldindicate a pressure of 6 mm Hg (6 TORR)6 TORR or less. The unit shall not be used if the gauge reading
41、is above 6 mm Hg(6 TORR).6 TORR.6.1.3 Vacuum gauge used for verification shall be standardized for accuracy on annual basis.NOTE 4In line vacuum gauges, while capable of indicating vacuum performance of the pump, are not suitable for use in enclosed vacuum chambersand cannot accurately measure vacuu
42、m levels.NOTE 5The worksheet in the appendix is provided as an optional tool to 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, condition the
43、 pycnometer at 25 6 1C (7777 6 2F)2F by placing it inside a bucket of water that ismaintained at 25 6 1C (7777 6 2F).2F. Use a level indicator or the provided level to level the fixture.6.2.2 Remove the pycnometer from the water bucket and dry it with a towel. Place the pycnometer in the fixture and
44、 push itback until it makes contact with the stops.6.2.3 Fill the pycnometer with 25 6 1C (7777 6 2F)2F water to approximately 10 mm (0.375 in.)0.375 in. from the top.Using the alcohol spray bottle, spray the surface of the water to remove bubbles.6.2.4 Gently place the lid on the pycnometer and clo
45、se the clamps on the fixture.6.2.5 Using a syringe filled with 25 6 1C (7777 6 2F)2F water, slowly fill the pycnometer through the large fill hole onthe lid post. Make sure the syringe tip is far enough in the pycnometer to be below the water level. Gentle application in this stepprevents formation
46、of air bubbles inside the pycnometer. Fill the pycnometer until water comes out the 3 mm (0.12518 in.)in. holeon the surface of the lid.6.2.6 Wipe any remaining water from the top of the lid with a towel.6.2.7 Place the entire fixture with the pycnometer on the scale and record the mass to the neare
47、st 0.1 g.6.2.8 Clean the pycnometer and repeat steps 6.2.1 to 6.2.7 two more times and average the calibration masses obtained in 6.2.7.6.2.9 If the range for the 3 calibration masses is larger than 0.5 g, then the test is not being run correctly. Check to see if thefixture is level. Make certain th
48、e water injection with the syringe is done below the pycnometer water surface and is applied gently.Check the water temperature. Check the pycnometer temperature. Repeat the above procedure until you have three masses that arewithin 0.5 g range.6.2.10 Re-calibrate the pycnometer for each day of use.
49、6.3 Calibration of the Large Pycnometer:6.3.1 Prior to testing, condition the pycnometer at 25 6 1C (7777 6 2F)2F by placing it inside a bucket of water that ismaintained at 25 6 1C (7777 6 2F).2F.6.3.2 Remove the pycnometer from the water bucket and dry it with a towel. Set the pycnometer on a level surface.6.3.3 Fill the pycnometer with 25 6 1C (7777 6 2F)2F water to approximately 10 mm (0.375 in.)0.375 in. from the top.Using the alcohol spray bottle, spray the surface of the wat
