1、Designation: D 7172 061Standard Test Method forDetermining The Relative Density (Specific Gravity) AndAbsorption Of Fine Aggregates Using Infrared1This standard is issued under the fixed designation D 7172; the number immediately following the designation indicates the year oforiginal adoption or, i
2、n 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.1NOTE“2 in.” was editorially corrected to “27 in.” in Section 9.3.9 in March 2009.1. Scope1.1
3、This test method covers the determination of the relativedensity (specific gravity) and absorption of fine aggregates.1.2 The values stated in SI units are to be regarded as thestandard.1.3 This standard does not purport to address all of thesafety concerns, if any, associated with its use. It is th
4、eresponsibility of the 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 125 Ter
5、minology Relating to Concrete and ConcreteAggregatesC 128 Test Method for Density, Relative Density (SpecificGravity), and Absorption of Fine AggregateC 566 Test Method for Total Evaporable Moisture Contentof Aggregate by DryingC 670 Practice for Preparing Precision and Bias Statementsfor Test Metho
6、ds for Construction MaterialsC 702 Practice for Reducing Samples of Aggregate toTesting SizeC 1252 Test Methods for Uncompacted Void Content ofFine Aggregate (as Influenced by Particle Shape, SurfaceTexture, and Grading)D8 Terminology Relating to Materials for Roads and Pave-mentsD75 Practice for Sa
7、mpling AggregatesD 4753 Guide for Evaluating, Selecting, and SpecifyingBalances and Standard Masses for Use in Soil, Rock, andConstruction Materials Testing2.2 AASHTO Standards:3T-84 Test Method for Specific Gravity and Absorption ofFine Aggregate2.3 Other Documents:4Operational Instructions3. Termi
8、nology3.1 DefinitionsAs defined in C 125 and D83.1.1 Automatic Volumetric Mixer (AVM), nan automatedunit to hold and agitate a volumetric flask while applying avacuum to the flask.4. Significance and Use4.1 Bulk relative density (specific gravity) is the character-istic generally used for calculatio
9、n of the volume occupied bythe aggregate in various mixtures containing aggregate includ-ing Portland cement concrete, bituminous concrete, and othermixtures that are proportioned or analyzed on an absolutevolume basis. Bulk relative density (specific gravity) is used inthe computation of voids in a
10、ggregate in C 1252 and C 29/C 29M. Bulk relative density (specific gravity) determined onthe saturated surface dry (SSD) basis is used if the aggregate iswet, that is, if its absorption has been satisfied. Conversely, thebulk relative density (specific gravity) determined on the oven-dry basis is us
11、ed for computations when the aggregate is dry orassumed to be dry.4.2 Apparent relative density (specific gravity) pertains tothe relative density of the solid material making up theconstituent particles not including the pore space within theparticles that is accessible to water. This value is not
12、widelyused in construction aggregate technology.4.3 Water absorption values are used to calculate the changein the mass of an aggregate due to water absorbed in the porespaces within the constituent particles, compared to the drycondition, when it is deemed that the aggregate has been in1This test m
13、ethod is under the jurisdiction of ASTM Committee D04 on Roadand Paving Materials and is the direct responsibility of Subcommittee D04.51 onAggregate Tests.Current edition approved Feb. 15, 2006. Published March 2006.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact AST
14、M Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.3Available from American Association of State Highway and TransportationOfficials (AASHTO), 444 N. Capitol St., NW, Suite 249, Washington, DC 20
15、001.4Available from Barnstead International, 2555 Kerper Boulevard, P.O. Box 797,Dubuque, Iowa 52004-0797, U.S.A.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.contact with water long enough to satisfy most of the absorp-tion potent
16、ial. The laboratory standard for absorption is thatobtained after submerging dry aggregate for approximately 24hours in water. Aggregates mined from below the water tablemay have a higher absorption when used, if not allowed to dry.Conversely, some aggregates when used may contain anamount of absorb
17、ed moisture less than the 24 hours soakedcondition: For an aggregate that has been in contact with waterand that had free moisture on the particle surface, the percent-age of free moisture can be determined by deducting theabsorption from the total moisture content determined accord-ing to C 566 by
18、drying.5. Apparatus5.1 BalanceAbalance or scale, conforming to the require-ments of D 4753, accurate and readable to within 0.1 % of thetest sample mass at any point within the range of use.5.2 ThermometerShall be capable of accurately measur-ing the temperature throughout a range of 0 to 50 C, and
19、bereadable to 0.5 C (1 F).5.3 Large Neck Volumetric Flaskwith a capacity of 500mL.5.4 Timercapable of at least 5 minutes.5.5 AVM Unit (Automatic Volumetric Mixer)The unitshall perform an automated process for removing entrapped air.It shall consist of the following devices: an orbiting mixer thatcan
20、 securely hold a 500 mL large neck volumetric flask, aclamp and clamping rod capable of securely holding the neckof the volumetric flask, a vacuum pump, hose, and a stoppercapable of fitting the mouth of the volumetric flask. (See Note1)5.6 Infrared UnitThe device shall be automatically ca-pable of
21、detecting SSD using an infrared source and detector.It shall consist of an orbital mixer, water pump, infrared source,infrared detector, and a mixing bowl with a lid. The lid of themixing bowl shall consist of two sapphire lenses and contain aninjection nozzle for water injection. (See Note 1)NOTE 1
22、Units similar to the SSDetect manufactured by BarnsteadInternational5meet criteria described in Sections 5.3, 5.5 and 5.65.7 Distilled Water6. Sampling6.1 Sampling shall be accomplished in accordance withPractice D75.7. Preparation of Test Specimen7.1 Obtain 1.5 kg 6 10 g of the fine aggregate from
23、thesample using the applicable procedures described in PracticeC 702.7.2 Dry it in a suitable pan or vessel to constant mass at atemperature of 110 6 5C (230 6 9F). Allow it to cool to 236 2.0C (73 6 3F).7.3 Split the test sample according to Practice C 702 intotwo 500 6 5g samples. Discard excess.8
24、. Calibration8.1 Calibration of the water pump and the infrared unit shallbe performed once a month.8.2 Calibration of Water Pump:8.2.1 Fill the infrared device with distilled water per manu-facturers instructions.8.2.2 Weigh a clean container. Place the container under thenozzle in the lid to colle
25、ct the water. Position the container soas to minimize splashing. (Note 2).NOTE 2A 125 mL Erlenmeyer flask or similar container is recom-mended.8.2.3 Follow manufacturers instructions regarding initia-tion of an automatic preset number of injections from thenozzle into the test flask. (Note 3)NOTE 3A
26、 total of 3000 injections is recommended.8.2.4 At the end of the collection cycle, remove the con-tainer and place it on a scale to obtain the total mass. Subtractthe empty container mass obtained in step 8.2.2 from this valueand enter the resulting amount into the Infrared device, permanufacturers
27、instructions.8.3 Calibration of Infrared Unit:8.3.1 Check and ensure that the water reservoir on theinfrared unit is full. Turn on the power to the unit and allow itto warm-up per manufacturers instructions.8.3.2 Initiate infrared unit calibration routine per manufac-turers instructions.8.3.3 Insert
28、 exactly 500.0 g of Ottawa Silica sand into themixing bowl and initiate the calibration process. After the unitcompletes the calibration procedure, the unit will indicate thecalibration result. (Note 4)8.3.4 Return to the normal operation mode of the unit perthe manufacturers instructions.8.3.5 Dry
29、the Ottawa silica sand back to a constant mass ata temperature of 110 6 5C (230 6 9F), so it can be used forfuture calibrations.NOTE 4A calibration material can be obtained from the unit manu-facturer. When the calibration result is shown, it indicates that thecalibration process is complete.9. Proc
30、edure9.1 Make and record all mass determinations to 0.1 g.9.2 Determine the mass of a 500 ml, large neck volumetricflask filled to its calibration capacity with water at 23 6 2.0C(73 6 3F). Record the mass and discard the water.9.3 Film Coeffcient and Apparent Relative Density (SpecificGravity) Dete
31、rmination:9.3.1 Place approximately 250 mL of 23 6 2.0C (73 63F) water in the flask measured in 9.2.9.3.2 Place the flask and water from 9.3.1 on a balance andzero the balance.9.3.3 Set the timer to five minutes, start when instructed in9.3.4.9.3.4 Obtain 500.0 g 6 0.1 g, of aggregate and record the
32、mass. Transfer all of the aggregate into the flask with water5The sole source of supply of the apparatus known to the committee at this timeis Barnstead International, 2555 Kerper Boulevard, P.O. Box 797, Dubuque, Iowa52004-0797, U.S.A. If you are aware of alternative suppliers, please provide thisi
33、nformation to ASTM International Headquarters. Your comments will receivecareful consideration at a meeting of the responsible technical committee,1whichyou may attend.D71720612from 9.3.2. Without zeroing the balance, record the mass on thebalance from 9.3.2; make certain that the aggregate in the f
34、laskis covered with water. Start the five-minute timer from 9.3.3.Asmall amount of water can be added at this time to rinse thesides of the flask if necessary. Make certain not to overfill theflask, keeping the water level well below the calibration line.(Note 5)NOTE 5A funnel may be used to help tr
35、ansfer the sample into theflask.9.3.5 Add a few drops of isopropyl alcohol or use a papertowel to remove bubbles if necessary to reduce error in readingthe meniscus. (Note 6)NOTE 6An accurate meniscus determination is very important.9.3.6 After the 5 minutes on the timer has elapsed, fill theflask w
36、ith 23 6 2.00C (73 6 3F) water to the calibrationmark.9.3.7 Weigh and record the mass of the flask with itscontents.9.3.8 Place the flask containing the sample in the mountingbracket on top of mixer ofAVM unit. Tighten the clamp aroundthe top portion of flask and then insert the rubber stopper, with
37、vacuum hose attached, into flask.9.3.9 Turn the power switch for the AVM unit to the “on”position. Press the “start” button to begin the test. Mixer willbegin to agitate material in flask. The mixer will operate forthree minutes, then the vacuum pump will engage at a level of56 cm (22 in.) Hg for an
38、other three minutes to remove air fromthe sample. The last five minutes of the test the vacuum pumpwill engage at a level of 69 cm (27 in.) Hg. This operation isentirely automated. The AVM will continue mixing during theentire period. The unit will stop automatically when testing iscomplete (;11 min
39、utes).9.3.10 After the unit has stopped mixing, remove the flaskfrom mixing platform. Add a few drops of isopropyl alcohol oruse a paper towel to remove bubbles if necessary to reduceerror in reading the meniscus.9.3.11 Fill the flask to the calibration mark with water.9.3.12 Determine the total mas
40、s of the flask with the sampleand water filled to the calibration mark.9.3.13 Subtract the mass in step 9.3.7 from the mass in9.3.12. Enter this value into the following equation to deter-mine the film coefficient.Film Coefficient 5 52 1 4*X! 2 0.11 * X2! (1)Where:X = the difference between the valu
41、es determined in 9.3.7and 9.3.12,g.9.4 Bulk Relative Density (Specific Gravity) and PercentAbsorption Determination:9.4.1 Turn the infrared unit on and allow it to complete the30-minute warm up period.9.4.2 Place the empty, clean and completely dry bowl fromthe infrared unit on balance and record th
42、e mass of the bowl.9.4.3 Place 500 6 0.1 g of the sample into the bowl andrecord the mass of the bowl and sample.9.4.4 Calculate and record the dry aggregate weight bysubtracting the mass in step 9.4.2 from 9.4.3.9.4.5 Place the bowl with the aggregate into the infraredunit, making certain that the
43、notch in the front of the bowl fullyengages in the notch in the front of the metal mounting plate.(Feel this with your finger at the bottom front of the bowl asplaced.) Use the ring on the bowl to securely fasten the bowl tothe plate by pressing down and turning the ring14 of a turnuntil tight. Next
44、, place the top on the bowl and lightly pressdown to be certain it is engaged. The notch should be lined upin the front of the bowl. Then, close the lid to the infrared unitand latch in the front.9.4.6 Ensure that there is distilled water in the reservoir inthe unit.9.4.7 Set the film coefficient to
45、 that determined in step9.3.13. Press the enter button. The display will remind you toplace sample in the unit. Press the start button. The system willautomatically begin to determine the SSD point for thematerial. It will run for34 to 112 hours depending on theabsorption of the material being teste
46、d.9.4.8 At the completion of the run, Press the OK button.Compare the film coefficient on the display with the measuredfilm coefficient for that material to be certain it was enteredproperly. Press the OK button.9.4.9 Open the unit; remove the lid to the bowl and store asdirected by the manufacturer
47、. Remove the bowl. Immediatelyplace the bowl on the balance and record the mass. (Note 7)NOTE 7Be certain to determine the mass of the bowl immediatelyafter removing the lid. This ensures that material is not allowed to dry.9.4.10 Determine the amount of water absorbed by subtract-ing the mass in st
48、ep 9.4.3 from 9.4.9.10. Calculation10.1 Calculate the bulk relative density (specific gravity) onthe basis of mass of oven-dry aggregate, as defined in TestMethod C 128, as follows:Bulk relative density specific gravity!5A / A 1 B 2 C 1 D!(2)Where:A = mass of oven-dry specimen in air, g (9.4.4)B = m
49、ass of volumetric flask filled with water, g (9.2)C = mass of volumetric flask with specimen and water tocalibration mark, g (9.3.12)D = mass of water absorbed, g. (9.4.10)10.2 Calculate the bulk relative density (specific gravity) onthe basis of mass of saturated surface-dry aggregate, asfollows:Bulk relative density specific gravity!saturated surface2dry basis!5A 1D!/A1B2C1D! (3)10.3 Calculate the apparent relative density as follows:Apparent relative density specific gravity!5E / E 1 B 2 C!(4)Where:E = mass of oven-dry apparent s
