1、Designation: D 7172 06Standard 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, in
2、 the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon (e) indicates an editorial change since the last revision or reapproval.1. Scope1.1 This test method covers the determination of the relativedensity (specific gravity
3、) 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 theresponsibility of the user of this standard to establish appro-priate safety and
4、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 Terminology Relating to Concrete and ConcreteAggregatesC 128 Test Method for Density,
5、 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 Methods for Construction MaterialsC 702 Practice for Reducing Samples of Aggregate toTe
6、sting 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 Sampling AggregatesD 4753 Guide for Evaluating, Selecting, and SpecifyingBalances an
7、d 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. Terminology3.1 DefinitionsAs defined in C 125 and D83.1.1 Automatic Volumetric Mixer (A
8、VM), 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 calculation of the volume occupied bythe aggregate in various mixtures containing aggregate
9、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 aggregate in C 1252 and C 29/C 29M. Bulk relative density (specific gravity) determ
10、ined 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 used for computations when the aggregate is dry orassumed to be dry.4.2 Apparent rel
11、ative 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 widelyused in construction aggregate technology.4.3 Water absorption values are us
12、ed 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 incontact with water long enough to satisfy most of the absorp-tion potential. The laboratory st
13、andard for absorption is that1This 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 edition approved Feb. 15, 2006. Published March 2006.2For referenced ASTM standards, visit the
14、ASTM website, www.astm.org, orcontact ASTM 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. Capi
15、tol St., NW, Suite 249, Washington, DC 20001.4Available 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.obtained after submerging dry a
16、ggregate 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 absorbed moisture less than the 24 hours soakedcondition: For an aggregate that has been
17、 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 drying.5. Apparatus5.1 BalanceAbalance or scale, conforming to the require-ments o
18、f 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 bereadable to 0.5 C (1 F).5.3 Large Neck Volumetric Flaskwith a capacity of 500mL.
19、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 securely hold a 500 mL large neck volumetric flask, aclamp and clamping rod capab
20、le 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 detecting SSD using an infrared source and detector.It shall consist of an orbital
21、 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 1Units similar to the SSDetect manufactured by BarnsteadInternational5meet criteria
22、 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 thesample using the applicable procedures described in PracticeC 702.7.2 Dry it in
23、 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. Calibration8.1 Calibration of the water pump and the infrared unit shallbe perfo
24、rmed 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 collect the water. Position the container soas to minimize splashing. (Note 2).NOTE 2A
25、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 total of 3000 injections is recommended.8.2.4 At the end of the collection cycle,
26、 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 instructions.8.3 Calibration of Infrared Unit:8.3.1 Check and ensure that the wate
27、r 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 exactly 500.0 g of Ottawa Silica sand into themixing bowl and initiate the calibr
28、ation 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 the Ottawa silica sand back to a constant mass ata temperature of 110 6 5C (230 6
29、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. Procedure9.1 Make and record all mass determinations to 0.1 g.9.2 Determine the mass o
30、f 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) Determination:9.3.1 Place approximately 250 mL of 23 6 2.0C (73 63F) water in the flas
31、k 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 themass. Transfer all of the aggregate into the flask with water5The sole source of s
32、upply 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 thisinformation to ASTM International Headquarters. Your comments will receivecareful c
33、onsideration at a meeting of the responsible technical committee,1whichyou may attend.D7172062from 9.3.2. Without zeroing the balance, record the mass on thebalance from 9.3.2; make certain that the aggregate in the flaskis covered with water. Start the five-minute timer from 9.3.3.Asmall amount of
34、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 transfer the sample into theflask.9.3.5 Add a few drops of isopropyl alcohol or use a
35、 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 with 23 6 2.00C (73 6 3F) water to the calibrationmark.9.3.7 Weigh and record the ma
36、ss 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, withvacuum hose attached, into flask.9.3.9 Turn the power switch for the AVM unit to th
37、e “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 another three minutes to remove air fromthe sample. The last five minutes of the test
38、 the vacuum pumpwill engage at a level of 69 cm (2 in.) Hg. This operation isentirely automated. The AVM will continue mixing during theentire period. The unit will stop automatically when testing iscomplete (;11 minutes).9.3.10 After the unit has stopped mixing, remove the flaskfrom mixing platform
39、. 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 mass of the flask with the sampleand water filled to the calibration mark.9.3.13 Subtra
40、ct 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 values determined in 9.3.7and 9.3.12,g.9.4 Bulk Relative Density (Specific Gravity) and
41、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 the mass of the bowl.9.4.3 Place 500 6 0.1 g of the sample into the bowl andrecord the
42、 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 notch in the front of the bowl fullyengages in the notch in the front of the metal m
43、ounting 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, place the top on the bowl and lightly pressdown to be certain it is engaged. The n
44、otch 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 that determined in step9.3.13. Press the enter button. The display will remind you
45、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 tested.9.4.8 At the completion of the run, Press the OK button.Compare the film coefficie
46、nt 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. Remove the bowl. Immediatelyplace the bowl on the balance and record the mass. (No
47、te 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 step 9.4.3 from 9.4.9.10. Calculation10.1 Calculate the bulk relative density (specifi
48、c 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 = mass of volumetric flask filled with water, g (9.2)C = mass of volumetric flask with
49、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 specimen in air, g. (9.3.4)10.4 Calculate the percentage absorption, as defined inTerminol
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