1、Designation: D4125/D4425M 10Standard Test Methods forAsphalt Content of Bituminous Mixtures by the NuclearMethod1This standard is issued under the fixed designation D4125/D4425M; the number immediately following the designation indicates theyear of original adoption or, in the case of revision, the
2、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 These test methods cover the procedures for determin-ing the asphalt content of samples of uncompacted bitumin
3、ousmixtures (Test Method A), and of laboratory compactedspecimens of bituminous mixtures (Test Method B) by exam-ining a test sample with an apparatus that utilizes neutronthermalization techniques.1.2 The values stated in either SI units or inch-pound unitsare to be regarded separately as standard.
4、 The values stated ineach system may not be exact equivalents; therefore, eachsystem shall be used independently of the other. Combiningvalues from the two systems may result in non-conformancewith the standard.1.3 A precision and bias statement for Method B in thisstandard has not been developed at
5、 this time. Therefore,Method B should not be used for acceptance or rejection of amaterial 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 the user of this standard to establish appro-priate
6、safety and health practices and determine the applica-bility of regulatory limitations prior to use. See Section 6 and8.4.2, 8.5.6, and Note 4, for specific hazards.2. Referenced Documents2.1 ASTM Standards:2C670 Practice for Preparing Precision and Bias Statementsfor Test Methods for Construction M
7、aterialsD75 Practice for Sampling AggregatesD140 Practice for Sampling Bituminous MaterialsD979 Practice for Sampling Bituminous Paving MixturesD1461 Test Method for Moisture or Volatile Distillates inBituminous Paving MixturesD1559 Test Method for Resistance to Plastic Flow ofBituminous Mixtures Us
8、ing Marshall Apparatus3D1561 Practice for Preparation of Bituminous Mixture TestSpecimens by Means of California Kneading CompactorD3387 Test Method for Compaction and Shear Properties ofBituminous Mixtures by Means of the U.S. Corps ofEngineers Gyratory Testing Machine (GTM)D4013 Practice for Prepa
9、ration of Test Specimens of Bitu-minous Mixtures by Means of Gyratory Shear Compactor3. Significance and Use3.1 These test methods are useful as a rapid, nondestructivetechnique for determination of asphalt content of bituminousmixtures.3.2 These test methods are suitable for quality control andacce
10、ptance testing for construction and for research anddevelopment applications. The test method is used for deter-mination of asphalt content only as it does not provideextracted aggregate for gradation analysis.3.3 The non-destructive nature of the test allows repetitivemeasurements to be made on a s
11、ingle test sample for statisticalanalysis of test data.3.4 These test methods determine the asphalt content of atest sample by comparing the measured asphalt content withpreviously established calibration data.3.4.1 The asphalt content of a material expressed as apercentage, is the ratio of the mass
12、 of asphalt in a given massof material to the total mass of the sample or to the mass of thesolid material particles.4. Interferences4.1 The fundamental assumptions inherent in this testmethod are that the material under test is homogeneous andthat hydrogen present is in the form of asphalt or has b
13、eenotherwise accounted for in the calibration process.4.2 Accurate results will be dependent upon proper calibra-tion of the apparatus to the material being tested.4.3 This apparatus measures the total amount of hydrogen inthe sample including hydrogen present in the form of water.Unless the test sa
14、mple is free of water, such percentage must bedetermined in accordance with the provisions of Test Method1These test methods are under the jurisdiction of ASTM Committee D04 onRoad and Paving Materials and is the direct responsibility of Subcommittee D04.25on Analysis of Bituminous Mixtures.Current
15、edition approved Dec. 1, 2010. Published December 2010. Originallyapproved in 1983. Last previous edition approved in 2005 as D4125 05. DOI:10.1520/D4125_D4125M-10.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Boo
16、k of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.3Withdrawn.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.D1461 and the percentage determined subtracted from theasphalt percenta
17、ge as measured by the apparatus.4.3.1 Alternatively, the sample may be dried to a constantmass in an oven at 110 6 5C 230 6 9F, thereby nullifyingthe need for the correction.4.4 This apparatus may be sensitive to outside influences,therefore, any other source of neutron radiation shall be kept atlea
18、st 10 m 30 ft from the apparatus during use. The areaaround the apparatus shall be kept free of large amounts ofhydrogenous material, such as water, plastics, or asphalt duringuse.4.5 Moving the apparatus to a different location, even withinthe same laboratory, can cause a change in backgroundradiat
19、ion measurements. Also, if objects containing hydrog-enous materials are moved in the area near the apparatus, themeasurement counts may be affected. New background mea-surements shall be taken prior to use whenever backgroundconditions have changed (see Section 10).5. Apparatus5.1 While exact detai
20、ls of construction for the apparatusmay vary, the system shall consist of the following items:5.1.1 Neutron SourceAn encapsulated and sealed radio-active source such as americium/beryllium.5.1.2 DetectorsAny type of thermal neutron detectors,such as helium-3 or boron trifluoride.5.1.3 Read-Out Instr
21、ument, such as a scaler or a directreading digital device calibrated in percent asphalt.5.2 Other Apparatus:5.2.1 Stainless Steel Sample Pans, of uniform size andmass.5.2.2 Balance, capable of weighing to 20 kg 44 lb,readable to 1 g 0.0002 lbm.5.2.3 Oven, capable of heating to 177 6 3C 350 6 5F.5.2.
22、4 Straightedge, steel, approximately 450 mm 18 in. inlength.5.2.5 Flat Plate, metal or wood, having an area slightlylarger than the sample pan. The metal plate shall have aminimum thickness of 10 mm 38 in. The wooden plate shallhave a minimum thickness of 20 mm 34 in.5.2.6 Assorted Spoons and Mixing
23、 Bowls.5.2.7 Thermometer with a temperature range of 10 to250C 50 to 482F.5.3 Additional Apparatus for Test Method B:5.3.1 Molded Laboratory Specimen Container, (provided byinstrument manufacturer) to allow for proper testing of labo-ratory compacted samples (see Fig. 1).5.3.2 Apparatus, necessary t
24、o prepare compacted specimensas specified in Test Methods D1559, D1561, D3387,orPractice D4013.6. Hazards6.1 WarningThis equipment utilizes radioactive materi-als which may be hazardous to the health of the users unlessproper precautions are taken. Users of this equipment mustbecome completely famil
25、iar with possible safety hazards andwith all applicable regulations concerning the handling and useof radioactive materials. Effective user instructions togetherwith routine safety procedures are a recommended part of theoperation of this apparatus.7. Sampling7.1 Obtain random samples of aggregates
26、in accordancewith Practice D75.7.2 Obtain random samples of freshly produced bituminouspaving mixture in accordance with Practice D979.7.3 Obtain random samples of bituminous materials inaccordance with Practice D140.8. Calibration8.1 The test results obtained using this test method will beinfluence
27、d by the types of aggregate, source, and grade ofasphalt, and by the mix gradation. Accordingly, a calibrationcurve must be developed for each mix type and aggregateblend to be tested under this test method.8.1.1 A new calibration curve shall be developed wheneverthere is a change in the source of a
28、sphalt or aggregate or asignificant change in aggregate gradation.8.1.2 Anew calibration curve shall be established for new orrepaired apparatus.8.2 For Test Method A, calibrate the apparatus using thefollowing procedures:8.2.1 Sample the aggregates in accordance with 7.1 andblend the aggregates in
29、the proper proportions. Obtain enoughaggregate for a minimum of three samples. Approximately 30kg 65 lb will be required, and8.2.2 Sample the bituminous materials in accordance with7.3. Approximately 2.5 kg 5.5 lb will be required.FIG. 1 Molded Laboratory Specimen-Containers MeasurementValues in SI
30、Units (CM)Other Values for Reference OnlyD4125/D4425M 1028.3 Use a minimum of three prepared samples to establishthe calibration curve. The range of asphalt contents shall varyby at least two percent asphalt content from the lowest to thehighest contents in the samples. The range shall encompass the
31、asphalt content of the proposed mix design. The mass of thesamples shall be within 10 g 0.02 lb of each other.8.3.1 Unless the apparatus makes provision for temperaturecorrections, all calibration samples shall be tested at a uniformtemperature, within 65C 9F. Calibration samples shouldbe prepared a
32、nd tested as close as possible to the temperatureof test samples of completed mixes.8.4 Prepare a blank sample (sample of hot, dry aggregatewithout asphalt) to determine the mass to be used for calibra-tion and plant mix samples. Using this mass will ensure thesame average density for all test sampl
33、es.8.4.1 Thoroughly mix at least 10 kg 22 lb of the aggregateafter heating and drying it to a constant mass and temperature.8.4.2 Fill a sample pan with the aggregate in two or threelayers, avoiding segregation. Using a scoop or spatula, distrib-ute the aggregate to reduce voids and segregation. For
34、 eachlayer raise the pan approximately 20 to 50 mm 1 to 2 in. fromthe working surface and tap the pan against the workingsurface two or three times to settle the contents. Fill the pan toa point slightly above the top edge. Slide a straightedge alongthe top of the pan until the aggregate is absolute
35、ly flush withthe top edge of the pan. (CautionDo not compact thesample.)8.4.3 Determine the mass of the blank sample to the nearestgram and record data. Use this mass for all calibration andplant mix test samples. (See Note 2.)8.4.4 Place the pan containing the blank sample in theapparatus and take
36、a measurement in accordance with themanufacturers instructions.8.4.5 Record the blank sample count.8.4.6 To detect changes in aggregate that may affect testresults, a sample of aggregate may be prepared and tested eachday as described herein. If a significant change in the count60.5 % has occurred,
37、then check the calibration as describedin 9.3. If necessary, prepare a new calibration curve as outlinedin 8.5 (see Note 1).NOTE 1Batch plant hot bin samples may be used to obtain the dryaggregate count. Care must be taken to ensure that the aggregate iscompletely dried and properly mixed before tes
38、ting when using hot binsamples.8.5 Prepare a minimum of three calibration samples usingthe following procedures:8.5.1 Heat the aggregates and asphalt cement to approxi-mately 150C 300F. Heat all bowls, sample pans, and toolsto approximately 150C 300F.8.5.2 To prevent samples from being biased by res
39、idualasphalt retained in the mixing bowl, do not clean the bowl aftereach mixing of the samples. Scrape it clean, leaving a coatingof asphalt mix residue. This allows for a more accurate mixingof samples. Prior to mixing the first sample, a mixture ofasphalt and aggregate fines may be used as a ligh
40、t coating onthe interior of the mixing bowl.8.5.3 Using an aggregate sample of sufficient size to fill thesample pan, add the proper amount of asphalt (within 1 g0.002 lb of desired percent by mass) and mix thoroughly inthe mixing bowl.8.5.4 Fill the sample pan in three layers. After placing eachlay
41、er in the sample pan, using a scoop or spatula, distribute thelayer of material evenly in the pan to reduce voids andsegregation. Lift the pan approximately 20 to 50 mm 1 to 2in. and tap it on the working surface two or three times tosettle the contents. The last layer should fill the pan to a point
42、slightly above the top edge.8.5.5 Determine the mass of the sample and add or subtractmaterial until the mass is within 10 g 0.02 lb of the mass ofthe blank sample.NOTE 2The mass of the blank sample may not be sufficient tocompletely fill the calibration and plant mix test sample pans for all mixes.
43、The asphalt cement may act as a lubricant allowing additional consolida-tion of the aggregate particles. An adjusted blank sample mass may bedetermined by preparing a calibration sample using these procedures andusing the mass of this sample as the blank sample mass for this and allremaining samples
44、.8.5.6 Using a flat plate of wood or metal as a press,compress the sample until it is level with the top edge of thepan. Waxed paper may be used under the press to preventasphalt sticking to the press. (CautionThis is the onlycompactive effort the sample should receive.)8.5.7 Place the sample in the
45、 apparatus and take a timedmeasurement in accordance with the manufacturers instruc-tions.8.5.8 Repeat this process for the remainder of the calibrationsamples.8.6 For Test Method B calibrate the apparatus using thefollowing procedures:8.6.1 Sample the aggregates in accordance with 7.1 andprepare fo
46、r blending in accordance with the laboratory com-pacted method to be used,8.6.2 Sample the bituminous materials in accordance with7.3.8.6.3 At a minimum of four (4) known asphalt contents,prepare at least three (3) compacted specimens using TestMethods D1559, D1561, D3387, or Practice D4013. Vary th
47、erange of asphalt contents by at least 2 % from the lowest to thehighest. The masses of each set of replicate specimens shall bewithin 10 g 0.02 lb of each other.NOTE 3Specimens prepared for other purposes such as determiningthe laboratory mix design of bituminous mixtures may be used in thisprocedu
48、re, however, no other testing of the specimens should be doneprior to performing this procedure.8.6.3.1 Determine the mass of each specimen to the nearestgram,8.6.4 For 10 cm 4 in. specimens, select the two (2)specimens at each asphalt content having the mass nearest eachother. For 15 cm 6 in. speci
49、mens, select the one (1) specimenof each set that has a mass closest to the mass of the otherspecimens to be tested. The specimens not used in this processshould be retained for use in other testing procedures inaccordance with Note 3,D4125/D4425M 1038.6.5 Place the specimens in the molded laboratory speci-men container and place the container in the apparatus. Taketimed measurements in accordance with the manufacturersinstructions, and8.6.6 Repeat this process with each of the other three sets ofcalibrati
