1、Designation: D8188 18Standard Test Method forDetermination of Density and Relative Density of Asphalt,Semi-Solid Bituminous Materials, and Soft-Tar Pitch by Useof a Digital Density Meter (U-Tube)1This standard is issued under the fixed designation D8188; the number immediately following the designat
2、ion indicates 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 determ
3、ination of the relativedensity and density of semi-solid asphalt materials, asphaltbinders, asphalt cements, and soft-tar pitches by use of a digitaldensity meter (U-tube).NOTE 1Alternate methods for determining the density of semi-solidand solid asphalt materials and asphalt binders include Test Me
4、thodsD3289, D3142/D3142M, and D70.1.2 The values stated in SI units are to be regarded asstandard. The values given in parentheses are for informationonly. No other units of measurement are included in thisstandard, with the exception of temperature measurements.Units provided in degrees Fahrenheit
5、are for reference pur-poses only. Temperatures given in degrees Celsius are to beconsidered standard.1.3 The between-laboratory reproducibility of this testmethod is being determined and will be available on or beforeJune 2021. Therefore, this standard should not be used foracceptance or rejection o
6、f a material for purchasing purposes.1.4 This test method should not be applied to petroleumdistillates other than asphalt and asphalt binders. For thedetermination of density of all other petroleum distillates andviscous oils, use Test Method D4052 or D5002, or ISO 12185.1.5 The text of this standa
7、rd references notes and footnoteswhich provide explanatory material. These footnotes (exclud-ing those in tables and figures) shall not be considered asrequirements of the standard.1.6 This standard does not purport to address all of thesafety concerns, if any, associated with its use. It is theresp
8、onsibility of the user of this standard to establish appro-priate safety, health, and environmental practices and deter-mine the applicability of regulatory limitations prior to use.1.7 This international standard was developed in accor-dance with internationally recognized principles on standard-iz
9、ation established in the Decision on Principles for theDevelopment of International Standards, Guides and Recom-mendations issued by the World Trade Organization TechnicalBarriers to Trade (TBT) Committee.2. Referenced Documents2.1 ASTM Standards:2D8 Terminology Relating to Materials for Roads and P
10、ave-mentsD70 Test Method for Density of Semi-Solid Asphalt Binder(Pycnometer Method)D140/D140M Practice for Sampling Asphalt MaterialsD287 Test Method for API Gravity of Crude Petroleum andPetroleum Products (Hydrometer Method)D1250 Guide for Use of the Petroleum Measurement TablesD1298 Test Method
11、for Density, Relative Density, or APIGravity of Crude Petroleum and Liquid Petroleum Prod-ucts by Hydrometer MethodD3142/D3142M Test Method for Specific Gravity, APIGravity, or Density of Cutback Asphalts by HydrometerMethodD3289 Test Method for Density of Semi-Solid and SolidAsphalt Materials (Nick
12、el Crucible Method)D3666 Specification for Minimum Requirements for Agen-cies Testing and Inspecting Road and Paving MaterialsD4052 Test Method for Density, Relative Density, and APIGravity of Liquids by Digital Density MeterD4311/D4311M Practice for Determining Asphalt VolumeCorrection to a Base Te
13、mperatureD5002 Test Method for Density and Relative Density ofCrude Oils by Digital Density AnalyzerD6792 Practice for Quality Management Systems in Petro-leum Products, Liquid Fuels, and Lubricants TestingLaboratoriesD7578 Guide for Calibration Requirements for ElementalAnalysis of Petroleum Produc
14、ts and Lubricants1This test method is under the jurisdiction of ASTM Committee D04 on Roadand Paving Materials and is the direct responsibility of Subcommittee D04.47 onMiscellaneous Asphalt Tests.Current edition approved July 1, 2018. Published July 2018. Originally approvedin 2018. DOI: 10.1520/D8
15、188-18.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.Copyright ASTM International, 100 Barr Harbor Drive, P
16、O Box C700, West Conshohocken, PA 19428-2959. United StatesThis international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for theDevelopment of International Standards, Guides and Recommendations issued
17、by the World Trade Organization Technical Barriers to Trade (TBT) Committee.1D7961 Practice for Calibrating U-tube Density Cells overLarge Ranges of Temperature and Pressure2.2 ISO Standard:3ISO 12185 Crude Petroleum and Petroleum ProductsDetermination of DensityOscillating U-Tube Method3. Terminolo
18、gy3.1 Definitions:3.1.1 certified reference material (CRM), na referencematerial whose one or more property values are certified by atechnically valid procedure, accompanied by a traceable cer-tificate or other documentation which is issued by a certifyingbody, as defined in Practice D6792 and Guide
19、 D7578.3.1.2 density, nthe mass per unit volume of a material at aspecified temperature.3.1.3 relative density, nthe ratio of the density of amaterial at a stated temperature to the density of water at astated temperature.3.1.3.1 DiscussionRelative density is also known as “spe-cific gravity.” Commo
20、n stated temperatures are 20 C 20 C,15 C 15 C, 20 C 4 C, and 60 F 60 F.3.1.4 For definitions of general terms used in this standard,refer to Terminology D8.3.2 Definitions of Terms Specific to This Standard:3.2.1 adjustment, vthe operation of bringing the instru-ment to a state of performance suitab
21、le for its use, by setting oradjusting the density meter constants.3.2.1.1 DiscussionOn some digital density meters, an“adjustment” procedure may be performed rather than “cali-bration.” The adjustment procedure uses air and oil-basedcertified reference material as standards to establish the linear-
22、ity of measurements over a range of operating temperatures.3.2.2 test specimen, nthe volume of sample aliquot resid-ing in the U-tube during the measurement cycle.3.2.2.1 DiscussionSample material residing in fillingnozzles, tubing, and valve manifolds is not considered a “testspecimen.” A test spec
23、imen can be measured only once.4. Summary of Test Method4.1 A small volume, approximately 3 to 4 mL, of liquid hotsample is introduced into an oscillating U-shaped tube. Intro-duction of samples into the U-tube changes the oscillatingfrequency. The change in the frequency is used to determinethe den
24、sity, relative density, or API gravity of the sample.5. Significance and Use5.1 Values of density are used for converting volumes tounits of mass and for correcting measured volumes at themeasured temperature to a standard temperature using PracticeD4311/D4311M.NOTE 2The quality of the results produ
25、ced by this standard aredependent on the competence of the personnel performing the procedureand the capability, calibration, and maintenance of the equipment used.Agencies that meet the criteria of Specification D3666 are generallyconsidered capable of competent and objective testing, sampling,insp
26、ection, etc. Users of this standard are cautioned that compliance withSpecification D3666 alone does not completely ensure reliable results.Reliable results depend on many factors; following the suggestions ofSpecification D3666 or some similar acceptable guideline provides ameans of evaluating and
27、controlling some of those factors.6. Apparatus6.1 Digital Density MeterA digital density meter consistsof a U-shaped oscillating sample tube, temperature controlunit, and a system for electronic excitation, frequencycounting, and display. The analyzer shall accommodate theaccurate measurement of the
28、 sample temperature during mea-surement. The instrument shall be capable of meeting theprecision requirements described in this test method.6.2 Syringes, made of glass or PFA (perfluoroalkoxy al-kane). For use primarily in manual injections, which withstandelevated temperatures, at least 10 mL in vo
29、lume, with a tip oran adapter tip that will fit the opening of the U-tube.7. Reagents and Materials7.1 Purity of ReagentsReagent-grade chemicals shall beused in all tests. Unless otherwise indicated, it is intended thatall reagents shall conform to the specifications of the Commit-tee on Analytical
30、Reagents of the American Chemical Society,where such specifications are available.4Other grades may beused, provided it is first ascertained that the reagent is ofsufficiently high purity to permit its use without lessening theaccuracy of the determination.7.2 Cleaning Solvent, such as petroleum nap
31、htha, or othermaterials (for example, toluene or mesitylene) (WarningPetroleum naphtha, toluene, and mesitylene are extremelyflammable) that are capable of flushing and removing sampleresidue entirely from the U-tube and have a boiling pointhigher than the measuring temperature.8. Sampling, Test Spe
32、cimens, and Test Units8.1 Take samples in accordance with Practice D140/D140M. The sample shall be free of foreign substances.8.2 Thoroughly mix and homogenize the sample beforeremoving a representative portion for testing. Ensure mixingdoes not introduce air bubbles into the sample.8.3 Test Specime
33、nA portion or volume of homogeneoussample aliquot delivered to the density analyzer U-tube.9. Preparation of Apparatus9.1 Set up the oscillating U-tube density meter, followingthe manufacturers instructions. Adjust the instrument at thesame temperature at which the density or relative density of the
34、sample is to be measured.3Available from International Organization for Standardization (ISO), ISOCentral Secretariat, BIBC II, Chemin de Blandonnet 8, CP 401, 1214 Vernier,Geneva, Switzerland, http:/www.iso.org.4Reagent Chemicals, American Chemical Society Specifications, AmericanChemical Society,
35、Washington, DC. For suggestions on the testing of reagents notlisted by the American Chemical Society, see Analar Standards for LaboratoryChemicals, BDH Ltd., Poole, Dorset, U.K., and the United States Pharmacopeiaand National Formulary, U.S. Pharmaceutical Convention, Inc. (USPC), Rockville,MD.D818
36、8 18210. Adjustment of Apparatus10.1 The adjustment routine for digital density metersinvolves using a minimum of two reference media. Air andoil-based certified reference materials (CRMs) with densityvalues at relevant temperatures are usually used for adjustmentunder atmospheric conditions. Other
37、materials such as decane,dichlorotoluene, or toluene can also be used as appropriateadjustment materials, provided that the reference materialshave density values that are certified and traceable to nationalstandards (compare to Practice D7961).10.2 Follow the manufacturers instructions for the prop
38、eradjustment of the apparatus. The density of air varies withambient pressure and relative humidity. The relative humidityof air above 100 C is 0, therefore, the formula is simplified.The air density can be calculated using this formula by F.Spieweck and H. Bettin:5 50.34844*p273.151T(1)where: = den
39、sity (kg/m3),p = pressure (mbar), andT = temperature (C).11. Procedure11.1 Preparation of SampleHeat the sample with care,stirring to prevent local overheating, until the sample hasbecome sufficiently fluid to pour. In no case should thetemperature be raised to more than 55 C (131 F) above theexpect
40、ed softening point for soft-tar pitch, or to more than110 C (230 F) above the expected softening point for asphalt.Do not heat for more than 60 min, and avoid incorporating airbubbles into the sample.11.2 Draw an aliquot of sample slowly into a clean and drysyringe. It is recommended to pre-heat gla
41、ss and PFA syringesto the same temperature as the test specimen; however, cautionshould be exercised in heating medical plastic syringes. Takeprecautions to keep the tip of the syringe clean and preventinclusion of air bubbles. Fill the sample slowly into the U-tubedensity analyzer and start the mea
42、surement. Ensure sampledoes not experience significant temperature drop duringinjection, as the injection port may get clogged or samplemight lose its homogeneity.11.3 Ensure that the U-tube sample tube is properly filledand that no gas bubbles are present. The sample must be freeof even the smalles
43、t gas bubbles. Check the integrity of thefilled sample by measuring a duplicate test specimen.NOTE 3The presence of bubbles may result in the instrument failingto stabilize, which is necessary to provide a density reading.11.4 Start the measurement according to the manufacturersinstructions.11.5 All
44、ow the sample to equilibrate to the test temperaturebefore recording the density result or relative density. Forinstruments that can print out results from the display, theprintout can be used to meet the recording requirements.11.6 Flush the U-tube with a proper cleaning solvent (see7.2) and dry wi
45、th dry air. Allow the dry air in the U-tube tocome to thermal equilibrium with the test temperature andcompare the density value to the density of air using Eq 1.NOTE 4Some solvents may give vapors at higher temperatures, whichmight require a fume hood. Take precautions when flushing the U-tubewith
46、cleaning solvent. The boiling point of the used cleaning solvent shallbe at least 10 C above the measuring temperature. Handling solvents atboiling or near-boiling temperature can present a safety hazard. Wearappropriate personal protective equipment.12. Calculation or Interpretation of Results12.1
47、Calculating Density by AnalyzersThe recorded orprinted value is the final result when a single determination isconducted, expressed either as density in kg/m3or as relativedensity.12.2 If it is necessary to convert a result obtained at themeasuring temperature using the density meter to the reportin
48、gtemperature of 15.6 C (60 F), Practice D4311/D4311M shallbe used.12.3 If it is necessary to convert a result obtained by thedigital density meter to API gravity, or a density or relativedensity at another temperature, Guide D1250 can be used, onlyif the glass expansion factor has been excluded.NOTE
49、 5Some digital density meters are equipped to automaticallycalculate and report sample results in API gravity units (see Test MethodD287 or D1298), based on the density or relative density results, or acombination thereof, determined by this test method and using theappropriate conversion equation derived from Guide D1250 (whichexcludes the glass expansion factor) for the specific sample type beinganalyzed.13. Report13.1 Report density to the nearest 0.3 kg m3at the referencetemperature of 15.6 C (60 F).14. Precision and Bias14.1 The
