1、Designation: D2493/D2493M 09StandardViscosity-Temperature Chart for Asphalts1This standard is issued under the fixed designation D2493/D2493M; the number immediately following the designation indicates theyear of original adoption or, in the case of revision, the year of last revision. A number in p
2、arentheses indicates the year of lastreapproval. A superscript epsilon () indicates an editorial change since the last revision or reapproval.1. Scope1.1 The viscosity-temperature chart covered by this stan-dard is a convenient means of plotting data for estimating theviscosity of asphalts at any te
3、mperature within a limited range.Conversely, the chart may be used to ascertain the temperatureat which a desired viscosity is attained.1.2 The chart is suitable for original asphalt cements and forasphalts recovered from laboratory aging tests or extractedfrom pavements.1.3 The chart is based on a
4、viscositytemperature relation-ship that can be plotted using any appropriate set of units. Forconvenience, charts based on both conventional and SI unitsare provided.1.4 The range of the chart is sufficient for roofing asphalts.1.5 The range of the chart is sufficient for liquid asphalts(bitumens) w
5、hose viscosity exceeds 0.01 Pa.S (10 centipoise).1.6 The values stated in either SI units or inch-pound unitsare to be regarded separately as standard. The values stated ineach system may not be exact equivalents; therefore, eachsystem shall be used independently of the other. Combiningvalues from t
6、he two systems may result in non-conformancewith the standard.2. Referenced Documents2.1 ASTM Standards:2D341 Practice for Viscosity-Temperature Charts for LiquidPetroleum ProductsD2170 Test Method for Kinematic Viscosity of Asphalts(Bitumens)D2171 Test Method for Viscosity of Asphalts by VacuumCapi
7、llary ViscometerD3205 Test Method for Viscosity of Asphalt with Cone andPlate Viscometer3D4402 Test Method for Viscosity Determination of Asphaltat Elevated Temperatures Using a Rotational ViscometerD4957 Test Method for Apparent Viscosity of AsphaltEmulsion Residues and Non-Newtonian Bitumens byVac
8、uum Capillary Viscometer3. Significance and Use3.1 The viscosity-temperature chart is a convenient meansof plotting the viscosity data for estimating the viscosity ofasphalts, recovered asphalts, and roofing asphalts at anytemperature within a limited range. It is also a convenientmeans to estimate
9、the temperature at which a desired viscosityis attained. Charts may be constructed manually or usingcomputer graphing software.3.2 Kinematic viscosity-temperature charts are described inCharts D341.4. Description4.1 For Fig. 1, the chart coordinates are logarithm of thelogarithm of the viscosity in
10、mPa.S as the ordinate, andlogarithm of the absolute temperature in degrees Kelvin(degrees C + 273.2) as the abscissa. However, the viscosity inPa.S and the temperature in degrees Celsius is shown in thechart for convenience.1 Pa.s 5 mPa.s 3 103! (1)4.2 For Fig. 2, the chart coordinates are logarithm
11、 of thelogarithm of the viscosity in centipoise as the ordinate, andlogarithm of the absolute temperature in degrees Rankine(degrees F + 459.7) as the abscissa. However, viscosity inpoise, and the temperature in degrees Fahrenheit is shown inthe chart for convenience.4.3 The temperature range of the
12、 charts may be extended orabbreviated as necessary.5. Procedure5.1 If the viscosities are not known they should be deter-mined in accordance with Test Methods D2170, D2171,D3205, D4402,orD4957. Viscosities determined at tempera-tures other than the temperatures specified in each of these testmethods
13、 may be used.5.2 For temperatures above 60C 140F, plot twoviscosity-temperature points and carefully draw a straight linethrough the points. Plot at least three viscosity-temperature1This chart is under the jurisdiction of ASTM Committee D04 on Road andPaving Materials and is the direct responsibili
14、ty of Subcommittee D04.44 onRheological Tests.Current edition approved Dec. 1, 2009. Published January 2010. Originallyapproved in 1966. Last previous edition approved in 2001 as D2493 011. DOI:10.1520/D2493_D2493M-09.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact AS
15、TM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.3Withdrawn. The last approved version of this historical standard is referencedon www.astm.org.1Copyright ASTM International, 100 Barr Harbor D
16、rive, PO Box C700, West Conshohocken, PA 19428-2959, United States.points if the included temperature range is below 60C140F. Carefully draw a straight line or curve through thepoints.Apoint on this line, within the temperature range of thepoints plotted, shows the viscosity at the corresponding des
17、iredtemperature.NOTE 1These charts are appropriate for use at higher temperatures,where asphalts are primarily viscous.At lower temperatures most asphaltsbecome viscoelastic. When this occurs, viscosity alone is insufficient todescribe an asphalts flow properties. Most asphalts are primarily viscous
18、at temperatures above 60C 140F. Caution should be used whenapplying this standard below that temperature.NOTE 2Some asphalts have viscosity-temperature relationships toocomplex to be represented by only three points, as shown in Fig. 1. In thiscase determine the viscosity at sufficient temperatures
19、to produce a curveadequate for the purpose intended.NOTE 3Viscosities determined by extrapolation of data may beunreliable5.3 The viscosity values represented by the data points mayhave been obtained at different shear rates. This chart does notreflect the shear rate at which the viscosities were de
20、termined.6. Keywords6.1 asphalt; rheology; viscosity; viscosity-temperature chartFIG. 1 Viscosity-Temperature Chart for Asphalts on Which a Typical Experimental Curve Has Been PlottedD2493/D2493M 092APPENDIX(Nonmandatory Information)X1. SUGGESTIONS FOR DATA ANALYSISX1.1 The chart in Fig. 1 includes
21、the region where theviscosity of asphalts depends not only on the temperature, butalso on the shearing conditions. Therefore, the data plotted onthe viscosity-temperature chart must be obtained under stan-dardized shearing conditions, for example, at the same shearrate, or the same shear stress. Con
22、stant shearing conditions alsoimplies the use of the same viscometer, or viscometers of thesame type and size, to avoid differences in viscosity valuescaused by differences in the extent of breakdown of themicellar structure of the asphalt due to shearing in themeasurement process.X1.2 Asphalt visco
23、sities are often reported at an arbitraryshear rate of 0.05 s1. Interpolation or extrapolation of mea-sured viscosity data is often required to obtain values for thisshear rate. A useful model for interpolating or extrapolatingasphalt rheological measurements is the empirical “PowerLaw” relationship
24、:t5h1gc(X1.1)where:t = the shearing stress,g = the rate of shear,h1= the apparent viscosity at a shear rate of 1 s1, andc = the slope of a plot of log t versus log g .The parameter c is called the Complex Flow Index, and is anindicator of the rheological character of the material. ForNewtonian liqui
25、ds, whose viscosity does not vary with shearFIG. 2 Viscosity-Temperature Chart for Asphalts on Which a Typical Experimental Curve Has Been PlottedD2493/D2493M 093rate, c =1. If c 1, the apparent viscosityincreases with shear rate.X1.3 Because a small error in the value of c can cause alarge error in
26、 an extrapolated viscosity value, it is recom-mended that the Power Law slope be determined usingreplicate tests on the material. The average value of c can bedetermined by regression analysis of the log t versus log gdata. If the data for replicate tests do not superimpose on a plotof all the data
27、on the same chart, the calibration and operatingprocedure for the viscometer should be checked before pro-ceeding further with the data analysis. If there are a smallnumber of outliers, these can be discarded, and the remainderof the data used in the regression analysis. Fig. X1.1 shows anexample of
28、 data containing outliers that should be ignored.X1.3.1 The objective of screening for outliers should be toretain all data that legitimately belong in the population ofresults characteristic of the test method used, and to eliminateonly those that differ so drastically that their inclusion distorts
29、the shear stress versus shear rate relationship. Therefore, thecriterion for rejecting data should be conservative. If a statis-tical technique is used, the significance level of the test shouldbe no greater than one percent.X1.4 Large extrapolations of rheological data to obtainvalues at constant s
30、hear rate are often unavoidable becausemost viscometers allow a limited range of shear stress, and thelarge variation in viscosity over a range of temperatures resultsin large differences in observed shear rate at different testtemperatures. A procedure which circumvents this problem isto plot the a
31、pparent viscosity at constant power input per unitvolume as a function of temperature. This avoids long extrapo-lations of the shear stress/shear rate relationships. H. E.Schweyer and others have recommended that apparent viscosi-ties at a constant power input of 100 W/m3be used. However,this value
32、has no theoretical significance, and may not beappropriate for all viscometers. A value which minimizes theamount of extrapolation needed to estimate the apparentviscosities in the temperature range of interest should beselected.X1.5 To estimate the apparent viscosity at constant powerinput, first d
33、etermine the Power Law constants h1and c froma plot or regression analysis of log shear stress versus log shearrate. Calculate the apparent viscosity at power input P from:hP5h1 FPh1Gc 2 1c 1 1(X1.2)where:hP= apparent viscosity, Pa.s at power input P, W/m3,h1= apparent viscosity, Pa.s at 1 s1shear r
34、ate, andc = complex flow index.X1.6 The effect of temperature on apparent viscosity can beshown by plotting the constant power input viscosities at twoor more temperatures on the chart in Fig. 1. Because of thenon-linearity of the scales on this chart, the viscosities must beplotted in the units sho
35、wn. Many asphalts will have a straightline viscosity versus temperature relationship on the chart.However, a minimum of 3 points should be plotted, to ensurethat the nature of the relationship is shown. Because of thepossibility of curvature, particularly at very high viscositylevels, extrapolation
36、is not recommended.X1.7 Alternatively, a regression analysis of log log h versuslog T (absolute temperature) can be performed. To be consis-tent with Fig. 1, the viscosity values must be converted tomPa.s or cP before taking the logarithms. A straight regressionline of this type is shown in Fig. X1.
37、2.FIG. X1.1 Power Law Shear Stress versus Shear RateRelationshipFIG. X1.2 Viscosity versus Temperature RelationshipD2493/D2493M 094ASTM International takes no position respecting the validity of any patent rights asserted in connection with any item mentionedin this standard. Users of this standard
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