1、Designation: E1845 09Standard Practice forCalculating Pavement Macrotexture Mean Profile Depth1This standard is issued under the fixed designation E1845; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last revision. A
2、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 practice covers the calculation of mean profiledepth from a profile of pavement macrotexture.1.2 The mean profile depth has been s
3、hown to be useful inpredicting the speed constant (gradient) of wet pavementfriction.21.3 A linear transformation of the mean profile depth canprovide an estimate of the mean texture depth measuredaccording to Test Method E965.1.4 The values stated in SI units are to be regarded asstandard. No other
4、 units of measurement are included in thisstandard.1.5 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 health practices and determine the applica-bility of
5、regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:3E965 Test Method for Measuring Pavement MacrotextureDepth Using a Volumetric Technique2.2 ISO Standard:ISO 13473-1 AcousticsCharacterization of PavementTexture using Surface ProfilesPart 1: Determination ofMean Profile De
6、pth43. Terminology3.1 Definitions:3.1.1 baselength, nlength of a segment of a pavementmacrotexture profile being analyzed, required to be 100 mm inthis practice.3.1.2 estimated texture depth (ETD), nestimate of themean texture depth (MTD), by means of a linear transforma-tion of the mean profile dep
7、th (MPD).3.1.3 mean profile depth (MPD), naverage of all the meansegment depths of all of the segments of the profile.3.1.4 mean segment depth, naverage value of the profiledepth of the two halves of a segment having a given base-length.3.1.5 mean texture depth (MTD), nmean depth of thepavement surf
8、ace macrotexture determined by the volumetrictechnique of Test Method E965.3.1.6 profile depth (PD), ndifference between the ampli-tude measurements of pavement macrotexture and a horizontalline through the top of the highest peak within a givenbaselength.4. Summary of Practice4.1 This practice uses
9、 a measured profile of the pavementmacrotexture.4.2 The measured profile is divided for analysis purposesinto segments each having a baselength of 100 mm. The slope,if any, of each segment is suppressed by subtracting a linearregression of the segment. The segment is further divided inhalf and the h
10、eight of the highest peak in each half segment isdetermined. The difference between that height and the averagelevel of the segment is calculated. The average value of thesedifferences for all segments making up the measured profile isreported as the MPD.5. Significance and Use5.1 This practice is s
11、uitable for the calculation of theaverage macrotexture depth from profile data. The results ofthis calculation (MPD) have proven to be useful in theprediction of the speed dependence of wet pavement friction.25.2 The MPD can be used to estimate the result of ameasurement of macrotexture depth using
12、a volumetric tech-nique according to Test Method E965. The values of MPD and1This practice is under the jurisdiction of Committee E17 on Vehicle - PavementSystems and is the direct responsibility of Subcommittee E17.23 on SurfaceCharacteristics Related to Tire Pavement Slip Resistance.Current editio
13、n approved Nov. 1, 2009. Published December 2009. Originallyapproved in 1996. Last previous edition approved in 2005 as E1845 01 (2005)1.DOI: 10.1520/E1845-09.2Wambold, J. C., Antle, C. E., Henry, J. J., and Rado, Z., International PIARCExperiment to Compare and Harmonize Texture and Skid Resistance
14、 Measure-ments, Final report, Permanent International Association of Road Congresses(PIARC), Paris 1995.3For 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 standard
15、s Document Summary page onthe ASTM website.4Available from International Organization for Standardization (ISO), 1, ch. dela Voie-Creuse, Case postale 56, CH-1211, Geneva 20, Switzerland, http:/www.iso.ch.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-
16、2959, United States.MTD differ due to the finite size of the glass spheres used in thevolumetric technique and because the MPD is derived from atwo-dimensional profile rather than a three-dimensional sur-face. Therefore a transformation equation must be used.5.3 This practice may be used with paveme
17、nt macrotextureprofiles taken on actual road surfaces or from cores orlaboratory prepared samples.5.4 Aggregate size, shape, and distribution are featureswhich are not addressed in this practice. This practice is notmeant to provide a complete assessment of texture character-istics. In particular, c
18、are should be used when interpreting theresult for porous or grooved surfaces.5.5 This practice does not address the problems associatedwith obtaining a measured profile. Laser or other opticalnoncontact methods of measuring profiles are usually pre-ferred. However, contact methods using a stylus al
19、so canprovide accurate profiles if properly performed.6. Profile Requirements6.1 Amount of Data Required:6.1.1 Ideally, a continuous profile made along the entirelength of the test section should be used if possible.6.1.2 A minimum requirement shall be ten evenly spacedprofiles of 100 mm in length f
20、or each 100 m of the test section.However, for a uniform test section, it is sufficient to obtain 16evenly spaced profiles regardless of test section length. Forsurfaces having periodic texture (that is, grooved or tinedsurfaces) the total profile length shall include at least tenperiods of the text
21、ure.NOTE 1When characterizing a long test section with relatively shortsample lengths, it is important to ensure that the texture is sufficientlyhomogeneous to provide a representative measure. It is necessary for theuser to use sound judgment to determine the minimum number of samplesto characteriz
22、e a nonhomogeneous pavement.NOTE 2The texture of pavements that have been in service variesacross the pavement. In this case the transverse location of the measure-ments shall be determined by the intended use of the data.6.1.3 In the case of laboratory samples (either cores orrectangular slabs) the
23、 minimum requirement shall be at leastten profiles having a length of 100 mm evenly distributed overthe surface of the sample. Care should be taken to avoid edgeeffects. For this reason, samples having a characteristic lengthof at least 150 mm are recommended.NOTE 3Measurements on laboratory samples
24、 have many differentpurposes. Therefore it is difficult to specify general minimum require-ments. The specification here assumes that the purpose is to obtain valueswhich are reasonably representative of pavements.6.2 Resolution:6.2.1 Vertical resolution shall be at least 0.05 mm. Verticalrange shal
25、l be no less than 20 mm and vertical nonlinearityshall be no greater than 2 % of the range.NOTE 4For stationary devices on smooth pavements a lesser rangemay be used. In this case, non-linearity need not exceed the aboverequirement of 0.4 mm. The higher range is usually required to allow fora sensor
26、 mounted on a moving vehicle.6.2.2 Maximum spot size for a laser or other electro-opticaldevice shall be no greater than 1 mm. The stylus in a contactdevice shall have a tip having a major diameter no greater than1 mm.6.2.3 The sampling interval shall not be more than 1 mm.Variations of the sampling
27、 interval shall not be more than610 %. This requires that the sensor speed over the surface bemaintained within 610 % whether the device is stationery ormounted on a moving vehicle.6.3 The angles between the radiating emitting device andthe surface and between the radiation receiving device and thes
28、urface shall be no more than 30. The angle of the stylusrelative to the surface shall be no more than 30. Larger angleswill underestimate deep textures.6.4 Calibration shall be made using calibration surfaceshaving a known profile.The vertical accuracy of the calibrationsurface in relation to its th
29、eoretical profile shall be at least 0.05mm. The calibration shall be designed to provide a maximumerror of 5 % or 0.1 mm, whichever is lower.NOTE 5One suitable calibration surface is a surface machined toobtain a triangular profile with a peak-to-peak amplitude of 5 to 20 mm.This gives an indication
30、 of not only the amplitude, but also the nonlin-earity and the texture wavelength scale.7. Data Processing7.1 OutliersInvalid readings may be caused by dropoutsas a result of deep surface troughs or local photometricproperties of the surface. For this reason, those readings shouldbe eliminated when
31、their value is higher or lower than therange of the profile surrounding their location. The invalidvalue for that location shall be replaced with a value interpo-lated between the previous and following location. The maxi-mum proportion of outliers shall be 20 %. When the proportionexceeds 10 %, cau
32、tion should be used in interpreting the dataand the proportion of invalid readings shall be reported.7.2 Lowpass FilteringTo reduce the influence of noiseand transients and to have a relatively uniform influence ofnarrow profile peaks, the profile shall be filtered to removehigh frequency components
33、. Spatial frequency componentsabove 400 cycles per metre that correspond to a texturewavelength of 2.5 mm shall be removed. Spatial frequenciesbelow 200 cycles per metre that correspond to a texturewavelength of 5 mm shall not be affected by the filter.Attenuation shall be at least 3 dB at 2.5 mm an
34、d no morethan 1 dB at 5 mm with a slope of at least 6 dB per octave.The filtering may be achieved with a digital filter or with anelectronic filter. All or part of the filtering may be achieved bythe effect of the finite size of the sensor spot or stylus tip.7.3 Segmenting the ProfileThe measured pr
35、ofile shall bedivided into segments of 100 6 2 mm for analysis in thesubsequent steps of this practice. See Fig. 1.7.4 Slope SuppressionA linear regression of the profilevalues for each segment shall be performed and the regressionline shall be subtracted from the profile values of the segment.This
36、will produce a segment with a zero mean and suppress theslope of the segment, if any.7.5 Peak DeterminationEach segment shall be furtherdivided into two equal lengths of 50 mm and the maximumvalue of the profile shall be determined for each of the 50-mmsubsegments. These two values shall be averaged
37、 arithmeti-cally to obtain the mean segment depth. See Fig. 1.NOTE 6Some devices invert the profile so that it is necessary toE1845 092ensure that the profile for the segment being analyzed has the peaks asthose asperities with the highest positive value.7.6 Determination of MPDThe average value of
38、the meansegment depths for all segments of the measured profile shallbe averaged to obtain the mean profile depth (MPD).7.7 Calculation of ETD (optional)The MPD may betransformed to an estimated texture depth (ETD) by one of thefollowing transformation equations:2ETD 5 0.2 1 0.8 MPD (1)where:MPD and
39、 ETD are expressed in mm.The use of this transformation should yield ETD values thatare close to the MTD values of the volumetric techniqueaccording to Test Method E965.8. Report8.1 The test report for each test surface shall contain thefollowing items:8.1.1 Date of profile measurement;8.1.2 Locatio
40、n and identification of the test surface;8.1.3 Description of the surface type;8.1.4 Description of surface contamination that could not beavoided by cleaning, including moisture;8.1.5 Observations of surface condition such as excessivecracking, potholes, and so forth;8.1.6 The position of the profi
41、le on the surface, for examplein relation to the wheel track, and so forth;8.1.7 Identification of the profile equipment and its opera-tors;8.1.8 Type and date of calibration;8.1.9 Measurement speed;8.1.10 Percentage of invalid readings eliminated (dropouts);8.1.11 Total profile length and the numbe
42、r of segmentsanalyzed;8.1.12 Mean profile depth (MPD);8.1.13 Standard deviation of the mean segment depthswhich were averaged to obtain the MPD; and8.1.14 The estimated texture depth (ETD)optional.9. Precision and Bias9.1 PrecisionThe reproducibility using two different sys-tems and test crews was f
43、ound in the same experiment2to be0.15 mm corresponding to 10 % of the average MPD valuesincluded in the experiment.9.2 BiasThere is no basis for determination of the bias inmean profile depth. With respect to the MTD, the MPD isbiased by 0.2 mm that is due to the finite size of the glassspheres used
44、 in the volumetric technique.10. Keywords10.1 macrotexture profile; mean profile depth; mean texturedepthFIG. 1 Procedure for Computation of Mean Segment DepthE1845 093ASTM International takes no position respecting the validity of any patent rights asserted in connection with any item mentionedin t
45、his standard. Users of this standard are expressly advised that determination of the validity of any such patent rights, and the riskof infringement of such rights, are entirely their own responsibility.This standard is subject to revision at any time by the responsible technical committee and must
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48、West Conshohocken, PA 19428-2959,United States. Individual reprints (single or multiple copies) of this standard may be obtained by contacting ASTM at the aboveaddress or at 610-832-9585 (phone), 610-832-9555 (fax), or serviceastm.org (e-mail); or through the ASTM website(www.astm.org). Permission rights to photocopy the standard may also be secured from the ASTM website (www.astm.org/COPYRIGHT/).E1845 094
