1、Designation: E2666 09 (Reapproved 2014)Standard Practice forCorrelations of Mu Values of Continuous FrictionMeasurement Equipment to Determine Maintenance Levelsfor Use at Airports1This standard is issued under the fixed designation E2666; the number immediately following the designation indicates t
2、he 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 practice covers the method of calculating fr
3、ictionalvalues from correlations of continuous friction measurementequipment (CFME), using the Specification E1551 tire, for usein performing airport summer maintenance evaluations.1.2 The practice is intended to provide a unified frictionindex of levels for use in harmonizing the output of devices.
4、1.3 Airport operators use a variety of CFMEs to assess thefriction levels of their paved runway surfaces. The measure-ments are used to determine when the surfaces should beconsidered for or subjected to maintenance. However, manyare built differently and produce different values when mea-suring the
5、 same pavement surfaces. This practice provides amethod to harmonize these measurements so that the frictionvalues generated can be used to determine the maintenancerequirements as established by the operating authority.1.4 The practice provides correlations for four maintenancelevels of friction: N
6、ew Design/Construction with grooves, NewDesign/Construction without grooves, Maintenance Planning,and Minimum Acceptable.1.5 The values stated in SI units are to be regarded asstandard. No other units of measurement are included in thisstandard.1.6 ASTM International takes no position with respect t
7、othe validity of any patent rights asserted in connection with anyitem mentioned in this standard. Users of this standard areexpressly advised that determination of the validity of any suchpatent rights, and the risk of infringement of such rights, areentirely their own responsibility.1.7 This stand
8、ard 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 regulatory limitations prior to use.2. Referenced Documents2.1 AS
9、TM Standards:2E1551 Specification for Special Purpose, SmoothTreadTire, Operated on Fixed Braking Slip Continuous FrictionMeasuring EquipmentE1960 Practice for Calculating International Friction Indexof a Pavement SurfaceE2100 Practice for Calculating the International RunwayFriction Index2.2 Relate
10、d Documents3FAA Advisory Circular AC/150/5320-12 Measurement,Construction, and Maintenance of Skid Resistant AirportPavement SurfacesFriction Tester Manufacturers Instruction and ServicingManuals3. Terminology3.1 Definitions:3.1.1 brake force coeffcient (BFC), nfiltered mean of anumber of instantane
11、ous friction readings divided by thenormal force over a defined length.3.1.2 braking slip ratio, nratio of relative braking slipRPM to identical unbraked wheel RPM. An equivalent defini-tion is the ratio of the relative braking slip velocity to thehorizontal velocity of the wheel axle.3.1.3 continuo
12、us reading, fixed slip measuring equipment(CFME), nan apparatus that can be moved over the testsurface at the chosen test speed and that includes a test wheel,a system for retarding the test wheel and instrumentation formeasuring the resulting frictional force or the wheel torquebetween the test tir
13、e and test surface.1This practice is under the jurisdiction of ASTM Committee E17 on Vehicle -Pavement Systems and is the direct responsibility of Subcommittee E17.21 on FieldMethods for Measuring Tire Pavement Friction.Current edition approved Dec. 1, 2014. Published December 2014. Originallyapprov
14、ed in 2009. Last previous edition approved in 2009 as E2666 09. DOI:10.1520/E2666-09R14.2For 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 Summa
15、ry page onthe ASTM website.3Available from Federal Aviation Administration (FAA), 800 IndependenceAve., SW, Washington, DC 20591, http:/www.faa.gov.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States13.1.4 friction reading, nlongitudinal
16、force divided bynormal load or torque on the test wheel generated by longitu-dinal force divided by load times tire radius (moment arm).3.1.5 reporting length, ndefined length over which theBFC is calculated.3.1.6 standard test water film thickness, nwater flow ratedivided by the vehicle velocity ti
17、mes the width of application.3.2 Definitions of Terms Specific to This Standard:3.2.1 certifying calibration, nverification of testequipment, calibration equipment (separate or built-in), cali-bration procedures and equipment operation, recommended tobe performed once a year. This procedure records
18、both as foundvalues and adjusted values.3.2.2 field calibration, nprimary force calibration or theequivalent carried out before each test or series of tests by atrained operator using calibration equipment supplied by themanufacturer.3.2.3 routine friction testing, nmeasurement of the frictionof a s
19、urface under standardized test conditions, which normallyincludes a standard test speed and a rate of water flow whichgives a standard test water film thickness.3.2.4 test tire, nstandard tire for pavement friction testing.3.3 Acronyms:3.3.1 CVcoefficient of variation (standard deviation di-vided by
20、 the mean).3.3.2 CFMEcontinuous friction measuring equipment.3.3.3 EF60device estimate of the IFI F60.3.3.4 F60IFI F60 as per Practice E1960.3.3.5 FM60IFI F60 maintenance level from the originalMuMeter Mark II.3.3.6 FR60FR65(S) adjusted to a slip speed of 60 km/hr.3.3.7 FR65(S)CFME measurement at 65
21、 Km/hr at its slipspeed, S.3.3.8 FR95(S)CFME measurement at 95 Km/hr at its slipspeed, S.3.3.9 FBS(60)back calculation for the device from the IFIvalue F60 giving by the friction classification calculated fromthe Mu Meter.3.3.10 FB65(S)FBS adjusted for speed from 60 km/hr tothe devices slip speed (S
22、) at 65 km/hr, and is the value that theCFME must measure to meet a maintenance level.3.3.11 IFIinternational friction index (Practice E2100)with values F60 and Sp.3.3.12 MPDmean profile depth.3.3.13 MTDmean texture depth.3.3.14 SpIFI speed gradient as per Practice E1960.3.3.15 SD ERRstandard error.
23、3.3.16 SMpspeed gradient for a maintenance level thatgoes with FM60.4. Summary of Practice4.1 Since the benchmark (FAAs Mark II Mu Meter) wasretired in early 1990s, a new measure of friction had to befound that could be correlated back to the Boeing 727 frictionrequirements for the different mainten
24、ance levels. Fifteen yearsof NASA Wallops testing data was studied to find a measurethat could be related to the Mark II Mu Meter. Of all thefriction measurements made since 1993, only the InternationalFriction Index (IFI)4(1, 2)5F60 values were found to be stableand repeatable over the 15 years. To
25、 establish a correlationbetween 1990 based values and the present, the IFI wasemployed. The IFI was developed to compare and harmonizefriction measurements taken with different equipment to acommon calibrated index expressed as calibrated wet frictionat 60 km/h (F60) and the speed constant (Sp). Usi
26、ng data froma 1993 NASA friction workshop, the FAAs Mark II Mu Meterwas used to determine the IFI friction values, called FM60 andSMp, associated with each of the maintenance classifications.These IFI friction values which are now fixed in time and canbe used from 1993 forward to determine what a CF
27、ME mustmeasure to satisfy each of the maintenance classifications.4.2 ACFME is calibrated to IFI per Practice E1960. The IFIconstant values (A and B) found for the CFME are used todetermine what the CFMEs must measure (FB65(S) for eachmaintenance classification.4.3 The FB65(S) for each classificatio
28、n of maintenance isthen the friction level that CFME must measure to meet themaintenance level at 65km/hr.4.4 A second order regression is made from the CFMEmeasurements (FR65(S) at 65 km/hr to its measurements(FR95(S) on the same surfaces at 95 km/hr.4.5 The second order regression constants (A, B
29、and C) arethen used to convert the 65 km/hr (40 mph) maintenance levelsto 95 km/hr levels.4.6 At least 5 runs should be made on at least 5 surfaces,whose friction levels cover the range of 0.2 to 0.7. Each surfaceshall be uniform in friction and texture. However; it isrecommended that if more than f
30、ive surfaces are available theyshould be used.5. Significance and Use5.1 IntroductionMu numbers (friction values) measuredby CFME can be used as guidelines for evaluating the surfacefriction deterioration of runway pavements and for identifyingappropriate corrective actions required for safe aircraf
31、t opera-tions. The original levels were based on the work of theFAA/AS-90-1 (3). The report states that based on frictionvalues from a Mu Meter Mark II using Dunlop tires, and testsconducted by NASA in the 1970s using a Boeing 727, Table 1of Mu Meter friction level classifications for runway pavemen
32、tsurfaces was established for friction measurements at testspeeds of 65 Km/hr. Additionally, tests were conducted againwith the Mu Meter Mark II outfitted with the Dico tire at 95Km/h. Then a second order correlation was performed for theMu Meter operating at 95 Km/h and at 65 Km/h resulting in the4
33、An ASTM International Standard methodology specified by Practice E1960International Friction Index (IFI).5The boldface numbers in parentheses refer to a list of references at the end ofthis standard.E2666 09 (2014)2values shown in Table 2. These values were then fixed and usedwith correlations of ot
34、her CFMEs to establish the presentmaintenance levels given in Table 3.2 of FAA AdvisoryCircularAC/150/5320-12. From the Wallops 1993 data, the IFIvalues were calculated and the 65 Km/hr data in Table 2 wasused to calculate the FM60 value for each level. The data forthe two speeds for the four CFMEs
35、in the FAA report (3) wereused to establish the SMp values for each level. Then a newlevel, New Grooved, was added based on the differences ofgrooved and un-grooved sites at the NASA Wallops testfacility. Table 3 is a list of these values to be the standardvalues FM60 and SMp for any future calibrat
36、ion of CFME.5.2 AirportsRoutine testing is carried out in order toobtain data for scheduling remedial work on the runwaysurface. A single run on either side of the centerline may beregarded as sufficient or a set of runs covering the whole widthof the runway may be preferred. At 3m spacing, the fric
37、tionmap which can be prepared from a set of runs of this kindprovides excellent information on rubber buildup and surfacepolishing. Standard test speeds are typically 65 km/hr or 95km/hr and standard test water film thickness is typically 1 mm.6. Method for Determining CFME Friction Levels at 65km/h
38、rNOTE 1All calculations here are in Km/hr.6.1 The CFMEs slip speed is determined by multiplying theslip ratio times the vehicle speed of 65 km/h.S 5 Slip Ratio 365 or % Slip 365100(1)6.2 Following Practice E1960, the FR60 value (for eachcalibration site tested) is calculated from the CFME measure-me
39、nt at 65 km/h called the FRS65. The Sp is calculated fromthe MPD measured for that site during calibration and S is per6.1.FR60 5 FRS65 3 expSS 2 60!SPD(2)6.3 Again per Practice E1960, a linear correlation of FR60with F60 measured for all sites is performed to get thecorrelation constants (A and B),
40、 as well as the value of R2andthe standard error, SD ERR.F60 5 A1B 3 FR60 (3)6.4 Using the FM60 values from the original Mu MeterMark II given in Table 3, the procedure is reversed using Eq1-3 (with the A and B obtained in Section 6.3) to get the valuesfor the CFME (FB65(S) for that maintenance leve
41、l at 65Km/hr as follows:6.4.1 First the back calculation FB60 is found from revers-ing the calculation of Eq 3 and using the A and B determined.FB60 5FM60 2 A!B(4)6.4.2 Then the value that the CFME must measure for thatFM60 maintenance level is calculated from:FB65S! 5 FB60expS60 2 S!SMpD(5)where:FR
42、65(S) = the CFME measurement at 65 km/h at its slipspeed, S to meet that maintenance level,Sp = the speed constant measured for the site duringcalibration per Practice E1960,FR60 = FR65(S) adjusted to a slip speed of 60 Km/hr,FB60 = the back calculation for the device from the IFIvalue FM60 giving b
43、y the Friction Classificationcalculated from the Mu Meter, Table 3,FB65(S) = FB60 adjusted for speed from 60 Km/hr to thedevices slip speed (S) at 65 km/h, and is thevalue for the CFME must measure to meet thatmaintenance level.SMp = the speed gradient given in Table 3 for themaintenance level being
44、 calculated.7. Method for Determining CFME Friction Levels at 95Km/hrNOTE 2This method is what was used by the FAA (3) to establish thepresent Table 3.2 at 95 Km/hr.7.1 A second order regression is made from the CFMEmeasurements FRS65 at 65 km/hr to FRS95. Use the CFMEmeasurements on the same surfac
45、es at 95 km/hr to find theregression constants a, b and c. Also, R2and SD ERR are to becalculated.FRS95 5 a1b 3 FRS651c 3 FRS652(6)7.2 The second order regression is then used to convert the65 km/hr maintenance levels, FB65(S), to 95 km/hr levelsFB95(S).FB95S! 5 a1b 3 FB65S!1c 3 FB65S!2(7)8. Report8
46、.1 The test report for each test surface shall contain thefollowing items:TABLE 1 Original Mu Meter Friction Classifications of RunwayPavement Surfaces for 65 km/hr Test SpeedMu Value Classification40 Minimum50 Maintenance Planning70 New Design/ConstructionTABLE 2 Mu Meter Friction Classifications w
47、ith a Dico Tire ofRunway Pavement Surfaces for 65 km/hr and 95 km/hr TestSpeedMu Value65 km/hr 95 km/hr Classification42 26 Minimum52 38 Maintenance Planning72 66 NewDesign/ConstructionTABLE 3 Recommended Friction Classification Levels from theMu Meter for 65 km/hr65 km/hr Mu MeterFR65(S)SMp km/h FM
48、60Minimum 0.42 77 0.289Maintenance 0.52 120 0.370Construction 0.72 161 0.493New Grooved 01.00 185 0.547E2666 09 (2014)38.1.1 Date of friction and texture profile measurement,8.1.2 Number of surfaces used for correlation,8.1.3 Location and identification of the test surface,8.1.4 Description of the s
49、urface types,8.1.5 Observations of surface condition such as excessivecracking, potholes, etc,8.1.6 The position of the friction measurement and profileon the surface, for example in relation to the wheel track, etc,8.1.7 Identification of the friction and texture profile equip-ment and its operators,8.1.8 Measurement speed,8.1.9 Percentage of invalid readings eliminated,8.1.10 Total length measured and the number of segmentsanalyzed,8.1.11 The IFI values, F60 and Sp for each test site,8.1.12 The FR65(S) and FR95(S) for each test si
