ASTM_E_1960_-_07_2015.pdf

Designation:E196007(Reapproved 2015)Standard Practice forCalculating International Friction Index of a PavementSurface1This standard is issued under the fixed designation E1960;the number immediately following the designation 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 practice covers the calculation of the InternationalFriction Index(IFI)from a measurement of pavement macro-texture and wet pavement friction.The IFI was developed inthe PIARC International Experiment to Compare and Harmo-nize Texture and Skid Resistance Measurements.The indexallows for the harmonizing of friction measurements withdifferent equipment to a common calibrated index.This prac-tice provides for harmonization of friction reporting for devicesthat use a smooth tread test tire.1.2 The IFI consists of two parameters that report thecalibrated wet friction at 60 km/h(F60)and the speed constantof wet pavement friction(Sp).1.3 The mean profile depth(MPD)has been shown to beuseful in predicting the speed constant(gradient)of wetpavement friction.21.4 A linear transformation of the estimated friction at 60km/h provides the calibrated F60 value.The estimated frictionat 60 km/h is obtained by using the speed constant to calculatethe estimated friction at 60 km/h from a measurement made atany speed.1.5 The values stated in SI(metric)units are to be regardedas standard.The inchpound equivalents are rationalized,rather than exact mathematical conversions.1.6 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 regulatory limitations prior to use.2.Referenced Documents2.1 ASTM Standards:3E867 Terminology Relating to Vehicle-Pavement SystemsE1911 Test Method for Measuring Paved Surface FrictionalProperties Using the Dynamic Friction TesterE1845 Practice for Calculating Pavement MacrotextureMean Profile Depth2.2 ISO Standard:DIS 13473-1 Acoustics Characterization of PavementTexture using Surface Profiles Part 1:Determination ofMean Profile Depth43.Terminology3.1 Terminology used in this standard conforms to thedefinitions included in Terminology E867.4.Summary of Practice4.1 This practice uses measured data of the pavementsurface on:(1)macrotexture,and(2)measured friction(FRS)on wet pavement.The practice accommodates these datameasured with different equipment at any measuring speed.4.2 Measurement of the pavement macrotexture is used toestimate the speed constant(Sp).4.3 The measured friction(FRS)at some slip speed(S)isused with the speed constant of the pavement(Sp)to calculatethe friction at 60 km/h(FR60)and a linear regression is usedon FR60 to find the calibrated friction value at 60 km/h(F60).4.4 F60 and Spare then reported as IFI(F60,Sp).5.Significance and Use5.1 This is the practice for calculating the IFI of thepavement.The IFI has proven useful for harmonization of thefriction measuring equipment.F60 and Sphave proven to beable to predict the speed dependence of wet pavementrelated1This practice is under the jurisdiction of Committee E17 on Vehicle-PavementSystems and is the direct responsibility of Subcommittee E17.21 on Field Methodsfor Measuring Tire Pavement Friction.Current edition approved Sept.1,2015.Published December 2015.Originallyapproved in 1998.Last previous edition approved in 2011 as E1960 07(2011).DOI:10.1520/E1960-07R15.2Wambold,J.C.,Antle,C.E.,Henry,J.J.,and Rado,Z,International PIARCExperimenttoCompareandHarmonizeTextureandSkidResistanceMeasurements,Final report,Permanent International Association of Road Con-gresses(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 standards Document Summary page onthe ASTM website.4Draft International Standard under the jurisdiction of ISO/TC43/SC1 currentlyunder ballot.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1 measurements of the various types of friction-measuring equip-ment.2The two IFI parameters(F60 and Sp)have been foundto be reliable predictors of the dependence of wet pavementfriction on tire slip and vehicle speed.5.2 The IFI parameters,F60 and Sp,can be used to calculatethe calibrated friction at anotherslip speed using a transfor-mation equation.5.3 The IFI model given below describes the relationshipbetween the values of wet pavement friction FRS measured ata slip speed of S and between the friction values measured bydifferent types of equipment.5.4 A significance of the IFI Model is that the measurementof friction with a device does not have to be at one of th