1、Designation: E2340/E2340M 111Standard Test Method forMeasuring the Skid Resistance of Pavements and OtherTrafficked Surfaces Using a Continuous Reading, Fixed-SlipTechnique1This standard is issued under the fixed designation E2340/E2340M; the number immediately following the designation indicates th
2、e yearof original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval.A superscript epsilon () indicates an editorial change since the last revision or reapproval.1NOTEEditorially corrected units of measure formatting in Nove
3、mber 2013.1. Scope1.1 This test method covers the measurement of the skidresistance of a pavement or other trafficked surface using thecontinuous reading, fixed-slip technique.1.2 This test method covers braked wheel measurementsobtained with less than 100 % slip. It does not cover side forcemeasure
4、ments.1.3 This test method provides a record of the skid resistancealong the whole length of one track of the test surface andenables averages to be obtained for specified test segments.1.4 This test method is used to measure skid resistance on awide variety of surfaces in a wide variety of circumst
5、ances.Consequently, there are many different designs of continuousreading, fixed-slip measuring equipment (CFME) and as manydifferent test procedures governing their use.1.5 This test method does not attempt to detail thesedifferent equipments and procedures but does set out theessential common prin
6、ciples.1.6 CFMEs function by creating and measuring a frictionalforce between a test tire operating at a selected slip and the testsurface. Different types of CFME do not necessarily create thesame frictional force between their particular test tire and acommon test surface and do not necessarily us
7、e the samemethod to measure this frictional force.1.7 CFME measurements are obtained at a selected steadytest speed. This speed may vary according to the application.1.8 The test surface may be contaminated or clean and dry.If it is clean and dry, a measured amount of water is normallydeposited on t
8、he surface just in front of the test wheel.1.9 The measuring apparatus may be built into a vehicle,built into a trailer that is towed by a vehicle, or built into adevice that is manually pushed.1.10 The values stated in either SI units or inch-pound unitsare to be regarded separately as standard. Th
9、e values stated ineach system may not be exact equivalents; therefore, eachsystem shall be used independently of the other. Combiningvalues from the two systems may result in non-conformancewith the standard.1.11 This standard may involve hazardous materials,operations, and equipment. This standard
10、does not purport toaddress all of the safety concerns, if any, associated with itsuse. It is the responsibility of the user of this standard toestablish appropriate safety and health practices and deter-mine the applicability of regulatory limitations prior to use.Safety precautionary information is
11、 contained in Section 7.2. Referenced Documents2.1 ASTM Standards:2E178 Practice for Dealing With Outlying ObservationsE501 Specification for Rib Tire for Pavement Skid-Resistance TestsE524 Specification for Smooth Tire for Pavement Skid-Resistance TestsE867 Terminology Relating to Vehicle-Pavement
12、SystemsE1551 Specification for Special Purpose, SmoothTreadTire, Operated on Fixed Braking Slip Continuous FrictionMeasuring EquipmentE1844 Specification for A Size 10 45 Smooth-TreadFriction Test TireF408 Test Method for Tires for Wet Traction in Straight-Ahead Braking, Using a Towed TrailerF457 Te
13、st Method for Speed and Distance Calibration of1This test method is under the jurisdiction of ASTM Committee E17 on Vehicle- Pavement Systems and is the direct responsibility of Subcommittee E17.21 onField Methods for Measuring Tire Pavement Friction.Current edition approved Jan. 1, 2011. Published
14、March 2011. Originallyapproved in 2006. Last previous edition approved in 2006 as E2340 06. DOI:10.1520/E2340_E2340-11E01.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, ref
15、er to the standards Document Summary page onthe ASTM website.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States1Fifth Wheel Equipped With Either Analog or DigitalInstrumentation3. Terminology3.1 For definitions of terms used in this test
16、 method, refer toTerminology E867.3.2 Definitions:3.2.1 braking force, ndynamic instantaneous frictionalforce acting on the test wheel.3.2.2 braking force coeffcient (BFC), nappropriately fil-tered mean of a number of instantaneous friction readings overa defined distance.3.2.3 braking slip friction
17、, ntangential force generatedbetween the test tire and the test surface.3.2.4 braking slip ratio, nratio of relative braking slipcircumferential speed to identical unbraked wheel circumfer-ential speed, usually defined as a percent.3.2.4.1 DiscussionAn equivalent definition is the ratio ofthe relati
18、ve braking slip velocity to the horizontal velocity ofthe wheel axle.3.2.5 continuous reading, fixed slip-measuring equipment(CFME), napparatus that can be moved over the test surfaceat the chosen test speed and includes a test wheel, a system forbraking the test wheel, and instrumentation for measu
19、ring theresulting frictional force between the test tire and test surface.3.2.6 fixed slip, nbraking system that forces the test wheelto roll at a constant slip or fixed reduction of its free rollingspeed.3.2.7 frictional force, nresistance generated when onesurface moves relative to another with wh
20、ich it is in contact.3.2.8 instantaneous friction reading, nbraking force di-vided by load or equivalently divided by torque on the testwheel (generated by braking force) divided by load times tireradius (moment arm).3.2.9 load force, ndynamic instantaneous vertical forceacting on the test wheel.3.2
21、.10 nominal water film thickness, nthickness of thefilm that the water application system is designed to createahead of the test tire on an entirely smooth test surface.3.2.11 rate of water flow, nrate at which water is appliedto the test surface in front of the test tire.3.2.12 reporting length, nd
22、efined length over which theBFC is calculated.3.2.13 standard nominal water film thickness, nnominalwater film thickness associated with CFME measurements of aparticular type of test application to facilitate comparisonsbetween the results of different tests.3.2.14 standard test speed, nsteady test
23、speed associatedwith CFME measurements of a particular type of test applica-tion to facilitate comparisons between the results of differenttests.3.2.15 test speed, nsteady test speed associated withCFME measurements.3.2.16 water application system, nsystem for depositing agiven amount of water in fr
24、ont of the test tire so that it passesbetween the tire contact area and the test surface.3.3 Definitions of Terms Specific to This Standard:3.3.1 certifying calibration, nverification of testequipment, calibration equipment (separate or inbuilt), calibra-tion procedures, and equipment operation reco
25、mmended to becarried out once a year; the procedure records both as foundvalues and adjusted values.3.3.2 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; this
26、equipment may be built into the CFME.3.3.3 friction map, npresentation of friction readings ob-tained down the length of a test surface (typically an airportrunway) over a series of selected paths down the surface.3.3.4 operational friction testing, nmeasurement of thefriction of a surface in respon
27、se to an operational need and inwhatever conditions exist at the time of the test, which mayinclude contamination by ice, snow, slush, or water; these testsdo not include the application of water.3.3.5 routine friction testing, nmeasurement of the frictionof a surface under standardized test conditi
28、ons that normallyincludes a standard test speed and a rate of water flow whichgives a standard nominal water film thickness.3.3.6 test tire, nstandard tire for pavement friction testing;test tires for routine friction testing shall have a smooth tread.4. Summary of Test Method4.1 The test system is
29、moved over the test surface at thechosen test speed with the test wheel, fitted with a test tire, andforced to roll at a particular braking slip ratio.4.2 If routine friction testing is taking place, the rate ofwater flow is adjusted to the test speed so that the chosennominal water film is achieved
30、.4.3 The braking force or torque is measured (see Terminol-ogy E867) and the load is measured, calculated, or assumed tobe the same as the dead weight load.4.4 The instantaneous friction reading is calculated.4.5 Either the instantaneous friction reading is recorded orthe BFC for each friction lengt
31、h is calculated and recorded.4.6 Test speed (see Test Method F457), rate of water flow,and other essential supporting data are recorded.5. Significance and Use5.1 CFMEs are used to measure skid resistance on runways,roads, and various other trafficked surfaces. These tests maycomprise operational te
32、sting, performed to obtain an immedi-ate assessment of skid resistance in current conditions orroutine testing in standardized conditions which include theapplication of a precise amount of water in front of the test tire.5.2 Standard test speeds and nominal water film thicknessesare according to na
33、tional or international agency standards, thetype of CFME, and the test application. Some examples oftypical applications are given in Appendix X1.E2340/E2340M 11126. Apparatus6.1 Basic Measurements:6.1.1 The test apparatus shall be equipped with a forcetransducer to provide a direct measurement of
34、the braking forceor a torque transducer to measure the torque on the test wheelgenerated by this force or both.6.1.2 The design of the test apparatus shall ensure thatunless the average load force acting on the test wheel remainswithin 1 % of the static wheel load over the reporting length,the appar
35、atus shall be equipped with a force transducer tomeasure the load force.6.1.3 The test apparatus shall include a mechanism formeasuring test speed and distance traveled.6.1.4 Unless the test apparatus is to be used solely foroperational testing, it shall include a mechanism for measuringrate of wate
36、r flow.6.2 Tolerance for Adverse Conditions:6.2.1 The exposed portions of the system shall tolerate100 % relative humidity (RH) (rain or spray) and all otheradverse conditions, such as de-icing chemicals, dust, shock,and vibrations that may be encountered in the type of testingfor which the equipmen
37、t is designed. The suspension systemshall minimize the influence of normal pavement roughness onthe accuracy and fidelity of the data collection.6.3 Accuracy, Resolution, and Stability of Measuring Sys-tem:6.3.1 At outside ambient air temperatures between 40 and45C 40 and 110F, overall static system
38、 measurementaccuracy shall be 61.5 % of full scale.6.3.2 Certifying calibration or other time stability calibra-tion shall not be required more than once a year unless themeasuring system sustains damage requiring significant repair.6.3.3 If there is a force transducer that provides a directmeasurem
39、ent of the braking force, it shall do so with minimalinertial effects. It is recommended that this transducer providesoutput directly proportional to force with hysteresis less than1 % of the applied load up to the maximum expected loading.The mounting of the braking force-measuring transducer shall
40、be such that the effects of cross-axle loading or torque loadingshall be less than 1 % of the applied load. The braking forcetransducer shall be mounted in such a manner as to experienceless than 1 angular rotation with respect to its longitudinalmeasuring plane at the maximum expected loading.6.3.4
41、 If there is a torque transducer that measures the torqueon the test wheel generated by the braking force, this shallprovide output directly proportional to torque with hysteresisless than 1 % of the applied load and nonlinearity up to themaximum expected loading less than 1 % of the applied load.Th
42、e sensitivity to any cross-axis loading shall be less than 1 %of the applied load. Torque transducer measurements includerolling tire/wheel inertial effects, which shall be compensatedfor at all test speeds.6.3.5 If the load force is measured, the accuracy of themeasurement shall conform to the requ
43、irements set out in6.3.3. If the load force is assumed constant, it shall be possibleto show that the assumed dynamic wheel load is within 62%of the actual dynamic wheel load.6.3.6 Distance shall be measured with a resolution of 0.1 %and an accuracy of 60.5 % and shall be continuously recorded.6.3.7
44、 Speed shall be measured with a resolution of 2 kmh 1mph and an accuracy of 61 kmh 60.5 mph. It is recom-mended that these measurements be continuously recorded.6.4 Braking Slip:6.4.1 The test apparatus shall be such that the chosen fixedbraking slip can be maintained within 63 % of full scalethroug
45、hout the length of the test surface at the chosen testspeed (for example, if the chosen fixed braking slip is 15 %, abraking slip between 12 and 18 % shall be maintained).6.5 Test SpeedWith the test tire operating at the chosenfixed braking slip, the test apparatus shall be capable ofmaintaining the
46、 chosen test speed within 63 % for the durationof the survey.6.6 Test TireThe test tire shall conform to the applicableASTM, ISO, or BSI specification or equivalent. ApplicableASTM standards include Specifications E501, E524, E1551and E1844.6.7 Water Application System:6.7.1 Water shall be applied t
47、o the test surface just ahead ofthe test tire so as to provide the chosen nominal water filmthickness across the full width of the test tire at any test speed.6.7.2 The water application system shall be protected fromthe effects of side winds, either by use of a flexible nozzle veryclose to the test
48、 surface or by shielding the nozzle in some wayor by using a jet of water with horizontal speed equal andopposite to the test speed and applied slightly wider than thewidth of the test tire tread.6.7.3 Water used for testing shall be reasonably clean andhave no chemicals such as wetting agents or de
49、tergents addedand shall not be above 30C 86F.6.7.4 The nominal water film thickness shall be in accor-dance with the manufacturers handbook and the test applica-tion.6.7.5 Rate of water flow shall be continuously measured andit is recommended that it be continuously recorded.6.7.6 Regulation of rate of water flow shall be within610 %.6.8 Signal-Conditioning and Recording Systems:6.8.1 All signal-conditioning and recording equipment shallprovide linear output and allow data reading resolution to meetthe requirements of 6.3.All systems
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