ASTM E2177-2018 Standard Test Method for Measuring the Coefficient of Retroreflected Luminance (RL) of Pavement Markings in a Standard Condition of Wetness.pdf

1、Designation: E2177 11E2177 18Standard Test Method forMeasuring the Coefficient of Retroreflected Luminance (RL)of Pavement Markings in a Standard Condition of Wetness1This standard is issued under the fixed designation E2177; the number immediately following the designation indicates the year oforig

2、inal 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 test method covers the measurement of the wet retroreflect

3、ive (RL) properties of horizontal pavement markingmaterials, such as traffic stripes and road surface symbols, using a portable or mobile retroreflectometer that can be placed on orbefore the road marking to measure the retroreflection at the prescribed geometry.1.2 This method of measuring the wet

4、retroreflective properties (RL) of pavement markings measures the wet retroreflectivityin a standard condition of wetness (see Fig. 1).1.2.1 DiscussionThis test condition typically exists (1) after a rainfall has ended and the pavement markings are still wet or(2) as the markings are wet from dew or

5、 humidity.1.3 Retroreflective performance obtained with this test in conditions of wetness does not necessarily relate to how markingsperform in conditions of rain, that is, as markings are being rained upon. Test Method E2832 defines a method to measure theperformance of pavement markings in condit

6、ions of simulated rain.NOTE 1Test Method E2176 defines a method to use to measure the performance of pavement markings in conditions of simulated rain.1.4 This test method specifies the use of portable or mobile reflectometers that can measure pavement markings in accordancewith Test Method E1710.2

7、The entrance and observation angles required of the retroreflectometer in this test method are commonlyreferred to as “30 meter geometry.”21.5 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.1.6 This standard does not purport

8、to address all of the safety concerns, if any, associated with its use. It is the responsibilityof the user of this standard to establish appropriate safety safety, health, and healthenvironmental practices and determine theapplicability of regulatory limitations prior to use.1.7 This international

9、standard was developed in accordance with internationally recognized principles on standardizationestablished in the Decision on Principles for the Development of International Standards, Guides and Recommendations issuedby the World Trade Organization Technical Barriers to Trade (TBT) Committee.2.

10、Referenced Documents2.1 ASTM Standards:3B965 Specification for High Performance Tin-Coated Annealed Copper Wire Intended for Electrical and Electronic Applicationfor SolderabilityD6359 Specification for Minimum Retroreflectance of Newly Applied Pavement Marking Using Portable Hand-OperatedInstrument

11、s (Withdrawn 2006)4E177 Practice for Use of the Terms Precision and Bias in ASTM Test MethodsE691 Practice for Conducting an Interlaboratory Study to Determine the Precision of a Test MethodE965 Test Method for Measuring Pavement Macrotexture Depth Using a Volumetric Technique1 This test method is u

12、nder the jurisdiction ofASTM Committee E12 on Color andAppearance and is the direct responsibility of Subcommittee E12.10 on Retroreflection.Current edition approved June 1, 2011May 1, 2018. Published June 2011May 2018. Originally approved in 2001. Last previous edition approved in 20092011 asE2177

13、01 (2009).E2177 11. DOI: 10.1520/E217711.10.1520/E2177-18.2 Reference ASTM E1710 “Standard Test Method for Measurement of Retroreflective Pavement Markings with CEN-Prescribed Geometry Using a PortableRetroreflectometer.” The standard measurement condition is intended to represent the angles corresp

14、onding to a distance of 30 m for the driver of a passenger car with aneye height of 1.2 m and a headlight height of 0.65 m above the road. See Appendix X1.3 For referencedASTM standards, visit theASTM website, www.astm.org, or contactASTM Customer Service at serviceastm.org. For Annual Book of ASTM

15、Standardsvolume information, refer to the standards Document Summary page on the ASTM website.This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication of what changes have been made to the previous version. Becauseit may not be technically poss

16、ible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current versionof the standard as published by ASTM is to be considered the official document.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, We

17、st Conshohocken, PA 19428-2959. United States1E1710 Test Method for Measurement of Retroreflective Pavement Marking Materials with CEN-Prescribed Geometry Using aPortable RetroreflectometerE2176E2832 Test Method for Measuring the Coefficient of Retroreflected Luminance of Pavement Markings in a Stan

18、dardCondition of Continuous Wetting (RL-RainL-2) (Withdrawn 2013)2.2 Other Standard:CENEN 1436 Road Marking MaterialsRoad Marking Performance for Road Users and Test Methods43. Terminology3.1 coeffcient of retroreflected luminance, RL,nthe ratio of the luminance, L, of a projected surface to the nor

19、mal illuminance,E, at the surface on a plane normal to the incident light, expressed in candelas per square metremeter per lux (cdm(cd/m-22)/lx./lx1). Because of the low luminance of pavement markings, the units commonly used are millicandelas per square metremeterper lux (mcdm(mcd/m-22)/lx./lx).3.2

20、 condition of wetness, nthe test condition is created by liberally wetting the roadpavement marking and waiting a certaintime period after wetting for water to run off.3.2.1 DiscussionSimilar conditions exist when roadpavement markings are wet or damp such as typically found after a rain has ended o

21、r from dewand high humidity.3.3 mobile retroreflectometer, na retroreflectometer that has been mounted to a vehicle for purposes of taking measurementswhile the vehicle is moving.3.4 portable retroreflectometer, nan instrument that can be used in the field or laboratory for measuring the coefficient

22、 ofretroreflected luminance, RL.3.5 “recovery method” or “bucket method”, nalternative names commonly used to describe this test method for achievingmeasurements in condition of wetness.3.6 RL-wet,nthe retroreflectance value, RL, obtained 45 s after wetting. (See Fig. 2.)4. Significance and Use4.1 T

23、he nighttime performance of pavement markings is determined by the coefficient of retroreflected luminance, RL, be it dryor wet, and depends on the materials used, age, and wear pattern. These conditions shall be observed and noted by the user.4.2 Under the same conditions of headlight illumination

24、and driversdrivers viewing, larger values of RL correspond to higherlevels of visual performance at corresponding geometry.4.3 The pavement markings measured performance in the standard condition of wetness is used to characterize the performanceof the marking on the road when wet.4 Available from E

25、uropean Committee for Standardization (CEN), 36 rue de Stassart, B-1050, Brussels, Belgium, http:/www.cenorm.be.FIG. 1 Illustration of MeasurementFIG. 2 Definition of RL-WetE2177 1824.4 Newly installed pavement markings may have a natural surface tension or release agents that prevent wetting of the

26、 productby water. The water will tend to “bead up” on the marking. This “non wetting” condition is usually short lived. Pavement markingsthat have been on the road for one month prior to testing usually do not exhibit this non-wetting phenomenon. (WarningThisphenomenon produces an interference when

27、assessing the wet characteristics of a pavement marking. Attempts to measuremarkings with this surface “non-wetting” or “beading” of the water may give higher values.)4.5 The retroreflectivity, RL, of pavement (road) markings degrades with traffic wear and requires periodic measurement toensure that

28、 sufficient line visibility is provided to drivers. For example see Specification D6359 for dry retroreflectivityrequirements.4.6 For a given viewing distance, measurements of RL made with a retroreflectometer having a geometry corresponding to thatviewing distance are a good indicator of the visual

29、 ranking of the material measured.4.7 As specified by Test Method E1710, the measurement geometry of the instrument is based on a viewing distance of 30 m,an eye height of 1.2 m and a headlight mounting height of 0.65 m (see Appendix X1).4.8 It shall be the responsibility of the user to employ an in

30、strument having the specified observation and entrance angles.5. Apparatus5.1 Portable or Mobile RetroreflectometerThe reflectometer must comply with Test Method E1710.5.2 Stopwatch or Watch, with second hand.5.3 Water, for wetting the pavement marking.5.3.1 A portable hand sprayer (garden sprayer)

31、may be used to wet the pavement marking to create the wet condition. Theportable hand sprayer shall have an adjustable nozzle. A battery operated unit works well.5.3.1 Alternatively a bucket may A bucket capable of holding 3 liters shall be used to create the wet condition by pouring thewater over t

32、he marking. Approximately 2 to 5 L of water are needed.5.3.2 The water shall be clean tap water.6. Sampling6.1 The number of readings to be taken at each test location and the spacing between test locations shall be specified by theuser.6.2 It is common to take less frequent measurements than one wo

33、uld do when assessing dry retroreflectance.6.3 Measurements for each line type shall be averaged for a final result.7. Calibration and Precautions7.1 The portable or mobile retroreflectometer shall be calibrated (standardized) using the instructions from the instrumentmanufacturer. A reference or wo

34、rking standard is used and is supplied with the instrument.7.2 Transporting the portable reflectometer from an air conditioned area to the test site may result in fogging of mirrors in theinstrument. If there is any doubt concerning the calibration or if the readings of a reference or working standa

35、rd are not constant,allow the instrument to reach ambient conditions and recalibrate with the reference or working standard.7.3 Verification must be made that there is no moisture on the instruments lens when the instrument is being used for wetreadings. Sometimes the reflectometers lens will become

36、 “fogged over” in high temperatures due to water evaporation. Whenroads are hot one can pre-cool the road with water before applying the test method to prevent the reflectometer from fogging.7.4 Calibration RecheckIf the subsequent readings on the reference standard deviate by more than 5 % from the

37、 initial one,re-calibration shall be performed. If the readings on the reference standard deviate by more than 10 % from the initial one,recalibrate and, in addition, re-measure previous measurements.8. General Procedure8.1 Both a dry and a wet measurement are usually taken in order to characterize

38、the performance of the marking. The drymeasurement establishes the effectiveness of the marking in a dry condition plus acts as provides a bench mark for the markingto which the wet performance can be compared. However, the dry measurement is optional per this test method.8.2 Measuring Dry or Wet Re

39、troreflectance (RL) of Markings:8.2.1 Use the manufacturers instructions for calibration and operation of the retroreflectometer.8.2.2 Locate the area of the pavement marking to be measured.8.2.3 Place the retroreflectometer squarely on or in front of the pavement marking material behind the measure

40、ment area withthe illumination in the direction of travel. Ensure that the illuminated measurement area of the retroreflectometer fits within thewidth of the stripe, and take a measurement.8.3 Measuring Retroreflectance (RL) in a Standard Condition of Wetness:E2177 1838.3.1 Take a hand sprayer and w

41、et the area of the marking to be measured and the adjacent surrounding area (road surface andmarking) for 30 s. Verify that the marking and adjacent area are completely flooded. Or pour 2 to 5 litres of Pour 3.0 liters of cleanwater from a bucket. Slowly pour the water bucket over the area of the ma

42、rking to be measured plus the immediate surroundingarea.measurement area within 3 to 5 s and begin timing when the bucket is emptied. The water is poured evenly along the testsurface so that the measuring field and its surrounding area is momentarily flooded by a crest of water (see Fig. 3).8.3.2 Me

43、asure the coefficient of retroreflected luminance, RL, of the wetted marking 45 6 5 s after completion of spraying orpouring the pouring water on the marking as described in 8.3.1 (see Fig. 3).8.4 RecordsRecord the dry and wet measurements in millicandelas per square metremeter per lux, (mcdm(mcd/m-

44、22)/lx./lx). Move to next measurement location which is separated sufficiently to provide meaningful data and repeat procedures in 8.2and 8.38.2 and 8.3.9. Test Report9.1 Include the following in the test report.9.1.1 Test date.9.1.2 Average of the readings taken per line or marking expressed in mil

45、licandelas per square metremeter per lux(mcdm(mcd/m-22)/lx./lx). The average of the readings shall be reported for wet and for dry conditions and for each trafficdirection of interest.9.1.3 Readings for centerlines Retroreflectivity readings shall be taken for each direction of traffic. Readings for

46、 centerlines,edge lines, skip lines, etc.in the direction of traffic on each pavement marking. Markings which are exposed to bidirectional traffic(single or double centerlines, center skips, suicide lane lines etc.) shall be measured in both directions of travel.9.1.4 Geographical location of the te

47、st site. Global positioning system (GPS) location or distance from the nearest permanentsite identification, such as a mileage marker or crossroad.9.1.5 Identification of the pavement marking material tested: type, color, age, and the location on road (edge line, first line,second line, centerline,

48、etc.).9.1.6 Identification of the instrument used, value and date of calibration of the reference standard panel used.9.1.7 Remarks concerning the overall condition of the line, such as rubber skid marks, carryover of asphalt, snowplow damage,and other factors that may affect the retroreflection mea

49、surement.9.1.8 Ambient temperature and other weather conditions.9.1.9 Description of roadway slope and general drainage where measurement is made (that is, puddles on marking due to lowspot in road, water drained due to road incline, etc.)9.1.10 Description of road surface and road texture, that is, portland concrete cement (PCC) (broomed, brushed, worn),bituminous, chip seal, etc.NOTE 1Pavement texture may be identified and quantified by Test Method B965E965.10. Factors That May Influence Measurements10.1 There are several factors that may