1、Designation: E2177 01 (Reapproved 2009)Standard 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 y
2、ear 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 test method covers the measurement of the wetret
3、roreflective (RL) properties of horizontal pavement markingmaterials, such as traffic stripes and road surface symbols,using a portable or mobile retroreflectometer that can be placedon or before the road marking to measure the retroreflection atthe prescribed geometry.1.2 This method of measuring t
4、he wet retroreflective prop-erties (RL) of pavement markings measures the wet retroreflec-tivity in 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 stillwet or (2) as the markings are wet fr
5、om dew or humidity.1.3 Retroreflective performance obtained with this test inconditions of wetness does not necessarily relate to howmarkings perform in conditions of rain, that is, as markings arebeing rained upon.NOTE 1Test Method E2176 defines a method to use to measure theperformance of pavement
6、 markings in conditions of simulated rain.1.4 This test method specifies the use of portable or mobilereflectometers that can measure pavement markings in accor-dance with Test Method E1710.2The entrance and observationangles required of the retroreflectometer in this test method arecommonly referre
7、d to as “30 meter geometry.”21.5 The values stated in SI units are to be regarded asstandard. No other units of measurement are included in thisstandard.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 th
8、is 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:3D6359 Specification for Minimum Retroreflectance ofNewly Applied Pavement Marking Using Portable Hand-Operated Instrume
9、nts4E691 Practice for Conducting an Interlaboratory Study toDetermine the Precision of a Test MethodB965 Specification for High Performance Tin-Coated An-nealed Copper Wire Intended for Electrical and ElectronicApplication for SolderabilityE1710 Test Method for Measurement of RetroreflectivePavement
10、 Marking Materials with CEN-Prescribed Geom-etry Using a Portable RetroreflectometerE2176 Test Method for Measuring the Coefficient of Ret-roreflected Luminance of Pavement Markings in a Stan-dard Condition of Continuous Wetting (RL-Rain)2.2 Other Standard:CENEN 1436 Road Marking MaterialsRoad Marki
11、ngPerformance for Road Users53. Terminology3.1 coeffcient of retroreflected luminance, RL, nthe ratioof the luminance, L, of a projected surface to the normalilluminance, E, at the surface on a plane normal to the incident1This test method is under the jurisdiction of ASTM Committee E12 on Colorand
12、Appearance and is the direct responsibility of Subcommittee E12.10 onRetroreflection.Current edition approved Dec. 1, 2009. Published December 2009. Originallyapproved in 2001. Last previous edition approved in 2001 as E2177 - 01. DOI:10.1520/E2177-01R09.2Reference ASTM E1710 “Standard Test Method f
13、or Measurement of Retrore-flective Pavement Markings with CEN-Prescribed Geometry Using a PortableRetroreflectometer.” The standard measurement condition is intended to representthe angles corresponding to a distance of 30 m for the driver of a passenger car withan eye height of 1.2 m and a headligh
14、t height of 0.65 m above the road. SeeAppendix X1.3For 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.4Withdrawn.
15、 The last approved version of this historical standard is referencedon www.astm.org.5Available from European Committee for Standardization (CEN), 36 rue deStassart, B-1050, Brussels, Belgium, http:/www.cenorm.be.FIG. 1 Illustration of Measurement1Copyright ASTM International, 100 Barr Harbor Drive,
16、PO Box C700, West Conshohocken, PA 19428-2959, United States.light, expressed in candelas per square metre per lux (cdm-2)/lx. Because of the low luminance of pavement markings,the units commonly used are millicandelas per square metreper lux (mcdm-2)/lx.3.2 condition of wetness, nthe test condition
17、 is created byliberally wetting the road marking and waiting a certain timeperiod after wetting for water to run off.3.2.1 DiscussionSimilar conditions exist when roadmarkings are wet or damp such as typically found after a rainhas ended or from dew and high humidity.3.3 mobile retroreflectometer, n
18、a retroreflectometer thathas been mounted to a vehicle for purposes of taking measure-ments while the vehicle is moving.3.4 portable retroreflectometer, nan instrument that canbe used in the field or laboratory for measuring the coefficientof retroreflected luminance, RL.3.5 “recovery method” or “bu
19、cket method”, nalternativenames commonly used to describe this test method for achiev-ing measurements in condition of wetness.3.6 RL-wet, nthe retroreflectance value, RL, obtained 45 safter wetting. (See Fig. 2.)4. Significance and Use4.1 The nighttime performance of pavement markings isdetermined
20、by the coefficient of retroreflected luminance, RL,be it dry or wet, and depends on the materials used, age, andwear pattern. These conditions shall be observed and noted bythe user.4.2 Under the same conditions of headlight illumination anddrivers viewing, larger values of RLcorrespond to higherlev
21、els of visual performance at corresponding geometry.4.3 The pavement markings measured performance in thestandard condition of wetness is used to characterize theperformance of the marking on the road when wet.4.4 Newly installed pavement markings may have a naturalsurface tension or release agents
22、that prevent wetting of theproduct by water. The water will tend to “bead up” on themarking. This “non wetting” condition is usually short lived.Pavement markings that have been on the road for one monthprior to testing usually do not exhibit this non-wetting phe-nomenon. (WarningThis phenomenon pro
23、duces an interfer-ence when assessing the wet characteristics of a pavementmarking. Attempts to measure markings with this surface“non-wetting” or “beading” of the water may give highervalues.)4.5 The retroreflectivity, RL, of pavement (road) markingsdegrades with traffic wear and requires periodic
24、measurementto ensure that sufficient line visibility is provided to drivers.For example see Specification D6359 for dry retroreflectivityrequirements.4.6 For a given viewing distance, measurements of RLmadewith a retroreflectometer having a geometry corresponding tothat viewing distance are a good i
25、ndicator of the visual rankingof the material measured.4.7 As specified by Test Method E1710, the measurementgeometry of the instrument is based on a viewing distance of30 m, an eye height of 1.2 m and a headlight mounting heightof 0.65 m (see Appendix X1).4.8 It shall be the responsibility of the u
26、ser to employ aninstrument having the specified observation and entranceangles.5. Apparatus5.1 Portable or Mobile RetroreflectometerThe reflecto-meter 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
27、 (garden sprayer) may be usedto wet the pavement marking to create the wet condition. Theportable hand sprayer shall have an adjustable nozzle.Abatteryoperated unit works well.5.3.2 Alternatively a bucket may be used to create the wetcondition by pouring the water over the marking. Approxi-mately 2
28、to 5 L of water are needed.5.3.3 The water shall be clean tap water.6. Sampling6.1 The number of readings to be taken at each test locationand the spacing between test locations shall be specified by theuser.6.2 It is common to take less frequent measurements thanone would do when assessing dry retr
29、oreflectance.6.3 Measurements for each line type shall be averaged for afinal result.7. Calibration and Precautions7.1 The portable or mobile retroreflectometer shall be cali-brated (standardized) using the instructions from the instru-ment manufacturer. A reference or working standard is usedand is
30、 supplied with the instrument.7.2 Transporting the portable reflectometer from an airconditioned area to the test site may result in fogging of mirrorsin the instrument. If there is any doubt concerning thecalibration or if the readings of a reference or working standardare not constant, allow the i
31、nstrument to reach ambientconditions and recalibrate with the reference or workingstandard.7.3 Verification must be made that there is no moisture onthe instruments lens when the instrument is being used for wetreadings. Sometimes the reflectometers lens will become“fogged over” in high temperatures
32、 due to water evaporation.When roads are hot one can pre-cool the road with water beforeapplying the test method to prevent the reflectometer fromfogging.FIG. 2 Definition of RL-WetE2177 01 (2009)27.4 Calibration RecheckIf the subsequent readings on thereference standard deviate by more than 5 % fro
33、m the initialone, re-calibration shall be performed. If the readings on thereference standard deviate by more than 10 % from the initialone, recalibrate and, in addition, re-measure previous measure-ments.8. General Procedure8.1 Both a dry and a wet measurement are usually taken inorder to character
34、ize the performance of the marking. The drymeasurement establishes the effectiveness of the marking in adry condition plus acts as a bench mark for the marking towhich the wet performance can be compared. However, the drymeasurement is optional per this test method.8.2 Measuring Dry or Wet Retrorefl
35、ectance (RL) of Mark-ings:8.2.1 Use the manufacturers instructions for calibration andoperation of the retroreflectometer.8.2.2 Locate the area of the pavement marking to bemeasured.8.2.3 Place the retroreflectometer squarely on or in front ofthe pavement marking material with the illumination in th
36、edirection of travel. Ensure that the illuminated measurementarea of the retroreflectometer fits within the width of the stripe,and take a measurement.8.3 Measuring Retroreflectance (RL) in a Standard Condi-tion of Wetness:8.3.1 Take a hand sprayer and wet the area of the markingto be measured and t
37、he adjacent surrounding area (road surfaceand marking) for 30 s. Verify that the marking and adjacentarea are completely flooded. Or pour 2 to 5 litres of clean waterfrom a bucket. Slowly pour the water over the area of themarking to be measured plus the immediate surrounding area.The water is poure
38、d evenly along the test surface so that themeasuring field and its surrounding area is momentarilyflooded by a crest of water (see Fig. 3).8.3.2 Measure the coefficient of retroreflected luminance,RL, of the wetted marking 45 6 5 s after completion ofspraying or pouring the water on the marking as d
39、escribed in8.3.1 (see Fig. 3).8.4 RecordsRecord the dry and wet measurements inmillicandelas per square metre per lux, (mcdm-2)/lx. Move tonext measurement location which is separated sufficiently toprovide meaningful data and repeat procedures in 8.2 and 8.3.9. Test Report9.1 Include the following
40、in the test report.9.1.1 Test date.9.1.2 Average of the readings taken per line or markingexpressed in millicandelas per square metre per lux(mcdm-2)/lx. The average of the readings shall be reportedfor wet and for dry conditions and for each traffic direction ofinterest.9.1.3 Readings for centerlin
41、es shall be taken for eachdirection of traffic. Readings for centerlines, edge lines, skiplines, etc.9.1.4 Geographical location of the test site. Global position-ing system (GPS) location or distance from the nearestpermanent site identification, such as a mileage marker orcrossroad.9.1.5 Identific
42、ation of the pavement marking materialtested: type, color, age, and the location on road (edge line, firstline, second line, centerline, etc.).9.1.6 Identification of the instrument used, value and date ofcalibration of the reference standard panel used.9.1.7 Remarks concerning the overall condition
43、 of the line,such as rubber skid marks, carryover of asphalt, snowplowdamage, and other factors that may affect the retroreflectionmeasurement.9.1.8 Ambient temperature and other weather conditions.9.1.9 Description of roadway slope and general drainagewhere measurement is made (that is, puddles on
44、marking dueto low spot 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, etcNOTE 2Pavement texture may be identified and quantified by TestMethod B965.10. Factor
45、s That May Influence Measurements10.1 There are factors that may cause measurement vari-ability when taking readings in the field. Some of these are:10.1.1 Slight changes in the position of the reflectometer onor in front of the traffic line may yield different readings.10.1.2 The magnitude of the w
46、et measurement obtainedmay sometimes be dependent upon how well the water drains“off from” the marking. Steep inclines will allow the water torun off quickly and lead to higher values. Conversely, low areasor dips will allow the water to puddle and will give lowervalues.11. Precision and Bias11.1 Th
47、e precision and bias is based on three separatestudies, and their results can be found in Tables 1 and 2. Thetables show the repeatability for two instrument types and fortwo levels of wet performance. One level of wet performanceFIG. 3 Illustration of MeasurementTABLE 1 Repeatability in Conditions
48、of Wetnessfor Values ofWet Performance Under 100 (mcdm-2)/lxNOTE 1Individual readings range from 0 to 103 (mcdm-2)/lx.n Range ofValuesMeanValuePooledSt. Dev.Coef. ofVariation95 % C.I.2.8 (St. Dev.)Study 1Instrument A 24 0 to 36 7.5 0.8 29.9 % 62.2Study 2Instrument A 17 4 to 98 52 4.2 22.7 % 612E2177
49、 01 (2009)3is shown in Table 1 for values less than 100 (mcdm-2)/lx andthe other level is shown in Table 2 for values greater than 100(mcdm-2)/lx. The calculations and results follow PracticeE691.11.2 In each study, the wet reflective measurement wasperformed by wetting the marking, waiting 45 s for the waterto drain and then taking the measurement. For each study, 2-3replicate readings were obtained by simply triggering theinstruments a second or third time without moving the instru-ment (within 5 s). The wetting of the markings was
