1、Designation: E2177 11Standard 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 oforiginal ado
2、ption 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 wetretroreflective (RL)
3、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 the wet retroreflec
4、tive 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 from dew or humidity
5、.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 markings in condi
6、tions 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 referred to as “30 meter
7、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 this standard to est
8、ablish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:3B965 Specification for High Performance Tin-Coated An-nealed Copper Wire Intended for Electrical and ElectronicApplication for Solderabil
9、ityD6359 Specification for Minimum Retroreflectance ofNewly Applied Pavement Marking Using Portable Hand-Operated Instruments4E177 Practice for Use of the Terms Precision and Bias inASTM Test MethodsE691 Practice for Conducting an Interlaboratory Study toDetermine the Precision of a Test MethodE1710
10、 Test Method for Measurement of RetroreflectivePavement 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 Oth
11、er Standard:CENEN 1436 Road Marking MaterialsRoad MarkingPerformance for Road Users53. Terminology3.1 coeffcient of retroreflected luminance, RL, nthe ratioof the luminance, L, of a projected surface to the normal1This test method is under the jurisdiction of ASTM Committee E12 on Colorand Appearanc
12、e and is the direct responsibility of Subcommittee E12.10 onRetroreflection.Current edition approved June 1, 2011. Published June 2011. Originallyapproved in 2001. Last previous edition approved in 2009 as E2177 - 01 (2009).DOI: 10.1520/E217711.2Reference ASTM E1710 “Standard Test Method for Measure
13、ment 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 headlight height o
14、f 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. The last
15、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, PO Box C70
16、0, West Conshohocken, PA 19428-2959, United States.illuminance, E, at the surface on a plane normal to the incidentlight, 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 (mc
17、dm-2)/lx.3.2 condition of wetness, nthe test condition 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
18、dew and high humidity.3.3 mobile retroreflectometer, na 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 ret
19、roreflected luminance, RL.3.5 “recovery method” or “bucket 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 ni
20、ghttime performance of pavement markings isdetermined 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 anddrive
21、rs viewing, larger values of RLcorrespond to higherlevels 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 marking
22、s may have a naturalsurface tension or release agents 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 thi
23、s non-wetting phe-nomenon. (WarningThis phenomenon produces 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) mar
24、kingsdegrades with traffic wear and requires periodic 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 geome
25、try corresponding tothat viewing distance are a good indicator 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 Ap
26、pendix X1).4.8 It shall be the responsibility of the user 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 wett
27、ing the pavement marking.5.3.1 A portable hand sprayer (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
28、 pouring the water over the marking. Approxi-mately 2 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
29、 measurements thanone would do when assessing dry retroreflectance.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 manuf
30、acturer. A reference or working standard is usedand is 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 refe
31、rence or working standardare not constant, allow the instrument 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 reflectomet
32、ers lens will becomeFIG. 2 Definition of RL-WetE2177 112“fogged over” in high temperatures 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.7.4 Calibration RecheckIf the subsequent readings on the
33、reference standard deviate by more than 5 % from 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 mea
34、surement are usually taken inorder to characterize 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
35、 test method.8.2 Measuring Dry or Wet Retroreflectance (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 paveme
36、nt marking material with the illumination in thedirection 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
37、wet the area of the markingto be measured and the 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 th
38、e immediate surrounding area.The water is poured 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 ofsp
39、raying or pouring the water on the marking as described 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 a
40、nd 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 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 di
41、rection ofinterest.9.1.3 Readings for centerlines 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
42、as a mileage marker orcrossroad.9.1.5 Identification 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
43、.9.1.7 Remarks concerning the overall condition 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 drainage
44、where measurement is made (that is, puddles on 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, etc.NOTE 2Pavement texture may be identif
45、ied and quantified by TestMethod B965.10. Factors 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
46、different readings.10.1.2 The magnitude of the wet 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 wil
47、l give lowervalues.11. Precision and Bias611.1 The precision of this test method is based on aninterlaboratory study of ASTM E2177, Standard Test Methodfor Measuring the Coefficient of Retroreflected Luminance(RL) of Pavement Markings in a Standard Condition ofWetness, conducted in 2010. Ten laborat
48、ories participated inthis study. Each of the labs was asked to report fifteen replicatetest results for ten different materials. Every “test result”reported represents a single determination or measurement.6Supporting data have been filed at ASTM International Headquarters and maybe obtained by requ
49、esting Research Report RR:E12-1004.FIG. 3 Illustration of MeasurementE2177 113Practice E691 was followed for the design and analysis of thedata; the details are given in ASTM Research Report No.E121004.11.1.1 Repeatability Limit (r)Two test results obtainedwithin one laboratory shall be judged not equivalent if theydiffer by more than the “r” value for that material; “r”istheinterval representing the critical difference between two testresults for the same material, obtained by the same operatorusing the same equipment on the same day in the sam
