1、Designation:E283212Standard Test Method forMeasuring the Coefficient of Retroreflected Luminance ofPavement Markings in a Standard Condition of ContinuousWetting(RL-2)1This standard is issued under the fixed designation E2832;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 a measurement of the wetretroreflective(RL-2)p
3、roperties of horizontal pavement mark-ing materials,such as traffic stripes and road surface symbols.A standardized method utilizing a standardized continuouswetting device and a portable retroreflectometer is described toobtain measurements of the wet retroreflective properties ofhorizontal pavemen
4、t markings.1.2 Retroreflective performance obtained with this test in astandardized condition of continuous wetting does not neces-sarily relate to how markings perform in all conditions ofnatural rain.NOTE1Test Method E2177 may be used to describe the retroreflec-tive properties of pavement marking
5、s in conditions of wetness,such asafter a period of rain.1.3 This test method is suitable for measurements made inthe laboratory and in the field when the necessary controls andprecautions are followed.1.4 This test method specifies the use of external beamretroreflectometers conforming to Test Meth
6、od E1710.2Theentrance and observation angles required of the retroreflecto-meter in this test method are commonly referred to as“30meter geometry.”21.5 The test method excludes the effects of rain between thevehicle and the marking.1.6 Results obtained using this test method should not be thesole ba
7、sis for specifying and assessing the wet retroreflectiveeffectiveness of pavement marking systems.Users shouldcomplement the results of this test method with other evalua-tion results,such as nighttime visual inspections.1.7 The values stated in SI units are to be regarded asstandard.The values give
8、n in parentheses are for informationonly.1.8 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 li
9、mitations prior to use.2.Referenced Documents2.1 ASTM Standards:3E177 Practice for Use of the Terms Precision and Bias inASTM Test MethodsE691 Practice for Conducting an Interlaboratory Study toDetermine the Precision of a Test MethodE965 Test Method for Measuring Pavement MacrotextureDepth Using a
10、Volumetric TechniqueE1710 Test Method for Measurement of RetroreflectivePavement Marking Materials with CEN-Prescribed Ge-ometry Using a Portable RetroreflectometerE2177 Test Method for Measuring the Coefficient of Ret-roreflected Luminance(RL)of Pavement Markings in aStandard Condition of Wetness3.
11、Terminology3.1 Definitions:3.1.1 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 incidentlight,expressed in millicandelas per square metre per lux(mcd/m2/lx).3.1.2 conditions of continuou
12、s wetting,nthe test conditionwhere the pavement marking specimen is subjected to continu-ously uninterrupted water spray applied uniformly over apavement marking at a defined and controlled rate duringmeasurement.1This test method is under the jurisdiction of ASTM Committee E12 on Colorand Appearanc
13、e and is the direct responsibility of Subcommittee E12.10 onRetroreflection.Current edition approved April 1,2012.Published May 2012.DOI:10.15/E283212.2Reference Test Method E1710.The standard measurement condition is in-tended to represent the angles corresponding to a distance of 30 m for the driv
14、er ofa passenger car with an eye height of 1.2 m and a headlight height of 0.65 m abovethe road.See Annex A1.3For 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 standard
15、s Document Summary page onthe ASTM website.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1 3.1.3 external beam RLretroreflectometers,na pavementmarking retroreflectometer that measures the coefficient ofretroreflected luminance,RL,in a me
16、asurement area that fallsentirely outside the retroreflectometer.3.1.4 RL-2,nthe steady state coefficient of retroreflectedluminance,RL,determined under defined conditions of con-tinuous wetting at a rate of 2 inches per hour.3.1.4.1 DiscussionThe results from this test method shallbe reported as R(L-2)where“2”designates the wetting rate usedin inches per hour(in./h).3.1.5 steady state conditions,nthe measurements havereached steady state when six consecutive retroreflectometerinstrument reading
