1、Designation: D7735 17Standard Test Method forType A Durometer Hardness Testing of ThermoplasticPavement Marking at Elevated Temperatures1This standard is issued under the fixed designation D7735; the number immediately following the designation indicates the year oforiginal adoption or, in the case
2、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 Type A Durometer hardness ofthermoplastic pavement marking material a
3、t elevated tempera-tures.1.2 This test method is similar to Test Method D2240 forhardness with special attention given to keeping the tempera-ture of the test sample and instrument constant. Within thehighway materials community, it is sometimes known as“indentation resistance.”1.3 All materials, in
4、struments or equipment used for thedetermination of temperature, hardness and time shall betraceable to National Institute of Standards and Technology orother internationally recognized organizations parallel in na-ture.1.4 The values stated in SI units are to be regarded asstandard. The values give
5、n in parentheses are for informationonly.1.5 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
6、 limitations prior to use.1.6 This international standard was developed in accor-dance with internationally recognized principles on standard-ization established in the Decision on Principles for theDevelopment of International Standards, Guides and Recom-mendations issued by the World Trade Organiz
7、ation TechnicalBarriers to Trade (TBT) Committee.2. Referenced Documents2.1 ASTM Standards:2D16 Terminology for Paint, Related Coatings, Materials, andApplicationsD2240 Test Method for Rubber PropertyDurometer Hard-nessD7307 Practice for Sampling of Thermoplastic Traffic Mark-ing MaterialsD7308 Prac
8、tice for Sample Preparation of ThermoplasticPavement Marking MaterialsE177 Practice for Use of the Terms Precision and Bias inASTM Test MethodsE691 Practice for Conducting an Interlaboratory Study toDetermine the Precision of a Test Method3. Terminology3.1 Definitions:3.1.1 The terms and definitions
9、 in Terminology D16 applyto this method.3.1.2 hardness, advthe value of resistance of a smallpenetrating device. In the case of the Type A Durometer inaccordance with Test Method D2240, the presser foot/indentor(spherical to 0.79 6 0.03 mm or 0.03 6 0.001 in.) is connectedto a spring loaded to a tot
10、al of 0.075 N/Durometer units at fulldeflection. For reading of Type A hardness the instrumentsscale reads from 0 to 100. Minimal deflection is 0 (softest) andmaximum is 100 (hardest).3.1.3 thermoplastic, npavement marking (same as 3.1.4).3.1.4 thermoplastic pavement markinga highly filled100 % tota
11、l solids highway marking system that when heatedto a molten state can be extruded or sprayed onto a road surfaceand when cooled forms a solid durable delineator or thermo-plastic pavement marking usually melted to 220C (425F).4. Summary of Test Method4.1 This method was developed to enable the testi
12、ng ofhardness or indentation resistance of thermoplastic pavementmarking material at ambient roadway/highway temperatures.Due to the speed at which basic thermoplastic pavementmarking cools, testing its hardness at elevated temperatures isdifficult, even at a relatively low 46C (115F). Existingnon-s
13、tandard methods are not consistent because they allow thesamples to change temperature during testing. By keeping both1This test method is under the jurisdiction of ASTM Committee D01 on Paintand Related Coatings, Materials, and Applications and is the direct responsibility ofSubcommittee D01.44 on
14、Traffic Coatings.Current edition approved June 1, 2017. Published August 2017. Originallyapproved in 2011. Last previous edition approved in 2016 as D7735 11 (2016).DOI: 10.1520/7735-17.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceas
15、tm.org. For Annual Book of ASTMStandards volume information, refer 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 StatesThis international standard was developed in accordance with i
16、nternationally recognized principles on standardization established in the Decision on Principles for theDevelopment of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.1the test samples and the hardness tester in
17、a regulated environ-ment before and during testing, the results are much morerepeatable within a laboratory. The goal for this method is toallow results from this test to be more reproducible fromlaboratory to laboratory.4.2 The methodology involves measuring the hardness ofthermoplastic pavement ma
18、rking by keeping the test sample inthe elevated temperature environment (a water bath) during thetesting process and using a Durometer that can be placed in thewater bath and function. This method could be performed in aglove box/oven if the door was not opened before or during thetesting.5. Signifi
19、cance and Use5.1 This method is based on the penetration of a specifictype of indentor when forced into the material under specifiedconditions. The indentation hardness is inversely related to thepenetration and is dependent on the elastic modulus, viscoelas-tic behavior of the material, geometry of
20、 the indentor, theapplied force and temperature at test. This test method isempirical and therefore primarily for control purposes. Nosimple relationship exists between indentation hardness deter-mined by this test method and any fundamental property of thematerial tested.6. Apparatus6.1 Safety Glas
21、ses.6.2 Aluminum Pans (20 mL) or adequate size for tester base.6.3 A Hardness Tester Type A Needle-type Durometer inaccordance with Test Method D2240.6.4 Constant 1000 g Load Weight for Type A Durometer.6.5 OptionalTest Block Kit containing Type A Durometersamples with values traceable to an accredi
22、ted calibrationlaboratory.6.6 Oven controllable to 46 6 1.0C (115 6 3.0F) (orwithin 2.5 % of set point).6.7 Water Bath controllable to 46 6 1.0C (115 6 3.0F) (orwithin 2.5 % of set point). A minimum of filtered water shouldbe used so that minerals in normal tap water cannot settle outand clog the in
23、ner workings of the device.6.8 Digital Timer in seconds.7. Hazards7.1 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 app
24、licabil-ity of regulatory limitations prior to use.8. Calibration and Standardization8.1 Calibration of the Type A hardness tester shall be doneregularly by following the manufacturers recommendationsand following the Calibration section of Test Method D2240.The test block kit can be used to verify
25、that the instrument isworking properly.9. Procedure9.1 Sample the thermoplastic pavement marking in accor-dance with Practice D7307 then begin preparation of samplesin accordance with Practice D7308.9.2 Pour thermoplastic that has been heated to 425F (or permanufacturers recommendation) into a 20 mL
26、 aluminum pan,or larger, to approximately half full, and then allow cooling toroom temperature.9.3 Turn on heater on water bath and oscillator or stirrer andallow the temperature to stabilize to 46 6 1.0C (115 6 3.0F)or as agreed upon by the involved parties9.4 Turn on oven set to 46 6 1.0C (115 6 3
27、.0F) or asmutually agreed upon by the involved parties and place theType A Durometer insideNOTE 1A bath or oven operated outside the recommended tempera-ture control may result in greater result variability.9.4.1 Other temperatures can be used when agreed uponbetween the parties involved.9.5 Place c
28、ooled thermoplastic pavement marking hardnesssample in water bath.9.6 Samples should be allowed to equilibrate to the requiredtemperature for at least one hour before being tested.9.6.1 Samples should be tested within three hours of beingplaced into the water.9.7 Before testing sample, remove lid fr
29、om water bath.Quickly place hardness tester from oven in the water bathmaking sure that the needle point and bottom of weight isbelow the waterline. This will ensure that tester is exactly thesame temperature as sample.NOTE 2If the tester is removed from the water during the testingprocess, its temp
30、erature will change and cause variations in results.Sample(s) can be tested multiple times as long as sample and tester bottomare not removed from water during testing.9.8 To test the sample, first set the timer so that at least afifteen second countdown can be counted once the measure-ment begins.9
31、.9 Place the hardness tester over the sample keeping bothtester and sample under water at all times.9.10 Lower the hardness tester over the center of the testsample.9.11 As soon as contact is made, start or check timer andrelease tester. The tester dial normally moves constantly lower.9.12 When fift
32、een seconds is reached, note the Type Ahardness value on the dial and record.9.12.1 Make at least two readings then average.NOTE 3Caution should be taken when making multiple readings notto test in the same spot or after the tester has been removed from the water.NOTE 4Care should be taken to ensure
33、 that the force is appliedvertically to the indentor tip, as lateral force or uneven surface will causeerrors in results.NOTE 5Excess water left in the device after testing can causemalfunctioning of the device. Therefore a pressing of the needle on apaper towel after use can allow for the draining
34、of retained water.D7735 1729.13 If sample fails, another reading may be takenimmediately, but do not place needle point in the sameindentation.10. Report10.1 Hardness measurements and average (Type A).10.1.1 Date of testing.10.1.2 Oven and water bath temperature.10.1.3 Manufacturer, type and serial
35、number of the Durom-eter.10.1.4 Date of last calibration and calibration due date.11. Precision and Bias311.1 The precision of this test method is based on anInterlaboratory study of ASTM D7735 Standard Test Methodfor Hardness of Thermoplastic Pavement Marking, conductedin 2010. A single laboratory,
36、 with three technicians, partici-pated in this study. Each of the technicians tested two differentmaterials a total of twelve times over a period of two days.Every “test result” reported represents an individual determi-nation. Except for the use of only a single laboratory, PracticeE691 was followe
37、d for the design and analysis of the data; thedetails are given inASTM Research Report No. RR:D01-1160.11.1.1 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
38、 the critical difference between two testresults for the same material, obtained by the same operatorusing the same equipment on the same day in the samelaboratory.11.1.2 Repeatability limits are listed in Table 1 and Table 2.11.1.3 Repeatability Limit (R)Two test results shall bejudged not equivale
39、nt if they differ by more than the “R” valuefor that material; “R” is the interval representing the criticaldifference between two test results for the same material,obtained by different operators using different equipment indifferent laboratories.11.1.4 In this study, since three different technic
40、ians in asingle laboratory performed the analyses, only modified repro-ducibility limits can be listed in Table 1 and Table 2.11.1.5 The reproducibility limit mentioned above is notused as specified in Practice E177, as it represents theanticipated variability between technicians in the same labora-
41、tory.11.1.5.1 Any judgment in accordance with statements11.1.1 and 11.1.3 would normally have an approximate 95 %probability of being correct, however the precision statisticsobtained in this ILS must not be treated as exact mathematicalquantities which are applicable to all circumstances and uses.T
42、he limited number of materials tested and laboratories report-ing results guarantees that there will be times when differencesgreater than predicted by the ILS results will arise, sometimeswith considerably greater or smaller frequency that the 95 %probability limit would imply. The repeatability li
43、mit and thereproducibility limit should be considered as general guides,and the associated probability of 95 % as only a roughindicator of what can be expected.11.2 BiasAt the time of the study, there was no acceptedreference material suitable for determining the bias for this testmethod, therefore
44、no statement on bias is being made.11.3 The precision statement was determined through sta-tistical examination of 72 results, from one laboratory, on twomaterials.11.4 To judge the equivalency of two test results, it isrecommended to choose the marking material closest incharacteristics to the test
45、 material.3Supporting data have been filed at ASTM International Headquarters and maybe obtained by requesting Research Report RR:D01-1160. ContactASTM CustomerService at serviceastm.org.TABLE 1 Hardness Day 1 (Type A units)Material AverageARepeatabilityStandardDeviationReproducibilityStandardDeviat
46、ionRepeatabilityLimitReproducibilityLimitxsrSRrRWhite Alkyd ExtrudeThermoplastic Pavement Marking46.06 2.29 2.36 6.42 6.60Yellow Alkyd ExtrudeThermoplastic Pavement Marking54.83 2.04 2.08 5.70 5.82AThe average of the technicians calculated averages.TABLE 2 Hardness Day 2 (Type A units)Material Avera
47、geARepeatabilityStandardDeviationReproducibilityStandardDeviationRepeatabilityLimitReproducibilityLimitxsrSRrRWhite Alkyd ExtrudeThermoplastic Pavement Marking42.00 1.81 2.61 5.06 7.30Yellow Alkyd ExtrudeThermoplastic Pavement Marking49.89 2.32 2.32 6.51 6.51AThe average of the technicians calculate
48、d averages.D7735 17312. Keywords12.1 Durometer; hardness; indentation; indentation hard-ness; thermoplastic pavement markingASTM International takes no position respecting the validity of any patent rights asserted in connection with any item mentionedin this standard. Users of this standard are exp
49、ressly advised that determination of the validity of any such patent rights, and the riskof infringement of such rights, are entirely their own responsibility.This standard is subject to revision at any time by the responsible technical committee and must be reviewed every five years andif not revised, either reapproved or withdrawn. Your comments are invited either for revision of this standard or for additional standardsand should be addressed to ASTM International Headquarters. Your comments will receive careful consideration a
