1、Designation: D7735 11Standard Test Method forType A Durometer Hardness Testing of Road MarkingThermoplastic 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 of r
2、evision, 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 ofroad marking thermoplastic material at elevat
3、ed temperatures.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, instruments
4、 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 given in pare
5、ntheses 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 limitati
6、ons prior to use.2. Referenced Documents2.1 ASTM Standards:2D16 Terminology for Paint, Related Coatings, Materials,and ApplicationsD2240 Test Method for Rubber PropertyDurometerHardnessD7307 Practice for Sampling of Thermoplastic TrafficMarking MaterialsD7308 Practice for Sample Preparation of Therm
7、oplasticTraffic 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: The terms and definitions in TerminologyD16 apply to this method.3.
8、1.1 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 total of 0.075 N/Durometer units at fulldefle
9、ction. For reading of Type A hardness the instrumentsscale reads from 0 to 100. Minimal deflection is 0 (softest) andmaximum is 100 (hardest).3.1.2 thermoplastic, ntraffic marking (same as 3.1.3).3.1.3 thermoplastic traffc markinga highly filled 100 %total solids highway marking system that when hea
10、ted to amolten state can be extruded or sprayed onto a road surface andwhen cooled forms a solid durable delineator or road markingthermoplastic usually melted to 220C (425F).4. Summary of Test Method4.1 This method was developed to enable the testing ofhardness or indentation resistance of road mar
11、king thermoplas-tic material at ambient roadway/highway temperatures. Due tothe speed at which basic road marking thermoplastic cools,testing its hardness at elevated temperatures is difficult, even ata relatively low 46C (115F). Existing non-standard methodsare not consistent because they allow the
12、 samples to changetemperature during testing. By keeping both the test samplesand the hardness tester in a regulated environment before andduring testing, the results are much more repeatable within a1This test method is under the jurisdiction of ASTM Committee D01 on Paintand Related Coatings, Mate
13、rials, and Applications and is the direct responsibility ofSubcommittee D01.44 on Traffic Coatings.Current edition approved Nov. 1, 2011. Published December 2011. DOI:10.1520/7735-11.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.
14、org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.laboratory. The goal for this method is to allow results fromth
15、is test to be more reproducible from laboratory to laboratory.4.2 The methodology involves measuring the hardness ofroadmarking thermoplastic by keeping the test sample in theelevated temperature environment (a water bath) during thetesting process and using a Durometer that can be placed in thewate
16、r bath and function. This method could be performed in aglove box/oven if the door was not opened before or during thetesting.5. Significance and Use5.1 This method is based on the penetration of a specifictype of indentor when forced into the material under specifiedconditions. The indentation hard
17、ness is inversely related to thepenetration and is dependent on the elastic modulus, viscoelas-tic behavior of the material, geometry of the indentor, theapplied force and temperature at test. This test method isempirical and therefore primarily for control purposes. Nosimple relationship exists bet
18、ween indentation hardness deter-mined by this test method and any fundamental property of thematerial tested.6. Apparatus6.1 Safety Glasses.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 1
19、00 g Load Weight for Type A Durometer.6.5 OptionalTest Block Kit containing Type A Durometersamples with values traceable to an accredited 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) (orwith
20、in 2.5 % of set point).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 applica
21、bil-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 that
22、 the instrument isworking properly.9. Procedure9.1 Sample the road marking thermoplastic in accordancewith Practice D7307 then begin preparation of samples inaccordance with Practice D7308.9.2 Pour thermoplastic that has been heated to 425F (or permanufacturers recommendation) into a 20 mL aluminum
23、panto approximately half full, and then allow cooling to roomtemperature.9.3 Turn on heater on water bath and allow the temperatureto stabilize to 46 6 1.0C (115 6 3.0F) or as agreed upon bythe involved parties9.4 Turn on oven set to 46 6 1.0C (115 6 3.0F) or asmutually agreed upon by the involved p
24、arties 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 cooled hardness sample in water bath and turn ono
25、scillator or stirrer.9.6 Samples should be allowed to equilibrate to the requiredtemperature for at least one hour before being tested. Samplesshould be tested within three hours of being in the water. Whenall samples and testing equipment have stabilized to the settemperature, testing can begin.9.7
26、 Before testing sample, remove lid from water bath andturn off oscillator or stirrer. Quickly place hardness tester fromoven in water bath making sure that the needle point andbottom of weight is below the waterline. This will ensure thattester is exactly the same temperature as sample. If the teste
27、r isremoved from the water during the testing process, its tem-perature will change and cause variations in results. Sample(s)can be tested multiple times as long as sample and testerbottom are not removed from water during testing.9.8 To test sample, set timer so that a fifteen secondcountdown will
28、 begin. Place hardness tester over samplekeeping both under water at all times.9.9 Lower the hardness tester over the center of the testsample. As soon as contact is made, start timer and releasetester. The tester dial should move constantly lower. Whenfifteen seconds is reached, note the Type A har
29、dness value onthe dial and record. Make at least two readings then average.Caution should be taken when making multiple readings not totest in the same spot or after the tester has been removed fromthe water.9.10 Care should be taken to ensure that the force is appliedvertically to the indenter tip,
30、 as lateral force will cause errors incalibration.9.11 If sample fails, another reading may be taken immedi-ately, but do not place needle point in the same indentation.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 Manu
31、facturer, type and serial 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 Road Marking Thermoplastics, conducted in3Su
32、pporting data have been filed at ASTM International Headquarters and maybe obtained by requesting Research Report RR:D01-1160.D7735 1122010. A single laboratory, with three technicians, participatedin this study. Each of the technicians tested two differentmaterials a total of twelve times over a pe
33、riod of two days.Every “test result” reported represents an individual determi-nation. Except for the use of only a single laboratory, PracticeE691 was followed for the design and analysis of the data; thedetails are given in ASTM Research Report No. D011160.11.1.1 Repeatability Limit (r)Two test re
34、sults 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
35、 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 equivalent if they differ by more than the “R” valuefor that material; “R” is the interval representing the criticaldifference between two test results
36、for the same material,obtained by different operators using different equipment indifferent laboratories.11.1.4 In this study, since three different technicians in asingle laboratory performed the analyses, only modified repro-ducibility limits can be listed in Table 1 and Table 2.11.1.5 The reprodu
37、cibility limit mentioned above is notused as specified in Practice E177, as it represents theanticipated variability between technicians in the same labora-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, h
38、owever the precision statisticsobtained in this ILS must not be treated as exact mathematicalquantities which are applicable to all circumstances and uses.The limited number of materials tested and laboratories report-ing results guarantees that there will be times when differencesgreater than predi
39、cted by the ILS results will arise, sometimeswith considerably greater or smaller frequency that the 95 %probability limit would imply. The repeatability limit and thereproducibility limit should be considered as general guides,and the associated probability of 95 % as only a roughindicator of what
40、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 no statement on bias is being made.11.3 The precision statement was determined through sta-tistical examination of 72 results, from one laborato
41、ry, on twomaterials.11.4 To judge the equivalency of two test results, it isrecommended to choose the marking material closest incharacteristics to the test material.12. Keywords12.1 Durometer; hardness; indentation; indentation hard-ness; road marking thermoplasticTABLE 1 Hardness Day 1 (Type A uni
42、ts)Material AverageARepeatabilityStandardDeviationReproducibilityStandardDeviationRepeatabilityLimitReprocucibilityLimitx srSRrRWhite AlkydExtrude RoadMarkingThermoplastic46.06 2.29 2.36 6.42 6.60Yellow AlkydExtrude RoadMarkingThermoplastic54.83 2.04 2.08 5.70 5.82AThe average of the technicians cal
43、culated averages.TABLE 2 Hardness Day 2 (Type A units)Material AverageARepeatabilityStandardDeviationReproducibilityStandardDeviationRepeatabilityLimitReprocucibilityLimitx srSRrRWhite AlkydExtrude RoadMarkingThermoplastic42.00 1.81 2.61 5.06 7.30Yellow AlkydExtrude RoadMarkingThermoplastic49.89 2.3
44、2 2.32 6.51 6.51AThe average of the technicians calculated averages.D7735 113ASTM 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 expressly advised that determination of the validi
45、ty 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 commen
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47、t received a fair hearing you shouldmake your views known to the ASTM Committee on Standards, at the address shown below.This standard is copyrighted by ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959,United States. Individual reprints (single or multiple cop
48、ies) of this standard may be obtained by contacting ASTM at the aboveaddress or at 610-832-9585 (phone), 610-832-9555 (fax), or serviceastm.org (e-mail); or through the ASTM website(www.astm.org). Permission rights to photocopy the standard may also be secured from the ASTM website (www.astm.org/COPYRIGHT/).D7735 114
