1、Designation: D7735 11 (Reapproved 2016)D7735 17Standard Test Method forType A Durometer Hardness Testing of Road MarkingThermoplasticThermoplastic Pavement Marking at ElevatedTemperatures1This standard is issued under the fixed designation D7735; the number immediately following the designation indi
2、cates the year 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 Type A Durometer h
3、ardness of road marking thermoplasticthermoplastic pavement markingmaterial at elevated temperatures.1.2 This test method is similar to Test Method D2240 for hardness with special attention given to keeping the temperature ofthe test sample and instrument constant. Within the highway materials commu
4、nity, it is sometimes known as “indentationresistance.”1.3 All materials, instruments or equipment used for the determination of temperature, hardness and time shall be traceable toNational Institute of Standards and Technology or other internationally recognized organizations parallel in nature.1.4
5、 The values stated in SI units are to be regarded as standard. The values given in parentheses are for information only.1.5 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibilityof the user of this standard to establish appropr
6、iate safety and health practices and determine the applicability of regulatorylimitations prior to use.1.6 This international standard was developed in accordance with internationally recognized principles on standardizationestablished in the Decision on Principles for the Development of Internation
7、al Standards, Guides and Recommendations issuedby the World Trade Organization Technical Barriers to Trade (TBT) Committee.2. Referenced Documents2.1 ASTM Standards:2D16 Terminology for Paint, Related Coatings, Materials, and ApplicationsD2240 Test Method for Rubber PropertyDurometer HardnessD7307 P
8、ractice for Sampling of Thermoplastic Traffic Marking MaterialsD7308 Practice for Sample Preparation of Thermoplastic Pavement Marking MaterialsE177 Practice for Use of the Terms Precision and Bias in ASTM Test MethodsE691 Practice for Conducting an Interlaboratory Study to Determine the Precision o
9、f a Test Method3. Terminology3.1 Definitions:3.1.1 The terms and definitions in Terminology D16 apply to this method.3.1.2 hardness, advthe value of resistance of a small penetrating device. In the case of the Type A Durometer in accordancewith Test Method D2240, the presser foot/indentor (spherical
10、 to 0.79 6 0.03 mm or 0.03 6 0.001 in.) is connected to a springloaded to a total of 0.075 N/Durometer units at full deflection. For reading of Type A hardness the instruments scale reads from0 to 100. Minimal deflection is 0 (softest) and maximum is 100 (hardest).3.1.3 thermoplastic, ntrafficpaveme
11、nt marking (same as 3.1.4).1 This test method is under the jurisdiction of ASTM Committee D01 on Paint and Related Coatings, Materials, and Applications and is the direct responsibility ofSubcommittee D01.44 on Traffic Coatings.Current edition approved April 1, 2016June 1, 2017. Published April 2016
12、August 2017. Originally approved in 2011. Last previous edition approved in 20112016 as D7735 111. (2016). DOI: 10.1520/7735-11R16.10.1520/7735-17.2 For referencedASTM standards, visit theASTM website, www.astm.org, or contactASTM Customer Service at serviceastm.org. For Annual Book of ASTM Standard
13、svolume information, refer to the standards Document Summary page on the ASTM website.This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication of what changes have been made to the previous version. Becauseit may not be technically possible to
14、adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current versionof the standard as published by ASTM is to be considered the official document.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Consh
15、ohocken, PA 19428-2959. United States13.1.4 thermoplastic traffcpavement markinga highly filled 100 % total solids highway marking system that when heated toa molten state can be extruded or sprayed onto a road surface and when cooled forms a solid durable delineator or road markingthermoplasticther
16、moplastic pavement marking usually melted to 220C (425F).4. Summary of Test Method4.1 This method was developed to enable the testing of hardness or indentation resistance of road marking thermoplasticther-moplastic pavement marking material at ambient roadway/highway temperatures. Due to the speed
17、at which basic road markingthermoplasticthermoplastic pavement marking cools, testing its hardness at elevated temperatures is difficult, even at a relativelylow 46C (115F). Existing non-standard methods are not consistent because they allow the samples to change temperature duringtesting. By keepin
18、g both the test samples and the hardness tester in a regulated environment before and during testing, the resultsare much more repeatable within a laboratory. The goal for this method is to allow results from this test to be more reproduciblefrom laboratory to laboratory.4.2 The methodology involves
19、 measuring the hardness of roadmarking thermoplastic pavement marking by keeping the testsample in the elevated temperature environment (a water bath) during the testing process and using a Durometer that can be placedin the water bath and function. This method could be performed in a glove box/oven
20、 if the door was not opened before or duringthe testing.5. Significance and Use5.1 This method is based on the penetration of a specific type of indentor when forced into the material under specifiedconditions. The indentation hardness is inversely related to the penetration and is dependent on the
21、elastic modulus, viscoelasticbehavior of the material, geometry of the indentor, the applied force and temperature at test. This test method is empirical andtherefore primarily for control purposes. No simple relationship exists between indentation hardness determined by this test methodand any fund
22、amental property of the material 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 in accordance with Test Method D2240.6.4 Constant 1000 g Load Weight for Type A Durometer.6.5 OptionalTest Block Kit co
23、ntaining Type A Durometer samples with values traceable to an accredited calibration laboratory.6.6 Oven controllable to 46 6 1.0C (115 6 3.0F) (or within 2.5 % of set point).6.7 Water Bath controllable to 46 6 1.0C (115 6 3.0F) (or within 2.5 % of set point). A minimum of filtered water shouldbe us
24、ed so that minerals in normal tap water cannot settle out and clog the inner workings of the device.6.8 Digital Timer in seconds.7. Hazards7.1 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibilityof the user of this standard t
25、o establish appropriate safety and health practices and determine the applicability of regulatorylimitations prior to use.8. Calibration and Standardization8.1 Calibration of the Type A hardness tester shall be done regularly by following the manufacturers recommendations andfollowing the Calibratio
26、n section of Test Method D2240. The test block kit can be used to verify that the instrument is workingproperly.9. Procedure9.1 Sample the road marking thermoplasticthermoplastic pavement marking in accordance with Practice D7307 then beginpreparation of samples in accordance with Practice D7308.9.2
27、 Pour thermoplastic that has been heated to 425F (or per manufacturers recommendation) into a 20 mL aluminum pan pan,or larger, to approximately half full, and then allow cooling to room temperature.9.3 Turn on heater on water bath and oscillator or stirrer and allow the temperature to stabilize to
28、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 3.0F) or as mutually agreed upon by the involved parties and place the Type ADurometer insideD7735 172NOTE 1A bath or oven operated outside the recommended temperature control may result in greate
29、r result variability.9.4.1 Other temperatures can be used when agreed upon between the parties involved.9.5 Place cooled thermoplastic pavement marking hardness sample in water bath and turn on oscillator or stirrer.bath.9.6 Samples should be allowed to equilibrate to the required temperature for at
30、 least one hour before being tested. Samplesshould be tested within three hours of being in the water. When all samples and testing equipment have stabilized to the settemperature, testing can begin.9.6.1 Samples should be tested within three hours of being placed into the water.9.7 Before testing s
31、ample, remove lid from water bath and turn off oscillator or stirrer. bath. Quickly place hardness tester fromoven in the water bath making sure that the needle point and bottom of weight is below the waterline. This will ensure that testeris exactly the same temperature as sample. If the tester is
32、removed from the water during the testing process, its temperature willchange and cause variations in results. Sample(s) can be tested multiple times as long as sample and tester bottom are not removedfrom water during testing.NOTE 2If the tester is removed from the water during the testing process,
33、 its temperature will change and cause variations in results. Sample(s) canbe tested multiple times as long as sample and tester bottom are not removed from water during testing.9.8 To test the sample, first set the timer so that at least a fifteen second countdown can be counted once the measuremen
34、tbegins.9.9 To test sample, set timer so that a fifteen second countdown will begin. Place Place the hardness tester over the samplekeeping both tester and sample under water at all times.9.10 Lower the hardness tester over the center of the test sample.9.11 As soon as contact is made, start or chec
35、k timer and release tester. The tester dial normally moves constantly lower.9.12 Lower the hardness tester over the center of the test sample. As soon as contact is made, start timer and release tester. Thetester dial should move constantly lower. When fifteen seconds is reached, note the Type A har
36、dness value on the dial and record.Make at least two readings then average. Caution should be taken when making multiple readings not to test in the same spot orafter the tester has been removed from the water.9.12.1 Make at least two readings then average.9.10 Care should be taken to ensure that th
37、e force is applied vertically to the indenter tip, as lateral force will cause errors incalibration.NOTE 3Caution should be taken when making multiple readings not to test in the same spot or after the tester has been removed from the water.NOTE 4Care should be taken to ensure that the force is appl
38、ied vertically to the indentor tip, as lateral force or uneven surface will cause errors inresults.NOTE 5Excess water left in the device after testing can cause malfunctioning of the device. Therefore a pressing of the needle on a paper towel afteruse can allow for the draining of retained water.9.1
39、3 If sample fails, another reading may be taken immediately, 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.TABLE 1 Hardness Day 1 (Type A units)Material AverageARepeatabili
40、tyStandardDeviationReproducibilityStandardDeviationRepeatabilityLimitReprocucibilityReproducibilityLimitx sr SR r RWhite AlkydExtrude RoadMarkingThermoplastic46.06 2.29 2.36 6.42 6.60White AlkydExtrudeThermoplastic Pavement Marking46.06 2.29 2.36 6.42 6.60Yellow AlkydExtrude RoadMarkingThermoplastic
41、54.83 2.04 2.08 5.70 5.82Yellow AlkydExtrudeThermoplastic Pavement Marking54.83 2.04 2.08 5.70 5.82A The average of the technicians calculated averages.D7735 17310.1.3 Manufacturer, type and serial number of the Durometer.10.1.4 Date of last calibration and calibration due date.11. Precision and Bia
42、s311.1 The precision of this test method is based on an Interlaboratory study ofASTM D7735 Standard Test Method for Hardnessof Road Marking Thermoplastics,Thermoplastic Pavement Marking, conducted in 2010. A single laboratory, with threetechnicians, participated in this study. Each of the technician
43、s tested two different materials a total of twelve times over a periodof two days. Every “test result” reported represents an individual determination. Except for the use of only a single laboratory,Practice E691 was followed for the design and analysis of the data; the details are given in ASTM Res
44、earch Report No.RR:D01-1160.11.1.1 Repeatability Limit (r)Two test results obtained within one laboratory shall be judged not equivalent if they differ bymore than the “r” value for that material; “r” is the interval representing the critical difference between two test results for the samematerial,
45、 obtained by the same operator using the same equipment on the same day in the same laboratory.11.1.2 Repeatability limits are listed in Table 1 and Table 2.11.1.3 Repeatability Limit (R)Two test results shall be judged not equivalent if they differ by more than the “R” value for thatmaterial; “R” i
46、s the interval representing the critical difference between two test results for the same material, obtained by differentoperators using different equipment in different laboratories.11.1.4 In this study, since three different technicians in a single laboratory performed the analyses, only modifiedr
47、eproducibility limits can be listed in Table 1 and Table 2.11.1.5 The reproducibility limit mentioned above is not used as specified in Practice E177, as it represents the anticipatedvariability between technicians in the same laboratory.11.1.5.1 Any judgment in accordance with statements 11.1.1 and
48、 11.1.3 would normally have an approximate 95 % probabilityof being correct, however the precision statistics obtained in this ILS must not be treated as exact mathematical quantities whichare applicable to all circumstances and uses. The limited number of materials tested and laboratories reporting
49、 results guaranteesthat there will be times when differences greater than predicted by the ILS results will arise, sometimes with considerably greateror smaller frequency that the 95 % probability limit would imply. The repeatability limit and the reproducibility limit should beconsidered as general guides, and the associated probability of 95 % as only a rough indicator of what can be expected.11.2 BiasAt the time of the study, there was no accepted reference material suitable for determining the bias for this testmethod, therefore no statement o
