1、Designation:D479688(Reapproved2004) Designation: D4796 10Standard Test Method forBond Strength of Thermoplastic Traffic Marking Materials1This standard is issued under the fixed designation D4796; 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 provides an instrumental means for the determination of thermoplastic traff
3、ic marking material bondstrengths using cement bricks and steel cubes. loading fixtures.1.2 The values stated in SI units are to be regarded as the standard. The values given in parentheses are for information only.1.3 This standard does not purport to address all of the safety concerns, if any, ass
4、ociated with its use. It is the responsibilityof the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatorylimitations prior to use.2. Referenced Documents2.1 ASTM Standards:2C109/C109M Test Method for Compressive Strength of Hydrauli
5、c Cement Mortars (Using 2-in. or 50-mm Cube Specimens)D16 Terminology for Paint, Related Coatings, Materials, and ApplicationsC881/C881MSpecification for Epoxy-Resin-Base Bonding Systems for Concrete D4541 Test Method for Pull-Off Strength ofCoatings Using Portable Adhesion TestersD883Terminology Re
6、lating to Plastics 5179 Test Method for Measuring Adhesion of Organic Coatings to Plastic Substrates byDirect Tensile TestingE284Terminology of Appearance D7234 Test Method for Pull-Off Adhesion Strength of Coatings on Concrete Using PortablePull-Off Adhesion TestersF412Terminology Relating to Plast
7、ic Piping Systems D7307 Practice for Sampling of Thermoplastic Traffic Marking MaterialsD7308 Practice for Sample Preparation of Thermoplastic Traffic Marking MaterialsE177 Practice for Use of the Terms Precision and Bias in ASTM Test MethodsE691 Practice for Conducting an Interlaboratory Study to D
8、etermine the Precision of a Test Method3. Terminology3.1DefinitionsDefinitions are in accordance with Terminology D883, E284, and F412 unless otherwise indicated.3.1 The terms and definitions in Terminology D16 apply to this method.3.2 Definitions of Terms Specific to This Standard:3.2.1 cement bric
9、k, na brick formed by mixing cement and fine sand together and allowing to harden. a brick formed bymixing cement and fine sand together and allowing to harden with 210.9 to 351.5 kg/cm2(3000 to 5000 psi) compression strength.3.2.2 loading fixture, n(also referred to as dollies, studs, or jigs) meta
10、l fixture round and flat on one end for bonding to testsample and shaped on the other end for attaching to tensile testing device (Fig. 1).3.2.3 thermoplastic, ntraffic marking (same as 3.2.33.2.4).3.2.33.2.4 thermoplastic traffc marking, na highly filled 100 % total solids highway marking system th
11、at when heated to amolten state can be extruded or sprayed onto a road surface and when cooled forms a solid durable delineator or road markingthermoplastic usually melted to 218C (425F).4. Summary of Test Method4.1The thermoplastic specimen is prepared for this test by first melting a sample to its
12、 application temperature under continuousagitation. The specimen is then applied to the specified cement brick by a hot drawdown blade. Two steel cubes are thenimmediately placed onto the hot thermoplastic line and the excess thermoplastic trimmed away from around the two steel cubes.1This test meth
13、od 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 JuneDec. 1, 2004.2010. Published June 2004.March 2011. Originally approved in 1988. Last p
14、revious edition approved in 19982004 asD479688(1998).D4796 88 (2004). DOI: 10.1520/D4796-88R04.10.1520/D4796-10.2For referenced ASTM standards, visit the ASTM website, www.astm.org, or contact ASTM Customer Service at serviceastm.org. For Annual Book of ASTM Standardsvolume information, refer to the
15、 standards Document Summary page on the ASTM website.1This 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 adequately depict all changes ac
16、curately, 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 Conshohocken, PA 19428-2959, United S
17、tates.After the trimming is complete, the steel cubes are removed. A heated steel cube is bonded with epoxy to the square ofthermoplastic and allowed to cure overnight before determining the bond strength on a Dillon dynamometer or similar device.4.1 The thermoplastic specimen is prepared for this t
18、est by first melting a sample to its application temperature under continuousagitation. The specimen is then applied to the specified cement brick using a hot drawdown bar (Fig. 2), heated to 104 6 2C (2206 5F), at 3.175 mm (125 mils) thickness. While the thermoplastic is still soft, three cuts are
19、made with a 40.6 mm (1.6 in.)diameter die, heated to 104 6 2C (220 6 5F), in order to separate the test area from the rest of the drawdown. The die may beheated while submerged in glycerin to prevent thermoplastic from sticking to the die. The test areas are allowed to cool slightlyand then three 40
20、.6 mm (1.6 in.) diameter heated loading fixtures are laid on the test areas. The samples are then allowed to cureovernight before determining the bond strength on a tensile testing device.5. Significance and Use5.1 The function of this test method is to provide numerical instrumental results indicat
21、ing the cohesive or adhesive, orboth,and/or adhesive bond strength of thermoplastic traffic marking to a specified cement brick substrate.5.2 The use of this test method allows the user and manufacturer to control the quality of the product and make inferences aboutthe performance of the thermoplast
22、ic traffic marking product. Results from these tests also provide information helpful inresearching and developing thermoplastic traffic marking materials.5.3Strict adherence to the procedures outlined is necessary for precision of the test method. Under no conditions should the bondstrength be acce
23、pted unless there is conformance to 9.14. Precise results are obtained only when one steel block is epoxied to thethermoplastic traffic marking on the cement brick.5.3 The method has been revised to be more consistent to methodology in other ASTM bond methods for coatings in TestMethods D4541, D5179
24、, and D7234.5.4 Strict adherence to the procedures outlined is necessary for precision of the test method. Under no conditions should thebond strength be accepted unless there is conformance to the method.6. Types of Separation in Bond Strength Tests6.1 Thermoplastic to Steel Cube SeparationThis typ
25、e of separation occurs where there is an insufficient bond between thethermoplastic and steel cube probably due to insufficient coverage of the epoxy adhesive. Thermoplastic to Loading FixtureSeparationThis type of separation occurs where there is an insufficient bond between the thermoplastic and l
26、oading fixtureprobably due to insufficient coverage of the thermoplastic to the fixture at the time of placement or too low temperature or both.This separation is acceptable when it exceeds the specified bond strength.6.2 Thermoplastic to Thermoplastic SeparationThis type of separation is caused by
27、internal cohesive failure of thethermoplastic. This separation is acceptable when it exceeds the specified bond strength.6.3 Thermoplastic to Cement Brick SeparationThis type of separation is caused by the failure of the bond between thethermoplastic specimen and the cement brick. This type of separ
28、ation is caused by the failure of the bond between theFIG. 2 Drawdown Bar (in inches)D4796 102thermoplastic specimen and the cement brick. This separation is acceptable when it exceeds the specified bond strength.6.4 Cement Brick to Cement BrickThis type of separation is caused by the internal cohes
29、ive failure of the brick. This is due,in most cases, to a bond between the thermoplastic and cement brick that exceeds the cohesive strength of the cement brick. Thisseparation is not acceptable when the bond strength values are lower than specified.7. Apparatus7.1 Agitator Blade, 150 mm (6 in.) lon
30、g with a 10 mm (12-in.) steel shaft and a 45 by 25 by 3 mm (134 by 1 in. by18-in.) straighthorizontal steel blade. Loading Fixture (three), 40.6 mm (1.6 in.) diameter 50.8 sq mm (2 sq in.) area on one end and post forattaching to the tensile testing device and load cell (Fig. 1).7.2 Capped Bolts, tw
31、o, 16 mm (58 in.) in size.7.3Cement Bricks,9by5by19cm(312 by2by712-in.) in size with a compressive strength of 3000 to 5000 psi (Note 1). ,9 by 5.5 by 19 cm (3.75 by 2.5 by 7.75 in.) in size with a compressive strength of 210.9 to 351.5 kg/m2(3000 to 5000 psi).NOTE1Concrete bricks conforming to Test
32、 Method C109/C109M have been used but proved more variable due to migration of a thin veneer of cementto the top of the brick making determinations erratic. The cement bricks may be obtained from local block plants. The term “cement” brick is commonfor the industry and is used in this test method ex
33、tensively. 1Cement bricks can be obtained at a local block plant or Block USA. Home improvementpaving bricks usually do not have enough cohesive strength. Concrete bricks conforming to Test Method C109/C109M have been used but proved morevariable due to migration of a thin veneer of cement to the to
34、p of the brick making determinations erratic. The cement bricks may be obtained from localblock plants. The term cement brick is common for the industry and is used in this test method extensively.7.3 Tensile Testing Equipment with a minimum capacity of 910 6 1 kg (200 6 2 lbs) having a pull-rate ca
35、pability of 7 mm/min(0.275 in./min).NOTE2The unit should be fitted with a steel frame to hold the cement brick for testing.7.4Dynamometer, with a capacity of 6000 lbs in 2700 kg in 10 kg (25-lb) divisions having a pull-rate capability of14 in./min.(6 mm/min) (Note 2) (See Fig. 1, Fig. 2, 2The unit s
36、hould be fitted with a steel frame to hold the cement brick for testing (seeFig. 3, and Fig. 4).7.4 Draw Down Bar, 5 by 2.5 by 10 cm (2 by 1 by 4 in.) in size capable of laying down a 3.175 mm (125 mil or 0.125 in.)molten thermoplastic film 50.8 mm (2 in.) wide (Fig. 2).7.5 Draw Down Blade, 5 by 2.5
37、 by 10 cm (2 by 1 by 4 in.) in size capable of laying down a 125 mil (0.125 in.) wet thermoplasticfilm 2-in. wide. Hot Plate, capable of maintaining 104 6 2C (220 6 5F).FIG. 1 Loading FixtureD4796 1037.6 Drill Press, or other apparatus capable of agitating the thermoplastic during meltdown to the ap
38、plication temperature at 600to 800 r/min in the jacketed electric pots. Oven, capable of maintaining 218 6 2C (425 6 5F).7.7 Epoxy Resin and Hardener, Type I or II, Grade 2, Class C in accordance with Specification C881/C881M. Die Cutter, 40.6mm (1.6 in.) diameter (Fig. 4).7.8 Hot Plate, capable of
39、maintaining 537C.7.9Gravity Convection Oven, capable of maintaining 260C.7.10Electric Pots, Jacketed, for heating and melting the thermoplastic to 218C.7.11Spatulas, for cutting, stirring, and shaping the thermoplastic.7.12Steel Cubes, two, 50 by 50 by 50 mm (2 by 2 by 2 in.) in size threaded in the
40、 center of one side for a 16-mm (58-in.) cappedbolt. Metal Frame for holding concrete brick (Fig. 3).8. Sampling8.1Samples may be obtained by an appropriate quartering or riffle sampling method where deemed necessary considering thephysical form of the material.8.1 Samples may be obtained by followi
41、ng Practice D7307.9. Procedure9.1Under continuous agitation melt a specimen of the thermoplastic to be tested to a temperature of 218C. If the specimen isa dry powder mix, allow the specimen to cool to 193C under continuous agitation and reheat under agitation to 218C.9.1 After sampling a batch of r
42、oad marking thermoplastic by Practice D7307, prepare a representative molten sample for testingby following Practice D7308.NOTE3Dry powder mixed thermoplastic must be conditioned to ensure a homogeneous melt necessary for consistent results. Premelted blockthermoplastic does not require this conditi
43、oning. The specimen may be melted on a hot plate set at 537C or in a jacketed electric pot. Continuous agitationis necessary to prevent scorching and settling. If the specimen is melted in an oven set at 260C, the specimen must be agitated every 15 min until 218Cis reached.9.2Heat the draw down blad
44、e to 218C.FIG. 3 Brick HolderD4796 1049.3Obtain a dry room temperature cement brick that has been brushed or textured on the side to be coated with thermoplastic.9.4Heat one 50 by 50 by 50 mm (2 by 2 by 2 in.) steel cube in an oven or on a hot plate to 49C for 2 h prior to making thethermoplastic dr
45、aw down on the cement brick.9.5When the thermoplastic specimen is melted to 218C under continuous agitation, remove the agitator blade from thethermoplastic.9.6Remove the draw down blade from the hot plate and immediately place it on the cement brick and make the draw down thefull length of the bric
46、k with the melted thermoplastic on the brushed or rough textured side of the brick.9.7Immediately place two room temperature steel cubes on the thermoplastic approximately 25 mm (1 in.) from each end of thebrick and trim the plastic from around the two steel cubes before the plastic cools and harden
47、s.9.8Remove the steel cubes by hand and allow the thermoplastic to cool for 1 h.9.9Prepare the epoxy solution using the proper resin and hardener ratio and mix thoroughly.9.10Remove the steel cube heated to 49C from the oven and place a small amount of epoxy on the heated cube. Place the steelcube o
48、n the thermoplastic square and rub to ensure an even coating and good adhesion. To ensure an even coating, remove thesteel cube from the thermoplastic square and visually inspect the square and cube and then replace the steel cube on the squareand rub. Do not allow any excess epoxy solution to flow
49、from the steel cube and thermoplastic square onto the cement brick.NOTE4Only one steel cube can be epoxied at a time to the thermoplastic on the brick because the shock of the first pull will cause a premature releaseof the second thermoplastic square.9.11Place a weight such as a cement brick on the steel cube epoxied to the thermoplastic square and allow to cure for a minimumtime of 8 h.9.12Screw the 15.9-mm (58-in.) capped bolt into the steel cube epoxied to the thermoplastic and place the brick into the steelframe mounted
