1、Designation: F3181 16Standard Test Method forThe Un-notched, Constant Ligament Stress Crack Test(UCLS) for HDPE Materials Containing Post- ConsumerRecycled HDPE1This standard is issued under the fixed designation F3181; the number immediately following the designation indicates the year oforiginal a
2、doption 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 an un-notched constant liga-ment stress (UCLS
3、) test for use with HDPE materials thatcontain post-consumer recycled HDPE (PCR-HDPE). Con-taminants in the PCR-HDPE can initiate stress cracks atelevated temperatures, and this test method evaluates theresponse of these materials to a constant applied stress.1.2 The test method is focused on HDPE c
4、orrugated pipecontaining PCR-HDPE, but can be used in other applicationswhere PCR-HDPE is used.1.3 The test utilizes the same devices used to perform theNCTL test (Test Method D5397) and the NCLS test (TestMethod F2136), but the test is conducted with differentspecimens and with the use of water ins
5、tead of a surfactantsolution. The test specimen is larger than standard NCLS andNCTL specimens to increase the number of contaminantparticles in the specimen that might grow cracks.1.4 The values stated in inch-pound units are to be regardedas standard. The values given in parentheses are mathematic
6、alconversions to SI units that are provided for information onlyand are not considered standard.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 p
7、ractices and determine the applica-bility of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:2D1600 Terminology forAbbreviated Terms Relating to Plas-ticsD2837 Test Method for Obtaining Hydrostatic Design Basisfor Thermoplastic Pipe Materials or Pressure Design Basisfor
8、 Thermoplastic Pipe ProductsD4703 Practice for Compression Molding ThermoplasticMaterials into Test Specimens, Plaques, or SheetsD5397 Test Method for Evaluation of Stress Crack Resis-tance of Polyolefin Geomembranes Using Notched Con-stant Tensile Load TestD638 Test Method for Tensile Properties of
9、 PlasticsF412 Terminology Relating to Plastic Piping SystemsF2136 Test Method for Notched, Constant Ligament-Stress(NCLS) Test to Determine Slow-Crack-Growth Resis-tance of HDPE Resins or HDPE Corrugated Pipe2.2 AASHTO Documents:3Report 696 National Cooperative Highway Research Pro-gram (NCHRP)3. Te
10、rminology3.1 Definitions: Definitions are in accordance with Termi-nology F412, and abbreviations are in accordance with Termi-nology D1600, unless otherwise specified.3.2 Definitions of Terms Specific to This Standard:3.2.1 bi-directional shift constants, nConstants used toshift elevated temperatur
11、e and stress data to service conditions;e.g. Popelar shift constants for HDPE.3.2.2 contaminant, ninorganic particulate matter or othernon-HDPE material that creates inclusions or stress risers inthe crystalline structure of HDPE.3.2.3 post-consumer recycled HDPE (PCR-HDPE),nHDPE materials from prod
12、ucts that have served a previousconsumer purpose (for example, laundry detergent bottles,milk bottles and other consumer goods).4. Significance and Use4.1 This test method is a way to evaluate the effects ofcontaminant particles found in HDPE products containing1This test method is under the jurisdi
13、ction of ASTM Committee F17 on PlasticPiping Systems and is the direct responsibility of Subcommittee F17.40 on TestMethods.Current edition approved Feb. 1, 2016. Published March 2016. DOI: 10.1520/F3181162For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer S
14、ervice at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.3Available from American Association of State Highway and TransportationOfficials (AASHTO), 444 N. Capitol St., NW, Suite 249, Washington, DC 20001,http:/ww
15、w.transportation.org.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States1PCR-HDPE, primarily corrugated pipe. Particles of significantnumber, size and shape can reduce the slow crack growthresistance of the products. This test is performe
16、d in waterwithout a controlled defect such as a notch. Since there is nonotch, it is not necessary to use a surfactant in the water bath.It is a constant load test.4.2 This test may be used to evaluate various blends ofrecycled and virgin materials. For example, a material withhigh stress crack resi
17、stance and few contaminants can beblended with materials that are less resistant to cracking toenhance the overall stress crack resistance of the blend.4.3 The test can be conducted at various temperature andstress conditions. If at least three (3) different temperature/stress conditions are evaluat
18、ed, an estimate of the servicelifetime of the material can be predicted with the use ofbi-directional shifting or the rate process method.4.4 The test can also be performed under a single appliedload and a single temperature to create a single point test usefulfor comparative purposes as well as for
19、 quality control.5. Apparatus5.1 Blanking DieA die suitable of cutting Test MethodD638, Type I tensile specimens. Alternatively, specimens maybe prepared by machining.5.2 Stress-Crack Testing DeviceA lever-loading machinewith a mechanical advantage of up to 10:1. The most commondevices used for corr
20、ugated pipe resins have a maximummechanical advantage of 5:1, but higher ratios would allow fortesting of thicker specimens. The device is similar or identicalto those used for Test Methods D5397 and F2136. The deviceshall have a timer capable of recording failures within thenearest 0.1 hr. for each
21、 individual lever arm. The timer muststop when a test specimen fails. An example of an acceptabledevice is shown in Fig. 1 and Fig. 2. Fig. 1 shows some testspecimens mounted in the testing frame. Fig. 2 shows theframe mounted in a water bath with the weights hung on thelever arms.5.3 Water BathA he
22、ated and stirred water bath deepenough to cover the test specimens mounted in the frame to apoint above the reduced section and into the top tab. The bathmust be capable of heating to a constant temperature of 80 61 C.NOTE 1Baths that once contained surfactant solutions for other stresscrack tests a
23、re extremely difficult to clean. Residual surfactant will reducethe failure times of this test and may stay present for many months andafter many cleanings.5.4 Compression Molding Press and MoldA set-up forcompression molding a plaque at least 7 in. (178 mm) by 7 in.(178 mm) and cooling it at 15C pe
24、r minute in accordance withPractice D4703. The mold shall be designed in a way to allowthe removal of at least five Test method D638, Type I tensilespecimens with the geometry described in Section 6.6. Test Specimen6.1 PlaqueAcompression molded plaque manufactured inaccordance with Practice D4703 wi
25、th a cooling rate of 27F(15C) per minute. A flash picture-frame mold or a flash moldwith machined cavity can be used. The mold must be capableof producing a plaque that is 0.04 6 0.005 in. (1.0 6 0.1 mm)FIG. 1 Test ApparatusF3181 162thick for a width of 2.25 in. (57.1 mm), then transitions to athick
26、ness between 0.090 in (2.3 mm) and 0.095 in (2.4 mm).The transition must occur across 1.125 in. (28.6 mm) on eitherside of the narrow section and stay constant for the full lengthof the test specimen 6.5 in. (170 mm). This will result in anarrow area for the test specimen that is 0.50 in. (12.7 mm)w
27、ide and 2.25 in. long (57.1 mm) and 0.04 6 0.005 in. (1.0 60.1 mm) thick. The end tabs must be between 0.090 and 0.095in. (2.3 and 2.4 mm) thick. The thickness will transition fromthe narrow section to the ends across 1.125 in. (28.6 mm) oneither side.NOTE 2It is important that the material is adequ
28、ately homogenizedprior to compression molding into a plaque. This may be done via meltblending with a twin screw lab extruder or other methods that are deemedeffective at homogenizing blends of plastic materials.6.2 Test SpecimenThe test specimen produced from theplaque described in 6.1. The specime
29、n is prepared by cuttingout a Test Method D638 Type I specimen from a compressionmolded plaque prepared according to 5.4. Next, a hole, 0.219in. (5.6 mm) is placed in each tab with the use of a732 in. drillbit. The finished specimen and associated dimensions areshown in Fig. 3 and Table 1. At least
30、five (5) specimens arerecommended for each material tested.7. Procedure7.1 Measure the width and thickness of each test specimento an accuracy of 0.001 in. (0.03 mm) in accordance to D5397.Calculate the load necessary to apply a tensile stress of 650 psi(4.48 MPa) onto the test specimen with the fol
31、lowing equation:AL 5!t!w!# 2 lw1gwMA(1)where:AL = applied load (lbs) = applied stress (psi)t = thickness (in.)w = width (in.)lw = lever weight (lbs)gw = grip weight (lbs)MA = mechanical advantage7.2 Attach five test specimens to the load frame and placethe frame into the water bath that has been pre
32、-heated andstabilized at the test temperature.7.3 Prepare each weight tube to the weight necessary toapply the proper stress to each individual lever arm. Include theattachment pin as part of the applied load. Apply the weighttubes to the lever arms, taking care to apply the load gently.Reset the ti
33、mers to zero to start the test.7.4 Once the test has been terminated, record all the failuretimes and make note of whether the failure occurred in thereduced area or near the grip. Specimens that fail near the gripshall be classified as a non-test and shall not be considered inany data analysis. Als
34、o note whether the crack started at anedge (one ductile “horn”) or in the center of the specimen (2FIG. 2 Hanging WeightsF3181 163ductile “horns”). See Fig. 4 and Fig. 5 for illustrations oftypical failures that occur in this test.8. Single Stress and Single Temperature Test for QualityAssurance8.1
35、The standard conditions for quality control or qualityassurance testing is a temperature of 176 6 2F (80.0 6 1.0C) and an applied initial stress of 650 psi (4.48 MPa).8.2 The minimum required failure time at these standardconditions shall be specified in the respective product stan-dards.FIG. 3 UCLS
36、 Test Specimen (Dimensions shown below)TABLE 1 Dimensions for Test Specimen Shown in Fig. 3Description (see Fig. 1) Dimension in. (mm) Description (see Fig. 1) Dimension in. (mm)LO Overall length $6.50 (170) w Width of narrow section 0.50 0.02 (13 0.5)L Length of narrow section 2.25 0.02 (57 0.5) TO
37、 Maximum thickness of specimen $ 0.90 (23)D Distance between taper 3.96 0.04 (100 1) t Thickness of test section 0.040 0.005 (1 0.1)R Radius of fillet 3.00 0.04 (76.2 1) HC Distance to hole center 0.375 0.020 (9.5 0.5)G Gage length 2.00 0.01 (50.8 0.3) DH Hole diameter 0.219 0.020 (5.6 0.5)WO Overal
38、l width 0.75 0.25 (19 6) . .FIG. 4 Contaminant That Caused Stress Cracking in Test SpecimenF3181 1649. Multiple Conditions for Service Lifetime Estimates9.1 Test five specimens each under the following set ofconditions:176 2F (80C 1.0) and 650 psi (4.48 MPa) of stress176 2F (80C 1.0) and 450 psi (3.
39、10 MPa) of stress158 2F (70C 1.0 ) and 650 psi (4.48 MPa) of stressOnce each set of five specimens has broken, record thefailure times and note whether the failure occurred in thereduced section or near the grips. Failures that occur near thegrips shall not be considered in the analysis. The service
40、lifetime of the material at ambient temperatures and field stresscan be predicted by using bi-directional shifting to create amaster curve at the desired ambient temperature. Other meth-ods (for example, the Rate Process Method as detailed in theAppendices in Test Method D2837) may also be used to p
41、redictlifetime to cracking at service conditions based on this testingat elevated temperatures and stresses.10. Report10.1 Report the following general information:10.1.1 Complete identification of the material.10.1.2 Details of the plaque preparation, including coolingrate.10.1.3 The test temperatu
42、re.10.1.4 The applied initial room temperature stress.10.1.5 The length, width, and thickness of the reduced areasection of the test specimen.10.1.6 The calculations for applied stress, including anyadjustment for the weight of the loading levers.10.2 Report the following for a single point test:10.
43、2.1 The failure times for the five (5) specimens, theaverage failure time and the standard deviation.10.3 Report the following for a service lifetime estimate:10.3.1 The three sets of conditions (temperature and stress)10.3.2 The 15 failure times, the averages and standarddeviations for each set.10.
44、3.3 The multiplication factor used for shifting and thetemperature to which the data were shifted.10.3.4 A plot of log shifted stress vs. log shifted time.10.3.5 The estimated failure time under the typical condi-tions (factored service stress and temperature) and the esti-mated stress for 50 and 10
45、0 year estimated service lifetimes.11. Precision and Bias11.1 Since failure times of test specimens are dependent onthe presence of contaminants, there is naturally significantscatter in the test results. Data to determine the precision andbias of this test method is currently being generated and wi
46、ll beincorporated into this standard upon completion.12. Keywords12.1 BFF; contaminant; corrugated HDPE pipe; corrugatedplastic pipe; NCLS; post-consumer recycled HDPE; recycledmaterials; recycled plastics; UCLSASTM International takes no position respecting the validity of any patent rights asserte
47、d in connection with any item mentionedin this standard. Users of this standard are expressly 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 th
48、e 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
49、careful consideration at a meeting of theresponsible technical committee, which you may attend. If you feel that your comments have not 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 copies) of this standard may be obtained by contacting
