1、Designation: D 5970 96 (Reapproved 2002)Standard Practice forDeterioration of Geotextiles from Outdoor Exposure1This standard is issued under the fixed designation D 5970; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of
2、 last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon (e) indicates an editorial change since the last revision or reapproval.1. Scope1.1 This test method covers evaluating the deterioration intensile strength and strain after outdoor exposure.1.2 The de
3、terioration is assessed as a reduction in strengthand strain at failure from the unexposed geotextile.1.3 The specific location of the light and weather exposureis made on the basis of a site specific decision between theparties involved.1.4 The values stated in SI units are to be regarded as thesta
4、ndard. The inch-pound units given in parentheses are forinformation only.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
5、the applica-bility of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:D 5035 Test Method for Breaking Force and Elongation ofTextile Fabrics (Strip Method)23. Terminology3.1 Definitions:3.1.1 geotextilea permeable geosynthetic comprisedsolely of textiles.3.1.2 strain at
6、 failurethe strain of the geotextile at theelongation corresponding to the failure strength. It is expressedas elongation over original gage length.3.1.3 strengththe maximum, or ultimate, stress that amaterial can withstand. For geotextiles, expressed in units offorce per unit width.3.1.4 Discussion
7、In some geotextiles, after reaching maxi-mum stress, there is a lesser strength that retained. This lesserstrength is referred to as the ultimate strength of the geotextile.3.1.5 ultraviolet degradationthe photochemical changeinduced by exposure to ultraviolet radiation that results indeterioration
8、of the performance characteristics of the poly-meric structure.4. Summary of Test Method4.1 Geotextile coupons are attached to a test frame oriented45 from the horizontal and facing due South at designatedlocation for exposure times of 1, 2, 4, 8, 12, and 18 months.Exposure shall begin so as to ensu
9、re that material is exposedduring the maximum intensity of ultraviolet light of the year.On the continental United States this shall be mid-June.4.1.1 Unexposed control coupons shall be retained fortesting.4.2 After each exposure time the appropriate coupons arebrought into a laboratory for strength
10、 determination. Theresults of these tests are compared to the strength determinedfor the unexposed coupons. The user may be interested inexposure times other than specified in this test method. Thesetimes should be noted in reporting the results.4.3 The results are presented in the form of various p
11、lots.5. Significance and Use5.1 Artificial exposure tests or outdoor exposure tests at onelocation may not be applicable to a project site at anotherlocation. This test method evaluates geotextiles under sitespecific atmospheric conditions over an 18 month period. Adegradation curve based on strengt
12、h, elongation, or modulus,or all of these, may be developed for the geotextile beingevaluated.5.2 This test method can be used for comparative testing ofthe degradation of geotextiles.5.3 This test method is considered to be a performance testand as such the responsibility for its performance rests
13、with thespecifying or purchasing agency.NOTE 1The intent of this procedure is to provide the user of this testmethod and geotextiles a standard by which to evaluate ultravioletdegradation at a specific site in terms of expected life, not in terms ofincident radiation and temperature. If desired, the
14、 user may want to havethe necessary measurement and recording equipment at each site to dothis. However, the expense of doing so at each site may be prohibitive.Therefore, this is not a specific requirement of this test method.1This practice is under the jurisdiction of ASTM Committee D35 on Geosyn-
15、thetics and is the direct responsibility of Subcommittee D35.02 on EnduranceProperties.Current edition approved May 10, 1996. Published December 1996.2Annual Book of ASTM Standards, Vol 07.02.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United
16、States.6. Apparatus6.1 The frame for holding the coupons during the exposurephase of this test consists of a wooden frame (for example, asheet of exterior plywood) suitably braced so that it resides ata 45 angle with the horizontal.6.1.1 The frame is to be unpainted with the surface pro-tected from
17、the effects of water and sunlight by varnishing thesurface.6.1.2 The supported frame is firmly positioned in a locationfree from obstruction from trees or other sources of shade. Itshall face due South. It shall be placed such that no heat or sunlight is reflected on it from surrounding buildings. I
18、f this is notpossible, it shall be noted in the test results report.6.1.3 The frame shall be suitably anchored using anchors,stakes, or adequate weights on the support legs.6.2 The geotextiles coupons shall be fastened in such a wayso that undue stress, that could result in premature failure of theg
19、eotextile, are not induced with care, staples may be used.7. Sampling7.1 Lot SampleDivide the product into lots and take oneunit per lot as the lot sample.7.1.1 DiscussionThis test method is intended to be per-formed by the purchaser for the purpose of determine geotex-tile performance under site sp
20、ecific conditions. Should amanufacturer perform this test it is not intended that eachmanufactured lot be sampled and tested. This is because thetest is considered to be time intensive.7.2 Laboratory SampleTake for the laboratory sample asample of the geotextile extending the full width of the roll
21、ofsufficient length along the selvedge from each sample roll suchthat the requirements of 8.1 are met. The sample shall excludematerial from the outer wrap of the roll or the inner wraparound the core unless the sample is taken at the production siteat which point outer or inner wrap may be used.7.3
22、 See Fig. 1 for explanation of sample versus couponversus specimen.8. Test Coupon Preparation8.1 Cut six test coupons for each exposure time in themachine direction 300 by 180 mm (12 by 7 in.) from thelaboratory sample. The shortest measurement shall be in themachine direction:Machine or Cross Machi
23、ne DirectionControl 1C1 1C2 1C3 1C4 1C5 1C6Month 1 1M(CM)1 1M2 1M3 1M4 1M5 1M6Month 2 2M1 2M2 2M3 2M4 2M5 2M6Month 18 18M1 18M2 18M3 8M4 18M5 18M68.1.1 Repeat 8.1 for the cross machine direction, with theshortest measurement in the cross machine direction.8.2 Cut six test coupons from each direction
24、 to be used ascontrol coupons. These will act as the control specimens for allexposure times. Place the control coupons in a black polyeth-ylene bag, and seal to prevent deterioration of the controlsamples due to exposure to ultraviolet light. Store the bag withthe coupons in a cool, dry location.9.
25、 Procedure9.1 Firmly attach the six coupons for exposure to theoutdoor test frame as described in 6.2. In the case of staplesbeing used, locate them in the outer 25 mm (1 in.) of thecoupon, with approximately four staples per each 300 mm (12in.) width, and three staples along each 180 mm (7 in.) len
26、gth.NOTE 2If a full sheet of plywood, 1200 by 2400 mm (4 by 8 ft), isused, seven sets of coupons can be attached to the frame. This will allowan approximately 25 mm (1 in.) space around each sample. See lowerphotograph of Fig. 1.NOTE 3The long dimension of the frame and the coupons attached tothe fr
27、ame shall run parallel to the surface on which the frame rests.9.2 Obtain appropriate weather information, such as aver-age and mean temperatures, amount of rainfall, cloud coverversus sunlight, from the nearest national weather station.9.3 After each appropriate length of exposure, that is, 1, 2,4,
28、 8, 12, and 18 months, remove the appropriate coupons fromthe frame and bring them to the laboratory.9.3.1 Condition the coupons in the standard atmosphere fortesting geosynthetics.9.4 Trim the outer 25 mm (1 in.) of the long dimension fromeach side of the coupon such that the remaining samplemeasur
29、es 250 mm (10 in.) in width. Dispose of the trimmaterial.9.5 Carefully cut the remaining 250 mm (10 in.) widecoupon into five 50 mm (2 in.) wide, strip tensile testspecimens. The specimens will measure 180 mm (7 in.) long.9.6 Determine the breaking strength in kilonewtons permetre (pounds force per
30、inch) of the control coupons, asNOTE 1Product roll is from the manufacturer. Samples are cut fromthe product roll. Coupons for outdoor exposure are cut from samples.Specimens for tensile testing are cut from coupons.FIG. 1 Relation Between Sample, Coupon, SpecimenD 5970 96 (2002)2directed in Test Me
31、thod D 5035 using a 50 mm (2-in.) widthstrip, except, a CRE or CRT type testing device shall beoperated at 305 6 10 mm/min (12 612 in./min) unlessspecified otherwise. The distance between the clamps shall be75 6 1mm(36 0.05 in.). There may be no overall correlationbetween the results obtained with t
32、he CRE machine and theCRT machine. Consequently, these two breaking load testerscannot be used interchangeably.9.6.1 Determine the breaking strength of the exposed speci-mens from each exposure time, as directed in Test MethodD 5035 using a 50 mm (2-in.) width strip, except, a CRE orCRT type testing
33、 device shall be operated at 305 6 10 mm/min(12 612 in./min) unless specified otherwise. The distancebetween the clamps shall be 75 6 1mm(36 0.05 in.). Theremay be no overall correlation between the results obtained withthe CRE machine and the CRT machine. Consequently, thesetwo breaking load tester
34、s cannot be used interchangeably. Incase of controversy, the CRE method shall prevail.9.7 Record elongation at break.10. Calculation10.1 Determine the average ultimate force and elongationfor each exposure time.10.2 Calculate the average strength for each exposure timeas follows:Tavg5 Pavg/w (1)wher
35、e:Tavg= average strength in units of force per unit widthkN/m (lbf/in.),Pavg= average force from 10.1, andw = original width of test specimen, 50 mm (2 in.).10.3 Calculate a percent strength retained as follows:Tret5 Tavg/Tunexposed! 3 100 (2)where:Tret= percent strength retained,Tavg= strength of e
36、xposed specimens from 10.2,andTunexposed= strength of unexposed specimens from 10.2.10.4 Calculate the average elongation at break.10.5 Calculate the average strain at failure as follows:Savg5 Lavg2 Lorig!/Lorig(3)where:Savg= average strain at failure,Lavg= average elongation at failure from 10.4,Lo
37、rig= original gage length, that is, 75 mm (3 in.).10.6 Calculate a percent strain retained at failure by com-parison of the average strain at failure for exposed specimensto the average strain at failure for the unexposed specimens asfollows:Sret5 Savg/Sunex! 3 100 (4)where:Sret= percent strain at f
38、ailure retained,Savg= average strain at failure from 10.4, andSunex= average strain at failure for unexposed (control)specimens.10.7 From the results of 10.2, determine the standarddeviation and the coefficient of variation for each exposuretime, and each direction tested.10.8 Plot graphs of percent
39、 strength retained, percent strainat failure, or modulus versus exposure time, or all of these.10.8.1 Plot graphs of percent strength retained, percentstrain at failure, or modulus versus total ultraviolet radiation, ifmeasured, or all of these, for each exposure time.11. Report11.1 Report the follo
40、wing information:11.1.1 The test was performed according to this test method,11.1.2 Any variations from this test method,11.1.3 A listing of the test results from Section 10,11.1.3.1 If requested the following results may be reported:individual specimen results, standard deviations and coefficientof
41、 variations for each exposure time and,11.1.4 The plots developed in 10.8,11.1.5 A summary of mean and average temperatures,rainfall, and cloud cover versus sunlight, if obtained fromweather stations, for each exposure period,11.1.6 The inclusive dates of exposure for each set of testresults, and11.
42、1.7 The orientation of the exposure based on the azimuthof the exposed face.12. Precision and Bias12.1 PrecisionThe precision of this test method is beingdetermined.12.2 BiasThe bias of this test method, if any, is beingdetermined.13. Keywords13.1 degradation; geotextile; outdoor exposure; strengthr
43、etained; ultraviolet degradationD 5970 96 (2002)3ASTM 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 validity of any such patent rights
44、, 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 re
45、vision of this standard or for additional standardsand should be addressed to ASTM International Headquarters. Your comments will receive 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 yo
46、u 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 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).D 5970 96 (2002)4
