1、Designation: D 6454 99 (Reapproved 2006)Standard Test Method forDetermining the Short-Term Compression Behavior of TurfReinforcement Mats (TRMs)1This standard is issued under the fixed designation D 6454; the number immediately following the designation indicates the year oforiginal adoption or, in
2、the case of revision, the year of 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 The test method establishes the procedures for evalua-tion of the deformations of a
3、 turf reinforcement mat (TRM)under short-term compressive loading. This test method isstrictly an index test method to be used to verify the compres-sive strength consistency of a given manufactured geosyn-thetic. Results from this test method should not be consideredas an indication of actual or lo
4、ng-term performance of theTRM in field applications.1.2 Since these TRMs experience multidirectional compres-sive loadings in the field, this test method will not show actualfield performance and should not be used for this specificobjective. The evaluation of the results also should recognizethat t
5、he determination of the short term single plane compres-sive behavior of geosynthetics does not reflect the installedperformance of TRMs and, therefore, should not be used as theonly method of product or performance specification.1.3 The values in SI units are to be regarded as the standard.The valu
6、es stated in inch-pound units are provided in paren-theses for information only.1.4 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 det
7、ermine the applica-bility of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:2D 4354 Practice for Sampling of Geosynthetics for TestingD 4439 Terminology for GeosyntheticsD 5199 Test Method for Measuring the Nominal Thicknessof Geosynthetics3. Terminology3.1 Definitions
8、:3.1.1 compressive deformation, L, nthe decrease ingage length produced in the test specimen by a compressiveload.3.1.2 compressive strain, nd, nthe ratio of compressivedeformation to the gage length of the test specimen.3.1.3 gage length, L, nin compression testing, the mea-sured thickness of the t
9、est specimen under specified compres-sional force, expressed in units of length prior to compressiveloading. D 51993.1.4 geosynthetic, na planar product manufactured frompolymeric material used with foundation, soil, rock, earth, orany other geotechnical engineering related material as anintegral pa
10、rt of a man-made project, structure, or system.D 44393.1.5 index test, na test procedure which may contain aknown bias but which may be used to establish an order for aset of specimens with respect to the property of interest.D 44393.1.6 yield point, nthe first point on the load-deformationcurve at
11、which an increase in deformation occurs without acorresponding increase in load.3.1.6.1 DiscussionSome geosynthetics do not exhibit anexact yield point. The tested TRM may exhibit a less steepslope at yield. In addition, it should be stated that the yieldpoint also may be the ultimate strength of th
12、e TRM.3.1.7 For definitions of terms relating to geotextiles, refer toTerminology D 4439.4. Summary of Test Method4.1 Specimens are mounted between parallel plates in a loadframe. Compressive loads are applied at a constant rate ofcrosshead movement. The deformations are recorded as afunction of loa
13、d. The compressive stress and strain are evalu-ated and plotted. The compressive yield point is evaluated fromthe stress/strain relationship for those materials that exhibit adetectable compressive yield point.5. Significance and Use5.1 The compression behavior test for TRMs is intended tobe an inde
14、x test. It is anticipated that the results of the1This test method is under the jurisdiction of ASTM Committee D35 onGeosynthetics and is the direct responsibility of Subcommittee D35.05 on Geosyn-thetic Erosion Control.Current edition approved Jan. 1, 2006. Published February 2006. Originallyapprov
15、ed in 1999. Last previous edition approved in 1999 as D 645499.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM websit
16、e.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United Spression behavior test will be used to evaluate product.The results of the analyses also may be used to compare therelative compressive yield points of materials that exhibit adetectable co
17、mpressive yield point. It is anticipated that thistest will be used for quality control testing to evaluateuniformity and consistency within a lot or between lots wheresample geometry factors, for example, thickness, or materialsmay have changed.NOTE 1This is a one-dimensional test for compressive l
18、oading of aTRM in one plane.5.1.1 The compressive yield point of TRMs may be evalu-ated from the stress/strain relationship. Many materials exhibitcompressive deformation but may not show a distinct com-pressive yield point.5.2 This test method can be used to evaluate the short-termstress/strain beh
19、avior of TRMs under compressive stress whileloaded at a constant rate of deformation.5.3 This test method may be used for acceptance testing ofcommercial shipments of TRMs but caution is advised becauseinterlaboratory testing is incomplete.5.3.1 In the case of a dispute arising from differences inre
20、ported test results when using this test method for acceptancetesting of commercial shipments, the purchaser and the sup-plier should conduct comparative tests to determine if there isstatistically bias between their laboratories. Competent statis-tical assistance is recommended for the investigatio
21、ns of bias.As a minimum, two parties should take a group of testspecimens from material shipped to project. The test specimensthen should be assigned randomly in equal numbers to eachlaboratory for testing. The average results from the twolaboratories should be compared using the Students t-test for
22、unpaired data and an acceptable probability level chosen by thetwo parties before the testing is begun. If bias is found, eitherits cause must be found and corrected, or the purchaser andsupplier must agree to interpret future test results in the light ofthe known bias.6. Apparatus6.1 Loading Mechan
23、ismThe loading mechanism shall becapable of applying compressive loads at a constant rate ofdeformation of 10 % on the nominal thickness of the testspecimen/min or 1 mm/min, whichever is greater.NOTE 2Some loading mechanisms, especially the older models, donot have the capability of adjusting the ra
24、te of deformation to the specificrate required. For these instruments, the user and producer shouldestablish mutually agreed upon testing rates; however, the rate ofdeformation selected should not be greater than 10 % on the nominalthickness of the test specimen/min or 1 mm/min, whichever is greater
25、.6.2 Fixed PlateThe bottom fixed plate shall be larger thanthe specimen to be tested. It shall be flat, smooth, andsupported completely and uniformly.NOTE 3It is recommended that the minimum fixed plate width beequal to the sample width plus twice the thickness of the test sample. Thisshould support
26、 the sample through the range of deformation and preventdraping or flexing displacement.6.3 Movable PlateThe movable plate shall be of sufficientthickness and strength to preclude any bending during loading.It shall be parallel to the bottom fixed plate and attached to thecompression mechanism. A sp
27、herical loading block of thesuspended, self-aligning type is recommended. The dimensionsand shape of the top movable, plate shall depend on thespecimen dimensions and geometry. In general, both lengthand width of the top movable plate should each be at least 20 %greater than the length and width of
28、the specimens.6.4 Load IndicatorUse a load-indicating mechanism thathas an accuracy of 6 1 % of the maximum indicated value ofthe test (force).6.5 Deformation IndicatorUse a deformation-indicatingmechanism that has an accuracy of 6 1.0 % of the maximumindicated value of the test (deformation).6.6 Mi
29、crometer Dial Gage, caliper or steel rule, suitable formeasuring dimensions of the specimens to+1%.7. Sampling7.1 Lot SampleDivide the product into lots and take thelot sample as directed in Practice D 4354.7.2 Laboratory SampleUnits in the laboratory sampleshould be the same as the units in the lot
30、 sample for the lot tobe tested. Take a sample extending across the full width, that is,cross-machine direction, of the TRM production unit of suffi-cient length, that is, machine direction, so that the requirementsof 7.3 can be met. Take a sample that will exclude materialfrom the outer wrap of a r
31、oll, if applicable, unless the sampleis taken at the production site, then the inner and outer wrapmaterial may be used.7.3 Test SpecimensCut five specimens from each unit inthe laboratory sample with each specimen being at least 120 by120 mm/mm2(4.7 by 4.7 in.)2.8. Conditioning8.1 Bring the specime
32、ns to the moisture and temperatureequilibrium in the atmosphere for testing permanent rollederosion control products, that is, a temperature of 21+ 2C (70+ 4F) and a relative humidity of 60 + 10 %.9. Procedure9.1 Measure the length, width and thickness of the specimento an accuracy of 6 1%.9.1.1 The
33、 nominal thickness shall be determined using TestMethod D 5199.9.2 The test specimen shall be placed on the bottom plateand centered with respect to the axis of the loading mechanism.The loading mechanism shall be moving at the requiredconstant speed at or before the point of contact with thesample.
34、9.3 The rate of crosshead movement shall be 10 % on thenominal thickness of the test specimen/min or 1 6 0.1 mm(0.046 0.004 in.)/min, whichever is greater or as agreed uponbetween the user and manufacturer.9.4 Use crosshead movement as a measure of deformation.If an automatic recorder is not used, m
35、easure the deformationin increments no greater than 0.5 % of the original thickness ofthe specimen. At each measurement, record the deformationand the corresponding load.9.5 Continue until a yield point is reached, or until themaximum acceptable deformation limit has been reached,whichever occurs fi
36、rst.D 6454 99 (2006)29.6 The test specimen then should be unloaded and removedfrom the loading mechanism.9.7 Repeat the preceding procedures until five specimensare tested.10. Calculation10.1 If an automatic recorder is not used, construct aload-deformation curve from the incremental values obtained
37、in accordance with 9.4.10.2 In a typical load-deformation curve (see Fig. 1) there isa toe region, AC, that may not represent a property of thematerial. It is an artifact caused by the alignment or seating ofthe specimen. If such a circumstance arises, in order to obtaincorrect values of such parame
38、ters as strain, yield point, etc.,this artifact must be compensated for to give the corrected zeropoint on the deformation axis. Using a straightedge, carefullyextend to the zero force line the steepest portion of theforce-deflection or force-strain curve. This establishes the“zero deformation” or “
39、zero strain” points (Point B in Fig. 1).Measure all distances for deformation or strain calculationsfrom this point.10.2.1 If there is a compressive yield point (as Point Y inFig. 1), read the load and measure the specimen deformation(distance B-D). Calculate the residual thickness of the speci-mens
40、 at various fixed loads in addition to the yield point.Follow this with a report that indicates the values of both yieldand residual thickness at various loads. These results can bereported in a graph or table.FIG. 1 Typical Load Deformation CurveFIG. 2 Stress Strain CurveD 6454 99 (2006)310.2.2 Cal
41、culate the compressive stress by dividing the loadat the compressive yield point by the initial horizontal cross-sectional area of the specimen.10.3 The compressive stress with the corresponding com-pressive strain shall be plotted for each test.10.4 The compressive yield point shall be reported as
42、thearithmetic mean and minimum of the five tests.NOTE 4Not all geosynthetics exhibit a well-defined compressiveyield point. In such cases, if a compressive stress value is needed forcomparative purposes, use a strain value agreed upon between thepurchaser and the buyer. Such a value might be the poi
43、nt where there is asignificant change in the slope of the stress-strain curve, as shown by thetwo curves in Fig. 2.11. Report11.1 Report the following information:11.1.1 The description of the type of TRM tested.11.1.2 The lot or production unit represented.11.1.3 The dimensions of the test specimen
44、s.11.1.4 The test data, including: initial thickness, cross-sectional area, rate of deformation, and the deformations,strains and corresponding stresses.11.1.5 Test curves expressing the compressive load (stress)as a function of the deformation.11.1.6 The results of each specimen tested, plus the av
45、erageof the compressive yield point of the TRM, if the TRM has acompressive yield point.11.1.7 Date of test.11.1.8 Astatement of any unusual occurrences or departuresfrom the suggested procedures.11.1.9 Machine type and date of last certification.12. Precision and Bias12.1 PrecisionThe precision of
46、the procedure in this testmethod is being evaluated.12.2 BiasThe value of the compressive yield point ofTRMs can be defined only in terms of a test method. When thistest method is the defining method, measurements of thecompressive yield point have no bias.13. Keywords13.1 compression; deformation;
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