1、Designation: D8058 17Standard Test Method forDetermining the Flexural Strength of a GeosyntheticCementitious Composite Mat (GCCM) Using the Three-PointBending Test1This standard is issued under the fixed designation D8058; the number immediately following the designation indicates the year oforigina
2、l 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 provides guidelines for testing theflexural stren
3、gth of cured geosynthetic cementitious compositemat (GCCM) products in a three (3)-point bend apparatus.1.2 The values in SI units are to be regarded as the standard.Values in inch-pound units are in parentheses for information.1.3 This standard may involve hazardous operations,equipment, and climat
4、es. This standard does not purport toaddress all of the safety concerns, if any, associated with itsuse. It is the responsibility of the user of this standard toestablish appropriate safety and health practices and deter-mine the applicability of regulatory limitations prior to use.1.4 This internat
5、ional standard was developed in accor-dance with internationally recognized principles on standard-ization established in the Decision on Principles for theDevelopment of International Standards, Guides and Recom-mendations issued by the World Trade Organization TechnicalBarriers to Trade (TBT) Comm
6、ittee.2. Referenced Documents2.1 ASTM Standards:2D76/D76M Specification for Tensile Testing Machines forTextilesD4354 Practice for Sampling of Geosynthetics and RolledErosion Control Products (RECPs) for TestingD4439 Terminology for GeosyntheticsD8030/D8030M Practice for Sample Preparation for GCCM3
7、. Terminology3.1 For definitions of common technical terms used in thisstandard, refer to Terminology D4439.3.2 Definitions:3.2.1 cured, adja description of the state of a GCCM afterhydration for a specified period of time and quantity of waterwhen known under specified conditions, followed by a per
8、iodof time where the GCCM is kept under a specified environ-mental condition during which the cementitious material con-tinues to cure and develop compressive strength.3.2.2 curing time, nthe time subsequent to initial hydra-tion of the GCCM and immediately prior to the testing of thematerial, durin
9、g which the cementitious material is allowed toharden and form its final strength using the specific process forcuring as specified in 8.3.3.2.3 dry, adja description of the state of a GCCM beforeit has been exposed to a hydration source and typicallydescribes the “as-received” dry product after con
10、ditioning in aprescribed manner.3.2.4 final breaking load, nthe maximum load achievedprior to rupture of materials.3.2.5 final deflectionthe deflection of the specimen fromits initial position (before testing begins) measured at mid spanat the final breaking load.3.2.6 final flexural strength, nthe
11、final flexural strength,expressed in megapascals (pound-force per square inch), iscalculated from the final breaking load of a hydrated and curedGCCM specimen, oriented in either the machine or cross-machine direction, loaded as simple beams, when breaks occurperpendicular to the specimen length, wi
12、th the load applied atthe center, in a three-point loading fixture.3.2.7 geosynthetic cementitious composite mat (GCCM),na factory-assembled geosynthetic composite consisting of acementitious layer contained within a layer or layers ofgeosynthetic materials that becomes hardened when hydrated.3.2.8
13、hydration, nexposure of the GCCM, in this case, towater in prescribed conditions for a prescribed time and waterquantity when known.3.2.9 initial breaking load, nthe maximum load at whichthe first crack in the cementitious matrix of the GCCM forms.1This test method is under the jurisdiction of ASTM
14、Committee D35 onGeosynthetics and is the direct responsibility of Subcommittee D35.05 on Geosyn-thetic Erosion Control.Current edition approved July 1, 2017. Published July 2017. Originally approvedin 2017. DOI: 10.1520/D8058-17.2For referenced ASTM standards, visit the ASTM website, www.astm.org, o
15、rcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United StatesThis international
16、standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for theDevelopment of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.13
17、.2.10 initial deflection, nthe deflection of the specimenfrom its initial position (before testing begins) measured at midspan at the initial breaking load.3.2.11 initial flexural strength, nthe initial flexuralstrength, expressed in megapascals (pound-force per squareinch), is calculated from the i
18、nitial breaking load (maximumload at first crack) of a hydrated and cured GCCM specimen,oriented in either the machine or cross-machine direction,loaded as simple beams, with the load applied at the center, ina three-point loading fixture.3.2.12 initial modulus of elasticity, na measure of aspecimen
19、s resistance to elastic deformation, measured in theregion of linear response, before the initial breaking load.3.2.13 mean final flexural strength, nthe mean final flex-ural strength is the average result of ten or more final flexuralstrength values expressed in megapascals (pound-force persquare i
20、nch).3.2.14 mean initial flexural strength, nthe mean initialflexural strength is the arithmetic mean of ten or more initialflexural strength values when breaks occur perpendicular to thespecimen length. Breaks expressed in megapascals (pound-force per square inch).3.2.15 topside, nthe side of the m
21、aterial that would faceupwards in a normal installation.4. Summary of Test Method4.1 A hydrated and cured GCCM specimen is loaded as asimple beam in a three-point loading fixture, with the loadapplied at the center. The load level is recorded simultaneouslywith the deflection to characterize the ini
22、tial and final flexuralstrength, the deflection of the specimen at those loads, and theinitial modulus of the specimen.5. Significance and Use5.1 This test method is applicable for testing geosyntheticcementitious composite mats in a cured state. It is used with aconstant rate of extension-type tens
23、ion apparatus.5.2 This test is an index test that may be used for manufac-turing quality control (MQC). This test is appropriate forcharacterizing the flexural properties of a GCCM.6. Apparatus6.1 Flexural Testing MachineA constant rate of extension(CRE)-type of testing machine described in Specific
24、ationD76/D76M shall be used. When using the CRE-type tensiletester, the recorder must have adequate pen response toproperly record the force-elongation curve as specified inSpecification D76/D76M.6.2 Three-Point Flexural FixtureA fixture designed foruse with the flexural testing machine with two bot
25、tom supportsand a third edge which is used to load the specimen from thetop at mid span. The fixture is designed so that the specimen isloaded and can be analyzed as a simple beam. The supports arecylindrical on the specimen contact surface with a 3.2-mm(18-in.) minimum radius and a 12.7-mm (12-in.)
26、 maximumradius. These support points must be designed so that theycannot exert longitudinal or vertical constraints (rocker-typebearing edges, rollers, etc.). The loading surface must have asimilar edge bearing. The test span shall be 100 6 1.6 mm (46116 in.) and the load line and support shall be p
27、arallel. Mounta dial micrometer reading to 0.25 mm (0.01 in.), or an equallysensitive apparatus, to bear on the loading member or on thespecimen at mid span to determine the deflection of thespecimen at the center of the test span as the load is measured.6.3 Sample ContainersSuitable containers whic
28、h are re-sistant to corrosion and change in mass upon repeated exposureto moisture, materials of varying pH, and cleaning.6.4 DieA sample-cutting device of dimensions consistentwith 8.2.6.5 Rotary Tile Saw, with diamond-tipped blades capable ofdry cutting samples, used for cutting cured samples to p
29、rede-termined dimensions using pattern marked on cured specimenwith template and markers.6.6 Miscellaneous Knives, Templates, Markers, Rulers,Saw, as required for marking, measuring, and cutting speci-mens to fixed dimensions before measurement of weight. Aknife with a “snap off” type blade is recom
30、mended for cuttingGCCMs, which can dull blade tips rapidly.6.7 Thickness GageA measurement device for character-izing the thickness of the specimens in the vicinity of thebreaks which occur during the flexural test. The thickness gageshall have flat parallel anvils of between 10-mm (0.4-in.) and15-m
31、m (0.6-in.) diameter with an accuracy of 60.05 mm(60.002 in.).6.8 MicrometerA calibrated measurement device used forprecise measurement of components with a required accuracyof 60.25 mm (60.01 in.), or an equally sensitive apparatus.7. Sampling, Test Specimens, and Test Units7.1 Lot SampleFor the lo
32、t sample, refer to Practice D4354for discussion of recommended practice for breaking upshipments of GCCMs into lots for testing.7.2 Laboratory SamplesFor the laboratory sample, take afull-width sample approximately 1 m (40 in.) long in themachine direction from each roll in the lot sample. The exact
33、length must be chosen to ensure enough sample is cured to cutthe required number of specimens for both the machine andcross-machine directions. The sample may be taken from theend portion of a roll, provided there is no evidence it isdistorted or different from other portions of the roll. In cases o
34、fdispute, take a sample that will exclude material from the outerwrap of the roll or the inner wrap around the core, of at least30 in. from the interior end of the roll (wrapped around thecore) or exterior end of the material roll, measured from theedge of the cementitious portion of the material.7.
35、3 Test SpecimensFor tests in the machine direction andthe cross-machine direction, respectively, take from eachsample in the laboratory sample the number of specimensdirected in Section 8. Take specimens at random from thelaboratory sample, with those for the measurement of themachine direction tens
36、ile properties from different positionsD8058 172across the sample width, and the specimens for the measure-ment of the cross-machine direction tensile properties fromdifferent positions along the length of the sample. Specimensmust not be taken near the edge of the material. Specimensmust be taken a
37、 minimum of 4 in. from the edge of thematerial, measured from the edge of the cementitious portionof the material. Specimens shall be collected for testing in boththe topside and bottom-side direction facing up.8. Test Specimen Preparation8.1 Number of Specimens:8.1.1 Unless otherwise agreed upon, t
38、he fixed number of ten(10) specimens for each the machine direction and the cross-machine direction tests should be used.8.2 Test Specimen Size:8.2.1 Prepare each finished specimen a minimum of 40 61.6 mm (1.6 6116 in.) wide by at least 160 6 1.6 mm (6.3 6116 in.) long with the length dimension bein
39、g designated andaccurately parallel to the direction for which the flexuralstrength is being measured. Specimens may be prepared usinga die, saw, or knives.8.2.2 The orientation of the specimen in the flexural test willaffect which face of the GCCM is under tensile load. Thespecimens should have a m
40、ark applied on the topside facewhich is to be up when loaded into the three-point flexuralfixture.8.3 Specimen Preparation:8.3.1 The specimens cut from the sample should be insatisfactory condition and representative of the bulk of theproduct delivered to the facility. For example, exclude innerand
41、outer wraps of the roll, any material containing folds,crushed areas, imperfections on either face, tears in either thetop or bottom material surrounding the cementitious material,or other distortions not representative of the sampled lot.8.3.2 All sample cutting should be carried out in a clean are
42、afree of debris, and preferentially with a surface covering tocollect any loose cementitious powder which may come fromthe material during cutting. The samples should be cut using adry rotary diamond saw to avoid a second hydration of thesamples which may affect results. The edges should be cutsquar
43、e and not notched or damaged by the cutter in the areathat will be between the testing fixture supports.8.3.3 Cure each GCCM sample specimen in accordancewith the recommendations provided by the manufacturerbefore testing.8.3.4 GCCM samples shall be prepared in accordance withPractice D8030/D8030M w
44、ith a sufficient number of speci-mens prepared for testing.8.3.5 It is important that the GCCM specimens be flat toobtain repeatable measurements using this procedure. If aspecimen is determined to have substantial curvature, thatspecimen must be discarded.Anew specimen must be obtainedto replace it
45、 for measurement. In the case of laboratory-hardened samples, each bar shall have a tolerance of flatness of5 mm (each surface shall lie between two parallel planes witha 5-mm separation) and in the case of field sample, each barshall have a tolerance of flatness of 8 mm.9. Procedure9.1 Measure the
46、specimen thickness, at four points along theline of break for an average result. This measurement may becompleted either before or after load testing using the thicknessgage.9.2 Measurement of the Initial and Final Breaking Load andInitial and Final Deflection:9.2.1 Set up a uniform deflection rate
47、on the flexural testingmachine such that the initial breaking load will occur in thespecimen between 5 and 30 s.9.2.2 The error in the load reading shall not exceed 1 % ofthe maximum load.9.2.3 The supports for the three-point flexural fixture arecylindrical on the specimen contact surface with a 3.
48、2-mm(18-in.) minimum radius and a 12.7-mm (12-in.) maximumradius. These support points must be designed so that theycannot exert longitudinal constraints (rocker-type bearingedges, rollers, etc.). The loading surface must have a similaredge bearing.9.2.4 The test span shall be 100 6 1.6 mm (4 6116 i
49、n.) andthe load line and support shall be parallel.NOTE 1Alternate test specimen dimensions and span may be used,provided that the ratio of the test span to specimen thickness is not lessthan 18, and that the actual span used is reported.9.2.5 Mount a micrometer reading or an equally sensitiveapparatus to bear on the loading member or on the specimen atmid span to determine the deflection of the specimen at thecenter of the test span.9.2.6 Position the specimen, based on previous topsidemarking of which side should be up, on the three-point flexural
