1、Designation: D8058 171D8058 19Standard 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
2、oforiginal 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 NOTESubsection 3.2.7 was corrected editorially in August 2017.1. Sc
3、ope1.1 This test method provides guidelines for testing the flexural strength of cured geosynthetic cementitious composite mat(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 informati
4、on.1.3 This standard may involve hazardous operations, equipment, and climates. This standard does not purport to address all ofthe safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safetysafety, health, and healthenviron
5、mental practices and determine the applicability of regulatory limitations prior to use.1.4 This international standard was developed in accordance with internationally recognized principles on standardizationestablished in the Decision on Principles for the Development of International Standards, G
6、uides and Recommendations issuedby the World Trade Organization Technical Barriers to Trade (TBT) Committee.2. Referenced Documents2.1 ASTM Standards:2D76/D76M Specification for Tensile Testing Machines for TextilesD4354 Practice for Sampling of Geosynthetics and Rolled Erosion Control Products (REC
7、Ps) for TestingD4439 Terminology for GeosyntheticsD8030/D8030M Practice for Sample Preparation for GCCM3. Terminology3.1 For definitions of common technical terms used in this standard, refer to Terminology D4439.3.2 Definitions:3.2.1 cured, adja description of the state of a GCCM after hydration fo
8、r a specified period of time and quantity of water whenknown under specified conditions, followed by a period of time where the GCCM is kept under a specified environmental conditionduring which the cementitious material continues to cure and develop compressive strength.3.2.2 curing time, nthe time
9、 subsequent to initial hydration of the GCCM and immediately prior to the testing of the material,during which the cementitious material is allowed to harden and form its final strength using the specific process for curing asspecified in 8.3.3.2.3 dry, adja description of the state of a GCCM before
10、 it has been exposed to a hydration source and typically describesthe “as-received” dry product after conditioning in a prescribed manner.3.2.4 final breaking load, nthe maximum load achieved prior to rupture of materials.3.2.5 final deflectionthe deflection of the specimen from its initial position
11、 (before testing begins) measured at mid span atthe final breaking load.1 This test method is under the jurisdiction of ASTM Committee D35 on Geosynthetics and is the direct responsibility of Subcommittee D35.05 on Geosynthetic ErosionControl.Current edition approved July 1, 2017Jan. 1, 2019. Publis
12、hed July 2017January 2019. Originally approved in 2017. Last previous edition approved in 2017 as D8058 17.DOI: 10.1520/D8058-17E01.10.1520/D8058-19.2 For referencedASTM standards, visit theASTM website, www.astm.org, or contactASTM Customer Service at serviceastm.org. For Annual Book of ASTM Standa
13、rdsvolume information, refer to the standards Document Summary page on the ASTM website.This 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 t
14、o adequately depict all changes accurately, 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 Con
15、shohocken, PA 19428-2959. United States13.2.6 final flexural strength, nthe final flexural strength, expressed in megapascals (pound-force per square inch), is calculatedfrom the final breaking load of a hydrated and cured GCCM specimen, oriented in either the machine or cross-machine direction,load
16、ed as simple beams, when breaks occur perpendicular to the specimen length, with the load applied at the center, in athree-point loading fixture.3.2.7 geosynthetic cementitious composite mat (GCCM), na factory-assembled geosynthetic composite consisting of acementitious material contained within a l
17、ayer or layers of geosynthetic materials that becomes hardened when hydrated.3.2.7 hydration, nexposure of the GCCM, in this case, to water in prescribed conditions for a prescribed time and waterquantity when known.3.2.8 initial breaking load, nthe maximum load at which the first crack in the cemen
18、titious matrix of the GCCM forms.3.2.9 initial deflection, nthe deflection of the specimen from its initial position (before testing begins) measured at mid spanat the initial breaking load.3.2.10 initial flexural strength, nthe initial flexural strength, expressed in megapascals (pound-force per sq
19、uare inch), iscalculated from the initial breaking load (maximum load at first crack) of a hydrated and cured GCCM specimen, oriented in eitherthe machine or cross-machine direction, loaded as simple beams, with the load applied at the center, in a three-point loading fixture.3.2.11 initial modulus
20、of elasticity, na measure of a specimens resistance to elastic deformation, measured in the region oflinear response, before the initial breaking load.3.2.12 mean final flexural strength, nthe mean final flexural strength is the average result of ten or more final flexural strengthvalues expressed i
21、n megapascals (pound-force per square inch).3.2.13 mean initial flexural strength, nthe mean initial flexural strength is the arithmetic mean of ten or more initial flexuralstrength values when breaks occur perpendicular to the specimen length. Breaks expressed in megapascals (pound-force per square
22、inch).3.2.14 topside, nthe side of the material that would face upwards in a normal installation.4. Summary of Test Method4.1 A hydrated and cured GCCM specimen is loaded as a simple beam in a three-point loading fixture, with the load appliedat the center. The load level is recorded simultaneously
23、with the deflection to characterize the initial and final flexural strength, thedeflection of the specimen at those loads, and the initial modulus of the specimen.5. Significance and Use5.1 This test method is applicable for testing geosynthetic cementitious composite mats in a cured state. It is us
24、ed with aconstant rate of extension-type tension apparatus.5.2 This test is an index test that may be used for manufacturing 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)-
25、type of testing machine described in SpecificationD76/D76M shall be used. When using the CRE-type tensile tester, the recorder must have adequate pen response to properly recordthe force-elongation curve as specified in Specification D76/D76M.6.2 Three-Point Flexural FixtureA fixture designed for us
26、e with the flexural testing machine with two bottom supports anda third edge which is used to load the specimen from the top at mid span. The fixture is designed so that the specimen is loadedand can be analyzed as a simple beam. The supports are cylindrical on the specimen contact surface with a 3.
27、2-mm (18-in.)minimum radius and a 12.7-mm (12-in.) maximum radius. These support points must be designed so that they cannot exertlongitudinal or vertical constraints (rocker-type bearing edges, rollers, etc.). The loading surface must have a similar edge bearing.The test span shall be 100 6 1.6 mm
28、(4 6 116 in.) and the load line and support shall be parallel. Mount a dial micrometer readingto 0.25 mm (0.01 in.), or an equally sensitive apparatus, to bear on the loading member or on the specimen at mid span to determinethe deflection of the specimen at the center of the test span as the load i
29、s measured.6.3 Sample ContainersSuitable containers which are resistant to corrosion and change in mass upon repeated exposure tomoisture, materials of varying pH, and cleaning.6.4 DieA sample-cutting device of dimensions consistent with 8.2.6.5 Rotary Tile Saw, with diamond-tipped blades capable of
30、 dry cutting samples, used for cutting cured samples topredetermined dimensions using pattern marked on cured specimen with template and markers.6.6 Miscellaneous Knives, Templates, Markers, Rulers, Saw, as required for marking, measuring, and cutting specimens tofixed dimensions before measurement
31、of weight. A knife with a “snap off” type blade is recommended for cutting GCCMs, whichcan dull blade tips rapidly.D8058 1926.7 Thickness GageAmeasurement device for characterizing the thickness of the specimens in the vicinity of the breaks whichoccur during the flexural test. The thickness gage sh
32、all have flat parallel anvils of between 10-mm (0.4-in.) and 15-mm (0.6-in.)diameter with an accuracy of 60.05 mm (60.002 in.).6.8 MicrometerA calibrated measurement device used for precise measurement of components with a required accuracy of60.25 mm (60.01 in.), or an equally sensitive apparatus.7
33、. Sampling, Test Specimens, and Test Units7.1 Lot SampleFor the lot sample, refer to Practice D4354 for discussion of recommended practice for breaking up shipmentsof GCCMs into lots for testing.7.2 Laboratory SamplesFor the laboratory sample, take a full-width sample approximately 1 m (40 in.) long
34、 in the machinedirection from each roll in the lot sample. The exact length must be chosen to ensure enough sample is cured to cut the requirednumber of specimens for both the machine and cross-machine directions. The sample may be taken from the end portion of a roll,provided there is no evidence i
35、t is distorted or different from other portions of the roll. In cases of dispute, take a sample that willexclude material from the outer wrap of the roll or the inner wrap around the core, of at least 30 in. from the interior end of theroll (wrapped around the core) or exterior end of the material r
36、oll, measured from the edge of the cementitious portion of thematerial.7.3 Test SpecimensFor tests in the machine direction and the cross-machine direction, respectively, take from each sample inthe laboratory sample the number of specimens directed in Section 8. Take specimens at random from the la
37、boratory sample, withthose for the measurement of the machine direction tensile properties from different positions across the sample width, and thespecimens for the measurement of the cross-machine direction tensile properties from different positions along the length of thesample. Specimens must n
38、ot be taken near the edge of the material. Specimens must be taken a minimum of 4 in. from the edgeof the material, measured from the edge of the cementitious portion of the material. Specimens shall be collected for testing in boththe topside and bottom-side direction facing up.8. Test Specimen Pre
39、paration8.1 Number of Specimens:8.1.1 Unless otherwise agreed upon, the fixed number of ten (10) specimens for each the machine direction and thecross-machine direction tests should be used.8.2 Test Specimen Size:8.2.1 Prepare each finished specimen a minimum of 40 6 1.6 mm (1.6 6 116 in.) wide by a
40、t least 160 6 1.6 mm (6.3 6 116in.) long with the length dimension being designated and accurately parallel to the direction for which the flexural strength is beingmeasured. Specimens may be prepared using a die, saw, or knives.8.2.2 The orientation of the specimen in the flexural test will affect
41、which face of the GCCM is under tensile load. Thespecimens should have a mark applied on the topside face which is to be up when loaded into the three-point flexural fixture.8.3 Specimen Preparation:8.3.1 The specimens cut from the sample should be in satisfactory condition and representative of the
42、 bulk of the productdelivered to the facility. For example, exclude inner and outer wraps of the roll, any material containing folds, crushed areas,imperfections on either face, tears in either the top or bottom material surrounding the cementitious material, or other distortionsnot representative o
43、f the sampled lot.8.3.2 All sample cutting should be carried out in a clean area free of debris, and preferentially with a surface covering to collectany loose cementitious powder which may come from the material during cutting. The samples should be cut using a dry rotarydiamond saw to avoid a seco
44、nd hydration of the samples, which may affect results. The edges should be cut square and not notchedor damaged by the cutter in the area that will be between the testing fixture supports.8.3.3 Cure each GCCM sample specimen in accordance with the recommendations provided by the manufacturer before
45、testing.8.3.4 GCCM samples shall be prepared in accordance with Practice D8030/D8030M with a sufficient number of specimensprepared for testing.8.3.5 It is important that the GCCM specimens be flat to obtain repeatable measurements using this procedure. If a specimenis determined to have substantial
46、 curvature, that specimen must be discarded. A new specimen must be obtained to replace it formeasurement. In the case of laboratory-hardened samples, each bar shall have a tolerance of flatness of 5 mm (each surface shalllie between two parallel planes with a 5-mm separation) and in the case of fie
47、ld sample, each bar shall have a tolerance of flatnessof 8 mm.9. Procedure9.1 Measure the specimen thickness,thickness at four points along the line of break for an average result.This measurement maybe completed either before or after load testing using the thickness gage.9.2 Measurement of the Ini
48、tial and Final Breaking Load and Initial and Final Deflection:D8058 1939.2.1 Set up a uniform deflection rate on the flexural testing machine 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 % of the maximum load.
49、9.2.3 The supports for the three-point flexural fixture are cylindrical on the specimen contact surface with a 3.2-mm (18-in.)minimum radius and a 12.7-mm (12-in.) maximum radius. These support points must be designed so that they cannot exertlongitudinal constraints (rocker-type bearing edges, rollers, etc.). The loading surface must have a similar edge bearing.9.2.4 The test span shall be 100 6 1.6 mm (4 6 116 in.) and the load line and support shall be parallel.NOTE 1Alternate test specimen dimensions and span may be used, provided that
