ASTM D7748 D7748M-2014 red 8148 Standard Test Method for Flexural Rigidity of Geogrids Geotextiles and Related Products《土工网 土工格栅及相关产品的抗弯刚度的标准试验方法》.pdf
《ASTM D7748 D7748M-2014 red 8148 Standard Test Method for Flexural Rigidity of Geogrids Geotextiles and Related Products《土工网 土工格栅及相关产品的抗弯刚度的标准试验方法》.pdf》由会员分享,可在线阅读,更多相关《ASTM D7748 D7748M-2014 red 8148 Standard Test Method for Flexural Rigidity of Geogrids Geotextiles and Related Products《土工网 土工格栅及相关产品的抗弯刚度的标准试验方法》.pdf(7页珍藏版)》请在麦多课文档分享上搜索。
1、Designation: D7748/D7748M13D7748/D7748M14 Standard Test Method for Flexural Rigidity of Geogrids, Geotextiles and Related Products 1 This standard is issued under the xed designation D7748/D7748M; the number immediately following the designation indicates the year of original adoption or, in the cas
2、e of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A superscript epsilon () indicates an editorial change since the last revision or reapproval. 1. Scope 1.1 This test method covers the measurement of stiffness properties of geogrids, geotextiles
3、 and geogrid-geotextile composites all of which are referred to as geosynthetics within this test method. Bending length is measured and exural rigidity is calculated through use of the cantilever test procedure. 1.1.1 This test method employs the principle of cantilever bending of the geosynthetic
4、under its own mass. 1.2 This test method applies to geogrids, geotextiles and geogrid-geotextile composites. 1.3 Thistestmethodisformanufacturingqualitycontrolpurposesonly,toensureuniformityandconsistencyofexuralrigidity for a specic product from roll to roll and lot to lot. 1.4 The values stated in
5、 either SI units or inch-pound units are to be regarded separately as standard. The values stated in each system may not be exact equivalents; therefore, each system shall be used independently of the other. Combining values from the two systems may result in non-conformance with the standard. 1.5 T
6、his standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use. 2. Referenced Docum
7、ents 2.1 ASTM Standards: 2 D123Terminology Relating to Textiles D1776Practice for Conditioning and Testing Textiles D4354Practice for Sampling of Geosynthetics and Rolled Erosion Control Products(RECPs) for Testing D4439Terminology for Geosynthetics E177Practice for Use of the Terms Precision and Bi
8、as in ASTM Test Methods E691Practice for Conducting an Interlaboratory Study to Determine the Precision of a Test Method 3. Terminology 3.1 For common denitions of terms in this test method, refer to Terminology D123 and Terminology D4439. 3.2 Denitions of Terms Specic to This Standard: 3.2.1 bendin
9、g length, na measure of the interaction between geosynthetic weight and geosynthetic stiffness as shown by the way in which a geosynthetic bends under its own weight. 3.2.1.1 Discussion Bending length reects the stiffness of a geosynthetic when bent in one plane under the force of gravity. 1 Thistes
10、tmethodisunderthejurisdictionofASTMCommitteeD35onGeosyntheticsandisthedirectresponsibilityofSubcommitteeD35.01onMechanicalProperties. Current edition approved May 1, 2013Jan. 1, 2014. Published May 2013January 2014. Originally approved in 2012. Last previous edition approved in 20122013 as D774812D7
11、748/D7748M13. e1 . DOI: 10.1520/D7748_D7748M13.10.1520/D7748_D7748M14. 2 ForreferencedASTMstandards,visittheASTMwebsite,www.astm.org,orcontactASTMCustomerServiceatserviceastm.org.ForAnnualBookofASTMStandards volume information, refer to the standards Document Summary page on the ASTM website. This d
12、ocument is not anASTM standard and is intended only to provide the user of anASTM standard an indication of what changes have been made to the previous version. Because it may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions a
13、s appropriate. In all cases only the current version of the standard as published by ASTM is to be considered the official document. Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States 14. Summary of Test Method 4.1 A specimen is slid at
14、a specied rate in a direction parallel to its long dimension, until its leading edge projects from the edgeofahorizontalsurface.Thelengthoftheoverhangismeasuredwhenthetipofthespecimenisdepressedunderitsownmass tothepointwherethelinejoiningthetoptotheedgeoftheplatformmakesa0.724radians41.5anglewithth
15、ehorizontal.From this measured length, the bending length and exural rigidity are calculated. 5. Signicance and Use 5.1 This test method is considered satisfactory for manufacturing quality control testing of a specic geosynthetic; however, caution is advised since information about between-laborato
16、ry precision is incomplete. Comparative tests as directed in 5.1.1 may be advisable. 5.1.1 In case of a dispute arising from differences in reported test results when using this test method for acceptance testing of commercial shipments, the purchaser and the supplier should conduct comparative test
17、s to determine if there is a statistical bias between their laboratories. Competent statistical assistance is recommended for the investigation of bias.As a minimum, the two parties should take a group of test specimens that are as homogeneous as possible and that are from a lot of material of the t
18、ype in question.Test specimens should then be randomly assigned in equal numbers to each laboratory for testing.The average results from the two laboratories should be compared using the appropriate statistical analysis and an acceptable probability level chosen by the two parties before testing is
19、begun. If a bias is found, either its cause must be found and corrected or the purchaser and the supplier must agree to interpret future test results with consideration to the known bias. 5.2 This test method is not suitable for very limp geosynthetics or those that show a marked tendency to curl or
20、 twist at a cut edge. 5.3 The stiffness of a geosynthetic may change with storage. 5.4 No evidence has been found showing that bending length is dependent on specimen width. The tendency for specimens to curl or twist will affect the result, because of the rigidity provided at the edge. Consequently
21、, the edge effect is less of an issue for a wider strip. 6. Apparatus 6.1 Flexural Rigidity Tester (Fig. 1). 6.1.1 Horizontal Platform, with a minimum area of 100 by 900 mm 4 by 36 in. and having a smooth low-friction, at aluminum surface. A leveling bubble shall be incorporated in the platform. 6.1
22、.1.1 Indicator, inclined at an angle of 0.724 6 0.01 radians 41.5 6 0.5 below the plane of the platform surface. 6.1.1.2 MovableSlide,consistingofametalplatenotlessthan50by200mm2by8in.byapproximately3mm1/8in.thick and having a mass of 270 6 5 g 0.6 6 0.01 lb. 6.1.1.3 Scale and Reference Point, to me
23、asure the length of the overhangoverhang. 6.1.1.4 Specimen Feed Unit, motorized set to 120 mm/min 4.75 in./min 6 5 %, or manual equivalent. FIG. 1 Example Test Rig Setup D7748/D7748M 14 27. Sampling and Test Specimens 7.1 Lot SampleAs a lot sample for acceptance testing, randomly select the number o
24、f rolls or pieces of geosynthetic directed in an applicable material specication or other agreement between the purchaser and the supplier. Consider the rolls or pieces of geosynthetictobetheprimarysamplingunits.Intheabsenceofsuchanagreement,takethenumberofgeosyntheticrollsspecied in Practice D4354.
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