1、Designation: C 880 06Standard Test Method forFlexural Strength of Dimension Stone1This standard is issued under the fixed designation C 880; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last revision. A number in par
2、entheses 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 the procedure for determiningthe flexural strength of stone by use of a simple beam usingquarter-point loading.1.2 Stone te
3、sts shall be made when pertinent for the situa-tion when the load is perpendicular to the bedding plane andwhen the load is parallel to the bedding plane.1.3 As required, the flexural tests shall also be conductedunder wet conditions.1.4 The values stated in inch-pound units are to be regardedas the
4、 standard. The values 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 the ap
5、plica-bility of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:E4 Practices for Force Verification of Testing MachinesC119 Terminology Relating to Dimension Stone3. Terminology3.1 DefinitionsAll definitions are in accordance withTerminology C119.4. Significance and Use
6、4.1 This test method is useful in indicating the differences inflexural strength between the various dimension stones. Thistest method also provides one element in comparing stones ofthe same type.5. Apparatus5.1 Testing Machine (Fig. 1), conforming to the require-ments of the applicable sections of
7、 Practices E4. The quarter-point loading method shall be used in making flexure tests ofstone employing bearing blocks which will ensure that forcesapplied to the beam will be vertical only and applied withouteccentricity. The apparatus should be capable of maintainingthe span length and distances b
8、etween load-applying blocksand support blocks constant within 61.3 mm (60.05 in.). Theload should be capable of being applied at a uniform rate andin such a manner as to avoid shock.6. Sampling6.1 Select the sample to represent a true average of the typeor grade of stone under consideration and of t
9、he qualitysupplied to the market under the type designation to be tested.The sample may be selected by the purchaser or his authorizedrepresentative from the quarried stone or taken from the naturalledge and shall be of adequate size to permit the preparation ofthe desired number of test specimens.
10、When perceptiblevariations occur, the purchaser may select as many samples asare necessary for determining the variations in flexuralstrength.7. Test Specimen7.1 The test specimens shall measure 102 mm (4 in.) wideby 32 mm (1.25 in.) thick by 381 mm (15 in.) long, with a spanas tested of 318 mm (12.
11、5 in.). The sides of the specimen shallbe at right angles with the top and bottom. The specimens shallhave a fine abrasive finish on the planes perpendicular to theload and a fine saw finish on the other four planes. Thedimensions of the specimen shall be measured and recorded tothe nearest 0.3 mm (
12、0.01 in.). A minimum of five specimensshall be tested for each condition of test. The average value ofthe test results is reported as the flexural strength of the stone.7.2 Where this test method is specified in the physicalrequirements of an ASTM C-18 Standard Specification for adimension stone, th
13、e test specimens shall meet the require-ments under 7.1.7.3 Where the job thickness has been set (for example, thethickness of the stone panels for the project has been estab-lished), it is often requested to perform flexure tests at the jobthickness. The following shall govern the specimen size whe
14、reit is requested to test at the job thickness and the job thicknessis other than 32 mm (1.25 in.). The span as tested shall be 10times the thickness. The specimen lengths shall be not less than51 mm (2 in.) and not more than 102 mm (4 in.) greater thanthe span as tested. Where the thickness is less
15、 than 68 mm(2.67 in.), the width of the specimen shall be 102 mm (4 in.).Where the thickness is greater than 68 mm (2.67 in.) the widthshall be 1.5 times the thickness. Where the thickness is other1This test method is under the jurisdiction of ASTM Committee C18 onDimension Stone and is the direct r
16、esponsibility of Subcommittee C18.01 on TestMethods.Current edition approved Feb. 1, 2006. Published February 2006. Originallyapproved in 1978. Last previous edition approved in 1998 as C 880 98.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, Unit
17、ed States.than 32 mm (1.25 in.) and the specimen size is in accordancewith the job thickness criteria noted in the foregoing, theaverage value of the test results shall be reported as the flexuralstrength of the stone at the job thickness. All other require-ments shall be in accordance with 7.1.7.4
18、Where the job surface finish has been set (for example,the architectural finish on the panels for the project has beenestablished), it is often requested to perform flexure tests onspecimens with the finish the same as on the job. The followingshall govern when it is requested to test at the job sur
19、facefinish. The specimens shall have a finish on one planeperpendicular to the load in accordance with the finish speci-fied for the job. Unless there is data to the contrary, thepositioning of the specimen should be with the finished face inflexural tension. The average value of the test results sh
20、all bereported as the flexural strength of the stone at the job surfacefinish. All other requirements shall be in accordance with 7.1and 7.3.7.5 Where the specimens conform to the requirements of 7.3and 7.4, the average value of the test results shall be reportedas the flexural strength of the stone
21、 at the job thickness andsurface finish.7.6 Test results obtained by this test method are those offlexural strength properties. In specific applications, test speci-mens of different geometry may give useful results in terms ofa modulus of rupture value.8. Conditioning8.1 Before testing the specimen
22、s in a dry condition, drythem for 48 h at 60 6 2C (140F 6 4F). At the 46th, 47thand 48th hour, weigh the specimens to ensure that the weightis the same. If the weight continues to drop, continue to dry thespecimens until there are three successive hourly readings withthe same weight. After removing
23、the specimens from the oven,cool them to room temperature in a desiccator before testingthem.8.2 Before testing the specimens in a wet condition, im-merse them in water for 48 h at 22 6 2C (72 6 4F). Testthem immediately upon removal from the bath, wiping thespecimens free of surface water.9. Proced
24、ure9.1 Assemble the apparatus and place the specimen on thespan supports and adjust the quarter point loading blocks intocontact with the specimen.9.2 Apply the load at a uniform stress rate of 4.14 MPa (600psi/min.) to failure.10. Calculation10.1 Calculate the flexural strength, s as follows:s534WL
25、bd2(1)where:s = flexural strength, MPa (psi),W = maximum load, N (lbf),L = span, mm (in.);L =10d,b = width of specimen, mm (in.); b $ 1.5d, andd = depth of specimen, mm (in.).11. Report11.1 The report shall include the following:11.1.1 Stone type.11.1.2 Sizes of the specimens used.11.1.3 Preconditio
26、ning procedure used.11.1.4 Individual test results for each specimen.11.1.5 Average value of the test results for each group usingthe following relation:s5sum of observed valuesnumber of tests11.1.6 Standard deviation, s, of the test results for eachgroup using the following relation:s 5sum of obser
27、ved value 2 s!2number of tests2111.1.7 Any variations from the above procedural tech-niques.11.2 The following additional information shall also bereported: identification of the sample, including name andlocation of the quarry, name and position of the ledge, datewhen sample was taken, and trade na
28、me or grade of the slate.NOTEApparatus may be used inverted.FIG. 1 Diagrammatic View of a Suitable Apparatus for Flexure Test of StoneC88006212. Precision and Bias12.1 Individual variations in a natural product may result indeviation from accepted values. A precision section will beadded when suffic
29、ient data are available to indicate acceptabletolerances in repeatability and reproducibility.13. Keywords13.1 dimension stone; flexural strength; flexure; stone; testASTM International takes no position respecting the validity of any patent rights asserted in connection with any item mentionedin th
30、is standard. Users of this standard are expressly advised that determination of the validity of any such patent rights, 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 b
31、e reviewed every five years andif not revised, either reapproved or withdrawn. Your comments are invited either for revision of this standard or for additional standardsand should be addressed to ASTM International Headquarters. Your comments will receive careful consideration at a meeting of theres
32、ponsible technical committee, which you may attend. If you feel that your comments have not received a fair hearing you 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).C880063
