1、Designation: C 120/C 120M 09Standard Test Methods ofFlexure Testing of Slate (Breaking Load, Modulus ofRupture, Modulus of Elasticity)1This standard is issued under the fixed designation C 120/C 120M; the number immediately following the designation indicates the yearof original adoption or, in the
2、case 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.This standard has been approved for use by agencies of the Department of Defense.INTRODUCTIONDue to
3、the unique properties of slate, the flexure test is better adapted to use for strength andelasticity determinations than either compression or tension tests. Furthermore, several uses of slatesare such that these determinations are of special interest and value, besides furnishing comparativedata.Th
4、e property of slate termed “grain” causes a slab of the material to break transversely in onedirection somewhat more readily than at right angles to this direction. For this reason it is desirableto test the strength and elasticity both parallel and perpendicular to the grain.Breaking load test resu
5、lts for samples of roofing slate are only valid for the commercial supply ofslates of that thickness or greater. For the commercial supply of thinner roofings slates, testing onsamples of the minimum specified thickness must be conducted.When comparing slates of equal thickness, but from various sou
6、rces, slates which meet the requiredbreaking load at the lowest specimen thickness will yield the best performance on the roof in termsof resistance to impact damage.1. Scope1.1 These test methods cover determination of the breakingload, modulus of rupture and modulus of elasticity of slate bymeans
7、of flexure tests.1.2 UnitsThe values stated in either SI units or inch-pound units are to be regarded separately as standard. Thevalues 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
8、in non-conformance with the standard.1.3 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 applica-bility of regulatory lim
9、itations prior to use.2. Referenced Documents2.1 ASTM Standards:2C99 Test Method for Modulus of Rupture of DimensionStoneC119 Terminology Relating to Dimension Stone3. Terminology3.1 DefinitionsAll definitions are in accordance with Ter-minology C119.4. Significance and Use4.1 These test methods are
10、 useful in indicating the differ-ences in flexure (breaking load, modulus of rupture, modulusof elasticity) between various slates. These test methods alsoprovide one element in the comparison of slates.1These test methods are under the jurisdiction of ASTM Committee C18 onDimension Stone and are th
11、e direct responsibility of Subcommittee C18.01 on TestMethods.Current edition approved April 1, 2009. Published April 2009. Originallyapproved in 1925. Last previous edition approved in 2006 as C 120061.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Ser
12、vice at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.5. Sampling5.1 Select the sample to represe
13、nt a true average of the typeor grade of stone under consideration and of the 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 adequ
14、ate size to permit the preparation ofthe desired number of test specimens. When perceptiblevariations occur, the purchaser may select as many samples asare necessary for determining the variations in flexure (break-ing load, modulus of rupture, modulus of elasticity).MODULUS OF RUPTURE6. Test Specim
15、ens6.1 Structural or Electrical SlateSix representative speci-mens, 12 by 112 by 1 in. 300 by 40 by 25 mm in size, of theparticular slate under consideration shall be tested.6.2 Roofing SlateAt least ten specimens 4 in. 101.6 mmin width, 5 in. 125 mm or greater in length and minimum316in. 5 mm thick
16、.7. Preparation of Specimens7.1 Structural or Electrical SlateSplit the slate for the testto a thickness of approximately 114 in. 30 mm and then sawinto strips 12 in. 300 mm in length by 112 in. 40 mm inwidth. Cut half of these with the length parallel to the grain andhalf with the length perpendicu
17、lar to the grain. Plane or rubdown the 12 by 112-in. 300 by 40-mm faces to a thickness ofapproximately 1 in. 25 mm, taking care to have the finishedsurfaces as nearly parallel as practicable.7.2 Roofing SlateCut one 4 by 5-in. 100 by 125-mmspecimen from each of a minimum 10 shingles. The saw bladesh
18、all be a continuous rim, diamond impregnated type, mountedto a water-cooled sliding bed saw capable of making a cleancut with no lacerated edges. Cut no part of the specimen nearerthan 1 in. 25 mm to a sheared edge or nail hole. The 5 in.125 mm or longer dimension is to be measured and cutparallel w
19、ith the long dimension of the slate shingle. Do notresurface the split faces.8. Conditioning8.1 Dry the specimens for 48 h in a ventilated oven at atemperature of 140 6 4F 60 6 2C. At the 46th, 47th and48th hour, weigh the specimens to ensure that the weight is thesame. If the weight continues to dr
20、op, continue to dry thespecimens until there are three successive hourly readings withthe same weight.9. Marking and Measuring9.1 On structural or electrical slate, rule the center lines witha try-square perpendicular to the edges of the specimens.Likewise, rule the span lines, parallel to, and 5 in
21、. 125 mmfrom, the center lines. On specimens of roofing slate rule thecenter lines perpendicular to an edge that is parallel to thelength of the shingle. Rule span lines parallel to, and 1 in.25 mm from, the center lines. Measure the specimen thick-ness at three points along the center line to the n
22、earest 0.01 in.0.1 mm and record the average as the specimen thickness.10. Procedure10.1 The testing machine shall be accurate to 1 % within therange from 100 to 2000 lbf 500 to 10 000 N. Place thespecimens flat on the rocker type knife-edges as shown in Fig.1 of Test Method C99. Apply the load at t
23、he center spanthrough a rocker or fixed type knife-edge. When a load of10 lbf 50 N has been applied, stop the loading and make allknife edges coincide with the marks on the specimen bycentering the specimen under the loading edge and moving thesupporting edges under the span marks. Apply loads at ra
24、tesnot exceeding 1000 lbf/min 5000 N/min until failure, andrecord the breaking load to the nearest 5 lbf 20 N.NOTE 1When all three knife edges are of the rocker type, care mustbe taken to adjust all three until the top face of the specimen is horizontalwhen loaded.11. CalculationStructural or Electr
25、ical Slate11.1 Calculate the modulus of rupture as follows:R 5 3Wl/2bd2! (1)where:R = modulus of rupture, psi MPa,W = breaking load, lbf N,l = span length between supporting knife-edges, in. mm,b = width of specimen at the center, in. mm, andd = thickness of specimen at the center, in. mm.12. Report
26、12.1 Structural or Electrical SlateReport all modulus ofrupture values and the average of all modulus of rupture valuesfor specimens cut parallel to the grain as the modulus ofrupture “across the grain.” Report all modulus of rupturevalues and the average of all modulus of rupture values forspecimen
27、s cut perpendicular to the grain as the modulus ofrupture “with the grain.” All determinations shall be reportedas information.12.2 Roofing SlateReport the span length, width of speci-men, average thickness of specimen along the center line andat the edges and breaking load of each specimen. The ave
28、rageof the breaking loads shall be reported as the breaking loadacross the length of the slate shingle. All determinations,conditioning time and weight data for each specimen shall bereported as information.12.3 The following additional information shall also bereported: Identification of the sample
29、, including name andlocation of the quarry, name and position of the ledge, datewhen sample was taken, and trade name or grade of the slate.MODULUS OF ELASTICITY13. Test Specimens and Preparation of Specimens13.1 The modulus of elasticity may be determined inconjunction with the modulus of rupture t
30、est. For this test onroofing slate it will be desirable to use a specimen 8 in.200 mm long.14. Conditioning14.1 Dry the specimens for 48 h in a ventilated oven at atemperature of 140 6 4F 60 6 2C. At the 46th, 47th andC 120/C 120M 09248th hour, weigh the specimens to ensure that the weight is thesam
31、e. If the weight continues to drop, continue to dry thespecimens until there are three successive hourly readings withthe same weight.15. Procedure15.1 Support and load the test specimen in the same way asfor the flexural strength determination, except that the roofingslate specimen shall be support
32、ed on a 6-in. 150-mm span.Set any type of deflectometer, capable of reading to 0.001 in.0.02 mm, to measure deflections at mid-span (Note 2). Stopthe loading at each 50-lbf 200-N increment, and record thecorresponding deflections.NOTE 2It is not ordinarily feasible to set the deflectomer to read zer
33、owhen there is no load on the specimen. The best practice is to put a smallinitial load on the specimen, such as 10 lbf 50 N and set thedeflectometer to read zero for this load. Since it is only the slope of thestress-strain curve that is desired, this initial load does not affect the finalresult.16
34、. Calculation16.1 Plot the load-deflection readings on cross-section paperto a convenient scale, and draw a straight line to represent, asnearly as possible, the average of the plotted points (Note 3). Ifthe line does not pass through the zero point, draw a correctedline through this point parallel
35、to the stress-strain line. Calcu-late the modulus of elasticity, E, from the coordinates of someconvenient point on the corrected line, as follows:E 5 W8l3/4Dbd3! (2)where:E = modulus of elasticity, psi MPa,W8 = load coordinate of the point, lbf N,D = deformation coordinate of the point, in. mm,l =
36、length of span, in. mm,b = width of specimen at the center, in. mm, andd = thickness of specimen at the center, in. mm.NOTE 3Slate does not show a definite yield point in the stress-straincurve.17. Report17.1 Report the average of the results obtained for speci-mens prepared with the length parallel
37、 to the grain as themodulus of elasticity across the grain. Likewise, report theaverage of the results obtained on specimens cut with thelength perpendicular to the grain as the modulus of elasticitywith the grain. All determinations shall be reported as infor-mation.17.2 The following additional in
38、formation 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 name or grade of the slate.18. Precision and Bias18.1 Individual variations in a natural product may result indeviation from a
39、ccepted values. A precision section will beadded when sufficient data are available to indicate acceptabletolerances in repeatability and reproducibility.19. Keywords19.1 breaking load; dimension stone; flexure; modulus ofelasticity; modulus of rupture; slate; testASTM International takes no positio
40、n respecting the validity of any patent rights asserted in connection with any item mentionedin this 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.
41、This standard is subject to revision at any time by the responsible technical committee and must be 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 I
42、nternational Headquarters. Your comments will receive careful consideration at a meeting of theresponsible 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 sho
43、wn 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).C 120/C 120M 093
