1、Designation: C 120 06e1Standard Test Methods ofFlexure Testing of Slate (Breaking Load, Modulus ofRupture, Modulus of Elasticity)1This standard is issued under the fixed designation C 120; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revi
2、sion, the year of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon (e) indicates an editorial change since the last revision or reapproval.This standard has been approved for use by agencies of the Department of Defense.e1NOTETo correct 10.1, the wor
3、ds “by centering the specimen” were added to the fourth sentence editorially in June 2006.INTRODUCTIONDue to 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 slat
4、esare such that these determinations are of special interest and value, besides furnishing comparativedata.The 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 desi
5、rableto test the strength and elasticity both parallel and perpendicular to the grain.Breaking load test results 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
6、 minimum specified thickness must be conducted.When comparing slates of equal thickness, but from various sources, 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 me
7、thods cover determination of the breakingload, modulus of rupture and modulus of elasticity of slate bymeans of flexure tests.1.2 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 ap
8、pro-priate safety and health practices and determine the applica-bility of regulatory limitations 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 a
9、re in accordance with Ter-minology C119.4. Significance and Use4.1 These test methods are 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.5. Sampl
10、ing5.1 Select the sample to represent 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
11、 naturalledge and shall be of adequate size to permit the preparation ofthe desired number of test specimens. When perceptible1These test methods are under the jurisdiction of ASTM Committee C18 onDimension Stone and are the direct responsibility of Subcommittee C18.01 on TestMethods.Current edition
12、 approved March 1, 2006. Published March 2006. Originallyapproved in 1925. Last previous edition approved in 2005 as C 120 05e1.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume informatio
13、n, 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.variations occur, the purchaser may select as many samples asare necessary for determining the variations in flexure (
14、break-ing load, modulus of rupture, modulus of elasticity).MODULUS OF RUPTURE6. Test Specimens6.1 Structural or Electrical SlateSix representative speci-mens, 12 by 112 by 1 in. (305 by 38.1 by 25.4 mm) in size,of the particular slate under consideration shall be tested.6.2 Roofing SlateAt least ten
15、 specimens 4 in. (101.6 mm)in width, 5 in. (127.0 mm) or greater in length and minimum316 in. (4.8 mm) thick.7. Preparation of Specimens7.1 Structural or Electrical SlateSplit the slate for the testto a thickness of approximately 114 in. (31.8 mm) and then sawinto strips 12 in. (304.8 mm) in length
16、by 112 in. (38.1 mm) inwidth. Cut half of these with the length parallel to the grain andhalf with the length perpendicular to the grain. Plane or rubdown the 12 by 112-in. (304.8 by 38.1-mm) faces to a thicknessof approximately 1 in. (25.4 mm), taking care to have thefinished surfaces as nearly par
17、allel as practicable.7.2 Roofing SlateCut one 4 by 5-in. (101.6 by 127.0-mm)specimen from each of a minimum 10 shingles. The saw bladeshall 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
18、 specimen nearerthan 1 in. (25.4 mm) to a sheared edge or nail hole. The 5 in.(127.0 mm) or longer dimension is to be measured and cutparallel with 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 atemperat
19、ure of 60 6 2C (140 6 4F). At the 46th, 47th and48th hour, weigh the specimens to ensure that the weight is thesame. If the weight continues to drop, continue to dry thespecimens until there are three successive hourly readings withthe same weight.9. Marking and Measuring9.1 On structural or electri
20、cal 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. (127 mm)from, the center lines. On specimens of roofing slate rule thecenter lines perpendicular to an edge that is parallel to thelength of the shingle
21、. Rule span lines parallel to, and 1 in. (25.4mm) from, the center lines. Measure the specimen thickness atthree points along the center line to the nearest 0.01 in. (0.254mm) and record the average as the specimen thickness.10. Procedure10.1 The testing machine shall be accurate to 1 % within thera
22、nge from 100 to 2000 lbf (444.8 to 8896 N). Place thespecimens flat on the rocker type knife-edges as shown in Fig.1 of Test Method C99. Apply the load at the center spanthrough a rocker or fixed type knife-edge. When a load of 10lbf (44 N) has been applied, stop the loading and make all knifeedges
23、coincide with the marks on the specimen by centeringthe specimen under the loading edge and moving the support-ing edges under the span marks. Apply loads at rates notexceeding 1000 lbf (4448 N)/min until failure, and record thebreaking load to the nearest 5 lbf (22.2 N).NOTE 1When all three knife e
24、dges are of the rocker type, care mustbe taken to adjust all three until the top face of the specimen is horizontalwhen loaded.11. Calculation - Structural or Electrical Slate11.1 Calculate the modulus of rupture as follows:R 5 3Wl/2bd2! (1)where:R = modulus of rupture, psi (MPa),W = breaking load,
25、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. Report12.1 Structural or Electrical SlateReport all modulus ofrupture values and the average of all modulus of rupture valuesfor sp
26、ecimens 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 forspecimens cut perpendicular to the grain as the modulus ofrupture “with the grain.” All determinations shall be reportedas informatio
27、n.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 averageof the breaking loads shall be reported as the breaking loadacross the length of the slate shingle. All determinations,co
28、nditioning time and weight data for each specimen shall bereported as information.12.3 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 name or grad
29、e 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 test. For this test onroofing slate it will be desirable to use a specimen 8 in. (203.2mm) long.14. Conditioning14.1 Dry the s
30、pecimens for 48 h in a ventilated oven at atemperature of 60 6 2C (140 6 4F). At the 46th, 47th and48th hour, weigh the specimens to ensure that the weight is thesame. If the weight continues to drop, continue to dry thespecimens until there are three successive hourly readings withthe same weight.1
31、5. Procedure15.1 Support and load the test specimen in the same way asfor the flexural strength determination, except that the roofingC12006e12slate specimen shall be supported on a 6-in. (152.4-mm) span.Set any type of deflectometer, capable of reading to 0.001 in.(0.025 mm), to measure deflections
32、 at mid-span (Note 2). Stopthe loading at each 50-lbf (222-N) increment, and record thecorresponding deflections.NOTE 2It is not ordinarily feasible to set the deflectomer to read zerowhen there is no load on the specimen. The best practice is to put a smallinitial load on the specimen, such as 10 l
33、bf (44 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. Calculation16.1 Plot the load-deflection readings on cross-section paperto a convenient scale, and draw a straigh
34、t 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 to the stress-strain line. Calcu-late the modulus of elasticity, E, from the coordinates of someconvenient point on
35、 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 = length of span, in. (mm),b = width of specimen at the center, in. (mm), andd = thickness of specimen at the c
36、enter, 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 to the grain as themodulus of elasticity across the grain. Likewise, report theaverage of the results
37、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 information shall also bereported: Identification of the sample, including name andlocation of the quarry
38、, 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 accepted values. A precision section will beadded when sufficient data are available to indicate accepta
39、bletolerances in repeatability and reproducibility.ASTM International takes no position 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 righ
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42、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).C12006e13
