1、Designation: C120/C120M 15Standard Test Methods ofFlexure Testing of Slate (Breaking Load, Modulus ofRupture, Modulus of Elasticity)1This standard is issued under the fixed designation C120/C120M; the number immediately following the designation indicates the yearof original adoption or, in the case
2、 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.INTRODUCTIONDue to the unique properties of slate, the flexure test is better adapted to use for strengt
3、h 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.The property of slate termed “grain” causes a slab of the material to break transversel
4、y 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 results for samples of roofing slate are only valid for the commercial supply ofslates of
5、 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 sources, slates which meet the requiredbreaking load at the lowest specimen thickness wi
6、ll 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 of flexure tests.1.2 The values stated in either SI units or inch-pound unitsare to b
7、e regarded separately as standard. The values stated ineach system may not be exact equivalents; therefore, eachsystem shall be used independently of the other. Combiningvalues from the two systems may result in non-conformancewith the standard.1.3 This standard does not purport to address all of th
8、esafety 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 limitations prior to use.2. Referenced Documents2.1 ASTM Standards:2C119 Terminology Relating t
9、o Dimension StoneC1799 Guide to Dimension Stone Test Specimen Samplingand Preparation3. Terminology3.1 DefinitionsAll definitions are 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 rup
10、ture, 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 the direct responsibility of Subcommittee C18.01 on TestMethods.Current edition ap
11、proved Nov. 1, 2015. Published November 2015. Originallyapproved in 1925. Last previous edition approved in 2012 as C120/C120M-12. DOI:10.1520/C0120_C0120M-15.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of
12、ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States15. Apparatus5.1 Testing MachineThe accuracy of the testing machineshall be within 1 % fo
13、r the range from 10 to 1000 lbf 50 to5000 N.5.2 Load Application and Support BlocksThe supports forthe specimen shall be of the rocker type (Fig. 1) with the edgesat least as long as the width of the specimen. The loadapplication block may be of either the rocker or rigid type. Theportions of the lo
14、ad application and support blocks contactingthe stone shall be rounded, with a nominal radius of12 in. 13mm.6. Sampling6.1 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.T
15、he 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. When perceptiblevariations occur, the purchaser may select as many samples
16、 asare necessary for determining the variations in flexure (break-ing load, modulus of rupture, modulus of elasticity).NOTE 1Refer to Guide C1799 for additional information on selecting,preparing, and conditioning test specimens.BREAKING LOAD AND MODULUS OF RUPTURE7. Test Specimens7.1 Structural or
17、Electrical SlateSix representativespecimens, 12 by 112 by 1 in. 300 by 40 by 25 mm in size,of the particular slate under consideration shall be tested.7.2 Roofing SlateAt least ten specimens 4 in. 100 mm inwidth, 5 in. 125 mm or greater in length and minimum316 in.5 mm thick.8. Preparation of Specim
18、ens8.1 Structural or Electrical SlateSplit the slate for the testto a thickness of approximately 114 in. 30 mm and then sawFIG. 1 Specimens and Preferred Type of Loading Application and Support Blocks for Determining the Breaking Load, Modulus of Rup-ture and Modulus of Elasticity of SlateC120/C120M
19、 152into 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 perpendicular 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 fini
20、shedsurfaces as nearly parallel as practicable.8.2 Roofing SlateCut one 4 by 5-in. 100 by 125-mmspecimen 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
21、. 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 with the long dimension of the slate shingle. Do notresurface the split faces.9. Conditioning9.1 Dry the specimens for 48 h in a ventilated oven
22、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 drop, continue to dry thespecimens until there are three successive hourly readings withthe same weight.10. Marking and Measuring10.1 On structura
23、l or electrical slate, rule the center lineswith a try-square perpendicular to the edges of the specimens.Likewise, rule the span lines, parallel to, and 5 in. 125 mmfrom, the center lines. On specimens of roofing slate rule thecenter lines perpendicular to an edge that is parallel to thelength of t
24、he 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 nearest 0.01 in.0.1 mm and record the average as the specimen thickness.11. Procedure11.1 The testing machine shall be accurate to 1 % within t
25、herange from 100 to 2000 lbf 500 to 10 000 N. Lay thespecimens flatwise on the rocker type support blocks as shownin Fig. 1. Apply the load at the center span through a rocker orfixed type load application block. When a load of 10 lbf 50 Nhas been applied, stop the loading and make all the blockscoi
26、ncide with the marks on the specimen by centering thespecimen under the load application block and moving thesupport blocks under the span marks. Apply loads at rates notexceeding 1000 lbf/min 5000 N/min until failure, and recordthe breaking load to the nearest 5 lbf 20 N.NOTE 2When all three load a
27、pplication and support blocks are of therocker type, care must be taken to adjust all three until the top face of thespecimen is horizontal when loaded.12. CalculationStructural or Electrical Slate12.1 Calculate the modulus of rupture as follows:R 5 3Wl/2bd2! (1)where:R = modulus of rupture, psi MPa
28、,W = breaking load, lbf N,l = span length between support blocks, in. mm,b = width of specimen at the center, in. mm, andd = thickness of specimen at the center, in. mm.13. Report13.1 Structural or Electrical SlateReport all modulus ofrupture values and the average of all modulus of rupture valuesfo
29、r 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 forspecimens cut perpendicular to the grain as the modulus ofrupture “with the grain.” All determinations shall be reportedas inform
30、ation.13.2 Roofing SlateReport the span length, width ofspecimen, average thickness of specimen along the center lineand at the edges and breaking load of each specimen. Theaverage of the breaking loads shall be reported as the breakingload across the length of the slate shingle. All determinations,
31、conditioning time and weight data for each specimen shall bereported as information.13.3 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 gr
32、ade of the slate.MODULUS OF ELASTICITY14. Test Specimens and Preparation of Specimens14.1 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.200 mm long.15. Conditioning15.1 Dry the spe
33、cimens 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 drop, continue to dry thespecimens until there are three successive hourly readings withthe same weight.16. P
34、rocedure16.1 Support and load the test specimen in the same way asfor the breaking load and flexural strength determination,except that the roofing slate specimen shall be supported on a6-in. 150-mm span. Set any type of deflectometer, capable ofreading to 0.001 in. 0.02 mm, to measure deflections a
35、tmid-span (Note 3). Stop the loading at each 50-lbf 200-Nincrement, and record the corresponding deflections.NOTE 3It 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 lbf 5
36、0 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.17. Calculation17.1 Plot the load-deflection readings on cross-section paperto a convenient scale, and draw a straight line
37、 to represent, asC120/C120M 153nearly as possible, the average of the plotted points (Note 4). 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
38、point on the corrected line, as follows:E 5 Wl3/4bd3! (2)where:E = modulus of elasticity, psi MPa,W = load coordinate of the point, lbf N, = 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 center,
39、 in. mm.NOTE 4Slate does not show a definite yield point in the stress-straincurve.18. Report18.1 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 obtained
40、 on specimens cut with thelength perpendicular to the grain as the modulus of elasticitywith the grain. All determinations shall be reported as infor-mation.18.2 The following additional information shall also bereported: Identification of the sample, including name andlocation of the quarry, name a
41、nd position of the ledge, datewhen sample was taken, and trade name or grade of the slate.19. Precision and Bias19.1 Individual variations in a natural product may result indeviation from accepted values. A precision section will beadded when sufficient data are available to indicate acceptabletoler
42、ances in repeatability and reproducibility.20. Keywords20.1 breaking load; dimension stone; flexure; modulus ofelasticity; modulus of rupture; slate; testASTM International takes no position respecting the validity of any patent rights asserted in connection with any item mentionedin this standard.
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