1、Designation: C120/C120M 09 C120/C120M 12Standard 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 o
2、r, in the 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.INTRODUCT
3、IONDue 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 slatesare such that these determinations are of special interest and value, besides furnishing comparat
4、ivedata.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 desirableto test the strength and elasticity both parallel and perpendicular to the grain.Breaking load
5、 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 minimum specified thickness must be conducted.When comparing slates of equal thickness, but from v
6、arious 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 methods cover determination of the breaking load, modulus of rupture and modulus of elasticity of sla
7、te by meansof flexure tests.1.2 UnitsThe values stated in either SI units or inch-pound units are to be regarded separately as standard. The values statedin each system may not be exact equivalents; therefore, each system shall be used independently of the other. Combining valuesfrom the two systems
8、 may result in non-conformance with the standard.1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibilityof the user of this standard to establish appropriate safety and health practices and determine the applicability of reg
9、ulatorylimitations prior to use.2. Referenced Documents2.1 ASTM Standards:2C99 Test Method for Modulus of Rupture of Dimension StoneC119 Terminology Relating to Dimension Stone3. Terminology3.1 DefinitionsAll definitions are in accordance with Terminology C119.4. Significance and Use4.1 These test m
10、ethods are useful in indicating the differences in flexure (breaking load, modulus of rupture, modulus ofelasticity) between various slates. These test methods also provide one element in the comparison of slates.1 These test methods are under the jurisdiction of ASTM Committee C18 on Dimension Ston
11、e and are the direct responsibility of Subcommittee C18.01 on Test Methods.Current edition approved April 1, 2009Oct. 15, 2012. Published April 2009November 2012. Originally approved in 1925. Last previous edition approved in 20062009as C120C120/C120M06-09.1. DOI: 10.1520/C0120_C0120M-09.10.1520/C01
12、20_C0120M-12.2 For referenced ASTM standards, visit the ASTM website, www.astm.org, or contact ASTM Customer Service at serviceastm.org. For Annual Book of ASTM Standardsvolume information, refer to the standards Document Summary page on the ASTM website.This document is not an ASTM standard and is
13、intended only to provide the user of an ASTM standard an indication of what changes have been made to the previous version. Becauseit may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the c
14、urrent versionof 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 States15. Apparatus5.1 Testing MachineThe accuracy of the testing machine shall be within 1 % for th
15、e range from 10 to 1000 lbf 50 to 5000N.5.2 Load Application and Support BlocksThe supports for the specimen shall be of the rocker type (Fig. 1) with the edgesat least as long as the width of the specimen. The load application block may be of either the rocker or rigid type. The portionsof the load
16、 application and support blocks contacting the stone shall be rounded, with a nominal radius of 12 in. 13 mm.6. Sampling6.1 Select the sample to represent a true average of the type or grade of stone under consideration and of the quality suppliedto the market under the type designation to be tested
17、. The sample may be selected by the purchaser or his authorized representativefrom the quarried stone or taken from the natural ledge and shall be of adequate size to permit the preparation of the desired numberof test specimens. When perceptible variations occur, the purchaser may select as many sa
18、mples as are necessary for determiningthe variations in flexure (breaking load, modulus of rupture, modulus of elasticity).BREAKING LOAD AND MODULUS OF RUPTURE7. Test Specimens7.1 Structural or Electrical SlateSix representative specimens, 12 by 112 by 1 in. 300 by 40 by 25 mm in size, of theparticu
19、lar slate under consideration shall be tested.FIG. 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 1227.2 Roofing SlateAt least ten specimens 4 in. 101.6100 mm in width, 5 in.
20、 125 mm or greater in length and minimum 316in. 5 mm thick.8. Preparation of Specimens8.1 Structural or Electrical SlateSplit the slate for the test to a thickness of approximately 114 in. 30 mm and then saw intostrips 12 in. 300 mm in length by 112 in. 40 mm in width. Cut half of these with the len
21、gth parallel to the grain and half withthe length perpendicular to the grain. Plane or rub down the 12 by 112-in. 300 by 40-mm faces to a thickness of approximately1 in. 25 mm, taking care to have the finished surfaces as nearly parallel as practicable.8.2 Roofing SlateCut one 4 by 5-in. 100 by 125-
22、mm specimen from each of a minimum 10 shingles. The saw blade shallbe a continuous rim, diamond impregnated type, mounted to a water-cooled sliding bed saw capable of making a clean cut withno lacerated edges. Cut no part of the specimen nearer than 1 in. 25 mm to a sheared edge or nail hole. The 5
23、in. 125 mm orlonger dimension is to be measured and cut parallel with the long dimension of the slate shingle. Do not resurface the split faces.9. Conditioning9.1 Dry the specimens for 48 h in a ventilated oven at a temperature of 140 6 4F 60 6 2C. At the 46th, 47th and 48th hour,weigh the specimens
24、 to ensure that the weight is the same. If the weight continues to drop, continue to dry the specimens untilthere are three successive hourly readings with the same weight.10. Marking and Measuring10.1 On structural or electrical slate, rule the center lines with a try-square perpendicular to the ed
25、ges of the specimens.Likewise, rule the span lines, parallel to, and 5 in. 125 mm from, the center lines. On specimens of roofing slate rule the centerlines perpendicular to an edge that is parallel to the length of the shingle. Rule span lines parallel to, and 1 in. 25 mm from, thecenter lines. Mea
26、sure the specimen thickness at three points along the center line to the nearest 0.01 in. 0.1 mm and record theaverage as the specimen thickness.11. Procedure11.1 The testing machine shall be accurate to 1 % within the range from 100 to 2000 lbf 500 to 10 000 N. PlaceLay thespecimens flatflatwise on
27、 the rocker type knife-edges support blocks as shown in Fig.Fig. 1 1 of Test Method C99. Apply the loadat the center span through a rocker or fixed type knife-edge. load application block. When a load of 10 lbf 50 N has been applied,stop the loading and make all knife edgesthe blocks coincide with t
28、he marks on the specimen by centering the specimen under theloading edge load application block and moving the supporting edgessupport blocks under the span marks. Apply loads at ratesnot exceeding 1000 lbf/min 5000 N/min until failure, and record the breaking load to the nearest 5 lbf 20 N.NOTE 1Wh
29、en all three knife edges load application and support blocks are of the rocker type, care must be taken to adjust all three until the top faceof the specimen is horizontal when loaded.12. CalculationStructural or Electrical Slate12.1 Calculate the modulus of rupture as follows:R 53Wl/2bd 2! (1)where
30、:R = modulus of rupture, psi MPa,W = breaking load, lbf N,l = span length between supporting knife-edges, in. mm,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 Slat
31、eReport all modulus of rupture values and the average of all modulus of rupture values forspecimens cut parallel to the grain as the modulus of rupture “across the grain.” Report all modulus of rupture values and theaverage of all modulus of rupture values for specimens cut perpendicular to the grai
32、n as the modulus of rupture “with the grain.”All determinations shall be reported as information.13.2 Roofing SlateReport the span length, width of specimen, average thickness of specimen along the center line and at theedges and breaking load of each specimen. The average of the breaking loads shal
33、l be reported as the breaking load across thelength of the slate shingle. All determinations, conditioning time and weight data for each specimen shall be reported asinformation.C120/C120M 12313.3 The following additional information shall also be reported: Identification of the sample, including na
34、me and location ofthe quarry, name and position of the ledge, date when sample was taken, and trade name or grade of the slate.MODULUS OF ELASTICITY14. Test Specimens and Preparation of Specimens14.1 The modulus of elasticity may be determined in conjunction with the modulus of rupture test. For thi
35、s test on roofing slateit will be desirable to use a specimen 8 in. 200 mm long.15. Conditioning15.1 Dry the specimens for 48 h in a ventilated oven at a temperature of 140 6 4F 60 6 2C. At the 46th, 47th and 48thhour, weigh the specimens to ensure that the weight is the same. If the weight continue
36、s to drop, continue to dry the specimensuntil there are three successive hourly readings with the same weight.16. Procedure16.1 Support and load the test specimen in the same way as for the breaking load and flexural strength determination, exceptthat the roofing slate specimen shall be supported on
37、 a 6-in. 150-mm span. Set any type of deflectometer, capable of reading to0.001 in. 0.02 mm, to measure deflections at mid-span (Note 2). Stop the loading at each 50-lbf 200-N increment, and recordthe corresponding deflections.NOTE 2It is not ordinarily feasible to set the deflectomer to read zero w
38、hen there is no load on the specimen. The best practice is to put a small initialload on the specimen, such as 10 lbf 50 N and set the deflectometer to read zero for this load. Since it is only the slope of the stress-strain curve thatis desired, this initial load does not affect the final result.17
39、. Calculation17.1 Plot the load-deflection readings on cross-section paper to a convenient scale, and draw a straight line to represent, asnearly as possible, the average of the plotted points (Note 3). If the line does not pass through the zero point, draw a correctedline through this point paralle
40、l to the stress-strain line. Calculate the modulus of elasticity, E, from the coordinates of someconvenient point on the corrected line, as follows:E 5Wl 3/4bd 3! (2)where:E = modulus of elasticity, psi MPa,W = load coordinate of the point, lbf N, = deformation coordinate of the point, in. mm,l = le
41、ngth 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-strain curve.18. Report18.1 Report the average of the results obtained for specimens prepared with the length parallel t
42、o the grain as the modulus ofelasticity across the grain. Likewise, report the average of the results obtained on specimens cut with the length perpendicular tothe grain as the modulus of elasticity with the grain. All determinations shall be reported as information.18.2 The following additional inf
43、ormation shall also be reported: Identification of the sample, including name and location ofthe quarry, name and position of the ledge, date when sample was taken, and trade name or grade of the slate.19. Precision and Bias19.1 Individual variations in a natural product may result in deviation from
44、 accepted values. A precision section will be addedwhen sufficient data are available to indicate acceptable tolerances in repeatability and reproducibility.C120/C120M 12420. Keywords20.1 breaking load; dimension stone; flexure; modulus of elasticity; modulus of rupture; slate; testASTM Internationa
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48、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). Permission rights to photocopy the standard may also be secured from the ASTM website (www.astm.org/COPYRIGHT/).C120/C120M 125
