ASTM C496 C496M-2017 Standard Test Method for Splitting Tensile Strength of Cylindrical Concrete Specimens《圆柱形混凝土试件的劈裂抗拉强度的标准试验方法》.pdf

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1、Designation: C496/C496M 17Standard Test Method forSplitting Tensile Strength of Cylindrical ConcreteSpecimens1This standard is issued under the fixed designation C496/C496M; the number immediately following the designation indicates the yearof original adoption or, in the case of revision, the year

2、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.1. Scope*1.1 This test method covers the determination of the split-ting tensile strength of cylindrical concrete specimens, su

3、ch asmolded cylinders and drilled cores.1.2 The values stated in either SI units or inch-pound unitsare to be 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 sy

4、stems may result in non-conformancewith 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, health, and environmental practices and deter-mine the

5、 applicability of regulatory limitations prior to use.1.4 The text of this standard references notes that provideexplanatory material. These notes shall not be considered asrequirements of the standard.1.5 This international standard was developed in accor-dance with internationally recognized princ

6、iples on standard-ization established in the Decision on Principles for theDevelopment of International Standards, Guides and Recom-mendations issued by the World Trade Organization TechnicalBarriers to Trade (TBT) Committee.2. Referenced Documents2.1 ASTM Standards:2C31/C31M Practice for Making and

7、 Curing Concrete TestSpecimens in the FieldC39/C39M Test Method for Compressive Strength of Cylin-drical Concrete SpecimensC42/C42M Test Method for Obtaining and Testing DrilledCores and Sawed Beams of ConcreteC125 Terminology Relating to Concrete and Concrete Ag-gregatesC192/C192M Practice for Maki

8、ng and Curing Concrete TestSpecimens in the LaboratoryC670 Practice for Preparing Precision and Bias Statementsfor Test Methods for Construction Materials3. Terminology3.1 DefinitionsFor definitions of terms used in this testmethod, refer to Terminology C125.4. Summary of Test Method4.1 This test me

9、thod consists of applying a diametralcompressive force along the length of a cylindrical concretespecimen at a rate that is within a prescribed range until failureoccurs. This loading induces tensile stresses on the planecontaining the applied load and relatively high compressivestresses in the area

10、 immediately around the applied load.Tensile failure occurs rather than compressive failure becausethe areas of load application are in a state of triaxialcompression, thereby allowing them to withstand much highercompressive stresses than would be indicated by a uniaxialcompressive strength test re

11、sult.4.2 Thin, plywood bearing strips are used to distribute theload applied along the length of the cylinder.4.3 The maximum load sustained by the specimen is dividedby appropriate geometrical factors to obtain the splitting tensilestrength.5. Significance and Use5.1 Splitting tensile strength is g

12、enerally greater than directtensile strength and lower than flexural strength (modulus ofrupture).5.2 Splitting tensile strength is used in the design ofstructural lightweight concrete members to evaluate the shearresistance provided by concrete and to determine the develop-ment length of reinforcem

13、ent.1This test method is under the jurisdiction of ASTM Committee C09 onConcrete and Concrete Aggregates and is the direct responsibility of SubcommitteeC09.61 on Testing for Strength.Current edition approved Oct. 1, 2017. Published October 2017. Originallyapproved in 1962. Last previous edition app

14、roved in 2011 as C496/C496M11.DOI: 10.1520/C0496_C0496M-17.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.*A

15、 Summary of Changes section appears at the end of this standardCopyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United StatesThis international standard was developed in accordance with internationally recognized principles on standardization establ

16、ished in the Decision on Principles for theDevelopment of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.16. Apparatus6.1 Testing MachineThe testing machine shall conform tothe requirements of Test Method C39/C39

17、M and be of a typewith sufficient capacity that will provide the rate of loadingprescribed in 8.5.6.2 Supplementary Bearing Bar or PlateIf the diameter orthe largest dimension of the upper bearing face or the lowerbearing block is less than the length of the cylinder to be tested,a supplementary bea

18、ring bar or plate of machined steel shall beused. The surfaces of the bar or plate shall be machined towithin 6 0.025 mm 6 0.001 in. of planeness, as measured onany line of contact of the bearing area. It shall have a width ofat least 50 mm 2 in., and a thickness not less than the distancefrom the e

19、dge of the spherical or rectangular bearing block tothe end of the cylinder. The bar or plate shall be used in suchmanner that the load will be applied over the entire length ofthe specimen.6.3 Bearing StripsTwo bearing strips of nominal 3.0 mm18 in. thick plywood, free of imperfections, approximate

20、ly 25mm 1 in. wide, and of a length equal to, or slightly longerthan, that of the specimen shall be provided for each specimen.The bearing strips shall be placed between the specimen andboth the upper and lower bearing blocks of the testing machineor between the specimen and supplemental bars or pla

21、tes, whenused (see 6.2). Bearing strips shall not be reused.7. Test Specimens7.1 The test specimens shall conform to the size, molding,and curing requirements set forth in either Practice C31/C31M(field specimens) or Practice C192/C192M (laboratory speci-mens). Drilled cores shall conform to the siz

22、e and moisture-conditioning requirements set forth in Test Method C42/C42M.Moist-cured specimens, during the period between their re-moval from the curing environment and testing, shall be keptmoist by a wet burlap or blanket covering, and shall be testedin a moist condition as soon as practicable.7

23、.2 The following curing procedure shall be used for evalu-ations of light-weight concrete: specimens tested at 28 daysshall be in an air-dry condition after 7 days moist curingfollowed by 21 days drying at 23.0 6 2.0C 73.5 6 3.5F and50 6 5 % relative humidity.8. Procedure8.1 MarkingDraw diametral li

24、nes on each end of thespecimen using a suitable device that will ensure that they arein the same axial plane (see Fig. 1, Fig. 2 and Note 1), or as analternative, use the aligning jig shown in Fig. 3 (Note 2).NOTE 1Figs. 1 and 2 show a suitable device for drawing diametrallines on each end of a 150

25、mm 300 mm 6 in. 12 in. cylinder in thesame axial plane. The device consists of three parts as follows:(1) Alength of 100-mm 4-in. steel channel, the flanges of which havebeen machined flat,(2) A section, part a, that is grooved to fit smoothly over the flanges ofthe channel and that includes cap scr

26、ews for positioning the verticalmember of the assembly, and(3) A vertical bar, part b, for guiding a pencil or marker,The assembly (part a and part b) is not fastened to the channel and ispositioned at either end of the cylinder without disturbing the position ofthe specimen when marking the diametr

27、al lines.NOTE 2Fig. 4 is a detailed drawing of the aligning jig shown in Fig.3 for achieving the same purpose as marking the diametral lines. Thedevice consists of:(1) A base for holding the lower bearing strip and cylinder,(2) A supplementary bearing bar conforming to the requirements inSection 6 a

28、s to critical dimensions and planeness, and(3) Two uprights to serve for positioning the test cylinder, bearingstrips, and supplementary bearing bar.8.2 MeasurementsDetermine the diameter of the testspecimen to the nearest 0.25 mm 0.01 in. by averaging threeFIG. 1 General Views of a Suitable Apparat

29、us for Marking End Diameters Used for Alignment of Specimen in Testing MachineC496/C496M 172diameters measured near the ends and the middle of thespecimen and lying in the plane containing the lines marked onthe two ends. Determine the length of the specimen to thenearest 2 mm 0.1 in. by averaging a

30、t least two lengthmeasurements taken in the plane containing the lines markedon the two ends.8.3 Positioning Using Marked Diametral LinesCenter oneof the plywood strips along the center of the lower bearingblock. Place the specimen on the plywood strip and align sothat the lines marked on the ends o

31、f the specimen are verticaland centered over the plywood strip. Place a second plywoodstrip lengthwise on the cylinder, centered on the lines markedon the ends of the cylinder. Position the assembly to ensure thefollowing conditions:8.3.1 The projection of the plane of the two lines marked onthe end

32、s of the specimen intersects the center of the upperbearing plate, and8.3.2 The supplementary bearing bar or plate, when used,and the center of the specimen are directly beneath the centerof thrust of the spherical bearing block (see Fig. 5).8.4 Positioning by Use of Aligning JigPosition the bearing

33、strips, test cylinder, and supplementary bearing bar by meansof the aligning jig as illustrated in Fig. 3 and center the jig sothat the supplementary bearing bar and the center of thespecimen are directly beneath the center of thrust of thespherical bearing block.8.5 Rate of LoadingApply the load co

34、ntinuously andwithout shock, at a constant rate within the range 0.7 to 1.4MPa/min 100 to 200 psi/min splitting tensile stress untilfailure of the specimen (Note 3). Record the maximum appliedload indicated by the testing machine at failure. Note the typeof failure and the appearance of the concrete

35、.FIG. 2 Detailed Plans for a Suitable Apparatus for Marking End Diameters Used for Aligning the SpecimenFIG. 3 Jig for Aligning Concrete Cylinder and Bearing StripsC496/C496M 173NOTE 3The relationship between splitting tensile stress and appliedload is shown in Section 9. The required loading range

36、in splitting tensilestress corresponds to applied total load in the range of 50 to 100 kN/min11 300 to 22 600 lbf/min for 150 by 300-mm 6 by 12-in. cylinders.FIG. 4 Detailed Plans for a Suitable Aligning Jig for 150 300 mm 6 12 in. SpecimenFIG. 5 Specimen Positioned in a Testing Machine for Determin

37、ation of Splitting Tensile StrengthC496/C496M 1749. Calculation9.1 Calculate the splitting tensile strength of the specimenas follows:T 5 2P/ld (1)where:T = splitting tensile strength, MPa psi,P = maximum applied load indicated by the testing machine,N lbf,l = length, mm in., andd = diameter, mm in.

38、10. Report10.1 Report the following information:10.1.1 Identification number,10.1.2 Diameter and length, in. mm,10.1.3 Maximum load, lbf N,10.1.4 Splitting tensile strength calculated to the nearest0.05 MPa 5 psi,10.1.5 Estimated proportion of coarse aggregate fracturedduring test,10.1.6 Age of spec

39、imen,10.1.7 Curing history,10.1.8 Defects in specimen,10.1.9 Type of fracture, and10.1.10 Type of specimen.11. Precision and Bias11.1 PrecisionAn interlaboratory study of this test methodhas not been performed. Available research data,3however,suggests that the within batch coefficient of variation

40、is 5 %(see Note 4) for 150 300-mm 6 12-in. cylindrical speci-mens with an average splitting tensile strength of 2.8 MPa 405psi. Results of two properly conducted tests on the samematerial, therefore, should not differ by more than 14 % (seeNote 4) of their average for splitting tensile strengths of

41、about2.8 MPa 400 psi.NOTE 4These numbers represent, respectively, the (1s %) and (d2s %)limits as defined in Practice C670.11.2 BiasThe test method has no bias because the splittingtensile strength can be defined only in terms of this testmethod.12. Keywords12.1 cylindrical concrete specimens; split

42、ting tension; ten-sile strengthSUMMARY OF CHANGESCommittee C09 has identified the location of selected changes to this test method since the last issue,C496/C496M11, that may impact the use of this test method. (Approved Oct. 1, 2017)(1) Addition of Section 3, Terminology.ASTM International takes no

43、 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 rights, and the riskof infringement of such rights, are entirely their own respons

44、ibility.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 t

45、o ASTM International 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 add

46、ress 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),

47、 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 Copyright Clearance Center, 222Rosewood Drive, Danvers, MA 01923, Tel: (978) 646-2600; http:/ P. J. F., “Comments on an Indirect Tensile Test on Concrete Cylinders,”Magazine of Concrete Research, Vol 7, No. 20, July 1955, pp. 8795.C496/C496M 175