1、Designation: C39/C39M 12 C39/C39M 12aStandard Test Method forCompressive Strength of Cylindrical Concrete Specimens1This standard is issued under the fixed designation C39/C39M; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the y
2、ear of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript 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.1. Scope*1.1 This test method covers deter
3、mination of compressive strength of cylindrical concrete specimens such as molded cylindersand drilled cores. It is limited to concrete having a density in excess of 800 kg/m3 50 lb/ft3.1.2 The values stated in either SI units or inch-pound units are to be regarded separately as standard. The inch-p
4、ound units areshown in brackets. The values stated in each system may not be exact equivalents; therefore, each system shall be usedindependently of the other. Combining values from the two systems may result in non-conformance with the standard.1.3 This standard does not purport to address all of t
5、he 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 regulatorylimitations prior to use. (WarningMeans should be provided to contain concrete fragments during
6、sudden rupture of specimens.Tendency for sudden rupture increases with increasing concrete strength and it is more likely when the testing machine is relativelyflexible. The safety precautions given in the Manual of Aggregate and Concrete Testing are recommended.)1.4 The text of this standard refere
7、nces notes which provide explanatory material. These notes shall not be considered asrequirements of the standard.2. Referenced Documents2.1 ASTM Standards:2C31/C31M Practice for Making and Curing Concrete Test Specimens in the FieldC42/C42M Test Method for Obtaining and Testing Drilled Cores and Sa
8、wed Beams of ConcreteC192/C192M Practice for Making and Curing Concrete Test Specimens in the LaboratoryC617 Practice for Capping Cylindrical Concrete SpecimensC670 Practice for Preparing Precision and Bias Statements for Test Methods for Construction MaterialsC873 Test Method for Compressive Streng
9、th of Concrete Cylinders Cast in Place in Cylindrical MoldsC1077 Practice for Agencies Testing Concrete and Concrete Aggregates for Use in Construction and Criteria for Testing AgencyEvaluationC1231/C1231M Practice for Use of Unbonded Caps in Determination of Compressive Strength of Hardened Concret
10、e CylindersE4 Practices for Force Verification of Testing MachinesE74 Practice of Calibration of Force-Measuring Instruments for Verifying the Force Indication of Testing MachinesManual of Aggregate and Concrete Testing3. Summary of Test Method3.1 This test method consists of applying a compressive
11、axial load to molded cylinders or cores at a rate which is within aprescribed range until failure occurs. The compressive strength of the specimen is calculated by dividing the maximum loadattained during the test by the cross-sectional area of the specimen.4. Significance and Use4.1 Care must be ex
12、ercised in the interpretation of the significance of compressive strength determinations by this test methodsince strength is not a fundamental or intrinsic property of concrete made from given materials. Values obtained will depend on1 This test method is under the jurisdiction of ASTM Committee C0
13、9 on Concrete and Concrete Aggregatesand is the direct responsibility of Subcommittee C09.61 onTesting for Strength.Current edition approved Feb. 1, 2012Sept. 1, 2012. Published March 2012October 2012. Originally approved in 1921. Last previous edition approved in 20112012 asC39/C39M11a.12. DOI: 10.
14、1520/C0039_C0039M-12.10.1520/C0039_C0039M-12a.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 documen
15、t is not an ASTM standard and is 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 app
16、ropriate. In all cases only the current versionof the standard as published by ASTM is to be considered the official document.*A 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 St
17、ates1the size and shape of the specimen, batching, mixing procedures, the methods of sampling, molding, and fabrication and the age,temperature, and moisture conditions during curing.4.2 This test method is used to determine compressive strength of cylindrical specimens prepared and cured in accorda
18、nce withPractices C31/C31M, C192/C192M, C617, and C1231/C1231M and Test Methods C42/C42M and C873.4.3 The results of this test method are used as a basis for quality control of concrete proportioning, mixing, and placingoperations; determination of compliance with specifications; control for evaluat
19、ing effectiveness of admixtures; and similar uses.4.4 The individual who tests concrete cylinders for acceptance testing shall meet the concrete laboratory technicianrequirements of Practice C1077, including an examination requiring performance demonstration that is evaluated by anindependent examin
20、er.NOTE 1Certification equivalent to the minimum guidelines for ACI Concrete Laboratory Technician, Level I or ACI Concrete Strength TestingTechnician will satisfy this requirement.5. Apparatus5.1 Testing MachineThe testing machine shall be of a type having sufficient capacity and capable of providi
21、ng the rates ofloading prescribed in 7.5.5.1.1 Verify calibration of the testing machines in accordance with Practices E4, except that the verified loading range shall beas required in 5.3. Verification is required under the following conditions:required:5.1.1.1 At least annually, but not to exceed
22、13 months,Within 13 months of the last calibration,5.1.1.2 On original installation or immediately after relocation,5.1.1.3 Immediately after making repairs or adjustments that affect the operation of the force applying system or the valuesdisplayed on the load indicating system, except for zero adj
23、ustments that compensate for the mass of bearing blocks or specimen,or both, or5.1.1.4 Whenever there is reason to suspect the accuracy of the indicated loads.5.1.2 DesignThe design of the machine must include the following features:5.1.2.1 The machine must be power operated and must apply the load
24、continuously rather than intermittently, and without shock.If it has only one loading rate (meeting the requirements of 7.5), it must be provided with a supplemental means for loading ata rate suitable for verification. This supplemental means of loading may be power or hand operated.5.1.2.2 The spa
25、ce provided for test specimens shall be large enough to accommodate, in a readable position, an elasticcalibration device which is of sufficient capacity to cover the potential loading range of the testing machine and which complieswith the requirements of Practice E74.NOTE 2The types of elastic cal
26、ibration devices most generally available and most commonly used for this purpose are the circular proving ring orload cell.5.1.3 AccuracyThe accuracy of the testing machine shall be in accordance with the following provisions:5.1.3.1 The percentage of error for the loads within the proposed range o
27、f use of the testing machine shall not exceed 61.0 %of the indicated load.5.1.3.2 The accuracy of the testing machine shall be verified by applying five test loads in four approximately equal incrementsin ascending order. The difference between any two successive test loads shall not exceed one thir
28、d of the difference between themaximum and minimum test loads.5.1.3.3 The test load as indicated by the testing machine and the applied load computed from the readings of the verificationdevice shall be recorded at each test point. Calculate the error, E, and the percentage of error, Ep, for each po
29、int from these dataas follows:E 5A 2B (1)Ep 5100A 2B!/Bwhere:A = load, kN lbf indicated by the machine being verified, andB = applied load, kN lbf as determined by the calibrating device.5.1.3.4 The report on the verification of a testing machine shall state within what loading range it was found to
30、 conform tospecification requirements rather than reporting a blanket acceptance or rejection. In no case shall the loading range be stated asincluding loads below the value which is 100 times the smallest change of load estimable on the load-indicating mechanism ofthe testing machine or loads withi
31、n that portion of the range below 10 % of the maximum range capacity.5.1.3.5 In no case shall the loading range be stated as including loads outside the range of loads applied during the verificationtest.5.1.3.6 The indicated load of a testing machine shall not be corrected either by calculation or
32、by the use of a calibration diagramto obtain values within the required permissible variation.C39/C39M 12a25.2 The testing machine shall be equipped with two steel bearing blocks with hardened faces (Note 3), one of which is aspherically seated block that will bear on the upper surface of the specim
33、en, and the other a solid block on which the specimenshall rest. Bearing faces of the blocks shall have a minimum dimension at least 3 % greater than the diameter of the specimen tobe tested. Except for the concentric circles described below, the bearing faces shall not depart from a plane by more t
34、han 0.02 mm0.001 in. in any 150 mm 6 in. of blocks 150 mm 6 in. in diameter or larger, or by more than 0.02 mm 0.001 in. in thediameter of any smaller block; and new blocks shall be manufactured within one half of this tolerance. When the diameter of thebearing face of the spherically seated block e
35、xceeds the diameter of the specimen by more than 13 mm 0.5 in., concentric circlesnot more than 0.8 mm 0.03 in. deep and not more than 1 mm 0.04 in. wide shall be inscribed to facilitate proper centering.NOTE 3It is desirable that the bearing faces of blocks used for compression testing of concrete
36、have a Rockwell hardness of not less than 55 HRC.5.2.1 Bottom bearing blocks shall conform to the following requirements:5.2.1.1 The bottom bearing block is specified for the purpose of providing a readily machinable surface for maintenance of thespecified surface conditions (Note 4). The top and bo
37、ttom surfaces shall be parallel to each other. If the testing machine is sodesigned that the platen itself is readily maintained in the specified surface condition, a bottom block is not required. Its leasthorizontal dimension shall be at least 3 % greater than the diameter of the specimen to be tes
38、ted. Concentric circles as describedin 5.2 are optional on the bottom block.NOTE 4The block may be fastened to the platen of the testing machine.5.2.1.2 Final centering must be made with reference to the upper spherical block. When the lower bearing block is used to assistin centering the specimen,
39、the center of the concentric rings, when provided, or the center of the block itself must be directly belowthe center of the spherical head. Provision shall be made on the platen of the machine to assure such a position.5.2.1.3 The bottom bearing block shall be at least 25 mm 1 in. thick when new, a
40、nd at least 22.5 mm 0.9 in. thick after anyresurfacing operations.5.2.2 The spherically seated bearing block shall conform to the following requirements:5.2.2.1 The maximum diameter of the bearing face of the suspended spherically seated block shall not exceed the values givenbelow:Diameter of Maxim
41、um DiameterTest Specimens, of Bearing Face,mm in. mm in.50 2 105 475 3 130 5100 4 165 6.5150 6 255 10200 8 280 11NOTE 5Square bearing faces are permissible, provided the diameter of the largest possible inscribed circle does not exceed the above diameter.5.2.2.2 The center of the sphere shall coinci
42、de with the surface of the bearing face within a tolerance of 65 % of the radius ofthe sphere. The diameter of the sphere shall be at least 75 % of the diameter of the specimen to be tested.5.2.2.3 The ball and the socket shall be designed so that the steel in the contact area does not permanently d
43、eform when loadedto the capacity of the testing machine.NOTE 6The preferred contact area is in the form of a ring (described as “preferred bearing area”) as shown on Fig. 1.5.2.2.4 At least every six months, or as specified by the manufacturer of the testing machine, clean and lubricate the curvedsu
44、rfaces of the socket and of the spherical portion of the machine. The lubricant shall be a petroleum-type oil such as conventionalmotor oil or as specified by the manufacturer of the testing machine.NOTE 7To ensure uniform seating, the spherically seated head is designed to tilt freely as it comes i
45、nto contact with the top of the specimen. Aftercontact, further rotation is undesirable. Friction between the socket and the spherical portion of the head provides restraint against further rotation duringloading. Petroleum-type oil such as conventional motor oil has been shown to permit the necessa
46、ry friction to develop. Pressure-type greases can reducethe desired friction and permit undesired rotation of the spherical head and should not be used unless recommended by the manufacturer of the testingmachine.5.2.2.5 If the radius of the sphere is smaller than the radius of the largest specimen
47、to be tested, the portion of the bearing faceextending beyond the sphere shall have a thickness not less than the difference between the radius of the sphere and radius of thespecimen. The least dimension of the bearing face shall be at least as great as the diameter of the sphere (see Fig. 1).5.2.2
48、.6 The movable portion of the bearing block shall be held closely in the spherical seat, but the design shall be such thatthe bearing face can be rotated freely and tilted at least 4 in any direction.5.2.2.7 If the ball portion of the upper bearing block is a two-piece design composed of a spherical
49、 portion and a bearing plate,a mechanical means shall be provided to ensure that the spherical portion is fixed and centered on the bearing plate.5.3 Load Indication:5.3.1 If the load of a compression machine used in concrete testing is registered on a dial, the dial shall be provided with agraduated scale that is readable to at least the nearest 0.1 % of the full scale load (Note 8). The dial shall be readable within 1 %C39/C39M 12a3of the indicated load at any given load level within the loading range. In no case sha
