AASHTO T 22-2014 Standard Method of Test for Compressive Strength of Cylindrical Concrete Specimens.pdf

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1、Standard Method of Test for Compressive Strength of Cylindrical Concrete Specimens AASHTO Designation: T 22-141ASTM Designation: C 39/C 39M-05 American Association of State Highway and Transportation Officials 444 North Capitol Street N.W., Suite 249 Washington, D.C. 20001 TS-3c T 22-1 AASHTO Standa

2、rd Method of Test for Compressive Strength of Cylindrical Concrete Specimens AASHTO Designation: T 22-141ASTM Designation: C 39/C 39M-05 1. SCOPE 1.1. This test method covers determination of compressive strength of cylindrical concrete specimens such as molded cylinders and drilled cores. It is lim

3、ited to concrete having a unit weight in excess of 800 kg/m3(50 lb/ft3). 1.2. The values stated in SI units are the preferred standard. 1.3. This standard may involve hazardous materials, operations, or equipment. This standard does not purport to address all of the safety concerns, if any, associat

4、ed with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use. WarningMeans should be provided to contain concrete fragments during sudden rupture of specimens. Tenden

5、cy for sudden rupture increases with increasing concrete strength (Note 1). Note 1The safety precautions given in the Manual of Aggregate and Concrete Testing, located in the Related Materials section of Volume 04.02 of the Annual Book of ASTM Standards, are recommended. 1.4. The text of this standa

6、rd references notes that provide explanatory material. These notes shall not be considered as requirements of the standard. 2. REFERENCED DOCUMENTS 2.1. AASHTO Standards: R 39, Making and Curing Concrete Test Specimens in the Laboratory T 23, Making and Curing Concrete Test Specimens in the Field T

7、24M/T 24, Obtaining and Testing Drilled Cores and Sawed Beams of Concrete T 231, Capping Cylindrical Concrete Specimens 2.2. ASTM Standards: C 31/C 31M, Standard Practice for Making and Curing Concrete Test Specimens in the Field C 42/C 42M, Standard Test Method for Obtaining and Testing Drilled Cor

8、es and Sawed Beams of Concrete C 192/C 192M, Standard Practice for Making and Curing Concrete Test Specimens in the Laboratory C 617/C 617M, Standard Practice for Capping Cylindrical Concrete Specimens C 670, Standard Practice for Preparing Precision and Bias Statements for Test Methods for Construc

9、tion Materials 2014 by the American Association of State Highway and Transportation Officials.All rights reserved. Duplication is a violation of applicable law.TS-3c T 22-2 AASHTO C 873/C 873M, Standard Test Method for Compressive Strength of Concrete Cylinders Cast in Place in Cylindrical Molds C 1

10、077, Standard Practice for Agencies Testing Concrete and Concrete Aggregates for Use in Construction and Criteria for Testing Agency Evaluation C 1231/C 1231M, Standard Practice for Use of Unbonded Caps in Determination of Compressive Strength of Hardened Concrete Cylinders E 4, Standard Practices f

11、or Force Verification of Testing Machines E 74, Standard Practice of Calibration of Force-Measuring Instruments for Verifying the Force Indication of Testing Machines Manual of Aggregate and Concrete Testing, Annual Book of ASTM Standards, Vol. 04.02 3. SUMMARY OF TEST METHOD 3.1. This test method c

12、onsists of applying a compressive axial load to molded cylinders or cores at a rate that is within a prescribed range until failure occurs. The compressive strength of the specimen is calculated by dividing the maximum load attained during the test by the cross-sectional area of the specimen. 4. SIG

13、NIFICANCE AND USE 4.1. Care must be exercised in the interpretation of the significance of compressive strength determinations by this test method because strength is not a fundamental or intrinsic property of concrete made from given materials. Values obtained will depend on the size and shape of t

14、he 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 may be used to determine compressive strength of cylindrical specimens prepared and cured in accordance with R 39, T 23,

15、 T 24M/T 24, T 231, and ASTM C 873/C 873M. 4.3. The results of this test method may be used as a basis for quality control of concrete proportioning, mixing, and placing operations; determination of compliance with specification; and control for evaluating effectiveness of admixtures and similar use

16、s. 5. APPARATUS 5.1. Testing MachineThe testing machine shall be of a type having sufficient capacity and capable of providing the rates of loading prescribed in Section 7.5. 5.1.1. Verify calibration of the testing machines in accordance with ASTM E 4, except that the verified loading range shall b

17、e as required in Section 5.3. Verification is required under the following conditions: 5.1.1.1. At least annually, but not to exceed 13 months; 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

18、 force applying system or the values displayed on the load indicating system, except for zero adjustments that compensate for the mass (weight) of tooling, or specimen, or both; or 2014 by the American Association of State Highway and Transportation Officials.All rights reserved. Duplication is a vi

19、olation of applicable law.TS-3c T 22-3 AASHTO 5.1.1.4. 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 continuously rather than int

20、ermittently, and without shock. If it has only one loading rate (meeting the requirements of Section 7.5), it must be provided with a supplemental means for loading at a rate suitable for verification. This supplemental means of loading may be power- or hand-operated. 5.1.2.2. The space provided for

21、 test specimens shall be large enough to accommodate, in a readable position, an elastic calibration device that is of sufficient capacity to cover the potential loading range of the testing machine and that complies with the requirement of ASTM E 74. Note 2The types of elastic calibration devices m

22、ost generally available and most commonly used for this purpose are the circular proving rings or load cells. 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 of use of th

23、e testing machine shall not exceed 1.0 percent 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 increments in ascending order. The difference between any two successive test loads shall not exceed one-third

24、of the difference between the maximum 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 verification device shall be recorded at each test point. Calculate the error, E, and the percentage of error, Ep, for each

25、point from these data as follows: E = A B (1) Ep= 100 (A B)/B (2) where: A = load, kN (or lbf) indicated by the machine being verified; and B = applied load, kN (or lbf) as determined by the calibrating device. 5.1.3.4. The report on the verification of a testing machine shall state within what load

26、ing range it was found to conform to specification requirements rather than reporting a blanket acceptance or rejection. In no case shall the loading range be stated as including loads below the value that is 100 times the smallest change of load that can be estimated on the load-indicating mechanis

27、m of the testing machine or loads within that portion of the range below 10 percent 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 verification test. 5.1.3.6. The indicated load of a testing machin

28、e shall not be corrected either by calculation or by the use of a calibration diagram to obtain values within the required permissible variation. 2014 by the American Association of State Highway and Transportation Officials.All rights reserved. Duplication is a violation of applicable law.TS-3c T 2

29、2-4 AASHTO 5.2. The testing machine shall be equipped with two steel bearing blocks with hardened faces (Note 3), one of which is a spherically seated block that will bear on the upper surface of the specimen, and the other a solid block on which the specimen shall rest. Bearing faces of the blocks

30、shall have a minimum dimension at least 3 percent greater than the diameter of the specimen to be tested. Except for the concentric circles described below, the bearing faces shall not depart from a plane by more than 0.02 mm (0.001 in.) in any 150 mm (6 in.) of blocks 150 mm (6 in.) in diameter or

31、larger, or by more than 0.02 mm (0.001 in.) in the diameter of any smaller block; and new blocks shall be manufactured within one-half of this tolerance. When the diameter of the bearing face of the spherically seated block exceeds the diameter of the specimen by more than 13 mm (0.5 in.), concentri

32、c circles not 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 have a Rockwell hardness of not less than 55 HRC. 5.2.1. Bottom bea

33、ring 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 the specified surface conditions (Note 4). The top and bottom surfaces shall be parallel to each other. Its least horiz

34、ontal dimension shall be at least 3 percent greater than the diameter of the specimen to be tested. Concentric circles as described in Section 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 refere

35、nce to the upper spherical block when the lower bearing block is used to assist in centering the specimen. The center of the concentric rings, when provided, or the center of the block itself must be directly below the center of the spherical head. Provision shall be made on the platen of the machin

36、e to assure such a position. 5.2.1.3. The bottom bearing block shall be at least 25 mm (1 in.) thick when new and at least 22.5 mm (0.9 in.) thick after resurfacing operations. Note 5If the testing machine is so designed that the platen itself can be readily maintained in the specified surface condi

37、tion, a bottom block is not required. 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 given in Table 1. Table 1Maximum Diameter of Bearing

38、Face Diameter of Test Specimens, mm (in.) Max Diameter of Bearing Face, mm (in.) 50 (2) 105 (4) 75 (3) 130 (5) 100 (4) 165 (6.5) 150 (6) 255 (10) 200 (8) 280 (11) Note 6Square bearing faces are permissible, provided the diameter of the largest possible inscribed circle does not exceed the above diam

39、eter. 2014 by the American Association of State Highway and Transportation Officials.All rights reserved. Duplication is a violation of applicable law.TS-3c T 22-5 AASHTO 5.2.2.2. The center of the sphere shall coincide with the surface of the bearing face within a tolerance of 5 percent of the radi

40、us of the sphere. The diameter of the sphere shall be at least 75 percent 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 deform when loaded to the capacity of the test machine. Note 7The pref

41、erred contact area is in the form of a ring (described as “preferred bearing area”) as shown in Figure 1. 5.2.2.4. The curved surfaces of the socket and the spherical portion shall be kept clean and shall be lubricated with a petroleum-type oil such as conventional motor oil, not with a pressure-typ

42、e grease. After contacting the specimen and application of a small initial load, further tilting of the spherically seated block is not intended and is undesirable. 5.2.2.5. If the radius of the sphere is smaller than the radius of the largest specimen to be tested, the portion of the bearing face e

43、xtending beyond the sphere shall have a thickness not less than the difference between the radius of the sphere and radius of the specimen. The least dimension of the bearing face shall be at least as great as the diameter of the sphere. (See Figure 1.) 5.2.2.6. The movable portion of the bearing bl

44、ock shall be held closely in the spherical seal, but the design shall be such that the bearing face can be rotated freely and tilted at least 4 degrees 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 portion and a bearing plate,

45、 a mechanical means shall be provided to ensure that the spherical portion is fixed and centered on the bearing plate. Note: Provision shall be made for holding the ball in the socket and for holding the entire unit in the testing machine. Figure 1Schematic Sketch of a Typical Spherical Bearing Bloc

46、k 2014 by the American Association of State Highway and Transportation Officials.All rights reserved. Duplication is a violation of applicable law.TS-3c T 22-6 AASHTO 5.3. Load Indication: 5.3.1. If the load of a compression machine used in concrete tests is registered on a dial, the dial shall be p

47、rovided with a graduated scale that can be read to at least the nearest 0.1 percent of the full scale load (Note 8). The dial shall be readable within 1 percent of the indicated load at any given load level within the loading range. In no case shall the loading range of a dial be considered to inclu

48、de loads below the value that is 100 times the smallest change of load that can be read on the scale. The scale shall be provided with a graduation line equal to zero and so numbered. The dial pointer shall be of sufficient length to reach the graduation marks; the width of the end of the pointer sh

49、all not exceed the clear distance between the smallest graduations. Each dial shall be equipped with a zero adjustment located outside the dial case and easily accessible from the front of the machine while observing the zero mark and dial pointer. Each dial shall be equipped with a suitable device that at all times, until reset, will indicate to within 1 percent accuracy the maximum load applied to the specimen. Note 8As close as can reasonably be read is considered to be 0.5 mm (0.02 in.) along the arc described by the end of the