AASHTO T 22-2017 Standard Method of Test for Compressive Strength of Cylindrical Concrete Specimens.pdf

1、Standard Method of Test for Compressive Strength of Cylindrical Concrete Specimens AASHTO Designation: T 22-171Technical Section: 3c, Hardened Concrete Release: Group 1 (April 2017) ASTM Designation: C39/C39M-16 American Association of State Highway and Transportation Officials 444 North Capitol Str

2、eet N.W., Suite 249 Washington, D.C. 20001 TS-3c T 22-1 AASHTO Standard Method of Test for Compressive Strength of Cylindrical Concrete Specimens AASHTO Designation: T 22-171Technical Section: 3c, Hardened Concrete Release: Group 1 (April 2017) ASTM Designation: C39/C39M-16 1. SCOPE 1.1. This test m

3、ethod covers determination of compressive strength of cylindrical concrete specimens such as molded cylinders and drilled cores. It is limited to concrete having a unit weight 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 separate

4、ly as standard. The inch-pound units are shown in parentheses. The values stated in each system may not be exact equivalents; therefore, each system shall be used independently of the other. Combining values from the two systems may result in nonconformance with the standard. 1.3. This standard may

5、involve hazardous materials, operations, or equipment. This standard does not purport to address all of the safety concerns, if any, associated 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

6、regulatory limitations prior to use. WarningMeans should be provided to contain concrete fragments during sudden rupture of specimens. Tendency for sudden rupture increases with increasing concrete strength (Note 1). Note 1The safety precautions given in the Manual of Aggregate and Concrete Testing,

7、 located in the Related Materials section of Vol. 04.02 of the Annual Book of ASTM Standards, are recommended. 1.4. The text of this standard references notes that provide explanatory material. These notes shall not be considered as requirements of the standard. 2. REFERENCED DOCUMENTS 2.1. AASHTO S

8、tandards: R 18, Establishing and Implementing a Quality Management System for Construction Materials Testing Laboratories R 39, Making and Curing Concrete Test Specimens in the Laboratory T 23, Making and Curing Concrete Test Specimens in the Field T 24M/T 24, Obtaining and Testing Drilled Cores and

9、 Sawed Beams of Concrete T 231, Capping Cylindrical Concrete Specimens 2017 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 2.2. ASTM Standards: C670, Standard Practice for Preparing Preci

10、sion and Bias Statements for Test Methods for Construction Materials C873/C873M, Standard Test Method for Compressive Strength of Concrete Cylinders Cast in Place in Cylindrical Molds C1231/C1231M, Standard Practice for Use of Unbonded Caps in Determination of Compressive Strength of Hardened Concre

11、te Cylinders E4, Standard Practices for Force Verification of Testing Machines E74, 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

12、 TEST METHOD 3.1. This test method consists 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-se

13、ctional area of the specimen. 4. SIGNIFICANCE 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 wi

14、ll depend on the 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 may be used to determine compressive strength of cylindrical specimens prepared and

15、cured in accordance with R 39, T 23, T 24M/T 24, T 231, and ASTM C873/C873M. 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 effective

16、ness of admixtures and similar uses (R 18). 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 E4, except

17、 that the verified loading range shall be 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 adju

18、stments that affect the operation of the 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 2017 by the American Association of State Highway and Transportation Officials.A

19、ll rights reserved. Duplication is a violation 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 appl

20、y the load continuously rather than intermittently, 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-op

21、erated. 5.1.2.2. The space provided for 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 E74. Note 2The

22、types of elastic calibration devices most 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

23、within the proposed range of use of the 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

24、test loads shall not exceed one third 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

25、the percentage of error, Ep, for each 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 testin

26、g machine shall state within what loading 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 est

27、imated on the load-indicating mechanism 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.

28、The indicated load of a testing machine shall not be corrected either by calculation or by the use of a calibration diagram to obtain values within the required permissible variation. 5.2. The testing machine shall be equipped with two steel bearing blocks with hardened faces (Note 3), one of which

29、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 shall have a minimum dimension at least 3 percent greater than the diameter of the specimen to be tested. Except for the concent

30、ric 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 2017 by the American Association of State Highway and Transportation Officials.All rights reserved. Duplication is a violation o

31、f applicable law.TS-3c T 22-4 AASHTO 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

32、more than 13 mm (0.5 in.), concentric 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

33、 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 the specified surface conditions (Note 4). The top and bottom surfaces shall be par

34、allel to each other. Its least horizontal 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. Fi

35、nal centering must be made with reference 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 sha

36、ll 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 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 mai

37、ntained in the specified surface condition, 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

38、1. Table 1Maximum Diameter of Bearing 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

39、 circle does not exceed the above diameter. 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 radius 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

40、. 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 preferred contact area is in the form of a ring (described as “preferred bearing area”) as shown in Figure 1. 2017 by the American

41、Association of State Highway and Transportation Officials.All rights reserved. Duplication is a violation of applicable law.TS-3c T 22-5 AASHTO 5.2.2.4. At least every six months, or as specified by the manufacturer of the testing machine, clean and lubricate the curved surfaces of the socket and of

42、 the spherical portion of the machine. The lubricant shall be a petroleum-type oil such as conventional motor oil or as specified by the manufacturer of the testing machine. Note 8To ensure uniform seating, the spherically seated head is designed to tilt freely as it comes into contact with the top

43、of the specimen. After contact, further rotation is undesirable. Friction between the socket and the spherical portion of the head provides restraint against further rotation during loading. Petroleum-type oil such as conventional motor oil has been shown to permit the necessary friction to develop.

44、 Pressure-type greases can reduce the desired friction and permit undesired rotation of the spherical head and should not be used unless recommended by the manufacturer of the testing machine. 5.2.2.5. If the radius of the sphere is smaller than the radius of the largest specimen to be tested, the p

45、ortion of the bearing face extending 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.) Note: Provision sh

46、all 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 Block 5.2.2.6. The movable portion of the bearing block shall be held closely in the spherical seal, but the design shall be such that the be

47、aring face can be rotated freely and tilted at least 4 degrees in any direction. 5.3. If the ball portion of the upper bearing block is a two-piece design composed of a spherical portion and a bearing plate, a mechanical means shall be provided to ensure that the spherical portion is fixed and cente

48、red on the bearing plate.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 provided with a graduated scale that can be read to at least the nearest 0.1 percent of the full scale load (Note 9). The dial shall be readable wit

49、hin 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 include loads below the value that is 100 times the smallest change of load that can be read on the scale. 2017 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 The scale shall be provided with a graduation line equal to zero and so numbered. The dial pointer shall be of sufficient leng