AASHTO T 198-2015 Standard Method of Test for Splitting Tensile Strength of Cylindrical Concrete Specimens.pdf

1、Standard Method of Test for Splitting Tensile Strength of Cylindrical Concrete Specimens AASHTO Designation: T 198-15 ASTM Designation: C496/C496M-11 American Association of State Highway and Transportation Officials 444 North Capitol Street N.W., Suite 249 Washington, D.C. 20001 TS-3c T 198-1 AASHT

2、O Standard Method of Test for Splitting Tensile Strength of Cylindrical Concrete Specimens AASHTO Designation: T 198-15 ASTM Designation: C496/C496M-11 1. SCOPE 1.1. This test method covers the determination of the splitting tensile strength of cylindrical concrete specimens, such as molded cylinder

3、s and drilled cores. Note 1For methods of molding cylindrical specimens, see R 39 and T 23. For methods of obtaining drilled cores, see T 24M/T 24. 1.2. The values stated in either inch-pound or SI units are to be regarded separately as standard. The SI units are shown in parentheses. The values sta

4、ted in each system may not be exactly equivalent; 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 does not purport to address all of the safety concerns, if any, associated with

5、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. 1.4. The text of this standard references notes that provide explanatory material. These notes shall not be cons

6、idered as requirements of the standard. 2. REFERENCED DOCUMENTS 2.1. AASHTO Standards: R 39, Making and Curing Concrete Test Specimens in the Laboratory T 22, Compressive Strength of Cylindrical Concrete Specimens T 23, Making and Curing Concrete Test Specimens in the Field T 24M/T 24, Obtaining and

7、 Testing Drilled Cores and Sawed Beams of Concrete 2.2. ASTM Standards: C31/C31M, Standard Practice for Making and Curing Concrete Test Specimens in the Field C39/C39M, Standard Test Method for Compressive Strength of Cylindrical Concrete Specimens C42/C42M, Standard Test Method for Obtaining and Te

8、sting Drilled Cores and Sawed Beams of Concrete C192/C192M, Standard Practice for Making and Curing Concrete Test Specimens in the Laboratory C670, Standard Practice for Preparing Precision and Bias Statements for Test Methods for Construction Materials 2015 by the American Association of State High

9、way and Transportation Officials.All rights reserved. Duplication is a violation of applicable law.TS-3c T 198-2 AASHTO 3. SUMMARY OF TEST METHOD 3.1. This test method consists of applying a diametral compressive force along the length of a cylindrical concrete specimen at a rate that is within a pr

10、escribed range until failure occurs. This loading induces tensile stresses on the plane containing the applied load and relatively high compressive stresses in the area immediately around the applied load. Tensile failure occurs rather than compressive failure because the areas of load application a

11、re in a state of triaxial compression, thereby allowing them to withstand much higher compressive stresses than would be indicated by a uniaxial compressive strength test result. 3.2. Thin plywood bearing strips are used to distribute the load applied along the length of the cylinder. 3.3. The maxim

12、um load sustained by the specimen is divided by appropriate geometrical factors to obtain the splitting tensile strength. 4. SIGNIFICANCE AND USE 4.1. Splitting tensile strength is generally greater than direct tensile strength and lower than flexural strength (modulus of rupture). 4.2. Splitting te

13、nsile strength is used in the design of structural lightweight concrete members to evaluate the shear resistance provided by concrete and to determine the development length of reinforcement. 5. APPARATUS 5.1. Testing MachineThe testing machine shall conform to the requirements of T 22 and be of a t

14、ype with sufficient capacity that will provide the rate of loading prescribed in Section 7.5. 5.2. Supplementary Bearing Bar or PlateIf the diameter or the largest dimension of the upper bearing face or the lower bearing block is less than the length of the cylinder to be tested, a supplementary bea

15、ring bar or plate of machined steel shall be used. The surfaces of the bar or plate shall be machined to within 0.001 in. (0.025 mm) of planeness, as measured on any line of contact of the bearing area. It shall have a width of at least 2 in. (50 mm) and a thickness not less than the distance from t

16、he edge of the spherical or rectangular bearing block to the end of the cylinder. The bar or plate shall be used in such manner that the load will be applied over the entire length of the specimen. 5.3. Bearing StripsTwo bearing strips of nominal 1/8-in. (3.2-mm) thick plywood, free of imperfections

17、, approximately 1 in. (25 mm) wide, and of a length equal to, or slightly longer than, that of the specimen shall be provided for each specimen. The bearing strips shall be placed between the specimen and both the upper and lower bearing blocks of the testing machine or between the specimen and supp

18、lemental bars or plates, when used. (See Section 5.2.) Bearing strips shall not be reused. 6. TEST SPECIMENS 6.1. The test specimens shall conform to the size, molding, and curing requirements set forth in either T 23 (field specimens) or R 39 (laboratory specimens). Drilled cores shall conform to t

19、he size and moisture-conditioning requirements set forth in T 24M/T 24. Moist-cured specimens, during the period between their removal from the curing environment and testing, shall be kept moist by a wet burlap or blanket covering and shall be tested in a moist condition as soon as practicable. 201

20、5 by the American Association of State Highway and Transportation Officials.All rights reserved. Duplication is a violation of applicable law.TS-3c T 198-3 AASHTO 6.2. The following curing procedure shall be used for evaluations of lightweight concrete: specimens tested at 28 days shall be in an air

21、-dry condition after 7 days moist-curing, followed by 21 days drying at 73.5 3.5F (23.0 2C) and 50 5 percent relative humidity. 7. PROCEDURE 7.1. MarkingDraw diametral lines on each end of the specimen using a suitable device that will ensure that they are in the same axial plane (Figure 1, Figure 2

22、, and Note 2), or, as an alternative, use the aligning jig shown in Figure 2 (Note 3). BA1 in.4 in.81/4in.C16 in. min11/4in.Concrete SpecimenTopSideEnd1 in.4 in.8 in.Metric Equivalents in. 1/161/83/161/41/23/41 11/42 21/24 71/28 81/415 16 mm 1.6 3.2 4.8 6.4 13 19 25 32 50 65 100 190 200 205 375 400

23、Figure 1Detailed Plans for a Suitable Apparatus for Marking End Diameters Used for Aligning the Specimen 2015 by the American Association of State Highway and Transportation Officials.All rights reserved. Duplication is a violation of applicable law.TS-3c T 198-4 AASHTO Figure 2Jig for Aligning Conc

24、rete Cylinder and Bearing Strips Note 2Figure 1 shows a suitable device for drawing diametral lines on each end of a 6-by- 12-in. (152-by-305-mm) cylinder in the same axial plane. The device consists of three parts as follows: 1. A length of 4-in. (100-mm) steel channel, the flanges of which have be

25、en machined flat. 2. A section, part B, that is grooved to fit smoothly over the flanges of the channel and that includes cap screws for positioning the vertical member of the assembly, and 3. A vertical bar, C, for guiding a pencil or marker. The assembly (part B and part C) is not fastened to the

26、channel and is positioned at either end of the cylinder without disturbing the position of the specimen when marking the diametral lines. Note 3Figure 3 is a detailed drawing of the aligning jig shown in Figure 2 for achieving the same purpose as marking the diametral lines. The device consists of:

27、1. A base for holding the lower bearing strip and cylinder. 2. A supplementary bearing bar conforming to the requirements in Section 4 as to critical dimensions and planeness, and 3. Two uprights to serve for positioning the test cylinder, bearing strips, and supplementary bearing bar. 2015 by the A

28、merican Association of State Highway and Transportation Officials.All rights reserved. Duplication is a violation of applicable law.TS-3c T 198-5 AASHTO Bearing StripUprightSpecimenBearing StripUprightSupplementaryBearing Plate71/2in.Base1/8-in. Dia Dowel Pins11/4in.1 in.1 in.21/2in.3/4in.1 in.2 in.

29、See Procedure forRequirement.1/2-in. Radius15 in.Figure 3Detailed Plans for a Suitable Aligning Jig for 6-by-12-in. (152-by-305-mm) Specimen 7.2. MeasurementsDetermine the diameter of the test specimen to the nearest 0.01 in. (0.25 mm) by averaging three diameters measured near the ends and the midd

30、le of the specimen and lying in the plane containing the lines marked on the two ends. Determine the length of the specimen to the nearest 0.1 in. (2.5 mm) by averaging at least two length measurements taken in the plane containing the lines marked on the two ends. 7.3. Positioning Using Marked Diam

31、etral LinesCenter one of the plywood strips along the center of the lower bearing block. Place the specimen on the plywood strip and align so that the lines marked on the ends of the specimen are vertical and centered over the plywood strip. Place a second plywood strip lengthwise on the cylinder, c

32、entered on the lines marked on the ends of the cylinder. Position the assembly to ensure the following conditions: 7.3.1. The projection of the plane of the two lines marked on the ends of the specimen intersects the center of the upper bearing plate, and 7.3.2. The supplementary bearing bar or plat

33、e, when used, and the center of the specimen are directly beneath the center of thrust of the spherical bearing block. (See Figure 4.) 2015 by the American Association of State Highway and Transportation Officials.All rights reserved. Duplication is a violation of applicable law.TS-3c T 198-6 AASHTO

34、 Figure 4Specimen Positioned in a Testing Machine for Determination of Splitting Tensile Strength 7.4. Positioning by Use of Aligning JigPosition the bearing strips, test cylinder, and supplementary bearing bar by means of the aligning jig as illustrated in Figure 2 and center the jig so that the su

35、pplementary bearing bar and the center of the specimen are directly beneath the center of thrust of the spherical bearing block. 7.5. Rate of LoadingApply the load continuously and without shock, at a constant rate within the range 100 to 200 psi (689 to 1380 kPa)/min splitting tensile stress, until

36、 failure of the specimen (Note 4). Record the maximum applied load indicated by the testing machine at failure. Note the type of failure and the appearance of the concrete. Note 4The relationship between splitting tensile stress and applied load is shown in Section 8. The required loading range in s

37、plitting tensile stress corresponds to applied total load in the range of 11.300 to 22.600 lbf (50 to 100 kN)/min for 6-by-12-in. (152-by-305-mm) cylinders. 8. CALCULATION 8.1. Calculate the splitting tensile strength of the specimen as follows: 2PTld=(1) where: T = splitting tensile strength, psi (

38、kPa); P = maximum applied load indicated by the testing machine, lbf (kN); l = length, in. (m); and d = diameter, in. (m). 2015 by the American Association of State Highway and Transportation Officials.All rights reserved. Duplication is a violation of applicable law.TS-3c T 198-7 AASHTO 9. REPORT 9

39、.1. Report the following information: 9.1.1. Identification number; 9.1.2. Diameter and length, in. (m); 9.1.3. Maximum load, lbf (kN); 9.1.4. Splitting tensile strength calculated to the nearest 5 psi (35 kPA); 9.1.5. Estimated proportion of coarse aggregate fractured during the test; 9.1.6. Age of

40、 specimen; 9.1.7. Curing history; 9.1.8. Defects in specimen; 9.1.9. Types of fracture; and 9.1.10. Type of specimen. 10. PRECISION AND BIAS 10.1. PrecisionAn interlaboratory study of this test method has not been performed. Available research data, however, suggest that the within batch coefficient

41、 of variation is 5 percent (Note 5) for 6-by-12-in. (152-by-305-mm) cylindrical specimens with an average splitting tensile strength of 405 psi (2.8 MPa). Results of two properly conducted tests on the same material, therefore, should not differ by more than 14 percent (Note 5) of their average for

42、splitting tensile strengths of 400 psi (2.8 MPa). Note 5These numbers represent, respectively, the (1s percent) and (d2s percent) limits as defined in ASTM C670. 10.2. BiasThe test method has no bias because the splitting tensile strength can be defined only in terms of this test method. 11. KEYWORDS 11.1. Cylindrical concrete specimens; splitting tension; tensile strength. 2015 by the American Association of State Highway and Transportation Officials.All rights reserved. Duplication is a violation of applicable law.