AASHTO R 39-2007 Standard Practice for Making and Curing Concrete Test Specimens in the Laboratory《实验室制作及固化混凝土试样规程》.pdf

1、TS-3c R 39-1 AASHTO Standard Practice for Making and Curing Concrete Test Specimens in the Laboratory AASHTO Designation: R 39-07 (2012) ASTM Designation: C 192/C 192M-06 1. SCOPE 1.1. This standard practice covers procedures for making and curing test specimens of concrete in the laboratory under a

2、ccurate control of materials and test conditions using concrete that can be consolidated by rodding or vibration as described herein. This standard practice does not address and does not apply to self-consolidating concrete. 1.2. The values stated in the inch-pound units are to be regarded as standa

3、rd. The values given in parentheses are for information purposes only. 1.3. This standard practice does not purport to address the safety concerns associated with its use. It is the responsibility of the user of this standard practice to establish appropriate safety and health practices and determin

4、e the applicability of regulatory limitations prior to use. 2. REFERENCED DOCUMENTS 2.1. AASHTO Standards: M 6, Fine Aggregate for Hydraulic Cement Concrete M 43, Sizes of Aggregate for Road and Bridge Construction M 80, Coarse Aggregate for Hydraulic Cement Concrete M 194M/M 194, Chemical Admixture

5、s for Concrete M 195, Lightweight Aggregates for Structural Concrete M 201, Mixing Rooms, Moist Cabinets, Moist Rooms, and Water Storage Tanks Used in the Testing of Hydraulic Cements and Concretes M 205M/M 205, Molds for Forming Concrete Test Cylinders Vertically R 60, Sampling Freshly Mixed Concre

6、te T 23, Making and Curing Concrete Test Specimens in the Field T 84, Specific Gravity and Absorption of Fine Aggregate T 85, Specific Gravity and Absorption of Coarse Aggregate T 119M/T 119, Slump of Hydraulic Cement Concrete T 121M/T 121, Density (Unit Weight), Yield, and Air Content (Gravimetric)

7、 of Concrete T 152, Air Content of Freshly Mixed Concrete by the Pressure Method T 196M/T 196, Air Content of Freshly Mixed Concrete by the Volumetric Method T 197M/T 197, Time of Setting of Concrete Mixtures by Penetration Resistance T 231, Capping Cylindrical Concrete Specimens 2013 by the America

8、n Association of State Highway and Transportation Officials.All rights reserved. Duplication is a violation of applicable law.TS-3c R 39-2 AASHTO T 255, Total Evaporable Moisture Content of Aggregate by Drying T 309M/T 309, Temperature of Freshly Mixed Hydraulic Cement Concrete 2.2. ASTM Standards:

9、C 125, Standard Terminology Relating to Concrete and Concrete Aggregates C 330/C 330M, Standard Specification for Lightweight Aggregates for Structural Concrete C 470/C 470M, Standard Specification for Molds for Forming Concrete Test Cylinders Vertically C 1064/C 1064M, Standard Test Method for Temp

10、erature of Freshly Mixed Hydraulic-Cement Concrete C 1077, Standard Practice for Agencies Testing Concrete and Concrete Aggregates for Use in Construction and Criteria for Testing Agency Evaluation 2.3. American Concrete Institute (ACI) Publications: 211.3 Practice for Selecting Proportions for No S

11、lump Concrete1 309 Guide for Concrete Consolidation13. SIGNIFICANCE AND USE 3.1. This standard practice provides standardized requirements for preparation of materials, mixing concrete, and making and curing concrete test specimens under laboratory conditions. 3.2. If specimen preparation is control

12、led as stipulated herein, the specimens may be used to develop information for the following purposes: 3.2.1. Mixture proportioning for project concrete; 3.2.2. Evaluation of different mixtures and materials; 3.2.3. Correlation with nondestructive tests; and 3.2.4. Providing specimens for research p

13、urposes. Note 1The concrete test results for concrete specimens made and cured using this standard practice are widely used. They may be the basis for acceptance testing for project concrete, research evaluation, and other studies. Careful and knowledgeable handling of materials, mixing concrete, mo

14、lding test specimens, and curing test specimens is necessary. Many laboratories performing this important work are independently inspected or accredited. ASTM C 1077 identifies and defines duties; responsibilities, including minimum responsibilities of the laboratory personnel; and minimum technical

15、 requirements for laboratory equipment used. Many laboratories ensure qualified technicians by participating in national certification programs such as the American Concrete Institute Laboratory program or equivalent program. 4. APPARATUS 4.1. Molds, GeneralMolds for specimens or fastenings thereto

16、in contact with the concrete shall be made of steel, cast iron, or other nonabsorbent material, nonreactive with concrete containing portland or other hydraulic cements. Molds shall conform to the dimensions and tolerances specified in the method for which the specimens are required. Molds shall hol

17、d their dimensions and shape under conditions of severe use. Watertightness of molds during use shall be judged by their ability to hold water poured into them. Test procedures for watertightness are given in the section on Test Methods for Elongation, Absorption, and Watertightness in ASTM C 470. 2

18、013 by the American Association of State Highway and Transportation Officials.All rights reserved. Duplication is a violation of applicable law.TS-3c R 39-3 AASHTO A suitable sealantsuch as heavy grease, modeling clay, or microscrystalline waxshall be used where necessary to prevent leakage through

19、the joints. Positive means shall be provided to hold base plates firmly to the molds. Reusable molds shall be lightly coated with mineral oil or a suitable nonreactive release material before use. 4.2. Cylinder Molds: 4.2.1. Molds for casting specimens vertically shall conform to the requirements of

20、 Section 4.1 and M 205M/M 205. 4.2.2. Horizontal molds for creep test cylinders shall conform to the requirements of Section 4.1 and to the requirements for symmetry and dimensional tolerance in Section 3.1.2 of M 205M/M 205. The use of horizontal molds is intended only for creep specimens that cont

21、ain axially embedded strain gauges. Molds for creep cylinders to be filled while supported in a horizontal position shall have a filling slot parallel to the axis of the mold that extends the full length to receive the concrete. The width of the slot shall be one-half the diameter of the specimen. I

22、f necessary, the edges of the slot shall be reinforced to maintain dimensional stability. Unless specimens are to be capped or ground to produce plane ends, the molds shall be provided with two machined metal end plates at least 1 in. (25 mm) thick, and the working surfaces shall comply with the req

23、uirements for planeness and surface roughness of Section 3.1 of T 231. Provision shall be made for fixing both end plates firmly to the mold. The inside surface of each end plate shall be provided with at least three lugs or studs approximately 1 in. (25 mm) long, firmly fastened to the plate for em

24、bedment in the concrete. One base plate shall be drilled from the inside at an angle to permit the lead wire from the strain gauge to exit the specimen through the edge of the plate. Provision shall be made for accurately positioning the strain gauge. All necessary holes shall be as small as possibl

25、e to minimize disturbance to subsequent strain measurements and shall be sealed to prevent leakage. 4.3. Beam and Prism MoldsBeam and prism molds shall be rectangular in shape (unless otherwise specified) and of the dimensions required to produce the desired specimen size. The inside surfaces of the

26、 molds shall be smooth and free from indentations. The sides, bottom, and ends shall be at right angles to each other and shall be straight and true and free of warpage. Maximum variation from the nominal cross section shall not exceed 1/8in. (3 mm) for molds with depth or breadth of 6 in. (150 mm)

27、or more, or 1/16in. (1.6 mm) for molds of smaller depth or breadth. Except for flexure specimens, molds shall not vary from the nominal length by more than 1/16in. (1.6 mm). Flexure molds shall not be shorter than 1/16in. (1.6 mm) of the required length, but may exceed it by more than that amount. 4

28、.4. Tamping RodsTwo sizes are specified in AASHTO methods. Each shall be a round, straight steel rod with at least the tamping end rounded to a hemispherical tip of the same diameter as the rod. Both ends may be rounded, if preferred. 4.4.1. Larger Rod5/8in. (16 mm) in diameter and approximately 24

29、in. (600 mm) long. 4.4.2. Small Rod3/8in. (10 mm) in diameter and approximately 12 in. (300 mm) long. 4.5. MalletsA mallet with a rubber or rawhide head weighing 1.25 0.50 lb (0.6 0.20 kg) shall be used. 2013 by the American Association of State Highway and Transportation Officials.All rights reserv

30、ed. Duplication is a violation of applicable law.TS-3c R 39-4 AASHTO 4.6. Vibrators: 4.6.1. Internal VibratorsThe vibrator frequency shall be at least 7000 vibrations per minute (115 Hz) while the vibrator is operating in the concrete. The diameter of a round vibrator shall be no more than one-fourt

31、h the diameter of the cylinder mold or one-fourth the width of the beam or prism mold. Other shaped vibrators shall have a perimeter equivalent to the circumference of an appropriate round vibrator. The combined length of the vibratory shaft and vibrating element shall exceed the depth of the sectio

32、n being vibrated by at least 3 in. (75 mm). 4.6.2. External VibratorsThe two types of external vibrators permitted are either table or plank. The external vibrator frequency shall be 3600 vibrations per minute (60 Hz) or higher. 4.6.2.1. Provisions shall be made for clamping the mold securely to the

33、 apparatus. Note 2For more information on size and frequency of various vibrators and method to periodically check vibrator frequency, see ACI 309. Note 3Vibratory impulses are frequently imparted to a table or plank vibrator through electromagnetic means, or by use of an eccentric weight on the sha

34、ft of an electric motor or on a separate shaft driven by a motor. 4.7. Small ToolsTools and items such as shovels, pails, trowels, wood float, blunted trowels, straightedge, feeler gauge, scoops, rulers, rubber gloves, and metal mixing bowls shall be provided. 4.8. Slump ApparatusThe apparatus for m

35、easurement of slump shall conform to the requirements of T 119M/T 119. 4.9. Sampling and Mixing PanThe pan shall be flat-bottomed and of heavy-gauge metal, watertight, of convenient depth, and of sufficient capacity to allow easy mixing by shovel or trowel of the entire batch, or, if mixing is by ma

36、chine, to receive the entire batch on discharge of the mixer and allow remixing in the pan by trowel or shovel. 4.10. Wet-Sieving EquipmentIf wet-sieving is required, the equipment shall conform to the requirements of R 60. 4.11. Air Content ApparatusThe apparatus for measuring air content shall con

37、form to the requirements of T 196M/T 196 or of T 152. 4.12. ScalesScales for determining the mass of batches of materials and concrete shall be accurate within 0.3 percent of the test load at any point within the range of use. Note 4In general, the mass of small quantities should not be determined o

38、n large capacity scales. In many applications, the smallest quantity weighed on a scale should be greater than about 10 percent of the maximum capacity of the scale; however, this will vary with the performance characteristics of the scale and the required accuracy of the determination. Acceptable s

39、cales used for weighing concrete materials preferably should weigh accurately to about 0.1 percent of total capacity and the foregoing precaution is applicable. However, certain analytical and precision balances are exceptions to this rule and may weigh accurately to 0.001 percent. Particular care m

40、ust be exercised in measuring small quantities of material by determining the difference between two much larger weights. 2013 by the American Association of State Highway and Transportation Officials.All rights reserved. Duplication is a violation of applicable law.TS-3c R 39-5 AASHTO 4.13. Tempera

41、ture Measuring DeviceThe temperature measuring device shall conform to the requirements of T 309M/T 309. 4.14. Concrete MixerA power-driven concrete mixer shall be a revolving drum, tilting mixer, or suitable revolving pan or revolving-paddle mixer capable of thoroughly mixing batches of the prescri

42、bed sizes at the required slump. Note 5A pan mixer may be found more suitable for mixing concrete with less than 1-in. (25-mm) slump than a revolving drum mixer. The rate of rotation, degree of tilt, and rated capacity of tilting mixers may not always be suitable for laboratory mixed concrete. It ma

43、y be found desirable to reduce the rate of rotation, decrease the angle of tilt from the horizontal, and use the mixer at somewhat less than the manufacturers rated capacity. 5. SPECIMENS 5.1. Cylindrical SpecimensCylinder dimensions shall be as stipulated in the specification, test method, or pract

44、ice for the laboratory studies being performed and shall meet the requirements of Section 5.4. If dimensions are not stipulated in a specification, test method, or practice, the specimen selected shall have a length that is twice the diameter and meet the requirements of Section 5.4. Note 6When mold

45、s in SI units are required and not available, equivalent inch-pound unit size molds should be permitted. Note 7The same cylinder size should be used for the reference (control) concrete mixture and test concrete mixtures when conducting comparative studies such as those required in M 194M/M 194. For

46、 mixture proportioning of project concrete, it is preferable for the cylinder size in the laboratory to be the same as that specified for acceptance testing. 5.1.1. Cylindrical specimens for tests other than creep shall be molded and allowed to harden with the axis of the cylinder vertical. 5.1.2. C

47、ylindrical creep specimens may be cast with the cylindrical axis either vertically or horizontally and allowed to harden in the position in which cast. 5.2. Prismatic SpecimensBeams for flexural strength, prisms for freezing and thawing, bond, length change, volume change, etc., shall be formed with

48、 their long axes horizontally, unless otherwise required by the method of test in question, and shall conform in dimension to the requirements of the specific test method. 5.3. Other SpecimensOther shapes and sizes of specimens for particular tests may be molded as desired following the general proc

49、edures set forth in this standard practice. 5.4. Specimen Size versus Aggregate SizeThe diameter of a cylindrical specimen or minimum cross-sectional dimension of a rectangular section shall be at least three times the nominal maximum size of the coarse aggregate in the concrete (as defined in ASTM C 125). Occasional oversized aggregate particles (of a size not normally found in the average aggregate grading) shall be removed by handpicking during the molding of the specimens. When the concrete contain