AASHTO R 39-2017 Standard Practice for Making and Curing Concrete Test Specimens in the Laboratory.pdf

1、Standard Practice for Making and Curing Concrete Test Specimens in the Laboratory AASHTO Designation: R 39-17 Technical Section: 3c, Hardened Concrete Release: Group 1 (April 2017) ASTM Designation: C192/C192M-16a American Association of State Highway and Transportation Officials 444 North Capitol S

2、treet N.W., Suite 249 Washington, D.C. 20001 TS-3c R 39-1 AASHTO Standard Practice for Making and Curing Concrete Test Specimens in the Laboratory AASHTO Designation: R 39-17 Technical Section: 3c, Hardened Concrete Release: Group 1 (April 2017) ASTM Designation: C192/C192M-16a 1. SCOPE 1.1. This st

3、andard practice covers procedures for making and curing test specimens of concrete in the laboratory under accurate control of materials and test conditions using concrete that can be consolidated by rodding or vibration as described herein. 1.2. The values stated in either inch-pound units or SI un

4、its are to be regarded separately as standard. 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 practice does not pu

5、rport 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 determine the applicability of regulatory limitations prior to use. WarningFresh hydraulic cementitious mixtures are c

6、austic and may cause chemical burns to exposed skin and tissue upon prolonged exposure. 2. REFERENCED DOCUMENTS 2.1. AASHTO Standards: M 194M/M 194, Chemical Admixtures for Concrete M 201, Mixing Rooms, Moist Cabinets, Moist Rooms, and Water Storage Tanks Used in the Testing of Hydraulic Cements and

7、 Concretes M 205M/M 205, Molds for Forming Concrete Test Cylinders Vertically R 60, Sampling Freshly Mixed Concrete 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

8、119, Slump of Hydraulic Cement Concrete T 121M/T 121, Density (Unit Weight), Yield, and Air Content (Gravimetric) 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

9、 of Concrete Mixtures by Penetration Resistance 2017 by the American Association of State Highway and Transportation Officials.All rights reserved. Duplication is a violation of applicable law.TS-3c R 39-2 AASHTO T 231, Capping Cylindrical Concrete Specimens T 255, Total Evaporable Moisture Content

10、of Aggregate by Drying T 309, Temperature of Freshly Mixed Portland Cement Concrete 2.2. ASTM Standards: C125, Standard Terminology Relating to Concrete and Concrete Aggregates C330/C330M, Standard Specification for Lightweight Aggregates for Structural Concrete C470/C470M, Standard Specification fo

11、r Molds for Forming Concrete Test Cylinders Vertically C1064/C1064M, Standard Test Method for Temperature of Freshly Mixed Hydraulic-Cement Concrete 2.3. American Concrete Institute (ACI) Publications: 211.3 Practice for Selecting Proportions for No Slump Concrete1 309 Guide for Concrete Consolidati

12、on13. 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 controlled as stipulated herein, the specimens may be us

13、ed 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 purposes. Note 1The concrete test results for conc

14、rete 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, molding test specimens, and curing test specimens i

15、s necessary. Many laboratories performing this important work are independently inspected or accredited. ASTM C1077 identifies and defines duties; responsibilities, including minimum responsibilities of the laboratory personnel; and minimum technical requirements for laboratory equipment used. Many

16、laboratories accredited and ensure qualified technicians by participating in national certification programs. AASHTO, ASTM, and the American Concrete Institute are examples of entities that can provide guidance on laboratory inspections and accreditation programs as well as technician qualifications

17、 and certifications. 4. APPARATUS 4.1. Molds, GeneralMolds for specimens or fastenings thereto 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 dimensio

18、ns and tolerances specified in the method for which the specimens are required. Molds shall hold 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

19、 in the 2017 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 section on Test Methods for Elongation, Absorption, and Watertightness in ASTM C470/C470M. A suitable sealantsuch as heavy grea

20、se, modeling clay, or microcrystalline waxshall be used where necessary to prevent leakage through 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.

21、 Cylinder Molds: 4.2.1. Molds for casting specimens vertically shall conform to the requirements of 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 Sectio

22、n 3.1.2 of M 205M/M 205. The use of horizontal molds is intended only for creep specimens that contain 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 leng

23、th to receive the concrete. The width of the slot shall be one-half the diameter of the specimen. If 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 machine

24、d metal end plates at least 1 in. (25 mm) thick, and the working surfaces shall comply with the requirements 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

25、 at least three lugs or studs approximately 1 in. (25 mm) long, firmly fastened to the plate for embedment 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

26、 made for accurately positioning the strain gauge. All necessary holes shall be as small as possible 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 specifi

27、ed) and of the dimensions required to produce the desired specimen size. The inside surfaces of the 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 nomi

28、nal cross section shall not exceed 1/8in. (3 mm) for molds with depth or breadth of 6 in. (150 mm) 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

29、shorter than 1/16in. (1.6 mm) of the required length but may exceed it by more than that amount. 4.4. Tamping RodA round, smooth, straight steel rod with a diameter conforming to the requirements in Table 2. The length of the tamping rod shall be at least 4 in. (100 mm) greater than the depth of the

30、 mold in which the rodding is being performed, but not greater than 24 in. (600 mm) in overall length (see Note 2). The rod shall have the tamping end or both ends rounded to a hemispherical tip of the same diameter as the rod. Note 2A rod length of 16 in. (400 mm) to 24 in. (600 mm) meets the requi

31、rements of the following: T 23, T 119M/T 119, T 121M/T 121, T 152, and T 196M/T 196. 4.5. MalletsA mallet with a rubber or rawhide head weighing 1.25 0.50 lb (0.6 0.20 kg) shall be used. 4.6. Vibrators: 4.6.1. Internal VibratorsThe vibrator frequency shall be at least 9000 vibrations per minute (vpm

32、) (150 Hz) while the vibrator is operating in the concrete. The diameter of a round vibrator shall be no more than one fourth 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 2017

33、by the American Association of State Highway and Transportation Officials.All rights reserved. Duplication is a violation of applicable law.TS-3c R 39-4 AASHTO appropriate round vibrator. The combined length of the vibratory shaft and vibrating element shall exceed the depth of the section being vib

34、rated by at least 3 in. (75 mm). The vibrator frequency shall be checked with a vibrating-reed tachometer or other suitable device at an interval not to exceed two years. If the vibrator manufacturer recommends a shorter verification interval or a verification procedure, the manufacturers recommenda

35、tion shall be followed. 4.6.2. External VibratorsThe two types of external vibrators permitted are either table or plank. The external vibrator frequency shall be 3600 vpm (60 Hz) or higher. 4.6.2.1. Provisions shall be made for clamping the mold securely to the apparatus. Note 3For more information

36、 on size and frequency of various vibrators and method to periodically check vibrator frequency, see ACI 309. Note 4Vibratory impulses are frequently imparted to a table or plank vibrator through electromagnetic means, or by use of an eccentric weight on the shaft of an electric motor or on a separa

37、te 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 measurement of slump shall conform to t

38、he 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 machine, to receive the entire batch on

39、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 conform to the requirements of T 196M/T 1

40、96 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 5In general, the mass of small quantities should not be determined on large-capacity scales. In many appli

41、cations, 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 scales used for weighing concrete mater

42、ials 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 must be exercised in measuring small qu

43、antities of material by determining the difference between two much larger weights. 4.13. Temperature Measuring DeviceThe temperature measuring device shall conform to the requirements of T 309. 4.14. Concrete MixerA power-driven concrete mixer shall be a revolving drum, tilting mixer, or suitable r

44、evolving pan or revolving-paddle mixer capable of thoroughly mixing batches of the prescribed sizes at the required slump. Note 6A 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

45、capacity 2017 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 of tilting mixers may not always be suitable for laboratory mixed concrete. It may be found desirable to reduce the rate of ro

46、tation, 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 specificatio n, test method, or practice for the laboratory studies being perform

47、ed 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 7When molds in SI units are required and not available

48、, equival ent inch-pound unit size molds should be permitted. Note 8The same cylinder size should be used for the reference (contr ol) concrete mixture and test concrete mixtures when conducting comparative studies such as those required in M 194M/M 194. For mixture proportioning of project concrete

49、, 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. Cylindrical 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, p risms for freezing and thawing, bond, length change,