1、Designation: C31/C31M 18bC31/C31M 19Standard Practice forMaking and Curing Concrete Test Specimens in the Field1This standard is issued under the fixed designation C31/C31M; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year
2、of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.This standard has been approved for use by agencies of the U.S. Department of Defense.1. Scope*1.1 This practice covers procedu
3、res for making and curing cylinder and beam specimens from representative samples of freshconcrete for a construction project.1.2 The concrete used to make the molded specimens shall be sampled after all on-site adjustments have been made to themixture proportions, including the addition of mix wate
4、r and admixtures. This practice is not satisfactory for making specimensfrom concrete not having measurable slump or requiring other sizes or shapes of specimens.1.3 The values stated in either SI units or inch-pound units are to be regarded separately as standard. The values stated in eachsystem ma
5、y not be exact equivalents; therefore, each system shall be used independently of the other. Combining values from thetwo systems may result in non-conformance with the standard.1.4 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the respo
6、nsibilityof the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability ofregulatory limitations prior to use. (WarningFresh hydraulic cementitious mixtures are caustic and may cause chemical burnsto exposed skin and tissue upon prol
7、onged exposure.2)1.5 The text of this standard references notes which provide explanatory material. These notes shall not be considered asrequirements of the standard.1.6 This international standard was developed in accordance with internationally recognized principles on standardizationestablished
8、in the Decision on Principles for the Development of International Standards, Guides and Recommendations issuedby the World Trade Organization Technical Barriers to Trade (TBT) Committee.2. Referenced Documents2.1 ASTM Standards:3C125 Terminology Relating to Concrete and Concrete AggregatesC138/C138
9、M Test Method for Density (Unit Weight), Yield, and Air Content (Gravimetric) of ConcreteC143/C143M Test Method for Slump of Hydraulic-Cement ConcreteC172/C172M Practice for Sampling Freshly Mixed ConcreteC173/C173M Test Method for Air Content of Freshly Mixed Concrete by the Volumetric MethodC231/C
10、231M Test Method for Air Content of Freshly Mixed Concrete by the Pressure MethodC330/C330M Specification for Lightweight Aggregates for Structural ConcreteC403/C403M Test Method for Time of Setting of Concrete Mixtures by Penetration ResistanceC470/C470M Specification for Molds for Forming Concrete
11、 Test Cylinders VerticallyC511 Specification for Mixing Rooms, Moist Cabinets, Moist Rooms, and Water Storage Tanks Used in the Testing of HydraulicCements and ConcretesC617/C617M Practice for Capping Cylindrical Concrete SpecimensC1064/C1064M Test Method for Temperature of Freshly Mixed Hydraulic-C
12、ement Concrete1 This practice is under the jurisdiction ofASTM Committee C09 on Concrete and ConcreteAggregates and is the direct responsibility of Subcommittee C09.61 on Testingfor Strength.Current edition approved Aug. 1, 2018Jan. 1, 2019. Published August 2018January 2019. Originally approved in
13、1920. Last previous edition approved in 2018 asC31/C31M18a.18b. DOI: 10.1520/C0031_C0031M-18B.10.1520/C0031_C0031M-19.2 See Section on Safety Precautions, Manual of Aggregate and Concrete Testing, Annual Book of ASTM Standards, Vol. 04.02.3 For referencedASTM standards, visit theASTM website, www.as
14、tm.org, or contactASTM Customer Service at serviceastm.org. For Annual Book of ASTM Standardsvolume information, refer to the standards Document Summary page on the ASTM website.This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication of what c
15、hanges have been made to the previous version. Becauseit may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current versionof the standard as published by ASTM is to be considered the of
16、ficial document.*A Summary of Changes section appears at the end of this standardCopyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States1C1077 Practice forAgencies Testing Concrete and ConcreteAggregates for Use in Construction and Criteria f
17、or TestingAgencyEvaluationC1611/C1611M Test Method for Slump Flow of Self-Consolidating ConcreteC1758/C1758M Practice for Fabricating Test Specimens with Self-Consolidating Concrete2.2 American Concrete Institute Publication:4309R Guide for Consolidation of Concrete3. Terminology3.1 For definitions
18、of terms used in this practice, refer to Terminology C125.3.2 Definitions of Terms Specific to This Standard:3.2.1 initial curing temperature, ntemperature of the environment surrounding the specimen during initial curing.3.2.1.1 DiscussionThe environment surrounding the test specimens may be air, w
19、ater, or sand. The temperature of the environment surrounding thetest specimen might not be the same as the concrete temperature.4. Significance and Use4.1 This practice provides standardized requirements for making, curing, protecting, and transporting concrete test specimensunder field conditions.
20、4.2 If the specimens are made and standard cured, as stipulated herein, the resulting strength test data when the specimens aretested are able to be used for the following purposes:4.2.1 Acceptance testing for specified strength,4.2.2 Checking adequacy of mixture proportions for strength, and4.2.3 Q
21、uality control.4.3 If the specimens are made and field cured, as stipulated herein, the resulting strength test data when the specimens are testedare able to be used for the following purposes:4.3.1 Determination of whether a structure is capable of being put in service,4.3.2 Comparison with test re
22、sults of standard cured specimens or with test results from various in-place test methods,4.3.3 Adequacy of curing and protection of concrete in the structure, or4.3.4 Form or shoring removal time requirements.5. Apparatus5.1 Molds, GeneralMolds for specimens or fastenings thereto in contact with th
23、e concrete shall be made of steel, cast iron,or other nonabsorbent material, nonreactive with concrete containing portland or other hydraulic cements. Molds shall hold theirdimensions and shape under all conditions of use. Molds shall be watertight during use as judged by their ability to hold water
24、poured into them. Provisions for tests of water leakage are given in the Test Methods for Elongation, Absorption, and WaterLeakage section of Specification C470/C470M. A suitable sealant, such as heavy grease, modeling clay, or microcrystalline waxshall be used where necessary to prevent leakage thr
25、ough the joints. Positive means shall be provided to hold base plates firmlyto the molds. Reusable molds shall be lightly coated with mineral oil or a suitable nonreactive form release material before use.5.2 Cylinder MoldsMolds for casting concrete test specimens shall conform to the requirements o
26、f SpecificationC470/C470M. Cardboard cylinder molds shall not be used for standard-cured specimens.5.3 Beam MoldsBeam molds shall be of the shape and dimensions required to produce the specimens stipulated in 6.2. Theinside surfaces of the molds shall be smooth. The sides, bottom, and ends shall be
27、at right angles to each other and shall be straightand true and free of warpage. Maximum variation from the nominal cross section shall not exceed 3 mm 18 in. for molds withdepth or breadth of 150 mm 6 in. or more. Molds shall produce specimens at least as long but not more than 2 mm 116 in. shorter
28、than the required length in 6.2.5.4 Tamping RodA round, smooth, straight, steel rod with a diameter conforming to the requirements in Table 1. The lengthof the tamping rod shall be at least 100 mm 4 in. greater than the depth of the mold in which rodding is being performed, butnot greater than 600 m
29、m 24 in. in overall length (see Note 1). The rod shall have the tamping end or both ends rounded to ahemispherical tip of the same diameter as the rod.NOTE 1Arod length of 400 mm 16 in. to 600 mm 24 in. meets the requirements of the following: Practice C31/C31M, Test Method C138/C138M,Test Method C1
30、43/C143M, Test Method C173/C173M, and Test Method C231/C231M.4 Available from American Concrete Institute (ACI), P.O. Box 9094, Farmington Hills, MI 48333-9094, http:/www.aci-int.org.C31/C31M 1925.5 VibratorsInternal vibrators shall be used. The vibrator frequency shall be at least 150 Hz 9000 vibra
31、tions per minutewhile the vibrator is operating in the concrete. The diameter of a round vibrator shall be no more than one-fourth the diameter ofthe cylinder mold or one-fourth the width of the beam mold. Other shaped vibrators shall have a perimeter equivalent to thecircumference of an appropriate
32、 round vibrator. The combined length of the vibrator shaft and vibrating element shall exceed thedepth of the section being vibrated by at least 75 mm 3 in. The vibrator frequency shall be checked periodically with avibrating-reed tachometer or other suitable device.NOTE 2For information on size and
33、 frequency of various vibrators and a method to periodically check vibrator frequency see ACI 309R.5.6 MalletA mallet with a rubber or rawhide head weighing 0.6 6 0.2 kg 1.25 6 0.50 lb shall be used.5.7 Placement Toolsof a size large enough so each amount of concrete obtained from the sampling recep
34、tacle is representativeand small enough so concrete is not spilled during placement in the mold. For placing concrete in a cylinder mold, the acceptabletool is a scoop. For placing concrete in a beam mold, either a shovel or scoop is permitted.5.8 Finishing Toolsa handheld float or a trowel.5.9 Slum
35、p ApparatusThe apparatus for measurement of slump shall conform to the requirements of Test MethodC143/C143M.5.10 Sampling ReceptacleThe receptacle shall be a suitable heavy gauge metal pan, wheelbarrow, or flat, clean nonabsorbentboard of sufficient capacity to allow easy remixing of the entire sam
36、ple with a shovel or trowel.5.11 Air Content ApparatusThe apparatus for measuring air content shall conform to the requirements of Test MethodsC173/C173M or C231/C231M.5.12 Temperature Measuring DevicesThe temperature measuring devices shall conform to the applicable requirements of TestMethod C1064
37、/C1064M.6. Testing Requirements6.1 Cylindrical SpecimensCompressive or splitting tensile strength specimens shall be cylinders cast and allowed to set in anupright position. The number and size of cylinders cast shall be as directed by the specifier of the tests. In addition, the length shallbe twic
38、e the diameter and the cylinder diameter shall be at least 3 times the nominal maximum size of the coarse aggregate. Whenthe nominal maximum size of the coarse aggregate exceeds 50 mm 2 in., the concrete sample shall be treated by wet sievingthrough a 50-mm 2-in. sieve as described in Practice C172/
39、C172M. For acceptance testing for specified compressive strength,cylinders shall be 150 by 300 mm 6 by 12 in. or 100 by 200 mm 4 by 8 in. (Note 3).NOTE 3When molds in SI units are required and not available, equivalent inch-pound unit size mold should be permitted.6.2 Beam SpecimensFlexural strength
40、 specimens shall be beams of concrete cast and hardened in the horizontal position. Thelength shall be at least 50 mm 2 in. greater than three times the depth as tested. The ratio of width to depth as molded shall notexceed 1.5.6.2.1 The minimum cross-sectional dimension of the beam shall be as stat
41、ed in Table 2. Unless otherwise specified by thespecifier of tests, the standard beam shall be 150 by 150 mm 6 by 6 in. in cross section.6.2.2 When the nominal maximum size of the coarse aggregate exceeds 50 mm 2 in., the concrete sample shall be treated bywet sieving through a 50-mm 2-in. sieve as
42、described in Practice C172/C172M.6.2.3 The specifier of tests shall specify the specimen size and the number of specimens to be tested to obtain an average testresult (Note 4). The same specimen size shall be used when comparing results and for mixture qualification and acceptance testing.NOTE 4The
43、modulus of rupture can be determined using different specimen sizes. However, measured modulus of rupture generally increases asTABLE 1 Tamping Rod Diameter RequirementsDiameter of Cylinderor Width of Beammm in.Diameter or Rodmm in.200 8 3 or more equal depths,each not to exceed150 mm 6 in.see 9.3TA
44、BLE 5 Molding Requirements by VibrationSpecimen Typeand SizeNumber ofLayersNumber ofVibratorInsertionsper LayerApproximate Depth ofLayer, mm in.Cylinders:Diameter, mm in.100 4 2 1 one-half depth of specimen150 6 2 2 one-half depth of specimen225 9 2 4 one-half depth of specimenBeams:Width, mm in.100
45、 4 to200 81 see 9.4.2 depth of specimenover 200 8 2 or more see 9.4.2 200 8 as near aspracticableC31/C31M 195mallet, to close holes that remain and to release entrapped air voids. Use an open hand to tap molds that are susceptible to dentingor other permanent distortion if tapped with a mallet.9.4.2
46、.2 BeamsInsert the vibrator at intervals not exceeding 150 mm 6 in. along the center line of the long dimension of thespecimen. For specimens wider than 150 mm 6 in., use alternating insertions along two lines. Allow the shaft of the vibrator topenetrate into the bottom layer about 25 mm 1 in. After
47、 each layer is vibrated, tap the outsides of the mold sharply at least 10times with the mallet to close holes left by vibrating and to release entrapped air voids.9.5 FinishingPerform all finishing with the minimum manipulation necessary to produce a flat even surface that is level withthe rim or ed
48、ge of the mold and that has no depressions or projections larger than 3.3 mm 18 in.9.5.1 CylindersAfter consolidation, finish the top surfaces by striking them off with the tamping rod where the consistencyof the concrete permits or with a handheld float or trowel. If desired, cap the top surface of
49、 freshly made cylinders with a thin layerof stiff portland cement paste which is permitted to harden and cure with the specimen. See section on Capping Materials ofPractice C617/C617M.9.5.2 BeamsAfter consolidation of the concrete, use a handheld float or trowel to strike off the top surface to the requiredtolerance to produce a flat, even surface.9.6 IdentificationMark the specimens to positively identify them and the concrete they represent. Use a method that will notalter
