1、Designation: C31/C31M 12C31/C31M 15Standard 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 o
2、f 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 procedur
3、es 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 water
4、 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 may
5、 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 respon
6、sibilityof the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatorylimitations prior to use. (WarningFresh hydraulic cementitious mixtures are caustic and may cause chemical burns to exposedskin and tissue upon prolonged exposure.2)
7、1.5 The text of this standard references notes which provide explanatory material. These notes shall not be considered asrequirements of the standard.2. Referenced Documents2.1 ASTM Standards:3C125 Terminology Relating to Concrete and Concrete AggregatesC138/C138M Test Method for Density (Unit Weigh
8、t), Yield, and Air Content (Gravimetric) of ConcreteC143/C143M Test Method for Slump of Hydraulic-Cement ConcreteC172C172/C172M Practice for Sampling Freshly Mixed ConcreteC173/C173M Test Method for Air Content of Freshly Mixed Concrete by the Volumetric MethodC231C231/C231M Test Method for Air Cont
9、ent of Freshly Mixed Concrete by the Pressure MethodC330C330/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 Test Cylinders Verticall
10、yC511 Specification for Mixing Rooms, Moist Cabinets, Moist Rooms, and Water Storage Tanks Used in the Testing of HydraulicCements and ConcretesC617C617/C617M Practice for Capping Cylindrical Concrete SpecimensC1064/C1064M Test Method for Temperature of Freshly Mixed Hydraulic-Cement ConcreteC1077 P
11、ractice forAgencies Testing Concrete and ConcreteAggregates for Use in Construction and Criteria for TestingAgencyEvaluation2.2 American Concrete Institute Publication:4309R Guide for Consolidation of Concrete1 This practice is under the jurisdiction ofASTM Committee C09 on Concrete and ConcreteAggr
12、egates and is the direct responsibility of Subcommittee C09.61 on Testingfor Strength.Current edition approved July 1, 2012July 1, 2015. Published September 2012August 2015. Originally approved in 1920. Last previous edition approved in 20092012 asC31/C31M10.12. DOI: 10.1520/C0031_C0031M-12.10.1520/
13、C0031_C0031M-15.2 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.astm.org, or contactASTM Customer Service at serviceastm.org. For Annual Book of ASTM Standardsvolume in
14、formation, refer to the standards Document Summary page on the ASTM website.4 Available from American Concrete Institute (ACI), P.O. Box 9094, Farmington Hills, MI 48333-9094, http:/www.aci-int.org.This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an
15、indication of what changes 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
16、be considered the official 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 States13. Terminology3.1 For definitions of terms used in this practice, refer to Terminolog
17、y C125.4. Significance and Use4.1 This practice provides standardized requirements for making, curing, protecting, and transporting concrete test specimensunder field conditions.4.2 If the specimens are made and standard cured, as stipulated herein, the resulting strength test data when the specimen
18、s 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 Quality control.4.3 If the specimens are made and field cured, as stipulated herein, the resulting strength test data when
19、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 results of standard cured specimens or with test results from various in-place test methods,4.3.3 Adequacy of curing and pro
20、tection 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 the concrete shall be made of steel, cast iron,or other nonabsorbent material, nonreactive with concrete containing portland
21、 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 waterpoured into them. Provisions for tests of water leakage are given in the Test Methods for Elongation, Absorption, and Wate
22、rLeakage section of Specification C470/C470M. A suitable sealant, such as heavy grease, modeling clay, or microcrystalline waxshall be used where necessary to prevent leakage through the joints. Positive means shall be provided to hold base plates firmlyto the molds. Reusable molds shall be lightly
23、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 of SpecificationC470/C470M.5.3 Beam MoldsBeam molds shall be of the shape and dimensions required to produce the specimens
24、stipulated in 6.2. Theinside surfaces of the molds shall be smooth. The sides, bottom, and ends shall be 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 exceed18 in. 3 mm 3 mm18 in. for molds with dept
25、h or breadth of 6 in. 150 mm150 mm 6 in. or more. Molds shall produce specimens at least as longbut not more than than 2116 in. 2 mm mm 116 in. shorter 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 l
26、engthof the tamping rod shall be at least 4 in. 100 mm100 mm 4 in. greater than the depth of the mold in which rodding is beingperformed, but not greater than 24 in. 600 mm600 mm 24 in. in overall length (see Note 1). The rod shall have the tampingend or both ends rounded to a hemispherical tip of t
27、he same diameter as the rod.NOTE 1A rod length of 16 in. 400 mm to 24 in. 600 mm400 mm 16 in. to 600 mm 24 in. meets the requirements of the following: PracticeC31/C31M, Test Method C138/C138M, Test Method C143/C143M, Test Method C173/C173M, and Test Method C231C231/C231M.5.5 VibratorsInternal vibra
28、tors shall be used. The vibrator frequency shall be at least 9000 vibrations per minute 150 Hzwhile 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 vib
29、rators shall have a perimeter equivalent to theTABLE 1 Tamping Rod Diameter RequirementsDiameter of Cylinderor Width of Beamin. mmDiameter or Rodin. mm8 200 3 or more equal depths,each not to exceed6 in. 150 mm.see 9.3200 8 3 or more equal depths,each not to exceed150 mm 6 in.see 9.3TABLE 4 Molding
30、Requirements by VibrationSpecimen Typeand SizeNumber ofLayersNumber ofVibratorInsertionsper LayerApproximate Depth ofLayer, in. mmmm in.Cylinders:Diameter, in. mmDiameter, mm in.4 100 2 1 one-half depth of specimen100 4 2 1 one-half depth of specimen6 150 2 2 one-half depth of specimen150 6 2 2 one-
31、half depth of specimen9 225 2 4 one-half depth of specimen225 9 2 4 one-half depth of specimenBeams:Width, in. mmWidth, mm in.6 150 to 8 200 1 see 9.4.2 depth of specimen150 6 to 200 8 1 see 9.4.2 depth of specimenover 8 200 2 or more see 9.4.2 8 200 as near aspracticableover 200 8 2 or more see 9.4
32、.2 200 8 as near aspracticableC31/C31M 1549.2 Casting CylindersSelect the proper tamping rod from 5.4 and Table 1 or the proper vibrator from 5.5. Determine themethod of consolidation from Table 2, unless another method is specified. If the method of consolidation is rodding, determinemolding requir
33、ements from Table 3. If the method of consolidation is vibration, determine molding requirements from Table 4.Select a scoop of the size described in 5.7. While placing the concrete in the mold, move the scoop around the perimeter of themold opening to ensure an even distribution of the concrete wit
34、h minimal segregation. Each layer of concrete shall be consolidatedas required. In placing the final layer, add an amount of concrete that will fill the mold after consolidation.9.3 Casting BeamsSelect the proper tamping rod from 5.4 and Table 1 or proper vibrator from 5.5. Determine the method ofco
35、nsolidation from Table 2, unless another method is specified. If the method of consolidation is rodding, determine the moldingrequirements from Table 3. If the method of consolidation is vibration, determine the molding requirements from Table 4.Determine the number of roddings per layer, one for ea
36、ch 2 in.14 cm2 14 cm2 in.2 of the top surface area of the beam. Selecta placement tool as described in 5.7. Using the scoop or shovel, place the concrete in the mold to the height required for each layer.Place the concrete so that it is uniformly distributed within each layer with minimal segregatio
37、n. Each layer shall be consolidatedas required. In placing the final layer, add an amount of concrete that will fill the mold after consolidation.9.4 ConsolidationThe methods of consolidation for this practice are rodding or internal vibration.9.4.1 RoddingPlace the concrete in the mold in the requi
38、red number of layers of approximately equal volume. Rod each layeruniformly over the cross section with the rounded end of the rod using the required number of strokes. Rod the bottom layerthroughout its depth. In rodding this layer, use care not to damage the bottom of the mold. For each upper laye
39、r, allow the rod topenetrate through the layer being rodded and into the layer below approximately 1 in. 25 mm.25 mm 1 in. After each layeris rodded, tap the outsides of the mold lightly 10 to 15 times with the mallet to close any holes left by rodding and to release anylarge air bubbles that may ha
40、ve been trapped. Use an open hand to tap light-gauge single-use cylinder molds whichthat aresusceptible to damage denting or other permanent distortion if tapped with a mallet.After tapping, spade each layer of the concretealong the sides and ends of beam molds with a trowel or other suitable tool.
41、Underfilled molds shall be adjusted with representativeconcrete during consolidation of the top layer. Overfilled molds shall have excess concrete removed.9.4.2 VibrationMaintain a uniform duration of vibration for the particular kind of concrete, vibrator, and specimen moldinvolved. The duration of
42、 vibration required will depend upon the workability of the concrete and the effectiveness of the vibrator.Usually sufficient vibration has been applied as soon as the surface of the concrete has become relatively smooth and large airbubbles cease to break through the top surface. Continue vibration
43、 only long enough to achieve proper consolidation of theconcrete (see Note 5). Fill the molds and vibrate in the required number of approximately equal layers. Place all the concrete foreach layer in the mold before starting vibration of that layer. In compacting the specimen, insert the vibrator sl
44、owly and do notallow it to rest on the bottom or sides of the mold. Slowly withdraw the vibrator so that no large air pockets are left in the specimen.When placing the final layer, avoid overfilling by more than than14 in. 6 mm. 6 mm 14 in.NOTE 5Generally, no more than 5 s of vibration should be req
45、uired for each insertion to adequately consolidate concrete with a slump greater than3 in. 75 mm.75 mm 3 in. Longer times may be required for lower slump concrete, but the vibration time should rarely have to exceed 10 s perinsertion.9.4.2.1 CylindersThe number of insertions of the vibrator per laye
46、r is given in Table 4.When more than one insertion per layeris required distribute the insertion uniformly within each layer. Allow the vibrator to penetrate through the layer being vibrated,and into the layer below, about 1 in. 25 mm.25 mm 1 in. After each layer is vibrated, tap the outsides of the
47、 mold at least 10times with the mallet, to close holes that remain and to release entrapped air voids. Use an open hand to tap cardboard andsingle-use metal molds that are susceptible to damage denting or other permanent distortion if tapped with a mallet.9.4.2.2 BeamsInsert the vibrator at interval
48、s not exceeding 6 in. 150 mm150 mm 6 in. along the center line of the longdimension of the specimen. For specimens wider than 6 in., 150 mm 6 in., use alternating insertions along two lines. Allow theshaft of the vibrator to penetrate into the bottom layer about 1 in. 25 mm.25 mm 1 in. After each la
49、yer is vibrated, tap theoutsides of the mold sharply at least 10 times 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 edge of the mold and that has no depressions or projections larger than than 3.318 in. 3.3 mm. mm 18 in.9.5.1 CylindersAfter consolidation, finish t
