1、Designation: C31/C31M 18aC31/C31M 18bStandard 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 proced
3、ures 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 wat
4、er 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 m
5、ay 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 resp
6、onsibilityof 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 pro
7、longed 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/C13
9、8M 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/
10、C231M 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 Concret
11、e 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-
12、Cement 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 March 15, 2018Aug. 1, 2018. Published April 2018August 2018. Originally approved in
13、 1920. Last previous edition approved in 2018 asC31/C31M18.18a. DOI: 10.1520/C0031_C0031M-18A.10.1520/C0031_C0031M-18B.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.a
14、stm.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
15、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 be considered the o
16、fficial 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
17、for 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 C125.4. 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
19、, 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 Quality control.4.3 If the specimens are made and field cured, as stipu
20、lated 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 results of standard cured specimens or with test results from various in
21、-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 the concrete shall be made of steel, cast iron,or other nonabsorbent mat
22、erial, 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 waterpoured into them. Provisions for tests of water leakage are given in t
23、he 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 through the joints. Positive means shall be provided to hold base plates
24、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 of SpecificationC470/C470M.5.3 Beam MoldsBeam molds shall be of the sha
25、pe 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 at right angles to each other and shall be straightand true and free of warpage. Maximum variation from the nominal cross section shall not exc
26、eed 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. shorterthan 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.
27、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 mm 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
28、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 C143/C143M, Test Method C173/C173M, and Test Method C231/C231M.4 Available from American Concrete Institute (ACI), P.O. Box 9094, Farmington Hill
29、s, MI 48333-9094, http:/www.aci-int.org.TABLE 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 9.3TABLE 5 Molding Requirements by VibrationSpecimen Typeand SizeNumber ofLayersNumber ofVibr
30、atorInsertionsper 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 4 to200 81 see 9.4.2 depth of specimenover 200 8 2 or more see 9.4.2 200 8 as near aspr
31、acticableC31/C31M 18b59.5.2 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 t
32、hat will notalter the top surface of the concrete. Do not mark the removable caps. Upon removal of the molds, mark the test specimens to retaintheir identities.10. Curing10.1 Standard CuringStandard curing is the curing method used when the specimens are made and cured for the purposesstated in 4.2.
33、10.1.1 StorageIf specimens cannot be molded at the place where they will receive initial curing, immediately after finishingmove the specimens to an initial curing place for storage. The supporting surface on which specimens are stored shall be level towithin 20 mm/m within 20 mm/m 14 in.ft. If cyli
34、nders in the single use molds are moved, lift and support the cylinders fromthe bottom of the molds with a large trowel or similar device. in./ft. If specimens are not molded in the location where they willreceive initial curing, ensure that the specimens have been moved to the initial curing locati
35、on no later than 15 min after moldingoperations have been completed. If a specimen in a single-use mold is moved, support the bottom of the mold. If the top surfaceis marredof a specimen is disturbed during movement to the place of initial storage, immediately refinish. refinish the surface.NOTE 7So
36、me single-use molds, such as cylinder molds constructed of sheet metal or treated cardboard, may be permanently distorted if movedwithout proper support. Using a large trowel or a hand to support the bottom of these molds are acceptable means to prevent permanent deformation.It is acceptable to slig
37、htly tilt the mold to facilitate lifting and supporting the mold. If a cover is to be placed on the top of a specimen, the cover shouldbe placed on the specimen after moving the specimen to the initial curing location to ensure the required finish of the top surface of the specimen. Forexample, if a
38、 specimen will be stored in water for initial curing, it would be appropriate to perform a final check of the surface finish prior to placingthe cover and setting the specimen into the water.10.1.2 Initial CuringImmediately after molding and finishing, the specimens shall be stored for a period up t
39、o 48 h in atemperature range from 16 to 27C 60 to 80F and in an environment preventing moisture loss from the specimens. For concretemixtures with a specified strength of 40 MPa 6000 psi or greater, the initial curing temperature shall be between 20 and 26C68 and 78F. Various procedures are capable
40、of being used during the initial curing period to maintain the specified moisture andtemperature conditions.An appropriate procedure or combination of procedures shall be used (Note 78). Shield all specimens fromthe direct sunlight and, if used, radiant heating devices. The storage temperature shall
41、 be controlled by use of heating and coolingdevices, as necessary. Record the temperature using a maximum-minimum thermometer. If cardboard molds are used, protect theoutside surface of the molds from contact with wet burlap or other sources of water.NOTE 8A satisfactory moisture environment can be
42、created during the initial curing of the specimens by one or more of the following procedures:(1) immediately immerse molded specimens with plastic lids in water saturated with calcium hydroxide, (2) store in properly constructed wooden boxesor structures, (3) place in damp sand pits, (4) cover with
43、 removable plastic lids, (5) place inside plastic bags, or (6) cover with plastic sheets ornonabsorbent plates if provisions are made to avoid drying and damp burlap is used inside the enclosure, but the burlap is prevented from contacting theconcrete surfaces. A satisfactory temperature environment
44、 can be controlled during the initial curing of the specimens by one or more of the followingprocedures: (1) use of ventilation, (2) use of ice, (3) use of thermostatically controlled heating or cooling devices, or (4) use of heating methods suchas stoves or light bulbs. Other suitable methods may b
45、e used provided the requirements limiting specimen storage temperature and moisture loss are met.For concrete mixtures with a specified strength of 40 MPa 6000 psi or greater, heat generated during the early ages may raise the temperature abovethe required storage temperature. Immersion in water sat
46、urated with calcium hydroxide may be the easiest method to maintain the required storagetemperature. When specimens are to be immersed in water saturated with calcium hydroxide, specimens in cardboard molds or other molds that expandwhen immersed in water should not be used. Early-age strength test
47、results may be lower when stored at 16C 60F and higher when stored at 27C80F. On the other hand, at later ages, test results may be lower for higher initial storage temperatures.10.1.3 Final Curing:10.1.3.1 CylindersUpon completion of initial curing and within 30 min after removing the molds, cure s
48、pecimens with freewater maintained on their surfaces at all times at a temperature of 23.0 6 2.0C 73.5 6 3.5F using water storage tanks or moistrooms complying with the requirements of Specification C511, except when capping with sulfur mortar capping compound andimmediately prior to testing. When c
49、apping with sulfur mortar capping compound, the ends of the cylinder shall be dry enoughto preclude the formation of steam or foam pockets under or in cap larger than 6 mm 14 in. as described in Practice C617/C617M.For a period not to exceed 3 h immediately prior to test, standard curing temperature is not required provided free moisture ismaintained on the cylinders and ambient temperature is between 20 and 30C 68 and 86F .10.1.3.2 BeamsBeams are to be cured the same as cylinders (se
