1、Designation: C470/C470M 15Standard Specification forMolds for Forming Concrete Test Cylinders Vertically1This standard is issued under the fixed designation C470/C470M; the number immediately following the designation indicates the yearof original adoption or, in the case of revision, the year of la
2、st revision. A number in parentheses indicates the year of last reapproval.A superscript 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 specification covers molds f
3、or use in formingcylindrical concrete specimens. The provisions of this specifi-cation include the requirements for both reusable and single-use molds.NOTE 1Sizes included are molds having diameters from 50 mm 2 in.to 900 mm 36 in.1.2 The text of this standard references notes and footnoteswhich pro
4、vide explanatory material. These notes and footnotes(excluding those in tables and figures) shall not be consideredas requirements of the standard.1.3 The values stated in either SI units or inch-pound unitsare to be regarded separately as standard. The values stated ineach system may not be exact e
5、quivalents; therefore, eachsystem shall be used independently of the other. Combiningvalues from the two systems may result in non-conformancewith the standard. The inch-pound units are shown in brackets.1.4 The following safety hazards caveat pertains only to thetest method described in this specif
6、ication: This standard doesnot purport to address all of the safety concerns, if any,associated with its use. It is the responsibility of the user of thisstandard to establish appropriate safety and health practicesand determine the applicability of regulatory limitations priorto use.2. Referenced D
7、ocuments2.1 ASTM Standards:2C31/C31M Practice for Making and Curing Concrete TestSpecimens in the FieldC33 Specification for Concrete AggregatesC192/C192M Practice for Making and Curing Concrete TestSpecimens in the LaboratoryC1077 Practice for Agencies Testing Concrete and ConcreteAggregates for Us
8、e in Construction and Criteria forTesting Agency EvaluationD256 Test Methods for Determining the Izod PendulumImpact Resistance of PlasticsD570 Test Method for Water Absorption of Plastics3. General Requirements3.1 The following provisions apply to both reusable andsingle-use molds:3.1.1 Molds shall
9、 be constructed in the form of right circularcylinders which stand with the cylindrical axis vertical and thetop open to receive the concrete. They shall be made ofmaterials that do not react with concrete containing portland orother hydraulic cements. They shall be watertight and suffi-ciently stro
10、ng and tough to permit their use without tearing,crushing, or deforming.NOTE 2Reusable lids may be used on molds to reduce moisture loss.3.1.2 Molds shall have a nominal inside height equal totwice the nominal inside diameter. The diameter of a mold,consisting of the average of two measurements take
11、n at rightangles to each other at the top of the mold, shall not differ fromthe nominal diameter by more than 1 %. The height, deter-mined by averaging two measurements taken 180 apart, shallnot differ from the nominal height by more than 2 %. Theplanes of the top rim of the mold and the bottom shal
12、l beperpendicular to the axis of the mold within 0.5 degreesapproximately equivalent to 3 mm in 300 mm 18 in. in 12 in.No diameter of a mold shall differ from any other diameter ofthe same mold by more than 2 % except that molds that fail tomeet this requirement may be used when the user is able tod
13、emonstrate that no diameter of hardened concrete specimenproduced in a similar mold differs from any other diameter onthe same specimen by more than 2 % (see Note 3).NOTE 3Certain single-use molds may require the use of a specialdevice such as a tube of heavy-gage metal around the mold duringmolding
14、 to maintain the dimensional tolerances specified in 3.1.2.3.1.3 The bottom inside surface of the mold shall not departfrom a plane by more than 2 mm in 150 mm 116 in. in 6 in.(1 % of the diameter of the mold).1This specification is under the jurisdiction of ASTM Committee C09 onConcrete and Concret
15、e Aggregates and is the direct responsibility of SubcommitteeC09.61 on Testing for Strength.Current edition approved Feb. 1, 2015. Published March 2015. Originallyapproved in 1961. Last previous edition approved in 2009 as C470/C470M 09.DOI: 10.1520/C0470_C0470M-15.2For referenced ASTM standards, vi
16、sit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.*A Summary of Changes section appears at the end of this standardCopyright ASTM International,
17、100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States14. Reusable Molds4.1 Reusable molds are those which are designed to be usedmore than a single time. Reusable molds shall be made ofnonabsorptive materials, and constructed as either one piece orseveral pieces (see No
18、te 4).4.2 Reusable molds shall be provided with a closure or baseon the lower end at right angles to the axis of the cylinder.Molds may be single piece molds or made from castings witha separate detachable base plate or a base that is an integral partof the sidewall. The mold shall be either coated
19、or made of amaterial that will prevent adherence to the concrete.At the timeof use, molds shall not leak water. An inside fillet, if any, at thebottom of the side wall shall have an indentation around thecircumference no more than 3 mm 18 in. in the verticaldirection or no more than 5 mm 316 in. in
20、the horizontaldirection.4.3 Reusable molds shall be tested for water leakage asdescribed in 6.4, for resistance to damage as described in 6.3.1,and for dimensional stability in accordance with 3.1.2 and 3.1.3initially and after every 50 uses or every six months, whichevercomes first.NOTE 4Satisfacto
21、ry molds can be made from lengths of steel tubingor pipe that is slit on one side parallel to the axis and fitted with a meansof closing the vertical slit as well as a means of attaching a base plate. Therequired dimensional tolerances must be maintained after slitting,clamping, and attaching the ba
22、se plate. Other nonabsorptive materialswhich have been used include iron, brass, steel, and various plastics.Although aluminum and magnesium alloys have been used, some of thesealloys may be reactive with cement constituents and are thereforeunacceptable.5. Single-Use Molds5.1 Single-use molds are m
23、olds designed to be used onceand discarded. They are permitted to be made of sheet metal,plastic, suitably treated paper products, or other materials andshall conform to the requirements of this specification.5.2 Physical RequirementsThe molds as prepared for useshall comply with the following:5.2.1
24、 Water LeakageWhen tested as described in Section6, there shall be no visible leakage.5.2.2 AbsorptivityWhen tested as described in Section 6,the absorption shall not exceed the values given in Table 1.Intermediate values are proportional to the square of the height.5.2.3 ElongationWhen tested as de
25、scribed in Section 6,the elongation after test shall not exceed 0.2 % of height.5.3 Single-use Plastic MoldsMolds shall conform to thefollowing additional requirements when plastic is the predomi-nant material used in construction:5.3.1 Wall ThicknessThe side walls shall be of sufficientstiffness to
26、 meet the requirements of 3.1 (See Note 5).NOTE 5This can be achieved through sufficient side wall thicknessalone, or in combination with a stiffened top.5.3.2 Bottom DesignThe bottom shall be designed so thatit will be flush with the bottom of the sidewall within atolerance of 2 mm 116 in. An insid
27、e fillet, if any, at thebottom of the sidewall shall have an indentation around thecircumference no more than 4 mm 18 in. in the verticaldirection or no more than 5 mm 316 in. in the radial direction.The bottom shall be of adequate rigidity to prevent permanentdeformation when specimens are molded i
28、n accordance withthe applicable provisions of Practice C31/C31M or C192/C192M.5.3.3 MaterialThe mold manufacturer shall certify that:(1) the plastic material used in molds has a maximum waterabsorption of less than 0.5 % in 24 h when tested in accordancewith Test Method D570;(2) the plastic has an I
29、zod impacttoughness of at least 117 J/m 2.2 ft lb/in. of notch fora4mm18 in. thick specimen tested in accordance with Test MethodsD256; and (3) after being held at 12 C 10 F for 24 h, theplastic shall not fracture when subject to tapping and jarringthat is judged to be typical of what occurs when sp
30、ecimens aremolded in accordance with the applicable provisions of Prac-tice C31/C31M or C192/C192M.5.4 Paper MoldsWhen paper or other potentially absorp-tive fiber material is used as the primary structural material inthe construction of the side walls or bottom of the mold, themold shall conform to
31、 the following additional requirements:5.4.1 Side WallsThe side walls of paper molds shall bemade with a minimum of three plies having a combinedthickness of not less than 2 mm 0.070 in. Seams on the insideof the mold shall not be open by more than 2 mm 116 in.NOTE 6The minimum thickness of material
32、 used in side walls andbottoms is considered adequate for cylinders up to 150 mm 6 in. indiameter. For larger cylinders thicker material may be required to meetrequirements of 3.1.5.4.2 Bottom CapsThe bottom cap of the mold shall bemade of either metal or paper. If metal, it shall not be less than0.
33、23 mm 0.009 in. in thickness and coated to preventcorrosion (Note 6). It shall be designed so that it will be flushwith the bottom edge of the side wall within a tolerance of 2mm 116 in. and the inside crimp, if any, shall produce anindentation around the circumference of the cylinder no morethan5mm
34、316 in. in the radial, and no more than 4 mm18 in. in the vertical direction. If made of paper, the bottomcap of the mold shall be of parchment-lined cap stock not lessthan 0.7 mm 0.028 in. thick (Note 6). It shall be glued to theoutside of the walls by means of a flange not less than 19 mm34 in. hi
35、gh. The glue shall be water-insoluble adhesive of theresin type that will not react with fresh concrete. Only thepracticable minimum amount of adhesive shall be exposed onthe inner side of the bottom of the mold.5.4.3 WaterproofingThe mold made from paper or fibershall be completely coated on inside
36、 and outside, side walls,TABLE 1 Limits for Absorption and ElongationNominal MoldHeight,mm in.Absorption, max gElongation, maxmm in.100 4 2.7 0.2 0.008150 6 6.0 0.3 0.012200 8 11 0.4 0.016300 12 24 0.6 0.024450 18 54 0.9 0.036600 24 96 1.2 0.048900 36 216 1.8 0.072C470/C470M 152and bottom with a sui
37、table waterproofing medium (Note 7).The top edge shall be waterproofed, or coated, to limitabsorption. The surfaces of metal bottoms, which must complywith 5.4.2, need not be coated.Any waterproofing coating usedin this application shall have a melting point not less than 49 C120 F (Note 8). The coa
38、ting shall provide a film over theinside that will minimize adherence of the concrete to the sidewalls and the bottom.NOTE 7Paraffin coating for this use may be of the grade known to thetrade as crude scale wax or of any superior grade. In general, a film ofparaffin of sufficient thickness to accomp
39、lish the intended purposes willpermit one to raise a curl of paraffin with the thumbnail.NOTE 8Such coatings may be unsuitable for molds that are subjectedto temperatures above 49 C 120 F, either before or after filling withconcrete.5.5 Single-Use Sheet Metal MoldsMolds shall conform tothe following
40、 additional requirements when light-gage sheetmetal is the predominant material used in their construction:5.5.1 Metal ThicknessThe side wall of steel sheet metalmolds shall be manufactured from sheet metal not thinner thancan-making quality blackplate and shall have a minimum metalthickness corresp
41、onding to that of 48.5-kg 107-lb blackplate,which is approximately 0.300 mm 0.0118 in. thick or3012 gage. The metal for the bottom of the mold shall have aminimum thickness of 0.23 mm 0.009 in. (Note 6).5.5.2 Bottom DesignThe bottom shall be so designed thatit will be flush with the bottom of the si
42、de wall within atolerance of 2 mm 116 in. An inside crimp, if used, shallproduce an indentation around the circumference of the cylin-der no more than 4 mm 18 in. in the vertical or 5 mm 316 in.in the radial direction.5.5.3 Top EdgeThe top edge of the side wall shall becurled or beaded to strengthen
43、 the mold and protect the userfrom sharp edges. If such bead protrudes to the inside of themold, the indentation produced in the concrete cylinder shallnot exceed 4 mm 18 in. in either a radial or vertical direction.5.5.4 CoatingIf the mold is made of material which willrust, corrode, react, or adhe
44、re to the freshly mixed or hardenedconcrete, it must be coated with a protective coating of lacqueror other suitable material.5.6 Packaging:5.6.1 The manufacturer shall state on containers of single-use molds that molds are intended to be used a single time.5.6.2 Containers of single-use molds shall
45、 be marked withthe manufacturers lot number or date of manufacture.5.6.3 Containers of single-use molds shall be marked with adirectional arrow indicating orientation of the vertical axis ofthe molds.NOTE 9Shipping and storing single-use molds with their axis in thevertical position reduces the inci
46、dence of distortion.6. Test Methods for Elongation, Absorption, and WaterLeakage6.1 ApparatusThe assembly used for the absorption-elongation test shall follow the principles illustrated in Fig. 1.6.2 SpecimensMolds shall be selected as described inSection 2. Single-use molds shall not be reused nor
47、the samemold retested.6.3 Test Procedure for Molds:6.3.1 Samples of all types of single-use molds and reusableplastic molds shall be subjected to the dry rodded coarseaggregate test as described in 6.3.2 to evaluate their resistanceto damage under use and to the water leakage test described in6.3.3
48、and 6.3.4. Paper or other potentially absorptive moldsshall additionally be tested for absorptivity and elongationdescribed in 6.3.5. Plastic and sheet metal molds need not beFIG. 1 Apparatus for Absorption-Elongation Test of Paper MoldsC470/C470M 153tested for elongation and absorption, but should
49、be tested forwater leakage. Dimensional requirements for all molds shall beverified.6.3.2 Prepare the mold for test by filling with dry crushedstone coarse aggregate meeting the grading requirements ofSpecification C33 size No. 57, 25.0 to 4.75 mm 1 in. to No. 4or No. 67, 19.0 to 4.75 mm 34 in. to No. 4. Fill and compactthe mold by the rodding procedure specified in PracticeC192/C192M for compression test specimens using the
