1、Designation: C 470/C 470M 08Standard Specification forMolds for Forming Concrete Test Cylinders Vertically1This standard is issued under the fixed designation C 470/C 470M; the number immediately following the designation indicates the yearof original adoption or, in the case of revision, the year o
2、f last revision. A number in parentheses indicates the year of last reapproval.A superscript epsilon () indicates an editorial change since the last revision or reapproval.1. Scope*1.1 This specification covers molds for use in formingcylindrical concrete specimens. The provisions of this specifi-ca
3、tion include the requirements for both reusable and single-use molds.NOTE 1Sizes included are molds having diameters from 50 mm 2in. to 900 mm 36 in.1.2 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
4、 equivalents; 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.1.3 The following safety hazards caveat pertains only to thetest method described in this spec
5、ification: 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.1.4 The text
6、of this standard references notes and footnoteswhich provide explanatory material. These notes and footnotes(excluding those in tables and figures) shall not be consideredas requirements of the standard.2. Referenced Documents2.1 ASTM Standards:2C 31/C 31M Practice for Making and Curing Concrete Tes
7、tSpecimens in the FieldC33 Specification for Concrete AggregatesC 192/C 192M Practice for Making and Curing ConcreteTest Specimens in the LaboratoryD 256 Test Methods for Determining the Izod PendulumImpact Resistance of PlasticsD 570 Test Method for Water Absorption of Plastics3. General Requiremen
8、ts3.1 The following provisions apply to both reusable andsingle-use molds:3.1.1 Molds shall 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 con
9、taining portland orother hydraulic cements. They shall be watertight and suffi-ciently strong 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
10、 inside diameter. The diameter of a mold,consisting of the average of two measurements taken 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 th
11、e nominal height by more than 2 %. Theplanes of the top rim of the mold and the bottom shall 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
12、% except that molds that fail tomeet this requirement may be used when the user is able todemonstrate 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
13、the use of a specialdevice such as a tube of heavy-gage metal around the mold duringmolding 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)
14、.4. 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 Note 4).1This specification is under the jurisdiction of ASTM Committee C09 onConcret
15、e and Concrete Aggregates and is the direct responsibility of SubcommitteeC09.61 on Testing for Strength.Current edition approved July 1, 2008. Published August 2008. Originallyapproved in 1961. Last previous edition approved in 2002 as C 470/C 470M-02a.2For referenced ASTM standards, visit the ASTM
16、 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.1*A Summary of Changes section appears at the end of this standard.Copyright ASTM International, 100 Barr H
17、arbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.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
18、is an integral partof the sidewall. The mold shall be either coated 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
19、 mm 18 in. in the verticaldirection or no more than 5 mm 316 in. in 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 3.1.3after every 50 uses or e
20、very six months, whichever comes first.NOTE 4Satisfactory 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 m
21、aintained after slitting, clamp-ing, and attaching the base plate. Other nonabsorptive materials whichhave been used include iron, brass, steel, and various plastics. Althoughaluminum and magnesium alloys have been used, some of these alloysmay be reactive with cement constituents and are therefore
22、unacceptable.5. Single-Use Molds5.1 Single-use molds are molds 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 mold
23、s as prepared for useshall comply with the following:5.2.1 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
24、the square of the height.5.2.3 ElongationWhen tested as described 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
25、ThicknessThe side walls shall be of sufficientstiffness to 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
26、of the sidewall within atolerance of 2 mm 116 in. An inside 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 t
27、o prevent permanentdeformation when specimens are molded in accordance withthe applicable provisions of Practice C 31/C 31M or C 192/C 192M.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 test
28、ed in accordancewith Test Method D 570;(2) the plastic has an Izod impacttoughness of at least 117 J/m 2.2 ft lb/in. of notch fora4mm18 in. thick specimen tested in accordance with Test MethodsD 256; and (3) after being held at 12 C 10 F for 24 h, theplastic shall not fracture when subject to tappin
29、g and jarringthat is judged to be typical of what occurs when specimens aremolded in accordance with the applicable provisions of Prac-tice C 31/C 31M or C 192/C 192M.5.4 Paper MoldsWhen paper or other potentially absorp-tive fiber material is used as the primary structural material inthe constructi
30、on of the side walls or bottom of the mold, themold shall conform to 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 o
31、pen by more than 2 mm 116 in.NOTE 6The minimum thickness of material 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 be
32、made of either metal or paper. If metal, it shall not be less than0.23 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 a
33、nindentation around the circumference of the cylinder no morethan 5 mm 316 in. in the radial, and no more than 4 mm 18in. in the vertical direction. If made of paper, the bottom capof the mold shall be of parchment-lined cap stock not less than0.7 mm 0.028 in. thick (Note 6). It shall be glued to th
34、eoutside of the walls by means of a flange not less than 19 mm34 in. high. 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 Waterproofi
35、ngThe mold made from paper or fibershall be completely coated on inside and outside, side walls,and bottom with a suitable 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.
36、Any waterproofing coating usedin this application shall have a melting point not less than 49 C120 F (Note 8). The coating 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
37、 thetrade as crude scale wax or of any superior grade. In general, a film ofTABLE 1 Limits for Absorption and ElongationNominal Mold Height,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
38、 36 216 1.8 0.072C 470/C 470M 082paraffin of sufficient thickness to accomplish 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 withc
39、oncrete.5.5 Single-Use Sheet Metal MoldsMolds shall conform tothe following 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 thanca
40、n-making quality blackplate and shall have a minimum metalthickness corresponding to that of 48.5-kg 107-lb blackplate,which is approximately 0.300 mm 0.0118 in. thick or 3012gage. 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
41、 bottom shall be so designed thatit will be flush with the bottom of the side 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 316in. in the radial direction.5.5.3 T
42、op EdgeThe top edge of the side wall shall becurled or beaded to strengthen 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 Coa
43、tingIf the mold is made of material which willrust, corrode, react, or adhere to the freshly mixed or hardenedconcrete, it must be coated with a protective coating of lacqueror other suitable material.6. Test Methods for Elongation, Absorption, and WaterLeakage6.1 ApparatusThe assembly used for the
44、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 the samemold retested.6.3 Test Procedure for Molds:6.3.1 Samples of all types of single-use molds and reusableplastic m
45、olds 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 and 6.3.4. Paper or other potentially absorptive moldsshall additionally be tested for absorptivity and elongationdescr
46、ibed in 6.3.5. Plastic and sheet metal molds need not betested for elongation and absorption, but should 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 requireme
47、nts ofSpecification C33size No. 57, 25.0 to 4.75 mm 1 in. to No.4 or No. 67, 19.0 to 4.75 mm 34 in. to No. 4. Fill andcompact the mold by the rodding procedure specified inPractice C 192/C 192M for compression test specimens usingthe tamping rod, number of layers and number of strokes perlayer speci
48、fied. It will generally not be possible to obtain thepenetration of the tamping rod specified in Practice C 192/C 192M. After rodding the final layer, empty the coarseaggregate, wipe lightly with a dry cloth and examine the moldfor physical damage.6.3.3 After completion of 6.3.2, determine the mass
49、of themold and record to the nearest 0.004 g/mm 0.1 g/in. of moldheight. Place the mold on a firm, flat surface and fill with waterat room temperature to a depth of 90 to 95 % of the moldheight. Then place the mold on the dial stand, cover with theglass or metal plate and record the initial length by dialmicrometer to the nearest 0.025 mm 0.001 in.FIG. 1 Apparatus for Absorption-Elongation Test of Paper MoldsC 470/C 470M 083
