1、Designation: C 470/C 470M 02aStandard 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
2、of last revision. A number in parentheses indicates the year of last reapproval.A superscript epsilon (e) indicates an editorial change since the last revision or reapproval.1. Scope1.1 This specification covers molds for use in formingcylindrical concrete specimens. The provisions of this specifi-c
3、ation 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. Dimensions of commonly used single-use moldsare given in Fig. 1.1.2 The values stated in either SI units or in other units shallbe regarded separatel
4、y as standard. The values stated in eachsystem may not be exact equivalents; therefore, each systemmust be used independently of the other, without combining inany way. The inch-pound units are shown in brackets.1.3 The following safety hazards caveat pertains only to thetest method described in thi
5、s specification: 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
6、 text 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:C 31/C 31M Practice for Making and Curing Concret
7、e TestSpecimens in the Field2C 33 Specification for Concrete Aggregates2C 192/C 192M Practice for Making and Curing ConcreteTest Specimens in the Laboratory2D 256 Test Methods for Determining the Izod PendulumImpact Resistance of Plastics3D 570 Test Method for Water Absorption of Plastics33. General
8、 Requirements3.1 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 c
9、oncrete containing 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
10、the nominal 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 dif
11、fer from the 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 m
12、ore than 2 % 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 m
13、ay require 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 o
14、f the mold).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).4.2 Reusable molds shall be provided with a closure or baseon the
15、lower end at right angles to the axis of the cylinder.Molds may be single piece molds or made from castings with1This specification is under the jurisdiction of ASTM Committee C09 onConcrete and Concrete Aggregates and is the direct responsibility of SubcommitteeC09.61 on Testing for Strength.Curren
16、t edition approved Dec. 10, 2002. Published January 2003. Originallyapproved in 1961. Last previous edition approved in 2002 as C 470/C 470M-022Annual Book of ASTM Standards, Vol 04.02.3Annual Book of ASTM Standards, Vol 08.01.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West C
17、onshohocken, PA 19428-2959, United States.a separate detachable base plate or a base that 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
18、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 the horizontaldirection (see Fig. 1).4.3 Reusable molds shall be tested for water leakage asdescribed in 6.4, for resistance to damage as des
19、cribed in 6.3.1,and for dimensional stability in accordance with 3.1.2 and 3.1.3after every 50 uses or every 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
20、vertical slit as well as a means of attaching a base plate. Therequired dimensional tolerances must be maintained after slitting, clamp-ing, and attaching the base plate. Other nonabsorptive materials whichhave been used include iron, brass, steel, and various plastics. Althoughaluminum and magnesiu
21、m alloys have been used, some of these alloysmay be reactive with cement constituents and are therefore unacceptable.5. Single-Use Molds5.1 Single-use molds may be made of sheet metal, plastic,suitably treated paper products, or other materials and mustconform to the requirements of this specificati
22、on.5.2 Physical RequirementsThe molds 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.Inte
23、rmediate values are proportional to 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 mater
24、ial used in construction:5.3.1 Wall 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 t
25、hatit will be flush with the bottom 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 bo
26、ttom shall be of adequate rigidity to 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
27、of less than 0.5 % in 24 h when tested 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 MethodsFIG. 1 Dimensions of Single Use 150 by 300 mm 6 by 12-in. Paper or She
28、et Metal Cylinder MoldsTABLE 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 36 216 1.8 0.072C 470/C 470M 02a2D 256; and (3) afte
29、r being held at 12C 10F for 24 h, theplastic shall not fracture when subject to tapping 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
30、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 the following additional requirements:5.4.1 Side WallsThe side walls of paper molds shall bemade with a minimum of three plies having a combinedt
31、hickness 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 used in side walls andbottoms is considered adequate for cylinders up to 150 mm 6 in. indiameter. For larger cylinders thicker material may be re
32、quired 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 than0.23 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 sid
33、e wall within a tolerance of 2mm 116 in. and the inside crimp, if any, shall produce anindentation around the circumference of the cylinder no morethan5mm316 in. in the radial, and no more than 4 mm18 in. in the vertical direction (see Fig. 1). If made of paper,the bottom cap of the mold shall be of
34、 parchment-lined capstock not less than 0.7 mm 0.028 in. thick (Note 6). It shallbe glued to the outside of the walls by means of a flange notless than 19 mm 34 in. high. The glue shall be water-insolubleadhesive of the resin type that will not react with freshconcrete. Only the practicable minimum
35、amount of adhesiveshall be exposed on the inner side of the bottom of the mold.5.4.3 WaterproofingThe 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 l
36、imitabsorption. 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 49C120F (Note 8). The coating shall provide a film over theinside that will minimize adherence of the concrete to
37、 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 accomplish the intended purposes willpermit one to raise a curl of paraffin with the thumbnail
38、.NOTE 8Such coatings may be unsuitable for molds that are subjectedto temperatures above 49C 120F, either before or after filling withconcrete.5.5 Single-Use Sheet Metal MoldsMolds shall conform tothe following additional requirements when light-gage sheetmetal is the predominant material used in th
39、eir 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 corresponding to that of 48.5-kg 107-lb blackplate,which is approximately 0.300 mm 0.0118 in. thi
40、ck 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 side wall within atolerance of 2 mm 116 in. An inside crimp, if used, shallproduce an indent
41、ation 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 (see Fig. 1).5.5.3 Top 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
42、 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 adhere to the freshly mixed or hardenedconcrete, it must be coated with a protect
43、ive coating of lacqueror other suitable material.6. Test Methods for Elongation, Absorption, and WaterLeakage6.1 ApparatusThe assembly used for the absorption-elongation test shall follow the principles illustrated in Fig. 2.6.2 SpecimensMolds shall be selected as described inSection 2. Single-use m
44、olds 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 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 le
45、akage test described in6.3.3 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 betested for elongation and absorption, but should be tested forwater leakage. Dimensional require
46、ments 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 C 33 size 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
47、procedure specified inPractice C 192/C 192M for compression test specimens usingthe tamping rod, number of layers and number of strokes perlayer specified. 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,
48、 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 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
49、 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.6.3.4 Allow the mold to stand for 3 h and take a finalreading of the micrometer. Examine and record any visibleC 470/C 470M 02a3leakage. Empty water from the mold, dry lightly with a toweland record the final mass to the nearest
