1、Designation: C 617 98 (Reapproved 2003)Standard Practice forCapping Cylindrical Concrete Specimens1This standard is issued under the fixed designation C 617; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last revision
2、. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon (e) indicates an editorial change since the last revision or reapproval.This standard has been approved for use by agencies of the Department of Defense.1. Scope1.1 This practice covers apparatus, materials, and pr
3、oce-dures for capping freshly molded concrete cylinders with neatcement and hardened cylinders and drilled concrete cores withhigh-strength gypsum plaster or sulfur mortar.1.2 The values stated in inch-pound units are to be regardedas the standard. The SI equivalents of inch-pound units may beapprox
4、imate.1.3 This standard does not purport to address all of thesafety concerns, if any, associated with its use. It is theresponsibility of the user of this standard to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use. For spec
5、ificprecaution statements see 4.3 and 6.2.3.1.2. Referenced Documents2.1 ASTM Standards:2C 109/C 109M Test Method for Compressive Strength ofHydraulic Cement Mortars (Using 2-in. or 50-mm CubeSpecimens)C 150 Specification for Portland CementC 472 Test Methods for Physical Testing of Gypsum, Gyp-sum
6、Plasters and Gypsum ConcreteC 595M Specification for Blended Hydraulic CementsC 1231 Practice for Use of Unbonded Caps in Determina-tion of Compressive Strength of Hardened Concrete Cyl-inders2.2 ANSI Standard:B46.1 Standard for Surface Texture (Surface, Roughness,Waviness and Lay)33. Significance a
7、nd Use3.1 This practice describes procedures for providing planesurfaces on the ends of freshly molded concrete cylinders,hardened cylinders, or drilled concrete cores when the endsurfaces do not conform with the planeness and perpendicu-larity requirements of applicable standards. Practice C 1231de
8、scribes alternative procedures using unbonded caps or padcaps.4. Capping Equipment4.1 Capping PlatesNeat cement caps and high-strengthgypsum-plaster caps shall be formed against a glass plate atleast14 in. (6 mm) thick, a machined metal plate at least 0.45in. (11 mm) thick, or a polished plate of gr
9、anite or diabase atleast 3 in. (76 mm) thick. Sulfur mortar caps shall be formedagainst similar metal or stone plates except that the recessedarea which receives molten sulfur shall not be deeper than12in. (12 mm). In all cases, plates shall be at least 1 in. (25 mm)greater in diameter than the test
10、 specimen and the workingsurfaces shall not depart from a plane by more than 0.002 in.(0.05 mm) in 6 in. (152 mm). The surface roughness of newlyfinished metal plates shall not exceed that set forth in Table 4of American National Standard B46.1, or 125 in. (3.2 m) forany type of surface and directio
11、n of lay. The surface, whennew, shall be free of gouges, grooves, or indentations beyondthose caused by the finishing operation. Metal plates that havebeen in use shall be free of gouges, grooves, and indentationsgreater than 0.010 in. (0.25 mm) deep or greater than 0.05in.2(32 mm2) in surface area.
12、NOTE 1A Rockwell hardness of 48 HRC is suggested for cappingplates of devices used to form sulfur mortar caps.4.2 Alignment DevicesSuitable alignment devices, suchas guide bars or bulls-eye levels, shall be used in conjunctionwith capping plates to ensure that no single cap will departfrom perpendic
13、ularity to the axis of a cylindrical specimen bymore than 0.5 (approximately equivalent to18 in. in 12 in.(3.2 mm in 305 mm). The same requirement is applicable tothe relationship between the axis of the alignment device andthe surface of a capping plate when guide bars are used. Inaddition, the loc
14、ation of each bar with respect to its plate must1This practice is under the jurisdiction of ASTM Committee C09 on Concreteand Concrete Aggregates and is the direct responsibility of Subcommittee C09.61 onTesting for Strength.Current edition approved August 10, 1998. Published December 1998. Original
15、lyapproved in 1968. Last previous edition approved in 1998 as C 617 98 (2003).2For referenced ASTM standards, visit 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 on
16、the ASTM website.3Available from American Society of Mechanical Engineers, 345 E. 47th Street,New York, NY 10017.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.be such that no cap will be off-centered on a test specimen bymore than1
17、16 in. (2 mm).4.3 Melting Pots for Sulfur MortarsPots used for meltingsulfur mortars shall be equipped with automatic temperaturecontrols and shall be made of metal or lined with a material thatis nonreactive with molten sulfur.4.3.1 Caution: Melting pots equipped with peripheral heat-ing will ensur
18、e against accidents during reheating of cooledsulfur mixture that have a crusted-over surface. When usingmelting pots not so equipped, a build-up of pressure under thehardened surface crust on subsequent reheating may beavoided by use of a metal rod that contacts the bottom of thepot and projects ab
19、ove the surface of the fluid sulfur mix as itcools. The rod should be of sufficient size to conduct enoughheat to the top on reheating to melt a ring around the rod firstand thus avoid the development of pressure. A large metal ladlecan be substituted for the rod.4.3.1.1 Use sulfur melting pots in a
20、 hood to exhaust thefumes to outdoors. Heating over an open flame is dangerousbecause the flash point of sulfur is approximately 440F(227C) and the mixture can ignite due to overheating. Shouldthe mixture start to burn, covering will snuff out the flame. Thepot should be recharged with fresh materia
21、l after the flame hasbeen extinguished.5. Capping Materials5.1 The strength of the capping material and the thickness ofthe caps shall conform to the requirements of Table 1.5.1.1 If sulfur mortar, high strength gypsum plaster andother materials except neat cement paste are to be used to testconcret
22、e with a strength greater than 7000 psi (50 MPa), themanufacturer or the user of the material must provide docu-mentation:5.1.1.1 That the average strength of 15 cylinders cappedwith the material is not less than 98 percent of the averagestrength of 15 companion cylinders capped with neat cementpast
23、e or 15 cylinders ground plane to within 0.002 in. (0.05mm).5.1.1.2 That the standard deviation of the strengths of thecapped cylinders is not greater than 1.57 times that of thestandard deviation of the reference cylinders.5.1.1.3 That the cap thickness requirements were met in thequalification tes
24、ts, and5.1.1.4 Of the hardening time of the caps used in thequalification tests.5.1.2 Additionally, the qualification test report must includethe compressive strength of 2 in. cubes of the material qualifiedand of neat cement paste cubes, if used. Capping materialsconforming to these requirements is
25、 permitted to be used forcylinders with strengths up to 20 percent greater than theconcrete tested in these qualification tests. The manufacturermust requalify lots of material manufactured on an annual basisor whenever there is a change in the formulation or the rawmaterials. The user of the materi
26、al must retain a copy of thequalification results, and the dates of manufacture of materialqualified and of the material currently being used. See Table 2.5.1.3 The compressive strength of capping materials shallbe determined by testing 2 in. cubes following the proceduredescribed in Test Method C 1
27、09. Except for sulfur mortars,molding procedures shall be as in Test Method C 109 unlessother procedures are required to eliminate large entrapped airvoids. See Test Methods C 472 for alternative compactionprocedures. Cure cubes in the same environment for the samelength of time as the material used
28、 to cap specimens.5.1.4 The strength of the capping material shall be deter-mined on receipt of a new lot and at intervals not exceedingthree months. If a given lot of the capping material fails toconform to the strength requirements, it shall not be used, andstrength tests of the replacement materi
29、al shall be made weeklyuntil four consecutive determinations conform to specificationrequirements.5.2 Neat Hydraulic Cement Paste:5.2.1 Make qualification tests of the neat hydraulic cementpaste prior to use for capping to establish the effects ofwater-cement ratio and age on compressive strength of
30、 2 in. (50mm) cubes.NOTE 2The cements used generally conform to Specification C 150Types I, II or III; however, Specification C 595 blended cements, calciumaluminate or other hydraulic cements producing acceptable strength maybe used.5.2.2 Mix the neat cement paste to the desired consistency ata wat
31、er-cement ratio equal to or less than that required toproduce the required strength, generally 2 to 4 h before thepaste is to be used (Note 3). Remix as necessary to maintainacceptable consistency (Note 4). Some retempering of thepaste is acceptable if the required water-cement ratio is notexceeded.
32、 Optimum consistency is generally produced atwater-cement ratios of 0.32 to 0.36 by mass for Type I andType II cements and 0.35 to 0.39 by mass for Type III cements.NOTE 3Freshly mixed pastes tend to bleed, shrink, and make unac-ceptable caps. The 2 to 4 h period is generally appropriate for portlan
33、dcements.NOTE 4The required consistency of the paste is determined by theappearance of the cap when it is stripped. Fluid paste results in streaks inthe cap. Stiff paste results in thick caps.5.3 High-Strength Gypsum Cement Paste:5.3.1 No fillers or extenders may be added to neat high-strength gypsu
34、m cement paste subsequent to the manufactureof the cement. (Note 5) Qualification tests shall be made todetermine the effects of water-cement ratio and age on com-pressive strength of 2 in. (50 mm) cubes. Retarders may beused to extend working time, but their effects on requiredwater-cement ratio an
35、d strength must be determined. (Note 6)TABLE 1 Compressive Strength and Maximum Thickness ofCapping MaterialsCylinderCompressiveStrength psi(MPa)Minimum Strength of CappingMaterialMaximumAverageThicknessof CapMaximumThicknessAny Partof Cap500 to 7000psi (3.5 to50 MPa)5000 psi (35 MPa) or cylinderstr
36、ength whichever is greater14 in.(6 mm)516 in.(8 mm)greater than7000 psi(50 MPa)Compressive strength not lessthancylinder strength, except asprovided in 5.1.118 in.(3 mm)316 in.(5 mm)C 617 98 (2003)2NOTE 5Low-strength molding plaster, plaster of paris, or mixtures ofplaster of paris and portland ceme
37、nt are unsuitable for capping.NOTE 6The water-gypsum cement ratio should be between 0.26 and0.30. Use of low water-cement ratios and vigorous mixing will usuallypermit development of 5000 psi (35 MPa) at ages of 1 or 2 h. Higherwater-gypsum cement ratios extend working time, but reduce strength.5.3.
38、2 Mix the neat gypsum cement paste at the desiredwater-cement ratio and use it promptly since it sets rapidly.5.4 Sulfur Mortar:5.4.1 Proprietary or laboratory prepared sulfur mortars arepermitted if allowed to harden a minimum of 2 h before testingconcrete with strength less than 5000 psi (35 MPa).
39、 Forconcrete strengths of 5000 psi or greater, sulfur mortar capsmust be allowed to harden at least 16 h before testing, unlessa shorter time has been shown to be suitable as specified in5.1.1.5.4.2 Determination of Compressive StrengthPrepare testspecimens using a cube mold and base plate conformin
40、g to therequirements of Test Method C 109 and a metal cover plateconforming in principle to the design shown in Fig. 1 (Note 7).Bring the various parts of the apparatus to a temperature of 68to 86F (20 to 30C), lightly coat the surfaces that will be incontact with the sulfur mortar with mineral oil,
41、 and assemblenear the melting pot. Bring the temperature of the molten-sulfur mortar in the pot within a range of 265 to 290F (129 to143C), stir thoroughly, and begin casting cubes. Using a ladle,or other suitable pouring device, quickly fill each of the threecompartments until the molten material r
42、eaches the top of thefilling hole. Allow sufficient time for maximum shrinkage, dueto cooling, and solidification to occur (approximately 15 min)and refill each hole with molten material (Note 8). AfterTABLE 2 Sample Report of Qualification of a Capping MaterialNOTEManufacturer: Testing Supplies Co.
43、Capping Material: Super Strong AAA-Sulfor mortarLot: 12a45 Date Tested: 11/3/98Signed by:_ (testing agency and responsible official)ItemCappingMaterial Control Cylinders Ratio Criteria Pass/FailConcrete Cylinder Test DataType of capping material Sulfur GroundAverage Concrete Strength, psi MPa 11 061
44、 (76.2) 11 008 (75.9) 1.005 0.98 Xc PassStandard Deviation, psi MPa 376 (2.59) 250 (1.72) 1.504 #1.57 C PassNumber of cylinders tested 15 15Cap age when cylinders tested 7 days naCapping Material Test DataAverage cap thickness, in. mm 0.11 (2.8) naCompressive strength of 2 in. 50 mm cubes, psi (MPa)
45、 12 195 (91)Cube age when tested. 7 daysMaximum concrete strength qualified, psi (MPa) 1.2 Av. Str = 13 273 (91.5)AANominally a specified strength of 11 000 psi (75 MPa) and perhaps somewhat higher.FIG. 1 Sketch of Cover Plate for 2-in. (50-mm) Cube MoldC 617 98 (2003)3solidification is complete, re
46、move the cubes from the moldwithout breaking off the knob formed by the filling hole in thecover plate. Remove oil, sharp edges, and fins from the cubesand check the planeness of the bearing surfaces in the mannerdescribed in Test Method C 109. After storage at room tem-perature to the desired age,
47、but not less than 2 h, test cubes incompression following the procedure described in Test MethodC 109, and calculate the compressive strength.NOTE 7If desired, a plane phenol formaldehyde (bakelite) plate of18-in. (3-mm) thickness, provided with three appropriately spaced fillingholes, may be insert
48、ed between the cover plate and the mold to slow therate of cooling of test specimens.NOTE 8The second filling helps to prevent the formation of a largevoid or shrinkage pipe in the body of a cube. However, such defects mayoccur no matter how much care is exercised, and it therefore is advisableto in
49、spect the interior of tested sulfur mortar cubes for homogeneitywhenever the strength values obtained are significantly lower thananticipated.6. Capping Procedures6.1 Freshly Molded CylindersUse only neat portlandcement pastes (Note 9) to cap freshly molded cylinders. Makecaps as thin as practicable. Do not apply the neat paste to theexposed end until the concrete has ceased settling in the molds,generally from 2 to 4 h after molding. During the molding ofthe cylinder, strike off the upper end even with or sligh
