1、Designation: C617 10Standard Practice forCapping Cylindrical Concrete Specimens1This standard is issued under the fixed designation C617; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last revision. A number in parent
2、heses 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 Department of Defense.1. Scope*1.1 This practice covers apparatus, materials, and proce-dures for cappin
3、g freshly molded concrete cylinders with neatcement and hardened cylinders and drilled concrete cores withhigh-strength gypsum paste or sulfur mortar.1.2 The values stated in inch-pound units are to be regardedas standard. The values given in parentheses are mathematicalconversions to SI units that
4、are provided for information onlyand are not considered standard.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 appl
5、ica-bility of regulatory limitations prior to use. For specificprecaution statements see 4.3.1 and 6.2.4.1.2. Referenced Documents2.1 ASTM Standards:2C109/C109M Test Method for Compressive Strength ofHydraulic Cement Mortars (Using 2-in. or 50-mm CubeSpecimens)C150 Specification for Portland CementC
6、472 Test Methods for Physical Testing of Gypsum, Gyp-sum Plasters and Gypsum ConcreteC595 Specification for Blended Hydraulic CementsC1231/C1231M Practice for Use of Unbonded Caps inDetermination of Compressive Strength of Hardened Con-crete Cylinders2.2 ANSI Standard:3B46.1 Standard for Surface Tex
7、ture (Surface, Roughness,Waviness and Lay)3. Significance and 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-lar
8、ity requirements of applicable standards. Practice C1231/C1231M describes alternative procedures using unbonded capsor pad caps.4. Capping Equipment4.1 Capping PlatesNeat cement caps and high-strengthgypsum-paste caps shall be formed against a glass plate at least14 in. (6 mm) thick, a machined meta
9、l plate at least 0.45 in. (11mm) thick, or a polished plate of granite or diabase at least 3in. (76 mm) thick. Sulfur mortar caps shall be formed againstsimilar metal or stone plates except that the recessed areawhich receives molten sulfur shall not be deeper than12 in.(12 mm). In all cases, plates
10、 shall be at least 1 in. (25 mm)greater in diameter than the test 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 Stand
11、ard B46.1, or 125 in. (3.2 m) forany type of surface and direction 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.
12、 (0.25 mm) deep or greater than 0.05in.2(32 mm2) in surface area.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 capp
13、ing plates to ensure that no single cap will departfrom perpendicularity 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 to1This practice is under the jurisdiction of ASTM Committee C09 on Concre
14、teand ConcreteAggregates and is the direct responsibility of Subcommittee C09.61 onTesting for Strength.Current edition approved June 15, 2010. Published July 2010. Originallyapproved in 1968. Last previous edition approved in 2009 as C61709a. DOI:10.1520/C0617-10.2For referenced ASTM standards, vis
15、it 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.3Available from American National Standards Institute (ANSI), 25 W. 43rd St.,4th Floor, New York
16、, NY 10036, http:/www.ansi.org.1*A Summary of Changes section appears at the end of this standard.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.the relationship between the axis of the alignment device andthe surface of a capping pl
17、ate when guide bars are used. Inaddition, the location of each bar with respect to its plate mustbe such that no cap will be off-centered on a test specimen bymore than116 in. (2 mm).4.3 Melting Pots for Sulfur MortarsPots used for meltingsulfur mortars shall be equipped with automatic temperatureco
18、ntrols and shall be made of metal or lined with a material thatis nonreactive with molten sulfur.4.3.1 WarningMelting pots equipped with peripheralheating will ensure against accidents during reheating ofcooled sulfur mixture that have a crusted-over surface. Whenusing melting pots not so equipped,
19、a build-up of pressureunder the hardened surface crust on subsequent reheating maybe avoided by use of a metal rod that contacts the bottom of thepot and projects above the surface of the fluid sulfur mix as itcools. The rod should be of sufficient size to conduct enoughheat to the top on reheating
20、to melt a ring around the rod firstand thus avoid the development of pressure.Alarge metal ladlecan be substituted for the rod.4.3.1.1 Use sulfur melting pots in a hood to exhaust thefumes to outdoors. Heating over an open flame is dangerousbecause the flash point of sulfur is approximately 440 F (2
21、27C) and the mixture can ignite due to overheating. Should themixture start to burn, covering will snuff out the flame. The potshould be recharged with fresh material after the flame hasbeen extinguished.5. Capping Materials5.1 The strength of the capping material and the thickness ofthe caps shall
22、conform to the requirements of Table 1.5.1.1 If sulfur mortar, high strength gypsum paste and othermaterials except neat cement paste are to be used to testconcrete with a strength greater than 7000 psi (50 MPa) andtheir compressive strength is less than the cylinder compressivestrength, the manufac
23、turer or the user of the material mustprovide documentation: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 cementpaste or 15 cylinders ground plane to within 0.002 in. (0.05mm).5.
24、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 tests, and5.1.1.4 Of the hardening time of the caps used in thequ
25、alification 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 permitted to be used forcylinders with strengths up to 20 per
26、cent 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 material must retain a copy of thequalification results, and the dat
27、es 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 C109/C109M. Except for sulfurmortars, molding procedures shall be
28、 as in Test MethodC109/C109M unless other procedures are required to eliminatelarge entrapped air voids. See Test Methods C472 for alterna-tive compaction procedures. Cure cubes in the same environ-ment for the same length of time as the material used to capspecimens.5.1.4 The strength of the cappin
29、g 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 material shall be made weeklyuntil four consecutive dete
30、rminations 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 2 in. (50mm) cubes.NOTE 2The cements used general
31、ly conform to Specification C150Types I, II or III; however, Specification C595 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 water-cement ratio equal to or less than that required
32、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. Optimum consistency is generally produced atwater-c
33、ement 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 portlandcements.NOTE 4The required consistency of the paste
34、 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 gypsum cement paste subsequent to the manufactureTABLE 1
35、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 cylinderstrength whichever is greater14 in.(6 mm)516 in.(8
36、 mm)greater than7000 psi(50 MPa)Compressive strength not lessthancylinder strength, except asprovided in 5.1.118 in.(3 mm)316 in.(5 mm)C617 102of 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) cub
37、es. Retarders may beused to extend working time, but their effects on requiredwater-cement ratio and strength must be determined. (Note 6)NOTE 5Low-strength molding plaster, plaster of paris, or mixtures ofplaster of paris and portland cement are unsuitable for capping.NOTE 6The water-gypsum cement
38、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.5.3.2 Mix the neat gypsum cement paste at the desiredwater-cemen
39、t 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). Forconcrete strengths of 5000 psi or greater, sulfur mortar
40、 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 conforming to therequirements of Test Method C109/C109M and a metal c
41、overplate conforming in principle to the design shown in Fig. 1(Note 7). Bring the various parts of the apparatus to atemperature of 68 to 86 F (20 to 30 C), lightly coat thesurfaces that will be in contact with the sulfur mortar withTABLE 2 Sample Report of Qualification of a Capping MaterialNOTEMa
42、nufacturer: Testing Supplies Co.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 C
43、oncrete Strength, psi MPa 11 061 (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
44、 of 2 in. 50 mm cubes, psi (MPa) 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 MoldC617 103minera
45、l oil, and assemble near the melting pot. Bring thetemperature of the molten-sulfur mortar in the pot within arange of 265 to 290 F (129 to 143 C), stir thoroughly, andbegin casting cubes. Using a ladle, or other suitable pouringdevice, quickly fill each of the three compartments until themolten mat
46、erial reaches the top of the filling hole. Allowsufficient time for maximum shrinkage, due to cooling, andsolidification to occur (approximately 15 min) and refill eachhole with molten material (Note 8). After solidification iscomplete, remove the cubes from the mold without breakingoff the knob for
47、med by the filling hole in the cover plate.Remove oil, sharp edges, and fins from the cubes and check theplaneness of the bearing surfaces in the manner described inTest Method C109/C109M. After storage at room temperatureto the desired age, but not less than 2 h, test cubes incompression following
48、the procedure described in Test MethodC109/C109M, 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 inserted between the cover plate and the mold to slow thera
49、te 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 inspect 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 cylinder
