ASTM C617 C617M-2011 Standard Practice for Capping Cylindrical Concrete Specimens《处理圆柱形混凝土样顶部的标准操作规程》.pdf

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1、Designation: C617/C617M 11Standard Practice forCapping Cylindrical Concrete Specimens1This standard is issued under the fixed designation C617/C617M; the number immediately following the designation indicates the yearof original adoption or, in the case of revision, the year of last revision. A numb

2、er 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 Department of Defense.1. Scope*1.1 This practice covers apparatus, materials, and proce-dure

3、s for capping 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 either SI units or inch-pound unitsare to be regarded separately as standard. The values stated ineach system may

4、 not be exact equivalents; therefore, eachsystem shall be used independently of the other. Combiningvalues from the two systems may result in non-conformancewith the standard.1.3 This standard does not purport to address all of thesafety concerns, if any, associated with its use. It is theresponsibi

5、lity 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 specificprecaution statements see 4.3.1 and 6.2.4.1.2. Referenced Documents2.1 ASTM Standards:2C109/C109M Test Method for Compressive S

6、trength ofHydraulic Cement Mortars (Using 2-in. or 50-mm CubeSpecimens)C150 Specification for Portland CementC472 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 inDetermin

7、ation of Compressive Strength of Hardened Con-crete Cylinders2.2 ANSI Standard:3B46.1 Standard for Surface Texture (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

8、cylinders, or drilled concrete cores when the endsurfaces do not conform with the planeness and perpendicu-larity requirements of applicable standards. Practice C1231/C1231M describes alternative procedures using unbonded capsor pad caps.4. Capping Equipment4.1 Capping PlatesNeat cement caps and hig

9、h-strengthgypsum-paste caps shall be formed against a glass plate at least6mm14 in. thick, a machined metal plate at least 11 mm0.45 in. thick, or a polished plate of granite or diabase at least75 mm 3 in. thick. Sulfur mortar caps shall be formed againstsimilar metal or stone plates except that the

10、 recessed areawhich receives molten sulfur shall not be deeper than 12 mm12 in. In all cases, plates shall be at least 25 mm 1 in.greater in diameter than the test specimen and the workingsurfaces shall not depart from a plane by more than 0.05 mm0.002 in. in 150 mm 6 in. The surface roughness of ne

11、wlyfinished metal plates shall not exceed that set forth in Table 4of American National Standard B46.1, or 3.2 m 125 in. 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 th

12、at havebeen in use shall be free of gouges, grooves, and indentationsgreater than 0.25 mm 0.010 in. deep or greater than 30 mm20.05 in.2 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 alignme

13、nt devices, suchas guide bars or bulls-eye levels, shall be used in conjunctionwith capping plates to ensure that no single cap will departfrom perpendicularity to the axis of a cylindrical specimen bymore than 0.5 (approximately equivalent to 3 mm in 300 mm18 in. in 12 in.). The same requirement is

14、 applicable to therelationship between the axis of the alignment device and thesurface of a capping plate when guide bars are used. In1This practice is under the jurisdiction of ASTM Committee C09 on Concreteand ConcreteAggregates and is the direct responsibility of Subcommittee C09.61 onTesting for

15、 Strength.Current edition approved Aug. 1, 2011. Published September 2011. Originallyapproved in 1968. Last previous edition approved in 2010 as C61710. DOI:10.1520/C0617_C0617M-11.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.or

16、g. 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, NY 10036, http:/www.ansi.org.1*A Summary of Changes section appears at the end of

17、this standard.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.addition, the location of each bar with respect to its plate mustbe such that no cap will be off-centered on a test specimen bymore than 2 mm 116 in.4.3 Melting Pots for Su

18、lfur 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 WarningMelting pots equipped with peripheralheating will ensure against accidents during reheating ofco

19、oled sulfur mixture that have a crusted-over surface. Whenusing melting pots not so equipped, 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 a

20、s 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.Alarge metal ladlecan be substituted for the rod.4.3.1.1 Use sulfur melting pots in a hood to exhaust thefumes to outdoors. Heat

21、ing over an open flame is dangerousbecause the flash point of sulfur is approximately 207 C 405F and the mixture can ignite due to overheating. If themixture starts to burn, covering will snuff out the flame.Recharge the pot with fresh material after the flame has beenextinguished.5. Capping Materia

22、ls5.1 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 paste and othermaterials except neat cement paste are to be used to testconcrete with a strength greater than 50 MPa 7000 psi andtheir com

23、pressive strength is less than the cylinder compressivestrength, the manufacturer 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 % of the average strengthof 15 companion cylinders capped with neat ce

24、ment paste or 15cylinders ground plane to within 0.05 mm 0.002 in.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 thequalificati

25、on tests, 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 50 mm 2 in. cubes of the materialqualified and of neat cement paste cubes, if used. Cappingmaterials conforming to these req

26、uirements is permitted to beused for cylinders with strengths up to 20 % 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

27、material must retain a copy of thequalification results, and the dates of manufacture of materialqualified and of the material currently being used.NOTE 2Table 2 is an example of a report of test results to qualify acapping material.5.1.3 The compressive strength of capping materials shallbe determi

28、ned by testing 50 mm 2 in. cubes following theprocedure described in Test Method C109/C109M. Except forsulfur mortars, molding procedures shall be as in Test MethodC109/C109M unless other procedures are required to eliminatelarge entrapped air voids. See Test Methods C472 for alterna-tive compaction

29、 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 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

30、 to the strength requirements, it shall not be used, andstrength tests of the replacement material 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

31、use for capping to establish the effects ofwater-cement ratio and age on compressive strength of 50 mm2 in. cubes.NOTE 3The cements used generally conform to Specification C150Types I, II or III; however, Specification C595 blended cements, calciumaluminate or other hydraulic cements producing accep

32、table 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 toproduce the required strength, generally 2 to 4 h before thepaste is to be used (Note 4). Remix as necessary to maintainacceptable consistency (Note 5). S

33、ome retempering of thepaste is acceptable if the required water-cement ratio is notexceeded. 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 4Freshly mixed pastes tend to bleed, s

34、hrink, and make unac-ceptable caps. The 2 to 4 h period is generally appropriate for portlandcements.NOTE 5The 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-Strengt

35、h Gypsum Cement Paste:5.3.1 No fillers or extenders may be added to neat high-strength gypsum cement paste subsequent to the manufactureof the cement. (Note 6) Qualification tests shall be made toTABLE 1 Compressive Strength and Maximum Thickness ofCapping MaterialsCylinderCompressiveStrength MPapsi

36、Minimum Strength of CappingMaterialMaximumAverageThicknessof CapMaximumThicknessAny Partof Cap3.5 to50 MPa500 to 7000 psi35 MPa 5000 psi or cylinderstrength whichever is greater6mm14 in.8mm516 in.greater than50 MPa7000 psiCompressive strength not less thancylinder strength, except asprovided in 5.1.

37、13mm18 in.5mm316 in.C617/C617M 112determine the effects of water-cement ratio and age on com-pressive strength of 50 mm 2 in. cubes. Retarders may beused to extend working time, but their effects on requiredwater-cement ratio and strength must be determined. (Note 7)NOTE 6Low-strength molding plaste

38、r, plaster of paris, or mixtures ofplaster of paris and portland cement are unsuitable for capping.NOTE 7The water-gypsum cement ratio should be between 0.26 and0.30. Use of low water-cement ratios and vigorous mixing will usuallypermit development of 35 MPa 5000 psi at ages of 1 or 2 h. Higherwater

39、-gypsum cement ratios extend working time, but reduce strength.5.3.2 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

40、h before testingconcrete with strength less than 35 MPa 5000 psi. Forconcrete strengths of 35 MPa 5000 psi or greater, sulfurmortar caps must be allowed to harden at least 16 h beforetesting, unless a shorter time has been shown to be suitable asspecified in 5.1.1.5.4.2 Determination of Compressive

41、StrengthPrepare testspecimens using a cube mold and base plate conforming to therequirements of Test Method C109/C109M and a metal coverplate conforming in principle to the design shown in Fig. 1(Note 8). Bring the various parts of the apparatus to atemperature of 20 to 30 C 68 to 86 F, lightly coat

42、 thesurfaces that will be in contact with the sulfur mortar withmineral oil, and assemble near the melting pot. Bring thetemperature of the molten-sulfur mortar in the pot within arange of 129 to 143 C 265 to 290 F, stir thoroughly, andbegin casting cubes. Using a ladle, or other suitable pouringdev

43、ice, quickly fill each of the three compartments until themolten material 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 9). After solidification iscompl

44、ete, remove the cubes from the mold without breakingoff the knob formed 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 des

45、ired age, but not less than 2 h, test cubes incompression following the procedure described in Test MethodC109/C109M, and calculate the compressive strength.NOTE 8If desired, a 3-mm 1/8 in. thick plate of thermosettingplastic (such as phenol formaldehyde), provided with three appropriatelyspaced fil

46、ling holes, may be inserted between the cover plate and the moldto slow the rate of cooling of test specimens.NOTE 9The 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 th

47、erefore 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 10) to cap freshly molded cylinders. Makec

48、aps 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 slightlybelow the plane of the rim of the mold. Remove free wa

49、ter andlaitance from the top of the specimen immediately beforecapping. Form the cap by placing a conical mound of paste onthe specimen and then gently pressing a freshly oiled cappingplate on the conical mound until the plate contacts the rim ofthe mold. A very slight twisting motion may be required toextrude excess paste and minimize air voids in the paste. Thecapping plate must not rock during this operation. Carefullycover the capping plate and mold with a double layer of dam