ASTM C617 C617M-2015 Standard Practice for Capping Cylindrical Concrete Specimens《压顶圆柱型混凝土试样的标准实践规程》.pdf

1、Designation: C617/C617M 15Standard 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 U.S. Department of Defense.1. Scope*1.1 This practice covers apparatus, materials, and proce

3、-dures 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 syste

4、m may 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 therespo

5、nsibility 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 Compress

6、ive Strength 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 inDet

7、ermination 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,hard

8、ened 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 an

9、d high-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 tha

10、t the 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

11、of newlyfinished 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 plat

12、es that 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 al

13、ignment devices, such asguide 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 by1This practice is under the jurisdiction of ASTM Committee C09 on Concreteand ConcreteAggregat

14、es and is the direct responsibility of Subcommittee C09.61 onTesting for Strength.Current edition approved April 1, 2015. Published May 2015. Originallyapproved in 1968. Last previous edition approved in 2012 as C617/C617M 12.DOI: 10.1520/C0617_C0617M-15.2For referenced ASTM standards, visit the AST

15、M 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, NY 10036

16、, http:/www.ansi.org.*A Summary of Changes section appears at the end of this standardCopyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States1more than 0.5 (See Note 2). The same requirement isapplicable to the relationship between the axis o

17、f the alignmentdevice and the surface of a capping plate when guide bars areused. In addition, the location of each bar with respect to itsplate must be such that no cap will be off-centered on a testspecimen by more than 2 mm 116 in.NOTE 2A deviation from perpendicularity of 0.5 is equal to a slope

18、of approximately 1 mm in 100 mm 18 in. in 12 in.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 WarningMelting pots equipped wit

19、h peripheralheating will ensure against accidents during reheating ofcooled 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 bo

20、ttom 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 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

21、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 207C405F and the mixture can ignite due to overheating. If themixture starts to burn, covering will snuff out the flame.Recharge the pot with f

22、resh material after the flame has beenextinguished.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 paste and othermaterials except neat cement paste are to be used to t

23、estconcrete with a strength greater than 50 MPa 7000 psi andtheir compressive 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 %

24、 of the average strengthof 15 companion cylinders capped with neat cement 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

25、.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 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

26、cement paste cubes, if used. Cappingmaterials conforming to these requirements 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

27、 is a change in the formulation or the rawmaterials. The user of the material must retain a copy of thequalification results, and the dates of manufacture of materialqualified and of the material currently being used.NOTE 3Table 2 is an example of a report of test results to qualify acapping materia

28、l.5.1.3 The compressive strength of capping materials shallbe determined 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 e

29、ntrapped 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 capping material shall be deter-mined on receipt of a new lot and at intervals not exceedin

30、gthree 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 determinations conform to specificationrequirements.5.2 Neat Hydraulic Cement Paste:5.2.1

31、 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 50 mm2 in. cubes.NOTE 4The cements used generally conform to Specification C150Types I, II or III; however, Specification C595 blended

32、 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 toproduce the required strength, generally 2 to 4 h before thepaste is to be used (Note

33、 5). Remix as necessary to maintainacceptable consistency (Note 6). Some 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

34、mass for Type III cements.NOTE 5Freshly mixed pastes tend to bleed, shrink, and makeunacceptable caps. The 2 to 4 h period is generally appropriate forportland cements.TABLE 1 Compressive Strength and Maximum Thickness ofCapping MaterialsCylinderCompressiveStrength MPapsiMinimum Strength of CappingM

35、aterialMaximumAverageThicknessof CapMaximumThicknessAny Partof Cap3.5 to50 MPa500 to7000 psi35 MPa 5000 psi or cylinderstrength whichever isgreater6mm14 in.8mm516 in.greater than50 MPa7000 psiCompressive strength not lessthancylinder strength, except asprovided in 5.1.13mm18 in.5mm316 in.C617/C617M

36、152NOTE 6The 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 gypsum ceme

37、nt paste subsequent to the manufactureof the cement. (Note 7) Qualification tests shall be made todetermine 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 streng

38、th must be determined. (Note 8)NOTE 7Low-strength molding plaster, plaster of paris, or mixtures ofplaster of paris and portland cement are unsuitable for capping.NOTE 8The water-gypsum cement ratio should be between 0.26 and0.30. Use of low water-cement ratios and vigorous mixing will usuallypermit

39、 development of 35 MPa 5000 psi 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-cement ratio and use it promptly since it sets rapidly.5.4 Sulfur Mortar:5.4.1 Proprietary or laboratory prepared

40、sulfur mortars arepermitted if allowed to harden a minimum of 2 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 s

41、uitable asspecified in 5.1.1.5.4.2 Determination of Compressive StrengthPrepare testspecimens using a cube mold and base plate conforming to therequirements of Test Method C109/C109M and a metal coverplate conforming in principle to the design shown in Fig. 1(Note 9). Bring the various parts of the

42、apparatus to atemperature of 20 to 30C 68 to 86F, lightly coat 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 130 to 145C 265 to 290F, stir thoroughly, andbegi

43、n casting cubes. Using a ladle, or other suitable pouringdevice, 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

44、 with molten material (Note 10). After solidification iscomplete, 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 M

45、ethod C109/C109M. After storage at room temperatureto the desired age, but not less than 2 h, test cubes incompression following the procedure described in Test MethodC109/C109M, and calculate the compressive strength.NOTE 9If desired, a 3-mm 18 in. thick plate of thermosetting plastic(such as pheno

46、l formaldehyde), provided with three appropriately spacedfilling holes, may be inserted between the cover plate and the mold to slowthe rate of cooling of test specimens.NOTE 10The second filling helps to prevent the formation of a largevoid or shrinkage pipe in the body of a cube. However, such def

47、ects 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 portlandc

48、ement pastes (Note 11) 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 s

49、lightlybelow the plane of the rim of the mold. Remove free water 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. Ca