1、Designation: C617/C617M 11 C617/C617M 12Standard 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 re
2、vision. A number 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,
3、and procedures for capping freshly molded concrete cylinders with neat cementand hardened cylinders and drilled concrete cores with high-strength gypsum paste or sulfur mortar.1.2 The values stated in either SI units or inch-pound units are to be regarded separately as standard. The values stated in
4、 eachsystem may not be exact equivalents; therefore, each system shall be used independently of the other. Combining values from thetwo systems may result in non-conformance with the standard.1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. I
5、t is the responsibilityof the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatorylimitations prior to use. For specific precaution statements see 4.3.1 and 6.2.4.1.2. Referenced Documents2.1 ASTM Standards:2C109/C109M Test Method f
6、or Compressive Strength of Hydraulic Cement Mortars (Using 2-in. or 50-mm Cube Specimens)C150 Specification for Portland CementC472 Test Methods for Physical Testing of Gypsum, Gypsum Plasters and Gypsum ConcreteC595 Specification for Blended Hydraulic CementsC1231/C1231M Practice for Use of Unbonde
7、d Caps in Determination of Compressive Strength of Hardened Concrete 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 plane surfaces on the ends of freshly molded concrete
8、cylinders, hardenedcylinders, or drilled concrete cores when the end surfaces do not conform with the planeness and perpendicularity requirementsof applicable standards. Practice C1231/C1231M describes alternative procedures using unbonded caps or pad caps.4. Capping Equipment4.1 Capping PlatesNeat
9、cement caps and high-strength gypsum-paste caps shall be formed against a glass plate at least 6 mm14 in. thick, a machined metal plate at least 11 mm 0.45 in. thick, or a polished plate of granite or diabase at least 75 mm 3in. thick. Sulfur mortar caps shall be formed against similar metal or ston
10、e plates except that the recessed area which receivesmolten sulfur shall not be deeper than 12 mm 12 in. In all cases, plates shall be at least 25 mm 1 in. greater in diameter thanthe test specimen and the working surfaces shall not depart from a plane by more than 0.05 mm 0.002 in. in 150 mm 6 in.
11、Thesurface roughness of newly finished metal plates shall not exceed that set forth in Table 4 of American National Standard B46.1,or 3.2 m 125 in. for any type of surface and direction of lay. The surface, when new, shall be free of gouges, grooves, or1 This practice is under the jurisdiction of AS
12、TM Committee C09 on Concrete and Concrete Aggregatesand is the direct responsibility of Subcommittee C09.61 on Testingfor Strength.Current edition approved Aug. 1, 2011Nov. 15, 2012. Published September 2011December 2012. Originally approved in 1968. Last previous edition approved in 20102011as C617
13、10.11. DOI: 10.1520/C0617_C0617M-11.10.1520/C0617_C0617M-12.2 For referenced ASTM standards, visit the ASTM website, www.astm.org, or contact ASTM Customer Service at serviceastm.org. For Annual Book of ASTM Standardsvolume information, refer to the standards Document Summary page on the ASTM websit
14、e.3 Available from American National Standards Institute (ANSI), 25 W. 43rd St., 4th Floor, New York, NY 10036, http:/www.ansi.org.This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication of what changes have been made to the previous version.
15、Becauseit may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current versionof the standard as published by ASTM is to be considered the official document.*A Summary of Changes section a
16、ppears at the end of this standardCopyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States1indentations beyond those caused by the finishing operation. Metal plates that have been in use shall be free of gouges, grooves,and indentations greate
17、r than 0.25 mm 0.010 in. deep or greater than 30 mm2 0.05 in.2 in surface area.NOTE 1A Rockwell hardness of 48 HRC is suggested for capping plates of devices used to form sulfur mortar caps.4.2 Alignment DevicesSuitable alignment devices, such as guide bars or bulls-eye levels, shall be used in conj
18、unction withcapping plates to ensure that no single cap will depart from perpendicularity to the axis of a cylindrical specimen by more than0.5 (approximately(See Note 2equivalent to 3 mm in 300 mm ). 18 in. in 12 in.). The same requirement is applicable to therelationship between the axis of the al
19、ignment device and the surface of a capping plate when guide bars are used. In addition, thelocation of each bar with respect to its plate must be such that no cap will be off-centered on a test specimen by more than 2 mm116 in.NOTE 2A deviation from perpendicularity of 0.5 is equal to a slope of ap
20、proximately 1 mm in 100 mm 18 in. in 12 in.4.3 Melting Pots for Sulfur MortarsPots used for melting sulfur mortars shall be equipped with automatic temperaturecontrols and shall be made of metal or lined with a material that is nonreactive with molten sulfur.4.3.1 WarningMelting pots equipped with p
21、eripheral heating will ensure against accidents during reheating of cooled sulfurmixture that have a crusted-over surface. When using melting pots not so equipped, a build-up of pressure under the hardenedsurface crust on subsequent reheating may be avoided by use of a metal rod that contacts the bo
22、ttom of the pot and projects abovethe surface of the fluid sulfur mix as it cools. The rod should be of sufficient size to conduct enough heat to the top on reheatingto melt a ring around the rod first and thus avoid the development of pressure. A large metal ladle can be substituted for the rod.4.3
23、.1.1 Use sulfur melting pots in a hood to exhaust the fumes to outdoors. Heating over an open flame is dangerous becausethe flash point of sulfur is approximately 207 C 405 F and the mixture can ignite due to overheating. If the mixture starts toburn, covering will snuff out the flame. Recharge the
24、pot with fresh material after the flame has been extinguished.5. Capping Materials5.1 The strength of the capping material and the thickness of the caps shall conform to the requirements of Table 1.5.1.1 If sulfur mortar, high strength gypsum paste and other materials except neat cement paste are to
25、 be used to test concretewith a strength greater than 50 MPa 7000 psi and their compressive strength is less than the cylinder compressive strength, themanufacturer or the user of the material must provide documentation:5.1.1.1 That the average strength of 15 cylinders capped with the material is no
26、t less than 98 % of the average strength of 15companion cylinders capped with neat cement paste or 15 cylinders ground plane to within 0.05 mm 0.002 in.5.1.1.2 That the standard deviation of the strengths of the capped cylinders is not greater than 1.57 times that of the standarddeviation of the ref
27、erence cylinders.5.1.1.3 That the cap thickness requirements were met in the qualification tests, and5.1.1.4 Of the hardening time of the caps used in the qualification tests.5.1.2 Additionally, the qualification test report must include the compressive strength of 50 mm 2 in. cubes of the materialq
28、ualified and of neat cement paste cubes, if used. Capping materials conforming to these requirements is permitted to be used forcylinders with strengths up to 20 % greater than the concrete tested in these qualification tests. The manufacturer must requalifylots of material manufactured on an annual
29、 basis or whenever there is a change in the formulation or the raw materials. The userof the material must retain a copy of the qualification results, and the dates of manufacture of material qualified and of the materialcurrently being used.NOTE 3Table 2 is an example of a report of test results to
30、 qualify a capping material.5.1.3 The compressive strength of capping materials shall be determined by testing 50 mm 2 in. cubes following the proceduredescribed in Test Method C109/C109M. Except for sulfur mortars, molding procedures shall be as in Test Method C109/C109Munless other procedures are
31、required to eliminate large entrapped air voids. See Test Methods C472 for alternative compactionprocedures. Cure cubes in the same environment for the same length of time as the material used to cap specimens.TABLE 1 Compressive Strength and Maximum Thickness ofCapping MaterialsCylinderCompressiveS
32、trength MPapsiMinimum Strength of CappingMaterialMaximumAverageThicknessof CapMaximumThicknessAny Partof Cap3.5 to50 MPa500 to7000 psi35 MPa 5000 psi or cylinderstrength whichever isgreater6 mm14 in.8 mm516 in.greater than50 MPa7000 psiCompressive strength not lessthancylinder strength, except aspro
33、vided in 5.1.13 mm18 in.5 mm316 in.C617/C617M 1225.1.4 The strength of the capping material shall be determined on receipt of a new lot and at intervals not exceeding threemonths. If a given lot of the capping material fails to conform to the strength requirements, it shall not be used, and strength
34、 testsof the replacement material shall be made weekly until four consecutive determinations conform to specification requirements.5.2 Neat Hydraulic Cement Paste:5.2.1 Make qualification tests of the neat hydraulic cement paste prior to use for capping to establish the effects of water-cementratio
35、and age on compressive strength of 50 mm 2 in. cubes.NOTE 4The cements used generally conform to Specification C150 Types I, II or III; however, Specification C595 blended cements, calciumaluminate or other hydraulic cements producing acceptable strength may be used.5.2.2 Mix the neat cement paste t
36、o the desired consistency at a water-cement ratio equal to or less than that required to producethe required strength, generally 2 to 4 h before the paste is to be used (Note 45). Remix as necessary to maintain acceptableconsistency (Note 56). Some retempering of the paste is acceptable if the requi
37、red water-cement ratio is not exceeded. Optimumconsistency is generally produced at water-cement ratios of 0.32 to 0.36 by mass for Type I and Type II cements and 0.35 to 0.39by mass for Type III cements.NOTE 5Freshly mixed pastes tend to bleed, shrink, and make unacceptable caps. The 2 to 4 h perio
38、d is generally appropriate for portland cements.NOTE 6The required consistency of the paste is determined by the appearance of the cap when it is stripped. Fluid paste results in streaks in the cap.Stiff paste results in thick caps.5.3 High-Strength Gypsum Cement Paste:5.3.1 No fillers or extenders
39、may be added to neat high-strength gypsum cement paste subsequent to the manufacture of thecement. (Note 67) Qualification tests shall be made to determine the effects of water-cement ratio and age on compressive strengthof 50 mm 2 in. cubes. Retarders may be used to extend working time, but their e
40、ffects on required water-cement ratio and strengthmust be determined. (Note 78)NOTE 7Low-strength molding plaster, plaster of paris, or mixtures of plaster of paris and portland cement are unsuitable for capping.NOTE 8The water-gypsum cement ratio should be between 0.26 and 0.30. Use of low water-ce
41、ment ratios and vigorous mixing will usually permitdevelopment of 35 MPa 5000 psi at ages of 1 or 2 h. Higher water-gypsum cement ratios extend working time, but reduce strength.5.3.2 Mix the neat gypsum cement paste at the desired water-cement ratio and use it promptly since it sets rapidly.5.4 Sul
42、fur Mortar:5.4.1 Proprietary or laboratory prepared sulfur mortars are permitted if allowed to harden a minimum of 2 h before testingconcrete with strength less than 35 MPa 5000 psi. For concrete strengths of 35 MPa 5000 psi or greater, sulfur mortar caps mustbe allowed to harden at least 16 h befor
43、e testing, unless a shorter time has been shown to be suitable as specified in 5.1.1.5.4.2 Determination of Compressive StrengthPrepare test specimens using a cube mold and base plate conforming to therequirements of Test Method C109/C109M and a metal cover plate conforming in principle to the desig
44、n shown in Fig. 1 (Note89). Bring the various parts of the apparatus to a temperature of 20 to 30 C 68 to 86 F, lightly coat the surfaces that will bein contact with the sulfur mortar with mineral oil, and assemble near the melting pot. Bring the temperature of the molten-sulfurmortar in the pot wit
45、hin a range of 129 to 143 C 265 to 290 F, stir thoroughly, and begin casting cubes. Using a ladle, or othersuitable pouring device, quickly fill each of the three compartments until the molten material reaches the top of the filling hole.Allow sufficient time for maximum shrinkage, due to cooling, a
46、nd solidification to occur (approximately 15 min) and refill eachhole with molten material (Note 910). After solidification is complete, remove the cubes from the mold without breaking off theTABLE 2 Example of Report of Qualification of a Capping MaterialNOTE 1Manufacturer: Testing Supplies Co.Capp
47、ing Material: Super Strong AAA-Sulfur mortarLot: 12a45 Date Tested: 11/3/XXSigned by:_ (testing agency and responsible official)ItemCappingMaterial Control CylindersRatioCap/Control CriteriaPass/FailConcrete Cylinder Test DataType of capping material Sulfur GroundAverage Concrete Strength, psi 11 06
48、1 11 008 1.005 0.98 PassStandard Deviation, psi 376 250 1.504 #1.57 PassNumber of cylinders tested 15 15Cap age when cylinders tested 7 days naCapping Material Test DataAverage cap thickness, in. 0.11 naCompressive strength of 2 in. cubes, psi 12 195Cube age when tested. 7 daysMaximum concrete stren
49、gth qualified, psi 1.2 Av. Str = 13 273AA Nominally a specified strength of 11 000 psi and perhaps somewhat higher.C617/C617M 123knob formed by the filling hole in the cover plate. Remove oil, sharp edges, and fins from the cubes and check the planeness ofthe bearing surfaces in the manner described in Test Method C109/C109M. After storage at room temperature to the desired age,but not less than 2 h, test cubes in compression following the proc
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