ASTM C617-98
(Practice)Standard Practice for Capping Cylindrical Concrete Specimens
Standard Practice for Capping Cylindrical Concrete Specimens
SCOPE
1.1 This practice covers apparatus, materials, and procedures for capping freshly molded concrete cylinders with neat cement and hardened cylinders and drilled concrete cores with high-strength gypsum plaster or sulfur mortar.
1.2 The values stated in inch-pound units are to be regarded as the standard. The SI equivalents of inch-pound units may be approximate.
1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use. For specific precaution statements see 4.3 and 6.2.3.1.
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Standards Content (Sample)
NOTICE: This standard has either been superseded and replaced by a new version or withdrawn. Contact ASTM
International (www.astm.org) for the latest information.
Designation: C 617 – 98
Standard Practice for
Capping Cylindrical Concrete Specimens
This standard is issued under the fixed designation C 617; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript 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. Scope hardened cylinders, or drilled concrete cores when the end
surfaces do not conform with the planeness and perpendicu-
1.1 This practice covers apparatus, materials, and proce-
larity requirements of applicable standards. Practice C 1231
dures for capping freshly molded concrete cylinders with neat
describes alternative procedures using unbonded caps or pad
cement and hardened cylinders and drilled concrete cores with
caps.
high-strength gypsum plaster or sulfur mortar.
1.2 The values stated in inch-pound units are to be regarded
4. Capping Equipment
as the standard.The SI equivalents of inch-pound units may be
4.1 Capping Plates—Neat cement caps and high-strength
approximate.
gypsum-plaster caps shall be formed against a glass plate at
1.3 This standard does not purport to address all of the
least ⁄4 in. (6 mm) thick, a machined metal plate at least 0.45
safety concerns, if any, associated with its use. It is the
in. (11 mm) thick, or a polished plate of granite or diabase at
responsibility of the user of this standard to establish appro-
least 3 in. (76 mm) thick. Sulfur mortar caps shall be formed
priate safety and health practices and determine the applica-
against similar metal or stone plates except that the recessed
bility of regulatory limitations prior to use. For specific
area which receives molten sulfur shall not be deeper than
precaution statements see 4.3 and 6.2.3.1.
⁄2 in. (12 mm). In all cases, plates shall be at least 1 in. (25
2. Referenced Documents mm) greater in diameter than the test specimen and the
working surfaces shall not depart from a plane by more than
2.1 ASTM Standards:
0.002 in. (0.05 mm) in 6 in. (152 mm). The surface roughness
C 109/C 109M Test Method for Compressive Strength of
of newly finished metal plates shall not exceed that set forth in
Hydraulic Cement Mortars (Using 2-in. or 50-mm Cube
Table 4 ofAmerican National Standard B46.1, or 125 µin. (3.2
Specimens)
µm) for any type of surface and direction of lay. The surface,
C 150 Specification for Portland Cement
when new, shall be free of gouges, grooves, or indentations
C 472 Test Methods for Physical Testing of Gypsum, Gyp-
beyond those caused by the finishing operation. Metal plates
sum Plasters and Gypsum Concrete
that have been in use shall be free of gouges, grooves, and
C 595M Specification for Blended Hydraulic Cements
indentations greater than 0.010 in. (0.25 mm) deep or greater
C 1231 Practice for Use of Unbounded Caps in Determina-
2 2
than 0.05 in. (32 mm ) in surface area.
tion of Compressive Strength of Hardened Concrete Cyl-
inders
NOTE 1—A Rockwell hardness of 48 HRC is suggested for capping
2.2 ANSI Standard: plates of devices used to form sulfur mortar caps.
B46.1 Standard for Surface Texture (Surface, Roughness,
4.2 Alignment Devices—Suitable alignment devices, such
Waviness and Lay)
as guide bars or bull’s-eye levels, shall be used in conjunction
with capping plates to ensure that no single cap will depart
3. Significance and Use
from perpendicularity to the axis of a cylindrical specimen by
3.1 This practice describes procedures for providing plane
more than 0.5° (approximately equivalent to ⁄8 in. in 12 in.
surfaces on the ends of freshly molded concrete cylinders,
(3.2 mm in 305 mm)). The same requirement is applicable to
the relationship between the axis of the alignment device and
1 the surface of a capping plate when guide bars are used. In
This practice is under the jurisdiction of ASTM Committee C-9 on Concrete
addition, the location of each bar with respect to its plate must
andConcreteAggregatesandisthedirectresponsibilityofSubcommitteeC09.61on
Testing Concrete for Strength.
be such that no cap will be off-centered on a test specimen by
CurrenteditionapprovedAugust10,1998.PublishedDecember1998.Originally
more than ⁄16 in. (2 mm).
published as C 617 – 68. Last previous edition C 617 – 94.
Annual Book of ASTM Standards, Vol 04.01.
Annual Book of ASTM Standards, Vol 04.02.
Available fromAmerican Society of Mechanical Engineers, 345 E. 47th Street,
New York, NY 10017.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
NOTICE: This standard has either been superseded and replaced by a new version or withdrawn. Contact ASTM
International (www.astm.org) for the latest information.
C 617
4.3 Melting Pots for Sulfur Mortars—Pots used for melting conforming to these requirements is permitted to be used for
sulfur mortars shall be equipped with automatic temperature cylinders with strengths up to 20 percent greater than the
controlsandshallbemadeofmetalorlinedwithamaterialthat concrete tested in these qualification tests. The manufacturer
is nonreactive with molten sulfur. mustrequalifylotsofmaterialmanufacturedonanannualbasis
4.3.1 Caution: Meltingpotsequippedwithperipheralheat- or whenever there is a change in the formulation or the raw
ing will ensure against accidents during reheating of cooled materials. The user of the material must retain a copy of the
sulfur mixture that have a crusted-over surface. When using qualification results, and the dates of manufacture of material
melting pots not so equipped, a build-up of pressure under the qualified and of the material currently being used. See Table 2.
hardened surface crust on subsequent reheating may be 5.1.3 The compressive strength of capping materials shall
avoided by use of a metal rod that contacts the bottom of the be determined by testing 2 in. cubes following the procedure
pot and projects above the surface of the fluid sulfur mix as it described in Test Method C 109. Except for sulfur mortars,
cools. The rod should be of sufficient size to conduct enough molding procedures shall be as in Test Method C 109 unless
heat to the top on reheating to melt a ring around the rod first other procedures are required to eliminate large entrapped air
andthusavoidthedevelopmentofpressure.Alargemetalladle voids. See Test Methods C 472 for alternative compaction
can be substituted for the rod. procedures. Cure cubes in the same environment for the same
4.3.1.1 Use sulfur melting pots in a hood to exhaust the length of time as the material used to cap specimens.
fumes to outdoors. Heating over an open flame is dangerous 5.1.4 The strength of the capping material shall be deter-
because the flash point of sulfur is approximately 440°F mined on receipt of a new lot and at intervals not exceeding
(227°C) and the mixture can ignite due to overheating. Should three months. If a given lot of the capping material fails to
the mixture start to burn, covering will snuff out the flame.The conform to the strength requirements, it shall not be used, and
pot should be recharged with fresh material after the flame has strengthtestsofthereplacementmaterialshallbemadeweekly
been extinguished. until four consecutive determinations conform to specification
requirements.
5. Capping Materials
5.2 Neat Hydraulic Cement Paste:
5.1 Thestrengthofthecappingmaterialandthethicknessof 5.2.1 Make qualification tests of the neat hydraulic cement
paste prior to use for capping to establish the effects of
the caps shall conform to the requirements of Table 1.
5.1.1 If sulfur mortar, high strength gypsum plaster and water-cementratioandageoncompressivestrengthof2in.(50
mm) cubes.
other materials except neat cement paste are to be used to test
concrete with a strength greater than 7000 psi (50 MPa), the
NOTE 2—The cements used generally conform to Specification C 150
manufacturer or the user of the material must provide docu-
Types I, II or III; however, Specification C 595 blended cements, calcium
mentation:
aluminate or other hydraulic cements producing acceptable strength may
5.1.1.1 That the average strength of 15 cylinders capped be used.
with the material is not less than 98 percent of the average
5.2.2 Mixtheneatcementpastetothedesiredconsistencyat
strength of 15 companion cylinders capped with neat cement
a water-cement ratio equal to or less than that required to
paste or 15 cylinders ground plane to within 0.002 in. (0.05
produce the required strength, generally 2 to 4 h before the
mm).
paste is to be used (Note 3). Remix as necessary to maintain
5.1.1.2 That the standard deviation of the strengths of the
acceptable consistency (Note 4). Some retempering of the
capped cylinders is not greater than 1.57 times that of the
paste is acceptable if the required water-cement ratio is not
standard deviation of the reference cylinders.
exceeded. Optimum consistency is generally produced at
5.1.1.3 That the cap thickness requirements were met in the
water-cement ratios of 0.32 to 0.36 by mass for Type I and
qualification tests, and
Type II cements and 0.35 to 0.39 by mass forType III cements.
5.1.1.4 Of the hardening time of the caps used in the
NOTE 3—Freshly mixed pastes tend to bleed, shrink, and make unac-
qualification tests.
ceptable caps. The 2 to 4 h period is generally appropriate for portland
5.1.2 Additionally, the qualification test report must include
cements.
thecompressivestrengthof2in.cubesofthematerialqualified
NOTE 4—The required consistency of the paste is determined by the
and of neat cement paste cubes, if used. Capping materials
appearance of the cap when it is stripped. Fluid paste results in streaks in
the cap. Stiff paste results in thick caps.
TABLE 1 Compressive Strength and Maximum Thickness of
5.3 High-Strength Gypsum Cement Paste:
Capping Materials
5.3.1 No fillers or extenders may be added to neat high-
Cylinder Maximum Maximum
strength gypsum cement paste subsequent to the manufacture
Compressive Average Thickness
of the cement. (Note 5) Qualification tests shall be made to
Strength psi Minimum Strength of Capping Thickness Any Part
(MPa) Material of Cap of Cap
determine the effects of water-cement ratio and age on com-
1 5
500 to 7000 5000 psi (35 MPa) or cylinder ⁄4 in. ⁄16 in. pressive strength of 2 in. (50 mm) cubes. Retarders may be
psi (3.5 to strength whichever is greater (6 mm) (8 mm)
used to extend working time, but their effects on required
50 MPa)
water-cement ratio and strength must be determined. (Note 6)
1 3
greater than Compressive strength not less ⁄8 in. ⁄16 in.
7000 psi than (3 mm) (5 mm)
NOTE 5—Low-strength molding plaster, plaster of paris, or mixtures of
(50 MPa) cylinder strength, except as
plaster of paris and portland cement are unsuitable for capping.
provided in 5.1.1
NOTE 6—The water-gypsum cement ratio should be between 0.26 and
NOTICE: This standard has either been superseded and replaced by a new version or withdrawn. Contact ASTM
International (www.astm.org) for the latest information.
C 617
TABLE 2 Sample Report of Qualification of a Capping Material
NOTE—Manufacturer: Testing Supplies Co.
Capping Material: Super Strong AAA-Sulfor mortar
Lot: 12a45 Date Tested: 11/3/98
Signed by:______________________________ (testing agency and responsible official)
Capping
Item Material Control Cylinders Ratio Criteria Pass/Fail
Concrete Cylinder Test Data
Type of capping material Sulfur Ground
Average Concrete Strength, psi [MPa] 11 061 (76.2) 11 008 (75.9) 1.005 >0.98 Xc Pass
Standard Deviation, psi [MPa] 376 (2.59) 250 (1.72) 1.504 #1.57 C Pass
Number of cylinders tested 15 15
Cap age when cylinders tested 7 days na
Capping Material Test Data
Average cap thickness, in. [mm] 0.11 (2.8) na
Compressive strength of 2 in. [50 mm] cubes, psi (MPa) 12 195 (91)
Cube age when tested. 7 days
A
Maximum concrete strength qualified, psi (MPa) 1.2 Av. Str = 13 273 (91.5)
A
Nominally a specified strength of 11 000 psi (75 MPa) and perhaps somewhat higher.
0.30. Use of low water-cement ratios and vigorous mixing will usually
5.4.2 Determination of Compressive Strength—Prepare test
permit development of 5000 psi (35 MPa) at ages of 1 or 2 h. Higher
specimens using a cube mold and base plate conforming to the
water-gypsum cement ratios extend working time, but reduce strength.
requirements of Test Method C 109 and a metal cover plate
5.3.2 Mix the neat gypsum cement paste at the desired
conforming in principle to the design shown in Fig. 1 (Note 7).
water-cement ratio and use it promptly since it sets rapidly.
Bring the various parts of the apparatus to a temperature of 68
5.4 Sulfur Mortar:
to 86°F (20 to 30°C), lightly coat the surfaces that will be in
5.4.1 Proprietary or laboratory prepared sulfur mortars are
contact with the sulfur mortar with mineral oil, and assemble
permitted if allowed to harden a minimum of 2 h before testing
near the melting pot. Bring the temperature of the molten-
concrete with strength less than 5000 psi (35 MPa). For
sulfur mortar in the pot within a range of 265 to 290°F (129 to
concrete strengths of 5000 psi or greater, sulfur mortar caps
143°C), stir thoroughly, and begin casting cubes. Using a ladle,
must be allowed to harden at least 16 h before testing, unless
or other suitable pouring device, quickly fill each of the three
a shorter time has been shown to be suitable as specified in
compartments until the molten material reaches the top of the
5.1.1.
FIG. 1 Sketch of Cover Plate for 2-in. (50-mm) Cube Mold
NOTICE: This standard has either been superseded and replaced by a new version or withdrawn. Contact ASTM
International (www.astm.org) for the latest information.
C 617
filling hole.Allow sufficient time for maximum shrinkage, due 6.2.2 End Condition—The distance of any point on an
to cooling, and solidification to occur (approximately 15 min) uncapped end from a plane that passes through the highest
and refill each hole with molten material (Note 8). After
point of the end surface and is perpendicular to the axis of the
solidification is complete, remove the cubes from the mold cylinder shall not exceed ⁄8 in. (3 mm) (Note 11). If the end
without breaking off the knob formed by the filling hole in the
exceeds this limit, the end of the cylinder shall be cut, lapped
cover plate. Remove oil, sharp edges, and fins from the cubes
or ground prior to capping.
and check the planeness of the bearing surfaces in the manner
NOTE 11—This provision is to control the difference between the
described in
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