ASTM C1231/C1231M-07
(Practice)Standard Practice for Use of Unbonded Caps in Determination of Compressive Strength of Hardened Concrete Cylinders
Standard Practice for Use of Unbonded Caps in Determination of Compressive Strength of Hardened Concrete Cylinders
SIGNIFICANCE AND USE
This practice provides for using an unbonded capping system in testing hardened concrete cylinders made in accordance with Practices C 31/C 31M or C 192/C 192M in lieu of the capping systems described in Practice C 617.
The elastomeric pads deform in initial loading to conform to the contour of the ends of the cylinder and are restrained from excessive lateral spreading by plates and metal rings to provide a uniform distribution of load from the bearing blocks of the testing machine to the ends of the concrete or mortar cylinders.
SCOPE
1.1 This practice covers requirements for a capping system using unbonded caps for testing concrete cylinders molded in accordance with Practice C 31/C 31M or C 192/C 192M. Unbonded neoprene caps of a defined hardness are permitted to be used for testing for a specified maximum number of reuses without qualification testing up to a certain concrete compressive strength level. Above that strength, level neoprene caps will require qualification testing. Qualification testing is required for all elastomeric materials other than neoprene regardless of the concrete strength.
1.2 Unbonded caps are not to be used for acceptance testing of concrete with compressive strength below 1500 psi [10 MPa] or above 12 000 psi [85 MPa].
1.3 The values stated in either inch-pound or SI units shall be regarded as standard. SI units are shown in brackets. That values stated in each system may not be exact equivalents; therefore, each system must be used independently of the other, without combining the values in any way.
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. (Warning-Concrete cylinders tested with unbonded caps rupture more violently than comparable cylinders tested with bonded caps. The safety precautions given in the Manual of Aggregate and Concrete Testing are recommended.)
General Information
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Standards Content (Sample)
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Designation:C1231/C1231M–07
Standard Practice for
Use of Unbonded Caps in Determination of Compressive
1
Strength of Hardened Concrete Cylinders
This standard is issued under the fixed designation C1231/C1231M; 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.
1. Scope* C31/C31M Practice for Making and Curing Concrete Test
Specimens in the Field
1.1 This practice covers requirements for a capping system
C39/C39M Test Method for Compressive Strength of Cy-
using unbonded caps for testing concrete cylinders molded in
lindrical Concrete Specimens
accordance with Practice C31/C31M or C192/C192M. Un-
C192/C192M Practice for Making and Curing Concrete
bonded neoprene caps of a defined hardness are permitted to
Test Specimens in the Laboratory
be used for testing for a specified maximum number of reuses
C617 Practice for Capping Cylindrical Concrete Speci-
without qualification testing up to a certain concrete compres-
mens
sive strength level. Above that strength, level neoprene caps
D2000 Classification System for Rubber Products inAuto-
will require qualification testing. Qualification testing is re-
motive Applications
quired for all elastomeric materials other than neoprene
regardless of the concrete strength.
3. Terminology
1.2 Unbondedcapsarenottobeusedforacceptancetesting
3.1 Definitions of Terms Specific to This Standard:
of concrete with compressive strength below 1500 psi [10
3.1.1 pad, n—an unbonded elastomeric pad.
MPa] or above 12 000 psi [85 MPa].
3.1.2 unbonded cap, n—a metal retainer and an elastomeric
1.3 The values stated in either inch-pound or SI units shall
pad.
be regarded as standard. SI units are shown in brackets. That
values stated in each system may not be exact equivalents;
4. Significance and Use
therefore,eachsystemmustbeusedindependentlyoftheother,
4.1 This practice provides for using an unbonded capping
without combining the values in any way.
system in testing hardened concrete cylinders made in accor-
1.4 This standard does not purport to address all of the
dance with Practices C31/C31M or C192/C192M in lieu of
safety concerns, if any, associated with its use. It is the
the capping systems described in Practice C617.
responsibility of the user of this standard to establish appro-
4.2 The elastomeric pads deform in initial loading to con-
priate safety and health practices and determine the applica-
form to the contour of the ends of the cylinder and are
bility of regulatory limitations prior to use. (Warning—
restrained from excessive lateral spreading by plates and metal
Concrete cylinders tested with unbonded caps rupture more
ringstoprovideauniformdistributionofloadfromthebearing
violently than comparable cylinders tested with bonded caps.
blocks of the testing machine to the ends of the concrete or
The safety precautions given in the Manual of Aggregate and
2 mortar cylinders.
Concrete Testing are recommended. )
5. Materials and Apparatus
2. Referenced Documents
3 5.1 Materials and equipment necessary to produce ends of
2.1 ASTM Standards:
the reference cylinders that conform to planeness requirements
of Test Method C39/C39M and the requirements of Practice
1
C617. This may include grinding equipment or capping
This practice is under the jurisdiction of ASTM Committee C09 on Concrete
andConcreteAggregatesandisthedirectresponsibilityofSubcommitteeC09.61on
materials and equipment to produce neat cement paste, high
Testing for Strength.
strength gypsum plaster, or sulfur mortar caps.
Current edition approved July 15, 2007. Published August 2007. Originally
5.2 Elastomeric Pads:
approved in 1993. Last previous edition approved in 2006 as C1231/C1231M–06.
1 1
2
5.2.1 Pads shall be ⁄2 6 ⁄16 in. [136 2 mm] thick and the
Section on Safety Precautions, Manual of Aggregate and Concrete Testing,
1
Annual Book of ASTM Standards, Vol. 04.02.
diametershallnotbemorethan ⁄16in.[2mm]smallerthanthe
3
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
inside diameter of the retaining ring.
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
5.2.2 Pads shall be made from polychloroprene (neoprene)
Standards volume information, refer to the standard’s Document Summary page on
the ASTM website. meeting the requirements of Classification D2000 as follows:
*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.
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C1231/C1231M–07
[5 mm]. If cylinder ends do not meet this tolera
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