ASTM C426-06
(Test Method)Standard Test Method for Linear Drying Shrinkage of Concrete Masonry Units
Standard Test Method for Linear Drying Shrinkage of Concrete Masonry Units
SCOPE
1.1 This test method covers a routine standardized procedure for determining the linear drying shrinkage of concrete masonry units or related concrete units under specified accelerated drying conditions.
1.2 The values stated in inch-pound units are to be regarded as the standard. The values given in parentheses are for information only.
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.
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Standards Content (Sample)
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Designation:C426–06
Standard Test Method for
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Linear Drying Shrinkage of Concrete Masonry Units
This standard is issued under the fixed designation C426; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision.Anumber 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* 4. Significance and Use
1.1 This test method covers a routine standardized proce- 4.1 This test method is intended to evaluate the drying
dure for determining the linear drying shrinkage of concrete shrinkage characteristics of a given unit. The results of this
masonry units or related concrete units under specified accel- laboratory method are considered in determining concrete
erated drying conditions. masonry crack control provisions.
1.2 The values stated in inch-pound units are to be regarded
NOTE 1—The testing laboratory performing this test method should be
as the standard. The values given in parentheses are for
evaluated in accordance with Practice C1093.
information only.
5. Apparatus
1.3 This standard does not purport to address all of the
safety concerns, if any, associated with its use. It is the
5.1 Strain Gauge—The instruments for measuring linear
responsibility of the user of this standard to establish appro-
drying shrinkage shall be so designed as to permit or provide
priate safety and health practices and determine the applica-
the conditions described in 5.1.1 through 5.1.5.
bility of regulatory limitations prior to use.
NOTE 2—Strain gauges may be obtained with various gauge lengths.
The 10-in. (254-mm) gauge length is recommended for use with regular
2. Referenced Documents
concrete masonry units, however, particular sizes of products may require
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2.1 ASTM Standards:
other lengths. The length of the shrinkage specimen shall not be less than
C490 Practice for Use of Apparatus for the Determination
required for a minimum gauge length (distance between gauge plugs) of
of Length Change of Hardened Cement Paste, Mortar, and 6 in. (152.4 mm).
Concrete
5.1.1 A means of positive contact with the specimen that
C1093 Practice for Accreditation of Testing Agencies for
will ensure reproducible measurements of length.
Unit Masonry
5.1.2 Means for precise measurement, consisting of a dial
2.2 ANSI Standard:
micrometer or other measuring device graduated to read in
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B94.11M—1993 Twist Drills
0.0001-in. (0.0025-mm) units, and accurate within 0.0001 in.
(0.0025 mm) in any 0.0010-in. (0.025-mm) range, and within
3. Terminology
0.0002 in. (0.0050-mm) in any 0.0100-in. (0.254-mm) range.
3.1 Definition:
5.1.3 Sufficient range to allow for small variations in the
3.1.1 linear drying shrinkage—in this test method, the
gauge lengths.
change in linear dimension of the test specimen due to drying
NOTE 3—If the shrinkage reference points are set carefully to position,
from a saturated condition to an equilibrium weight and length
a dial micrometer with a travel of 0.2 or 0.3 in. (5.1 or 7.6 mm) provides
under specified accelerated drying conditions.
ample range in the instrument.
5.1.4 Means for checking the strain gauge at regular inter-
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vals against a standard reference bar. The standard reference
This test method is under the jurisdiction of ASTM Committee C15 on
Manufactured Masonry Units and is the direct responsibility of Subcommittee
bar shall be protected from air currents by placing it inside a
C15.03 on Concrete Masonry Units and Related Units.
wooden box which should be closed except when the strain
Current edition approved Dec. 15, 2006. Published January 2007. Originally
gauge is being checked against it.
approved in 1958. Last previous edition approved in 2005 as C426–05.
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For referenced ASTM standards, visit the ASTM website, www.astm.org, or
NOTE 4—A standard reference bar shall be furnished by the manufac-
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
turer of the instrument.Astandard bar of ordinary steel is satisfactory, but
Standards volume information, refer to the standard’s Document Summary page on
corrections must be made for variations in its length due to temperature
the ASTM website.
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changes. When a more nearly constant datum is desired, Invar is
Available fromAmerican National Standards Institute (ANSI), 25 W. 43rd St.,
4th Floor, New York, NY 10036, http://www.ansi.org. preferable because of its low coefficient of thermal expansion.
*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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