ASTM C451-08
(Test Method)Standard Test Method for Early Stiffening of Hydraulic Cement (Paste Method)
Standard Test Method for Early Stiffening of Hydraulic Cement (Paste Method)
SIGNIFICANCE AND USE
The purpose of this test method is to determine the degree to which a cement paste develops early stiffening or to establish whether or not a cement complies with a specification limit on early stiffening.
When used for establishing compliance with a specification limit, the specification requirement is customarily stated in terms of the minimum allowable final penetration, in percent, calculated in accordance with the Calculation Section. When used for estimating the relative tendency of a cement to manifest early stiffening, additional information of value may be obtained if the remix procedure described in the Procedure Section is employed. Under some conditions, a judgment may be made by comparing the behavior in the initial test and in the remix procedure to differentiate a relatively less serious and less persistent tendency to early stiffening (false set) from one that is more persistent and, consequently, more serious (flash set).
Severe false setting in a cement may cause difficulty from a placing and handling standpoint, but it is not likely to cause difficulties where concrete is mixed for a longer time than usual, as usually occurs in transit mixing, or where it is remixed prior to placing or transporting, as occurs in concrete pumping operations. It is most likely to be noticeable where concrete is mixed for a short period of time in stationary mixers and transported to the forms in non-agitating equipment, such as on some paving jobs, and when concrete is made in an on-site batch plant.
Cements with severe false setting usually require slightly more water to produce the same consistency, which may be expected to result in slightly lower strengths and increased drying shrinkage.
Early stiffening resulting from false set is not likely to cause a cement to fail the applicable time of setting requirement.
Early stiffening resulting from flash set, depending on severity, can cause a cement to fail the applicable time of setting requirement.
SCOPE
1.1 This test method covers the determination of early stiffening in hydraulic-cement paste.
1.2 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.
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.
Warning—Fresh hydraulic-cementitious mixtures are caustic and may cause chemical burns to skin and tissue upon prolonged exposure. The use of gloves, protective clothing, and eye protection is recommended. Wash contact area with copious amounts of water after contact. Wash eyes for a minimum of 15 min. Avoid exposure of the body to clothing saturated with the liquid phase of the unhardened material. Remove contaminated clothing immediately after exposure.
1.4 The text of this standard references notes and footnotes which provide explanatory material. These notes and footnotes (excluding those in tables and figures) shall not be considered as requirements of the standard.
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Designation: C451 − 08
StandardTest Method for
1
Early Stiffening of Hydraulic Cement (Paste Method)
This standard is issued under the fixed designation C451; 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 (´) indicates an editorial change since the last revision or reapproval.
1. Scope* C670 Practice for Preparing Precision and Bias Statements
for Test Methods for Construction Materials
1.1 This test method covers the determination of early
C1005 Specification for Reference Masses and Devices for
stiffening in hydraulic-cement paste.
Determining Mass and Volume for Use in the Physical
1.2 The values stated in SI units are to be regarded as
Testing of Hydraulic Cements
standard. No other units of measurement are included in this
D1193 Specification for Reagent Water
standard.
3. Terminology
1.3 This standard does not purport to address all of the
safety concerns, if any, associated with its use. It is the
3.1 Definitions:
responsibility of the user of this standard to establish appro-
3.1.1 early stiffening, n—the early development of stiffness
priate safety and health practices and determine the applica-
in the working characteristics of a hydraulic-cement paste,
bility of regulatory limitations prior to use.
mortar, or concrete; varieties include false set and flash set.
Warning—Fresh hydraulic-cementitious mixtures are caustic
3.1.2 false set, n—the early development of stiffness in the
and may cause chemical burns to skin and tissue upon
working characteristics of a hydraulic-cement paste, mortar, or
prolonged exposure. The use of gloves, protective clothing, and
concrete without the evolution of much heat, which stiffness
eye protection is recommended. Wash contact area with copi-
can be dispelled and plasticity regained by further mixing
ous amounts of water after contact. Wash eyes for a minimum
without addition of water; also known as “grab set,” “prema-
of 15 min. Avoid exposure of the body to clothing saturated
ture stiffening,” “ hesitation set,” and “rubber set.”
with the liquid phase of the unhardened material. Remove
3.1.3 flash set, n—the early development of stiffness in the
contaminated clothing immediately after exposure.
working characteristics of a hydraulic-cement paste, mortar, or
1.4 The text of this standard references notes and footnotes
concrete, usually with the evolution of considerable heat,
which provide explanatory material. These notes and footnotes
which stiffness cannot be dispelled nor can the plasticity be
(excluding those in tables and figures) shall not be considered
regained by further mixing without addition of water; also
as requirements of the standard.
known as “quick set.”
2. Referenced Documents
3.1.4 Refer to Terminology C219 for definitions of other
2
terms.
2.1 ASTM Standards:
C150 Specification for Portland Cement
4. Summary of Test Method
C183 Practice for Sampling and the Amount of Testing of
4.1 A paste is prepared with the cement to be tested, using
Hydraulic Cement
sufficient water to give a required initial penetration as mea-
C187 Test Method for Amount of Water Required for Nor-
sured by the Vicat apparatus at a stipulated time after comple-
mal Consistency of Hydraulic Cement Paste
tion of mixing. A second penetration, termed the final
C219 Terminology Relating to Hydraulic Cement
penetration, is measured at a later stipulated time. The ratio of
C305 Practice for Mechanical Mixing of Hydraulic Cement
final penetration to initial penetration is calculated as a
Pastes and Mortars of Plastic Consistency
percentage.
5. Significance and Use
1
This test method is under the jurisdiction ofASTM Committee C01 on Cement
and is the direct responsibility of Subcommittee C01.30 on Time of Set.
5.1 The purpose of this test method is to determine the
Current edition approved June 1, 2008. Published June 2008. Originally
degree to which a cement paste develops early stiffening or to
approved in 1960. Last previous edition approved in 2007 as C451 – 07. DOI:
establish whether or not a cement complies with a specification
10.1520/C0451-08.
2
For referenced ASTM standards, visit the ASTM website, www.astm.org, or limit on early stiffening.
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
5.2 When used for establishing compliance with a specifi-
Standards volume information, refer to the standard’s Document Summary page on
the ASTM website. cation limit, the specification requirement is customarily stated
*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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This document is not anASTM standard and is intended only to provide the user of anASTM standard an indication of what changes have been made to the previous version. Because
it 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 version
of the standard as published by ASTM is to be considered the official document.
Designation:C451–07 Designation: C 451 – 08
Standard Test Method for
1
Early Stiffening of Hydraulic Cement (Paste Method)
This standard is issued under the fixed designation C 451; 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 (´) indicates an editorial change since the last revision or reapproval.
1. Scope*
1.1 This test method covers the determination of early stiffening in hydraulic-cement paste.
1.2The values stated in SI units are to be regarded as the standard. The values given in parentheses are for information only.
1.2 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.
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.
Warning—Fresh hydraulic-cementitious mixtures are caustic and may cause chemical burns to skin and tissue upon prolonged
exposure. The use of gloves, protective clothing, and eye protection is recommended. Wash contact area with copious amounts of
water after contact. Wash eyes for a minimum of 15 min. Avoid exposure of the body to clothing saturated with the liquid phase
of the unhardened material. Remove contaminated clothing immediately after exposure.
1.4 The text of this standard references notes and footnotes which provide explanatory material. These notes and footnotes
(excluding those in tables and figures) shall not be considered as requirements of the standard.
2. Referenced Documents
2
2.1 ASTM Standards:
C 150 Specification for Portland Cement
C 183 Practice for Sampling and the Amount of Testing of Hydraulic Cement
C 187 Test Method for Normal Consistency of Hydraulic Cement
C 219 Terminology Relating to Hydraulic Cement
C 305 Practice for Mechanical Mixing of Hydraulic Cement Pastes and Mortars of Plastic Consistency
C 670 Practice for Preparing Precision and Bias Statements for Test Methods for Construction Materials
C 1005 Specification for Reference Masses and Devices for Determining Mass and Volume for Use in the Physical Testing of
Hydraulic Cements
D 1193 Specification for Reagent Water
3. Terminology
3.1 Definitions:
3.1.1 early stiffening, n—the early development of stiffness in the working characteristics of a hydraulic-cement paste, mortar,
or concrete; varieties include false set and flash set.
3.1.2 false set, n—the early development of stiffness in the working characteristics of a hydraulic-cement paste, mortar, or
concrete without the evolution of much heat, which stiffness can be dispelled and plasticity regained by further mixing without
addition of water; also known as “grab set,” “premature stiffening,” “ hesitation set,” and “rubber set.”
3.1.3 flash set, n—the early development of stiffness in the working characteristics of a hydraulic-cement paste, mortar, or
concrete, usually with the evolution of considerable heat, which stiffness cannot be dispelled nor can the plasticity be regained by
further mixing without addition of water; also known as “quick set.”
3.1.4 Refer to Terminology C 219 for definitions of other terms.
4. Summary of Test Method
4.1 A paste is prepared with the cement to be tested, using sufficient water to give a required initial penetration as measured
by the Vicat apparatus at a stipulated time after completion of mixing. A second penetration, termed the final penetration, is
1
This test method is under the jurisdiction of ASTM Committee C01 on Cement and is the direct responsibility of Subcommittee C01.30 on Time of Set.
Current edition approved July 15, 2007. Published August 2007. Originally approved in 1960. Last previous edition approved in 2005 as C451–05.
Current edition approved June 1, 2008. Published June 2008. Originally approved in 1960. Last previous edition approved in 2007 as C 451 – 07.
2
For referencedASTM standards, visit theASTM website, www.astm.org, or contactASTM Customer Service at service@astm.org. For Annual Book of ASTM Standards
volume information, refer to the standard’s Document Summary page on the ASTM website.
*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.
1
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