ASTM C451-13
(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
5.1 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.
5.2 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).
5.3 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.
5.4 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.
5.5 Early stiffening resulting from false set is not likely to cause a cement to fail the applicable time of setting requirement.
5.6 Early stiffening resulting from flash set, depending on severity, can cause a cement to fail the applicable time...
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.2
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 − 13
Standard Test 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* Determining Mass and Volume for Use in the Physical
Testing of Hydraulic Cements
1.1 This test method covers the determination of early
D1193 Specification for Reagent Water
stiffening in hydraulic-cement paste.
1.2 The values stated in SI units are to be regarded as
3. Terminology
standard. No other units of measurement are included in this
3.1 Definitions:
standard.
3.1.1 early stiffening, n—the early development of stiffness
1.3 This standard does not purport to address all of the
in the working characteristics of a hydraulic-cement paste,
safety concerns, if any, associated with its use. It is the
mortar, or concrete; varieties include false set and flash set.
responsibility of the user of this standard to establish appro-
3.1.2 false set, n—the early development of stiffness in the
priate safety and health practices and determine the applica-
working characteristics of a hydraulic-cement paste, mortar, or
bility of regulatory limitations prior to use.
concrete without the evolution of much heat, which stiffness
Warning: Fresh hydraulic-cementitious mixtures are caustic
can be dispelled and plasticity regained by further mixing
and may cause chemical burns to skin and tissue upon
without addition of water; also known as “grab set,” “prema-
2
prolonged exposure.
ture stiffening,” “ hesitation set,” and “rubber set.”
1.4 The text of this standard references notes and footnotes
3.1.3 flash set, n—the early development of stiffness in the
which provide explanatory material. These notes and footnotes
working characteristics of a hydraulic-cement paste, mortar, or
(excluding those in tables and figures) shall not be considered
concrete, usually with the evolution of considerable heat,
as requirements of the standard.
which stiffness cannot be dispelled nor can the plasticity be
regained by further mixing without addition of water; also
2. Referenced Documents
known as “quick set.”
3
2.1 ASTM Standards:
3.1.4 Refer to Terminology C219 for definitions of other
C150 Specification for Portland Cement
terms.
C183 Practice for Sampling and the Amount of Testing of
Hydraulic Cement
4. Summary of Test Method
C187 Test Method for Amount of Water Required for Nor-
mal Consistency of Hydraulic Cement Paste 4.1 A paste is prepared with the cement to be tested, using
C219 Terminology Relating to Hydraulic Cement sufficient water to give a required initial penetration as mea-
C305 Practice for Mechanical Mixing of Hydraulic Cement sured by the Vicat apparatus at a stipulated time after comple-
Pastes and Mortars of Plastic Consistency tion of mixing. A second penetration, termed the final
C670 Practice for Preparing Precision and Bias Statements penetration, is measured at a later stipulated time. The ratio of
for Test Methods for Construction Materials final penetration to initial penetration is calculated as a
C1005 Specification for Reference Masses and Devices for percentage.
5. Significance and Use
1
This test method is under the jurisdiction ofASTM Committee C01 on Cement
5.1 The purpose of this test method is to determine the
and is the direct responsibility of Subcommittee C01.30 on Time of Set.
degree to which a cement paste develops early stiffening or to
Current edition approved Dec. 1, 2013. Published January 2014. Originally
approved in 1960. Last previous edition approved in 2008 as C451 – 08. DOI:
establish whether or not a cement complies with a specification
10.1520/C0451-13.
limit on early stiffening.
2
Section on Safety, Manual of Cement Testing, Annual Book of ASTM
Standards, Vol 04.01.
5.2 When used for establishing compliance with a specifi-
3
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
cation limit, the specification requirement is customarily stated
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
in terms of the minimum allowable final penetration, in
Standards volume information, refer to the standard’s Document Summary page on
the ASTM website. percent, calculated in accordance with the Calculation Section.
*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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C451 − 13
When used for estimating the relative tendency of a cement to 7. Reagent
manifest
...
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. 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 − 08 C451 − 13
Standard Test 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*
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.
1.3 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
2
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
3
2.1 ASTM Standards:
C150 Specification for Portland Cement
C183 Practice for Sampling and the Amount of Testing of Hydraulic Cement
C187 Test Method for Amount of Water Required for Normal Consistency of Hydraulic Cement Paste
C219 Terminology Relating to Hydraulic Cement
C305 Practice for Mechanical Mixing of Hydraulic Cement Pastes and Mortars of Plastic Consistency
C670 Practice for Preparing Precision and Bias Statements for Test Methods for Construction Materials
C1005 Specification for Reference Masses and Devices for Determining Mass and Volume for Use in the Physical Testing of
Hydraulic Cements
D1193 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.”
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 June 1, 2008Dec. 1, 2013. Published June 2008January 2014. Originally approved in 1960. Last previous edition approved in 20072008 as
C451 – 07.C451 – 08. DOI: 10.1520/C0451-08.10.1520/C0451-13.
2
Section on Safety, Manual of Cement Testing, Annual Book of ASTM Standards, Vol 04.01.
3
For referenced ASTM standards, visit the ASTM website, www.astm.org, or contact ASTM 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
---------------------- Page: 1 ----------------------
C451 − 13
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 mix
...
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