ASTM C451-21
(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 o...
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, health, and environmental 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.
1.5 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
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Standards Content (Sample)
This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the
Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
Designation: C451 − 21
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* C219 Terminology Relating to Hydraulic and Other Inor-
ganic Cements
1.1 This test method covers the determination of early
C305 Practice for Mechanical Mixing of Hydraulic Cement
stiffening in hydraulic-cement paste.
Pastes and Mortars of Plastic Consistency
1.2 The values stated in SI units are to be regarded as
C511 Specification for Mixing Rooms, Moist Cabinets,
standard. No other units of measurement are included in this
Moist Rooms, and Water Storage Tanks Used in the
standard.
Testing of Hydraulic Cements and Concretes
1.3 This standard does not purport to address all of the
C670 Practice for Preparing Precision and Bias Statements
safety concerns, if any, associated with its use. It is the
for Test Methods for Construction Materials
responsibility of the user of this standard to establish appro-
C1005 Specification for Reference Masses and Devices for
priate safety, health, and environmental practices and deter-
DeterminingMassandVolumeforUseinPhysicalTesting
mine the applicability of regulatory limitations prior to use.
of Hydraulic Cements
(Warning—Fresh hydraulic-cementitious mixtures are caustic
and may cause chemical burns to skin and tissue upon
3. Terminology
2
prolonged exposure.)
3.1 Definitions:
1.4 The text of this standard references notes and footnotes
3.1.1 For definitions of terms used in this test method, refer
which provide explanatory material. These notes and footnotes
to Terminology C219.
(excluding those in tables and figures) shall not be considered
as requirements of the standard.
4. Summary of Test Method
1.5 This international standard was developed in accor-
dance with internationally recognized principles on standard- 4.1 A paste is prepared with the cement to be tested, using
ization established in the Decision on Principles for the sufficient water to give a required initial penetration as mea-
Development of International Standards, Guides and Recom- sured by the Vicat apparatus at a stipulated time after comple-
mendations issued by the World Trade Organization Technical
tion of mixing. A second penetration, termed the final
Barriers to Trade (TBT) Committee. penetration, is measured at a later stipulated time. The ratio of
final penetration to initial penetration is calculated as a
2. Referenced Documents
percentage.
3
2.1 ASTM Standards:
5. Significance and Use
C150/C150M Specification for Portland Cement
C183/C183M Practice for Sampling and the Amount of
5.1 The purpose of this test method is to determine the
Testing of Hydraulic Cement
degree to which a cement paste develops early stiffening or to
C187 Test Method for Amount of Water Required for Nor-
establishwhetherornotacementcomplieswithaspecification
mal Consistency of Hydraulic Cement Paste
limit on early stiffening.
5.2 When used for establishing compliance with a specifi-
1 cation limit, the specification requirement is customarily stated
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.
in terms of the minimum allowable final penetration, in
Current edition approved Oct. 1, 2021. Published November 2021. Originally
percent, calculated in accordance with the Calculation Section.
approved in 1960. Last previous edition approved in 2019 as C451 – 19. DOI:
When used for estimating the relative tendency of a cement to
10.1520/C0451-21.
2
manifest early stiffening, additional information of value may
Section on Safety, Manual of Cement Testing, Annual Book of ASTM
Standards, Vol 04.01.
be obtained if the remix procedure described in the Procedure
3
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
Section is employed. Under some conditions, a judgment may
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
be made by comparing the behavior in the initial test and in the
Standards volume information, refer to the standard’s Document Summary page on
the ASTM website. remix procedure to differentiate a relatively less serious and
*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
...
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 − 19 C451 − 21
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
2
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, health, and environmental practices and determine the applicability of
regulatory limitations prior to use. (Warning—Fresh hydraulic-cementitious mixtures are caustic and may cause chemical burns
2
to skin and tissue upon prolonged 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.
1.5 This international standard was developed in accordance with internationally recognized principles on standardization
established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued
by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
2. Referenced Documents
3
2.1 ASTM Standards:
C150/C150M Specification for Portland Cement
C183/C183M 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 and Other Inorganic Cements
C305 Practice for Mechanical Mixing of Hydraulic Cement Pastes and Mortars of Plastic Consistency
C511 Specification for Mixing Rooms, Moist Cabinets, Moist Rooms, and Water Storage Tanks Used in the Testing of Hydraulic
Cements and Concretes
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 Aug. 1, 2019Oct. 1, 2021. Published August 2019November 2021. Originally approved in 1960. Last previous edition approved in 20182019
as C451 – 18.C451 – 19. DOI: 10.1520/C0451-19.10.1520/C0451-21.
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
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C451 − 21
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 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.”
3.1.3 flash set, n—the early development of stiffness in the working characteris
...
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