ASTM C494/C494M-19e1
(Specification)Standard Specification for Chemical Admixtures for Concrete
Standard Specification for Chemical Admixtures for Concrete
ABSTRACT
This specification covers the materials and the test methods for use in chemical admixtures to be added to hydraulic-cement concrete mixtures in the field. The seven types of admixtures are indicated as follows: Type A—water reducing; Type B—retarding; Type C—accelerating; Type D—water reducing and retarding; Type E—water reducing and accelerating; Type F—water reducing, high range; and Type G—water reducing, high range, and retarding. The materials used in the concrete mixtures shall include Type I or Type II cement, pozzolan, fine and coarse aggregates, and air-entraining admixture. Samples of freshly mixed concrete from at least three separate batches for each condition of concrete shall be tested in accordance with the slump, air content, time of setting, and water content tests. Physical properties retesting shall consist of uniformity and equivalence tests using infrared analysis which is intended to compare qualitatively the composition of different samples, residue by oven drying which shall be either a forced circulation type or one with provision for free access of air, and specific gravity determination using hydrometers. Test specimens of the hardened concrete shall be prepared in accordance to compressive strength, flexural strength, resistance to freezing and thawing, and length change.
SCOPE
1.1 This specification covers materials for use as chemical admixtures to be added to hydraulic-cement concrete mixtures for the purpose or purposes indicated for the eight types as follows:
1.1.1 Type A—Water-reducing admixtures,
1.1.2 Type B—Retarding admixtures,
1.1.3 Type C—Accelerating admixtures,
1.1.4 Type D—Water-reducing and retarding admixtures,
1.1.5 Type E—Water-reducing and accelerating admixtures,
1.1.6 Type F—Water-reducing, high range admixtures,
1.1.7 Type G—Water-reducing, high range, and retarding admixtures, and
1.1.8 Type S—Specific performance admixtures.
1.2 Unless specified otherwise by the purchaser, test specimens for qualifying an admixture shall be made using concreting materials as described in 11.1 – 11.3.
Note 1: As discussed in Appendix X2, it is recommended that, whenever practicable, supplementary tests be made by the purchaser using the cement, pozzolan, aggregates, air-entraining admixture, and the mixture proportions, batching sequence, and other physical conditions proposed for the specific work because the specific effects produced by chemical admixtures may vary with the properties and proportions of the other ingredients of the concrete. For example, Types F and G admixtures may exhibit much higher water reduction in concrete mixtures having higher cement contents than that listed in 12.1.1.
Note 2: The purchaser should verify that the admixture supplied for use in the work is equivalent in composition to the admixture subjected to test under this specification (see Section 6, Uniformity and Equivalence).
Note 3: Admixtures that contain sufficient amounts of chloride may accelerate corrosion of steel reinforcement. Compliance with the requirements of this specification does not constitute assurance of acceptability of the admixture for use in reinforced concrete.
1.3 This specification provides for three levels of testing.
1.3.1 Level 1—During the initial approval stage, proof of compliance with the performance requirements defined in Table 1 demonstrates that the admixture meets the requirements of this specification. Proof of compliance shall be based on comparisons of the average test results from the batches of test concrete and the average test results from the batches of reference concrete. Admixtures (except for Types B, C, E, and S) shall qualify for provisional compliance if the time of setting, length change, and durability factor meet the physical requirements and any of the alternative compressive strength requirements shown in parentheses in Table 1 are met through the date of provisional acceptance (see Note...
General Information
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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.
´1
Designation:C494/C494M −19
Standard Specification for
1
Chemical Admixtures for Concrete
This standard is issued under the fixed designation C494/C494M; 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 (´) indicates an editorial change since the last revision or reapproval.
1
ε NOTE—Table 1 was editorially corrected in August 2022.
This standard has been approved for use by agencies of the U.S. Department of Defense.
1. Scope* Table 1 demonstrates that the admixture meets the require-
ments of this specification. Proof of compliance shall be based
1.1 This specification covers materials for use as chemical
on comparisons of the average test results from the batches of
admixtures to be added to hydraulic-cement concrete mixtures
test concrete and the average test results from the batches of
for the purpose or purposes indicated for the eight types as
reference concrete.Admixtures (except for Types B, C, E, and
follows:
S) shall qualify for provisional compliance if the time of
1.1.1 Type A—Water-reducing admixtures,
setting, length change, and durability factor meet the physical
1.1.2 Type B—Retarding admixtures,
requirements and any of the alternative compressive strength
1.1.3 Type C—Accelerating admixtures,
requirements shown in parentheses in Table 1 are met through
1.1.4 Type D—Water-reducing and retarding admixtures,
the date of provisional acceptance (see Note 4). If subsequent
1.1.5 Type E—Water-reducing and accelerating admixtures,
test results at six months or one year fail to meet the
1.1.6 Type F—Water-reducing, high range admixtures,
requirement of at least 100% of reference strength, the
1.1.7 Type G—Water-reducing, high range, and retarding
provisional compliance of the admixture to this standard is
admixtures, and
withdrawn and all users of the admixture shall be notified
1.1.8 Type S—Specific performance admixtures.
immediately. Uniformity and equivalence tests of Section 6
1.2 Unless specified otherwise by the purchaser, test speci-
shall be carried out to provide results against which later
mens for qualifying an admixture shall be made using concret-
comparisons shall be made.
ing materials as described in 11.1 – 11.3.
NOTE 4—Allowing for provisional compliance while retaining longer
NOTE 1—As discussed in Appendix X2, it is recommended that,
termcompressivestrengthrequirementspromotesmorerapidqualification
wheneverpracticable,supplementarytestsbemadebythepurchaserusing
of new materials, but also provides assurance that new admixture
the cement, pozzolan, aggregates, air-entraining admixture, and the
technologies will not exhibit unexpected longer term performance. The
mixture proportions, batching sequence, and other physical conditions
alternative compressive strength requirements in Table 1 are based on
proposed for the specific work because the specific effects produced by
statisticalanalysisof103SpecificationC494/C494Mevaluationtests.The
chemical admixtures may vary with the properties and proportions of the
alternative requirements shown in parentheses correspond to a 99%
2
other ingredients of the concrete. For example,Types F and G admixtures
probability of passing strength requirements at subsequent test ages, if
may exhibit much higher water reduction in concrete mixtures having
any one of the requirements is met. There is no requirement that all be
higher cement contents than that listed in 12.1.1.
met.
NOTE 2—The purchaser should verify that the admixture supplied for
1.3.2 Level 2—Limited retesting is described in 5.2 – 5.2.2.
useintheworkisequivalentincompositiontotheadmixturesubjectedto
Proof of compliance with the requirements of Table 1 demon-
test under this specification (see Section 6, Uniformity and Equivalence).
NOTE 3—Admixtures that contain sufficient amounts of chloride may
stratescontinuedconformityoftheadmixturewiththerequire-
accelerate corrosion of steel reinforcement. Compliance with the require-
ments of the specification.
mentsofthisspecificationdoesnotconstituteassuranceofacceptabilityof
1.3.3 Level 3—For acceptance of a lot or for measuring
the admixture for use in reinforced concrete.
uniformitywithinorbetweenlots,ifspecifiedbythepurchaser,
1.3 This specification provides for three levels of testing.
theuniformityandequivalencetestsofSection6shallbeused.
1.3.1 Level 1—During the initial approval stage, proof of
1.4 The values stated in either SI units or inch-pound units
compliance with the performance requirements defined in
are to be regarded separately as standard. The values
...
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