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ASTM C494/C494M-99a

Historical Revision

Standard Specification for Chemical Admixtures for Concrete

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1.1 This specification covers materials for use as chemical admixtures to be added to hydraulic-cement concrete mixtures in the field for the purpose or purposes indicated for the seven 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, and

1.1.7 Type G--Water-reducing, high range, and retarding admixtures.

1.2 This specification stipulates tests of an admixture with suitable concreting materials as described in 11.1 - 11.3 or with cement, pozzolan, aggregates, and an air-entraining admixture proposed for specific work (11.4). Unless specified otherwise by the purchaser, the tests shall be made using concreting materials as described in 11.1 - 11.3.

Note 1--It is recommended that, whenever practicable, tests be made using the cement, pozzolan, aggregates, air-entraining admixture, and the mixture proportions, batching sequence, and other physical conditions proposed for the specific work (11.4) because the specific effects produced by chemical admixtures may vary with the properties and proportions of the other ingredients of the concrete. For instance, Types F and G admixtures may exhibit much higher water reduction in concrete mixtures having higher cement factors than that listed in 12.1.

Mixtures having a high range water reduction generally display a higher rate of slump loss. When high-range admixtures are used to impart increased workability (6 to 8-in. slump [150 to 200-mm]), the effect may be of limited duration, reverting to the original slump in 30 to 60 min depending on factors normally affecting rate of slump loss. The use of chemical admixtures to produce high-slump (flowing) concrete is covered by Specification C 1017.

Note 2--The purchaser should ensure 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 relatively large amounts of chloride may accelerate corrosion of prestressing steel. Compliance with the requirements of this specification does not constitute assurance of acceptibility of the admixture for use in prestressed 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. Uniformity and equivalence tests of Section 6 shall be carried out to provide results against which later comparisons can be made.

1.3.2 Level 2--Limited retesting is described in , and . Proof of compliance with the requirements of demonstrates continued conformity of the admixture with the requirements of the specification.

1.3.3 Level 3--For acceptance of a lot or for measuring uniformity within or between lots, when specified by the purchaser, the uniformity and equivalence tests of Section 6 shall be used.

1.4 The values stated in either inch-pound or SI units shall be regarded separately as standard. The values stated in each system may not be exact equivalents; therefore, each system must be used independently of the other, without combining values in any way.

1.5 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.

1.6 The following precautionary caveat pertains only to the test method sections, Sections 11-18 of this Specification: 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.


SDO ASTM: ASTM International
Document Number C494
Publication Date Oct. 10, 1999
Language en - English
Page Count 9
Revision Level 99a
Supercedes
Committee C09.23
Publish Date Document Id Type View
June 15, 2024 C0494_C0494M-24 Revision
Dec. 15, 2019 C0494_C0494M-19E01 Revision
Dec. 15, 2019 C0494_C0494M-19 Revision
June 15, 2017 C0494_C0494M-17 Revision
July 1, 2016 C0494_C0494M-16 Revision
Oct. 1, 2015 C0494_C0494M-15A Revision
June 15, 2015 C0494_C0494M-15 Revision
April 1, 2013 C0494_C0494M-13 Revision
July 1, 2012 C0494_C0494M-12 Revision
July 1, 2011 C0494_C0494M-11 Revision
Oct. 1, 2010 C0494_C0494M-10A Revision
Feb. 1, 2010 C0494_C0494M-10 Revision
Sept. 1, 2008 C0494_C0494M-08A Revision
Jan. 1, 2008 C0494_C0494M-08 Revision
Dec. 15, 2005 C0494_C0494M-05A Revision
May 1, 2005 C0494_C0494M-05 Revision
Jan. 1, 2004 C0494_C0494M-04 Revision
Oct. 10, 1999 C0494_C0494M-99AE01 Revision
Oct. 10, 1999 C0494_C0494M-99A Revision