SYMPOSIA PAPER Published: 01 January 1966
STP49904S

Chemical Admixtures

Although concrete admixtures are chemicals in a literal sense, by convention in concrete technology, the term “chemical admixture” is restricted to water-soluble substances other than air-entraining agents. Most chemical admixtures react chemically with the cement in concrete. This discussion will be confined to set-controlling and water-reducing admixtures. Chemical admixtures of other types are classified and described in a recent report of the American Concrete Inst. [1]. A water-reducing admixture is defined as one that reduces the quantity of mixing water required to produce concrete of a given consistency; a retarding admixture as one that retards the setting of concrete; an accelerating admixture as one that accelerates the setting and early strength development of concrete; a water-reducing and retarding admixture as one that reduces the quantity of mixing water required to produce concrete of a given consistency and retards the setting of concrete; and a water-reducing and accelerating admixture as one that reduces the quantity of mixing water required to produce concrete of a given consistency and accelerates the setting and early strength development of concrete. These five types of admixtures are referred to in ASTM Specifications for Chemical Admixtures for Concrete (C 494 - 63 T) as Types A, B, C, D, and E, respectively.

Author Information

Foster, Bruce
National Bureau of Standards, Washington, D. C.
Price: $25.00
Contact Sales
Related
Reprints and Permissions
Reprints and copyright permissions can be requested through the
Copyright Clearance Center
Details
Developed by Committee: C09
Pages: 556–564
DOI: 10.1520/STP49904S
ISBN-EB: 978-0-8031-8113-7
ISBN-13: 978-0-8031-8109-0