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Founded in 1904 and headquartered in Farmington Hills, Michigan, USA, the American Concrete Institute is a leading authority and resource worldwide for the development, dissemination, and adoption of its consensus-based standards, technical resources, educational programs, and proven expertise for individuals and organizations involved in concrete design, construction, and materials, who share a commitment to pursuing the best use of concrete.
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Home > Publications > International Concrete Abstracts Portal
The International Concrete Abstracts Portal is an ACI led collaboration with leading technical organizations from within the international concrete industry and offers the most comprehensive collection of published concrete abstracts.
Title: Comparison of Different Methods for Testing the Pozzolanic Activity of Fly Ashes
Author(s): F. Sybertz
Publication: Special Publication
Appears on pages(s): 477-498
Keywords: accelerated tests; alkali content; alkalies; chemical analysis; compressive strength; concretes; fineness; fly ash; mortars (material); physical properties; pozzolans; slags; strength; tests; workability; Materials Research
Abstract:In the Federal Republic of Germany, adequate pozzolanic activity of fly ash as a concrete additive has so far been insured by requiring cement mortars containing fly ash to reach a certain compressive-strength ratio as compared to a reference mortar. Test results are known to be sensitive to other influencing factors, especially composition and properties of cement. A series of tests was conducted to establish the usefulness of various testing methods. Under investigation were the respective influences of cement, fly ash content, and preparation on the basis of constant water content or constant workability. Mortars were stored according to the German test guideline, to BS 3892, and to ASTM C 311. Certain physical and chemical properties of the fly ashes were also determined. This paper discusses the effects of cement, i.e., alkali content, fineness, and slag content, on the pozzolanic activity index at different ages. Also demonstrated is the suitability of accelerating strength testing methods. Finally, the strong influence of fly ash fineness on workability and strength is shown.
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