In today’s market, it is imperative to be knowledgeable and have an edge over the competition. ACI members have it…they are engaged, informed, and stay up to date by taking advantage of benefits that ACI membership provides them.
Read more about membership
Become an ACI Member
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.
American Concrete Institute
38800 Country Club Dr.
Farmington Hills, MI
Feedback via Email
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: Powder Additions to Mitigate Retardation in High-Volume Fly Ash Mixtures
Author(s): Dale P. Bentz
Publication: Materials Journal
Appears on pages(s): 508-514
Keywords: building technology; high-volume fly ash; hydration; isothermal calorimetry; retardation; sustainability
Abstract:While high-volume fly ash (HVFA) concrete mixtures are attractive from a sustainability viewpoint, they are sometimes plagued by long delays in finishing, producing a performance that is unacceptable to contractors. In this paper, isothermal calorimetry studies are conducted to examine excessive retardation in HVFA mixtures based on both Class C and Class F fly ash. In addition to quantifying the retardation, the calorimetric curves are also used to evaluate the performance of mitigation strategies based on various powder additions. Powder additions examined in the present study include an aluminum trihydroxide, calcium hydroxide, cement kiln dust, condensed silica fume, limestone, and a rapid-set cement. The addition of either 5% calcium hydroxide or 10% of the rapid-set cement by mass of total solids (powders) is observed to provide a significant reduction in the retardation measured in mixtures based on either class of fly ash for the material combinations examined in this study. Thus, these two powder additions may provide viable solutions to mitigating excessive retardation, extending the use of HVFA mixtures in practice.
Click here to become an online Journal subscriber