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: The Chemical Shrinkage of Pozzolanic Reaction Products
Author(s): H. Justnes,B. Ardoullie, E. Hendrix, E.J. Sellevold
and D. Van Gemert
Publication: Special Publication
Appears on pages(s): 191-206
Keywords: fly ash; pozzolans; shrinkage; silica fume.
Abstract:The total chemical shrinkage of silica fume and Class F fly ash, both as pozzolanic materials reacting with lime and as mineral additives replacing portland cement, was studied. The external chemical shrinkage of cement paste with silica fume and fly ash replacement was studied as well. By increasing pH the rate related to the pozzolanic reaction decreased for sitica fume and increased for fly ash. Although the presence of alkalis are catalytically necessary for a rapid pozzolanic reaction of silica fume, the pH increase reduces the solubihty of calcium hydroxide (CH) due to the common ion effect. This may explain why the reaction rate decreases if dissolution of CH, followed by precipitation of CSH, is the rate-limiting step. The increased reactivity of fly ash, caused by a pH increase, indicates that the dissolution of the glassy aluminosilicate phase by alkalis was determining the overall rate of the process. The total chemical shrinkage was crudely estimated to be 8.8 ml/l00 g of reacted silica fume and 10.0 ml/l00 g of reacted fly ash, as compared with 6.3 ml/l00 g of portland cement. The measured shrinkage for silica fume could be higher than the above value since minor amounts of silicon metal in the silica fume could produce an expansion due to evolved hydrogen gas.
Click here to become an online Journal subscriber