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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.
Showing 1-5 of 83 Abstracts search results
Document:
SP114-76
Date:
May 1, 1989
Author(s):
Jan Bijen and Hennie Waltje
Publication:
Symposium Papers
Volume:
114
Abstract:
Cements consisting of 60 percent ground granulated blast furnace slag and 40 percent fly ash activated by 7 percent sodium hydroxide have been investigated. Various slags were used, including some laboratory-made synthetic slags. The influence of additives like superplasticizers and defoaming agents has been examined. The most favorable composition with respect to strength development has been subjected to a durability testing program. A negative aspect appeared to be the carbonation resistance, which is low in comparison with portland cement. Carbonation leads to a decrease in strength. Other properties were favorable.
DOI:
10.14359/1900
SP114-39
K. Ohno, and F. Alhara
The effect of finely ground silica with a high specific surface of about 12 mý/g and 20 mý/g in mortar was compared with that containing silica fume. The dosage requirement of a high-range water-reducing agent to maintain a constant flow of fresh mortar was determined for 1:3 mortar containing 5 to 25 percent finely ground silica or silica fume as cement replacement. The compressive and flexural strengths of the mortar were investigated at different ages. Also, the resistance of mortar specimens to chemical attack and chloride penetration was determined. It was concluded that the use of finely ground silica was as effective as silica fume for improving quality of mortar.
10.14359/2405
SP114-40
M. Berra, G. Ferrara, and S. Tavano
The effectiveness of silica fume to improve the erosion resistance of cement mortars used to repair hydraulic structures was investigated. The mortars were fiber-reinforced and contained a superplasticizer. Other factors investigated were erosion resistance, mechanical properties, shrinkage, atmospheric, under vacuum absorption, freeze-thaw resistance, and adhesion of mortars to concrete substrates.
10.14359/2414
SP114-41
Olav Gautefall and Jan Havdahl
Reports on study of the chloride distribution profile in hardened cement paste cylinders of 5 cm diameter. The specimens were made from ordinary portland cement and blended cement with 10 percent fly ash. The condensed silica fume was used as cement replacement, with replacement levels of 5, 10, and 15 percent by weight of cement. Other experimental variables were water-to-(cement + silica fume) ratio of 0.5, 0.7, and 0.9. The specimens were immersed in stagnant seawater at 20 C. After 6 months of exposure, the specimens were cut, ground, dried, and the chloride ion content determined by a potentiometric titration procedure. By applying Fick's second law, the effective diffusion coefficient and the effective supply concentration of chloride were calculated by using an approximation method. Results show the effective diffusion coefficient is reduced highly when condensed silica fume is used as cement replacement.
10.14359/2424
SP114-18
S. Kobayashi, Y. Hozumi, T. Nakano, and T. Yanagida
Paper presents the results of the tests conducted on reactive andesite produced to determine if Japanese fly ashes produced in Japan have an effect in controlling the alkali-aggregate reactions in concrete. Fourteen fly ashes produced were subjected to Japan Industrial Standard (JIS) alkali-silica reaction (ASR) mortar bar test (40 x 40 x 160 mm, alkali content in cement 1.2 percent, s/a = 2.25) with (c + f) ranging from 5 to 30 percent. With f/(c + f) at 20 percent or higher, all the mortar test bars incorporating fly ash had little expansion even after 6 months, but with f/(c + f) at 10 percent, different expansions were produced depending on the type used. The analysis of the data indicated that the component Na2Oeq of fly ash would accelerate the expansion while the component SiO2 will restrain the expansion. The controlling ability is also related to the alkali content of the cement: the greater the alkali from the cement and fly ash, the greater the quantity of fly ash required for preventing the expansion. An empirical formula expressing such a relationship has been derived. 123-389
10.14359/2059
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