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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: Effects of Calcium Nitrite and Microsilica Admixtures on Corrosion Resistance of Steel in Concrete
Author(s): N. S. Berke and K. M Sundberg
Publication: Special Publication
Appears on pages(s): 265-280
Keywords: admixtures; calcium nitrite; chlorides; concrete piles; corrosion resistance; diffusion; marine atmospheres; reinforced concrete; reinforcing steels; silica fume; Materials Research
Abstract:Chloride-induced corrosion is a problem common to steel reinforced concrete exposed to chloride ions. A severe case is the use of reinforced concrete in seawater. The high-chloride concentration in salt water, the geometry of concrete piles, and the moisture differential between concrete above and below the water line are all factors that complicate the problem. The corrosion resistance of steel reinforced concrete is a function of the concrete cover of the steel, concrete permeability, surface chloride concentration, and ambient temperature. In this paper, the authors present diffusion curves for chloride ingress into concrete piles. The diffusion coefficients are based on extensive laboratory and field studies. They also discuss the usefulness of this model, based on Fick's law of diffusion. By estimating the chloride ion concentration at the steel reinforcement after a given amount of time, the lifetime of the structure can be predicted. In addition to concrete quality, concrete admixtures affect the corrosion of steel in concrete. Two concrete admixtures are discussed--calcium nitrite and microsilica. As demonstrated in other publications, both of these additives delay the onset of corrosion. It has also been shown that calcium nitrite affects the rate of corrosion upon initiation. The appropriate dosage of each admixture can be determined using the chloride diffusion curves. Examples are described in the paper.
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