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The effect of steel-concrete microstructure on the chloride threshold for chloride induced corrosion



Authors: A. Kenny, A. Katz
Paper category: conference
Book title: Concrete Durability and Service Life Planning – ConcreteLife’09
Editor(s): K. Kovler
Print ISBN: 978-2-35158-074-5
e-ISBN: 978-2-35158-085-1
Publisher: RILEM Publications SARL
Publication year: 2009
Pages: 92 – 99
Total Pages: 8
Language: English


Abstract: Wide range of values of the chloride threshold for corrosion initiation can be found in the literature. The threshold value ranges from 0.12% to 3.04% of the cement content in the mix. In addition, different ranges were found for measurements carried in simulated pore water, cement paste, mortar or concrete. Some of the differences between results published in different works might be attributed to variation in experimental setting, but the influence of different corrosion mechanisms on the degree of variation has not been identified yet. Literature review of past experience with cementitious composites and the mechanism of localized corrosion suggest that the microstructure of the steel – concrete interface has a major influence on the chloride threshold.
Sixteen concrete mixes were prepared with reinforcing bars (rebars) placed horizontally or vertically, to form a variety of microstructures at the concrete-steel interface. The specimens were analyzed to indicate chloride threshold and interfacial microstructure. Chloride threshold was determined by chloride concentration at rebar depth at the onset of de-passivation. Microstructure was characterized quantitatively by means of image analysis of SEM BSE images of the interfaces.
The chloride threshold was found to range from 0.28% to 2.9% of the cement content, and to be correlated with microstructure parameters.


Online publication: 2012-05-16
Publication Type: full_text
Public price (Euros): 0.00


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