Migrating Corrosion Inhibiting Admixtures Documentation Tests and Model for Increase of Service lifetime
E. Poulsen, J. E. Risberg, and J. E. Stilling
Appears on pages(s):
admixtures; concrete (reinforced); corrosion inhibitors
During 1997 the migrating corrosion inhibitors of the organic type were introduced in Denmark, mainly for the renovation of reinforced concrete structures. Before the introduction earlier tests were studied and supplied with various test series on the organic type of corrosion inhibiting admixtures. The paper deals with the review of earlier test series, the documentation tests carried out before the introduction and the conclusion drawn from these tests. It was the conclusion from this study that the organic type of corrosion inhibitor causes: Increase of the threshold value of chloride in concrete which involves that the initiation period of time can increase by appx. 100 %. Decrease of the corrosion rate after the rebars have started initiation. The rate of corrosion can be decreased to 15 - 25 % of the corrosion rate of rebars in concrete without the organic type corrosion inhibiting admixtures, all other parameters being equal. On the basis of these findings a mathematical model predicting service lifetime has been developed. This model is based upon the HETEK-model of chloride ingress into concrete exposed to marine environment, especially the marine atmosphere, cf. [l]. The model of chloride ingress applies an approximation in order to obtain simple mathematics. The application in Denmark of migrating organic corrosion inhibitor and corrosion inhibiting admixture of the organic type are mainly for repair work of RC structures degrading as a consequence of chloride exposure and carbonation.