When this "pressure-sensitive" zinc-hydrogel solution is applied an "iconic current" is conducted. Wires run through the rebar grid once the concrete is covered thoroughly with the adhesive gel. The bottom line here is the zinc slowly corrodes rather than the rebar. Ironically, the 3M companies developed this zinc hydrogel anode in Minneapolis in the year 2,000 -- seven years before I-35 crashed into a river in Minneapolis. A study conducted by Korean civil engineers Hyo-Gyoung Kwak and Young-Jae Seo puts forward, in short, another methodology in terms of predicting the life expectancy of a concrete bridge. The authors suggest the behaviors of "pre-stressed concrete" (PCS) girders can be predicted fairly accurately. This is because the PCS girders are constructed by placing in-situ concrete decks on the girders "at time intervals." Therefore a careful engineering assessment of the differences in materials, their properties and their age, at the time they are loaded, can lead to "time-dependent material behaviors."

Yet another model offering possible solutions for bridge engineers dealing with corrosion comes from Kim Anh T. Vu and Mark G. Stewart; the authors provide the obvious answer to one reason for long-term deterioration and reduction in structural safety is the use of de-icing salts during winter seasons. When the ratio of water to cement is heavier on the water than it should be "increases failure probabilities."

CONCLUSION

There are no simple one-size-fits-all solutions to repairing bridges once they have become corroded. Part of the answer lies in preventing corrosion in the first place, which this paper discusses. Another part of the repair dynamic is knowing when the corrosion will likely occur, which has also been reviewed in this paper. Meantime, Xion Corporation offers a coating for repair of bridge corrosion that is 85% zinc and 15% aluminum, and provides "good corrosion protection, and a hard polymer top coat" to resist weather attacks and wear and tear. This coating is used on concrete and on the rebar embedded in concrete and contains no volatile organic chemicals, the manufacturer insists. And the coatings cure "instantly." Now as far...

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