HOW TO MAKE IT LAST A LITTLE BIT LONGER

摘要

If we are to delay the evil hour when the wreckers' ball approaches, much more attention must be paid to the preservation of the passive film that exists on good steel in good concrete. The chloride ion is only one of the agents that attacks the passive film but may be the most destructive of them. Too often the corrosion engineer is only called on to try and put things right when the damage has already been done. Prevention of film rupture is better and in a perfect world should be more commercially attractive than the best repair technique. Proper design of a concrete mix to slow down the approach of the chloride ion; the use of inhibitors that aid the resistance of the film to higher concentrations of chloride; stainless and galvanized steel reinforcements and cathodic prevention are just some of the techniques that can be used to delay the onset of pitting corrosion. But none of them are of any use without adequate workmanship and supervision on site.