Reinforcement corrosion in concrete exposed to the north sea for more than 60 years

Of the some 1,000 almost identical, precast, reinforced concrete elements forming the 1.5-km-long, more than 60-year old promenade railing immediately adjacent to the North Sea at Arbroath, Scotland, more than 90% still appear to be in remarkably good condition with little evidence of external rust staining or reinforcement corrosion. However, the elements that have been replaced, some only about 15 years ago, mostly show severe reinforcement corrosion. Concrete quality, density, and cover to the reinforcement are generally similar, but concrete permeability does not correlate well with reinforcement corrosion.