Concrete Permeability and Durability Performance
Concrete as such is a very durable material. There are magnificent examples of concrete structures which have survived 2,000 years without substantial repair measures , and they will survive hundreds of years to come. The Pantheon in Rome and numerous bridges built during the Roman Empire in Italy and Spain that served up to 2,000 years are well-known examples.
Since the large-scale application of reinforced concrete, the construction industry has experienced enormous challenges with respect to achieving the designed service life of concrete structures. According to most standards, reinforced concrete structures are expected to have a service life of at least 100 years. In reality, however, expensive repair and renovation are frequently necessary after not more than 30 years.
In recent years, a number of bridges collapsed after less than 50 years. It is estimated that repair of a damaged bridge costs approximately six to eight times more than that of the construction of a new bridge. During repair operation or reconstruction process, the necessary deviation of traffic alone causes additional financial and environmental burdens. Therefore, one major subject in concrete technology research has been to increase repair-free service life of reinforced concrete structures.
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