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The lifetime of transport structures is largely governed by the durability of the structural elements.Deterioration of these elements is commonly due to the effects of corrosion of the steel or degradation of the concrete by chemical reactions such as sulphate attack.Corrosion may affect reinforced concrete elements as a result of concrete carbonation or chloride ingress from admixtures,deicing salts or marine environments.Coastal areas also form an aggressive environment for exposed steel elements,including suspension cables.Sulphate attack mainly affects elements below ground or in contact with wastewater.Chlorides and sulphates in combination represent a very aggressive environment to new and existing construction.