Corrosion of Reinforcement in Existing Concrete Façades

Abstract

The most common degradation mechanism causing the need to repair concrete façades in Finland, is the corrosion of reinforcement due to carbonation and the small cover depths of the reinforcement. During the last almost 20 years the repair of concrete façades and balconies has been very active and this work has produced a great deal of information about the actual condition of those repaired buildings. This active condition assessment and repair work have produced an extensive and growing information base, which can be used, for example, for anticipating the upcoming repair need of concrete structures. For this purpose the data is gathered from 947 concrete buildings, which includes the distribution of different kinds of states of damage and the interdependence between the damage and other factors. The carbonation of concrete has widely advanced in the façades made in 1970s or earlier. The corrosion of reinforcement has been possible approximately last 20–30 years in those façades. Despite insufficient cover depths of concrete and far advanced carbonation of concrete, visually seen corrosion damage are relative rare. Corrosion damage appear mostly on façades, which get more rain. In Finland those are upper parts of southern and western façades.KeywordsCorrosion of reinforcementCarbonationConcrete façadeAnnual rainfallCondition assessmentDurability