| Popis: |
The maintenance of the infrastructure is one of the key issues in almost all industrial countries. Especially in Europe and Northern America, the largest parts of the infrastructure were constructed in the 1960s and 1970s and require more intense condition monitoring and refurbishment today and in the next decades. If not performed properly, complete collapse of the structures can be the consequence. Among the possible deterioration mechanisms, reinforcement corrosion due to chloride ingress plays a dominant part. The reinforcement of concrete ensures the load-bearing capacity of most structures such as bridges, parking decks, tunnels, etc. The steel in reinforced concrete is normally protected against corrosion by a thin and impermeably dense passive layer formed in the alkaline medium of the pore solution of concrete. This passive layer can breakdown in the presence of chlorides at the steel surface or due to a decrease in pH of the pore solution caused by carbonation of the concrete. After the breakdown of the passive layer, corrosion at the reinforcement can be initiated, which can result in severe deterioration of the steel. Corrosion monitoring provides some important tools for the condition assessment of both newly built structures and aging structures, as it may supply additional information on the condition of structures which cannot be provided with common NDT techniques. Over the last decades, different techniques and sensor setups for corrosion monitoring of steel in concrete have been developed. In this contribution, the fundamentals of corrosion of steel in concrete, novel approaches for the service life management of reinforced concrete structures, and the basic principles of some of the most important techniques for corrosion monitoring will be discussed. Three case studies at the end of the chapter illustrate the application of corrosion monitoring for real structures and the vast potential that corrosion monitoring offers. |
