Title: Service Life of Structures with Regard to Corrosion of Embedded Steel

Author(s): K. Tuutti

Publication: Symposium Paper

Volume: 65

Issue:

Appears on pages(s): 223-236

Keywords: chlorides; corrosion; diffusion; durability; models; reinforcing steels.

DOI: 10.14359/6355

Date: 8/1/1980

Abstract:
This report deals with a calculation model for the corrosion of steel in concrete. The aim has been to make a highly complicated durability problem sufficiently simple to obtain a survey of the importance of various factors for the service life of the concrete structure. Some researchers will doublessly regard the model as an excessively rough simplification of the actual process but 90 to 95% of all corrosion problems which occur in practice agree well with this theory. The service life for concrete structures with regard to reinforement corrosion is broken down into a initial stage and a propagation stage. This breakdown is suitable since the primary parameters are different in the two sub-processes. The penetration of various passivation-breaking and activation substances to the steel is studied in the initiation stage, as well as the concentrations which give rise to corrosion or a marked increase in corrosion. The corrosion rate has increased considerably in the propagation stage and the factors which determine the rate of corrosion thus become interesting. In addition, the degree of corrosion which can be permitted with regard to load bearing capacity, esthetic aspects etc, must be determined. The report also presents examples of a number of material coefficients which are necessary for the model.