- Author
- Wu, S. T. | Clifton, J. R.
- Title
- Computational Models Developed for the Corrosion of Prestressing Steel.
- Coporate
- National Institute of Standards and Technology, Gaithersburg, MD
- Report
- NISTIR 4455, March 1991, 19 p.
- Distribution
- Available from National Technical Information Service
- Keywords
- concretes | fracture energy | fracture mechanics | general corrosion | modeling | prestressing steel | stress corrosion | cracking
- Abstract
- Stress corrosion cracking and general corrosion are the two major processes potentially responsible for corrosion failures in prestressed concrete. Modeling for the purpose of estimating the corrosion rates of steel in prestressed concrete are discussed in the paper. For steel in concrete, localized corrosion processes are not well understood. It is premature at present to develop a sophisticated but still incomplete mathematical model. Instead, a simplified approach is proposed for the quantitative evaluation considerations of diffusion processes and electrochemical reactions. The dominant chemical factors, such as the concentration of oxygen at the electrodes, are treated as primary variables in the differential equations. Two approaches which have been frequently used to treat stress corrosion cracking are briefly described. The first approach is based on a conventional engineering approach by estimating the stress intensity factors under various environments. In the second approach, the surface energy at grain boundaries is estimated along the crack path. It is suggested that the chemical potentials and concentratons of the important absorbed species be included in the energy expression.