Pitting corrosion model for reinforced concrete structures in a chloride environment

摘要

Different types of corrosion may arise in steel reinforcement, such as general corrosion, pitting corrosion, hydrogen embrittlement, stress corrosion cracking and corrosion fatigue. However, corrosion of steel reinforcement in reinforced concrete (RC) structures can be classified into two categories: general (uniform) corrosion and pitting (localised) corrosion. In general, concrete researchers use uniform corrosion to study the effect of corrosion on RC structures. This approach is not accurate for concrete structures subjected to chloride attack, which usually experiences pitting corrosion. This paper describes an accelerated corrosion test used to obtain statistical parameters of maximum pit-depths distribution of corroded steel in a RC structure. Using probabilistic analysis, these statistical parameters are combined with statistical parameters of RC beams (i.e. beam dimensions, concrete strength, steel yield strength, cover thickness, workmanship quality, in situ strength factor, model error for flexure and shear and also corrosion rate) to determine the effect of corrosion on flexural and shear strength of RC beams. Using the proposed pitting corrosion model improves service life prediction of RC structures in a chloride environment.