コンクリート構造物の塩害劣化におけるマクロセル腐食の定量的評価

コンクリート中における鋼材の腐食の進行を評価することを目的として，自然環境暴露実験を実施し，自然電位モニタリング結果と鉄筋の腐食量との関係を検討した．得られた結果は以下のとおりである．
1）簡易なマクロセル電流密度モデルを適用することによって，自然電位分布の経時変化により鋼材の腐食位置および腐食量を評価することができる．
2）部分的な表面被覆が施されている場合に，鋼材の腐食量を精度良く算定するためには，塗膜下の鋼材の電位を考慮する必要がある．また，部分的な補修は未補修部の腐食を促進する可能性があることが示唆された．

Quantitative estimation about macro cell corrosion of concrete structures damaged by salt contamination

An exposure test was executed for 32 months in marine environment and half-cell potential of re-bar was measured periodically by means of monitoring the corrosion progress. After the exposure test, the cross-section of each measurement point along the re-bar was determined in detail to calculate the amount of corroded portion of each cross-section. Location of the corrosion and increase in corrosive amount of the re-bar were calculated by measured half-cell potential based on the simple model of macro cell current density. Finally, it was clarified that the corrosive amount could be evaluated by monitoring of the half-cell potential. By applying the model based on macro cell current density, it was indicated that corrosion of the re-bar was probably promoted by partial repair.