Whereas steel bar corrosion is the main cause for durability deterioration of existing reinforced concrete structures, it is important to understand the steel bar corrosion in concrete and predict the corrosion process in a sufficient way. In this paper, the corrosion process of rebar in ordinary concrete and three types of fly ash concrete specimens casted with 15%, 30% and 45% fly ash replacement ratios by mass under constant climate conditions were investigated. Meanwhile, the advanced digital video microscope measure system was used to study the microstructure of the steel/concrete interface at the different stages of corrosion. The effects of fly ash replacement were analyzed in terms of the electrical resistivity of concrete and the corrosion rate in the corrosion process of steel bars in fly ash concrete. The results showed that the resistivity of concrete increased with an increase in fly ash replacement, and the corrosion rate declined with the fly ash replacement increases. In addition, in fly ash concrete, the corrosion rate of plain bars were obviously smaller than that of ribbed bars.

尽管钢筋腐蚀是导致现有钢筋混凝土结构耐久性下降的主要原因，但重要的是要了解混凝土中的钢筋腐蚀并充分预测腐蚀过程。本文研究了在恒定气候条件下，普通混凝土和三种粉煤灰替换质量比分别为15％，30％和45％的粉煤灰中钢筋的腐蚀过程。同时，采用先进的数字视频显微镜测量系统研究了钢/混凝土界面在腐蚀不同阶段的显微组织。从混凝土的电阻率和粉煤灰混凝土中钢筋腐蚀过程中的腐蚀速率分析了粉煤灰替代的影响。结果表明，混凝土的电阻率随粉煤灰替代量的增加而增加，腐蚀速率随粉煤灰替代量的增加而降低。另外，在粉煤灰混凝土中，普通钢筋的腐蚀速率明显小于肋筋。