Yuki SAITO
Effect of Non-uniformity of Corrosion of Steel in Concrete on Criteria of Corrosion Crack
Supervisorˇ§Takumi SHIMOMURA
To predict corrosion crack in reinforced concrete structures, it is necessary to clarify threshold degree of corrosion when crack occurs. Simulating corrosion crack, crack was induced in the concrete specimens by using a nonexplosive demolition agent in this study. The influence of the spatial non-uniformity of corrosion of steel on the occurence of corrosion crack was investigated by the experiment, in which length of the expansion section, the expansion angle in reinforcement section and thickness of concrete cover were set as test parameters.
The experimentally obtained corrosion loss at the occurrence of crack was between 8.7 and 34.4mg/cm2, depending on thickness of concrete cover and length of the expansion section. The obtained threshold corrosion losses were almost greater than 10mg/cm2 in Standard Specifications for Concrete Structures. This result implies that the threshold value in the Standard Specification can meet the decision in the safety side.
Three dimensional diagram was drawn with respect to concrete cover, expansion section length and threshold corrosion loss at cracking, and the experimental plane was identified. It was found that some data were not on the experimental plane because of the difference in cracking mode.
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