| Summary: | 碩士 === 國立屏東科技大學 === 土木工程系碩士班 === 92 === The study employed an electrochemical nondestructive test to measure the corrosion potential, and corrosion current density of steel bar and the concrete resistivity in reinforced concrete, where the Gecor 8 corrosion rate meter was used to compare with the corrosion potential measured by the Proceq CANIN corrosion instrument. Variables of the experiment concluded steel bar diameter, cover depth, chloride ion content and concrete age. The required time and volume of pre-wetting water were also discussed for the measurement value went flat.
The results showed that, the pre-wetting time required was less in the beginning period than in later period after concrete was cast. Gecor 8 needed not more than 70 seconds to achieve a stable potential value, while CANIN needed not more than 110 seconds. MANOVA statistical analysis showed that, steel bar diameter and cover depth are not significant to corrosion potential and concrete resistivity, but cover depth is not significant to corrosion current density. Gecor 8 and CANIN are significant when measuring the corrosion potential, but the variance is acceptable. Finally, several regression equations of corrosion potential, corrosion current density and concrete resistivity respective to concrete age were developed for the different chloride ions contents of specimens. The results showed that, when chloride ion content went higher, corrosion potential and concrete resistivity became lower, but the corrosion current density went higher. That meant higher chloride ion content would cause more serious corrosion and higher corrosion rate. As concrete age increased, corrosion potential and the current density went lower, but concrete resistivity went higher. That meant corrosion became more serious but corrosion rate decreased as concrete age increased.
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