| Summary: | 碩士 === 國立屏東科技大學 === 土木工程系所 === 97 === In the study, the electrification analytic technique was used to measure corrosion potential, concrete resistivity and corrosion current density, and then a direct current device was utilized to accelerate corrosion. The GECOR 8 corrosion rate meter was used to measure corrosion potential, concrete resistivity, and corrosion current density in different level of corrosion steel bars. The next values were then compared with the corrosion potential measured by the CANIN corrosion instrument. After the measurements, steel bars were taken from concrete and to calculate their losses by the weight loss method. The results were then compared with the measured values.
The test results show that, the measured corrosion potential by the apparatus basically increases with time. The point closer to the exposure of reinforcing bar probably has lower measured corrosion potential. The corrosion potential measured by detector B of GECOR 8 is closer to that by CANIN, and those by detector A and detector C are lower and close to each other. Therefore, the values of detector B may be more accurate. The concrete resistivity measured by detector B is more accurate than that by detector C. The corrosion current density detector A is too lower than that by detector C and is not accurate. The results also show that, in the corrosion-accelerated tests, the amount of steel corrosion is well correlated with the electricity amount. The regression equation is Wloss=0.32Q+4.6, R2 is 0.86.
The feasibility of using corrosion potential method to measure steel corrosion is bad. Concrete resistivity is to reflect the quality of concrete in protective layer, not the steel corrosion. Therefore, its correlation with steel corrosion is small. The corrosion current density by the weight loss method icorrW is well correlated with that by detector C icorrC. The regression equation is icorrW=1.24icorrC+5.5, R2 is 0.72. The intercept of the equation 5.5 μA/cm2 can be treated as the estimated corrosion current density for the exposed part of steel bar.
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