| Summary: | 碩士 === 國立屏東科技大學 === 土木工程系所 === 96 === In the studies, an electrochemical technique was used to accelerate the corrosion of reinforcements by direct electric current to make reinforcements corrode in a short time period. The GECOR 8 corrosion rate meter was then used to measure the corrosion potential, concrete resistivity and corrosion current density of the reinforcements. The results were compared with the corrosion potential measured by the CANIN corrosion instrument. After the measurements, the reinforcements were taken out from concrete specimen to calculate the corrosion rate by the weight loss method. The relationships between the corrosion rate and the above measurement results are discussed. The studies also discuss the required volume of pre-wetting water and waiting time for obtaining a stable corrosion potential value in the measurements.
The test results showed that, to obtain a stable measurement value of corrosion potential in 64cm×60cm×15cm specimen, the required sprinkling time of pre-wetting water with an average flow 0.368 kg/sec is 90 seconds (i.e. 33 kg in volume). After sprinkling, the required waiting time is 150 seconds. The corrosion weight is very well correlated the electric quantity. The correlation coefficient R2 is 0.96. The studies show that, the feasibility of detecting corrosion by the potential method is very poor. The measurementresults of concrete resistivity are to reflect the quality of reinforcement concrete cover, not the reinforcement corrosion state, so that, their correlation with corrosion weight is very little. The corrosion rate can’t be correctly measured by sensor A of GECOR 8. The regression analysis of the corrosion current density measured by sensor C icorrC versus that by the weight loss method icorrW gives the equation icorrW=0.47icorrC+5.18, where the intercept 5.18 μA/cm2 can be treated as an estimate for the corrosion current density of the uncover part of each reinforcement. And due to non-uniform corrosion on the reinforcements, the measurement values by sensor C is about 2 times of that by the weight loss method.
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