Study on the Influencing Factors of Reinforcement Corrosion Measurements in Concrete

• Main Authors: Ching-Hsien Wu, 吳靖賢
• Other Authors: Chun-tao Chen
• Format: Others
• Language: zh-TW
• Published: 2014
• Online Access: http://ndltd.ncl.edu.tw/handle/77736665675189041713

碩士 === 國立臺灣科技大學 === 營建工程系 === 102 === This study explores the influencing factors, reliability, and methods to increase the accuracy in reinforment corrosion measurements. The results are expected to be applicable onsite, thereby contributing to draft for a new standard and evaluate the lifecycles in existing or new buildings. During the tests, the specimens were immersed in 3.5% salt water and charged for accelerated coccorion. The corrosion currents were measured daily using galvanostatic technique, linear polarization and impendences. The corrosion rates and the amount of corrosion were then estimated and used to be compared with the weight loss. Results showed that the calculated weight loss is linearly proportional to the weight loss in mortar specimens with w/c of 0.4, 0.5, and 0.6, and cover thickness of 3 cm or 6 cm. The weight loss can be estimated by multiplying the calculated weight losses by 25, 50, 250, or 1000, respectively. In concrete specimens, such multiplying factor is only 5. In addition, the measuring values of the corrosion currents were reduced by 20% as the moisture content of the specimens were reduced by 5%. The measurements at the location where the dow bars overlapped were unstable and the dow bars had more severe corrosion than the main bars. Adequate polarization can be archieved by using impulse current of 100 μA and impulse time of 10 s, and stable measurements were obtained by using an overpotential of ±10 mV and duration of 30 s. On the other hand, the measurements were not taken in specimens with tiles ontop. Therefore, in future applications, the tiles must be removed and the cover properties must be considered prior to the corrosion measurements.