Effects of steel fibers on the electrochemical corrosion signals of rebar

• Main Authors: Jyun Gang Li, 李俊鋼
• Other Authors: Jiang Jhy Chang
• Format: Others
• Language: zh-TW
• Published: 2008
• Online Access: http://ndltd.ncl.edu.tw/handle/89967641983636154299

碩士 === 國立臺灣海洋大學 === 河海工程學系 === 96 === Abstract Rebar corrosion is a key issue for concrete durability. In this study, what is the effect of adding steel fibers in concrete on the electrochemical measurements is studied. First, the electrochemical measurements were taken for steel fiber and steel rebar in the simulated pore solution environment with chloride concentrations of 0, 1, 2 and 3 %. Then, the electrochemical measurements were taken for steel rebar in the simulated pore solution environment with various chloride concentrations with adding different amount of fibers (0, 0.25 and 0.5%) to see whether the fibers will affect the electrochemical measurements. Final, the mortar specimens were made and electrochemical measurements as well as the mechanical and physical properties, including the open circuit potential, corrosion rate, compressive strength, splitting tensile strength, four-probe electrical resistivity and water absorption test, were evaluated to see the effects of fibers. Results showed that steel fibers had better corrosion prevention capability than rebars, and fibers had better resistance to chloride ions. When no chloride ions existed, the steel fiber had a nobler potential. Adding steel fibers indeed disturb the electrochemical measurements of steel rebar. When steel fibers have no apparent corrosion, the corrosion rate showed a medium-to-high corrosion risk. It means the corrosion rate measurement for steel fibers cannot be taken as the corrosion index. For low chloride ion concentration environment, adding steel fibers did not retard the corrosion of steel rebar. For environments with chloride ions, adding steel fibers can retard the corrosion and this effect becomes more apparent as the volume ratio of steel fibers is higher. For long term trend, if the chloride ion existed in concrete the retarding effect of adding steel fibers is not apparent but more violent corrosion of rebar may occur due to the galvanic cell effect between corroded steel fibers and rebar. Keywords: rebar corrosion, steel fiber corrosion, chloride ions, corrosion behaviours