An Analysis and Prevention Plan of the Deterioration and Corrosion of Taiwan’s Coastal RC Bridge Structures

• Main Authors: Yi-Hsiung Liu, 劉益雄
• Other Authors: Chao-Lung Hwang
• Format: Others
• Language: zh-TW
• Published: 2004
• Online Access: http://ndltd.ncl.edu.tw/handle/07808811563563990019

碩士 === 國立臺灣科技大學 === 營建工程系 === 92 === Corrosion of bridge structures is a problem faced by countries throughout the world. Taiwan is no different; with narrow topography metropolitan and industrial areas have been forced to intersect with coastal regions creating a complicated corrosion problem. Especially in coastal regions, bridges are directly exposed to a harsh corrosive environment creating challenges for the durability of bridge structures. This research performs an analysis and examination of the current corrosion status of bridge structures in Taiwan. A survey and analysis of the climatic factors in corrosion is also conducted. Results of domestic and foreign research have been combined to find the correlations between corrosion of bridge structures and factors such as the environment and quality of materials. In regards to the patterns and factors in corrosion of domestic bridge structures, this research drafts a suitable prevention plan providing proper design, materials, and other related suggestions that would help prevent corrosion. Results of this research show that the warmth, humidity, and the coastal regions’ climatic conditions have a deep impact on corrosion. Using non-destructive electrochemical testing equipment to test steel reinforced concrete, a serious problem was revealed in the corrosion of coastal bridges. After undergoing destructive drill testing, concrete was extracted and tested for compressive resistance/strength as well as analyzed for chloride ion distribution and diffusion. Tests revealed that the ions in the concrete were diffusing, the rate of which has a close relationship with factors such as the environment, quality of material, and quality of construction. Research has shown that the level of adhesion of ions on the surface of concrete is clearly higher in older bridges than that of other bridges. The distance from the coastline will also have a clear effect on the level of ion adhesion. Bridges near the ocean (facing the ocean winds) have a clear higher rate of ion adhesion than bridges inland (facing away from ocean winds). There is no clear difference however between bridges facing ocean winds and those not facing ocean winds that are of a distance above 3km from the coastline. Thus in these cases, chloride ion is not an influence. Taiwan’s environment and climate create high levels of corrosion. Current structures already face the test of exposure to extremely harsh conditions. High quality materials and strict construction supervision need to be considered for the building of future structures. It is suggested that corrosion prevention policies employ density matching and high performance concrete during filling to increase the water tightness of concrete materials and increase the structure’s overall durability.