Risk assessment of environmental corrosion for reinforcing steel bars embedded in concrete in Taiwan
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Abstract
The main purpose of this work is to propose novel computational procedures for calculating the risk of corrosion of reinforcing steel bars induced by the environmental hazards including chloride ingress and carbonation in Taiwan; then, it can also be used to identify the appropriate thickness of a concrete cover for meeting a specified durability performance. Using the risk curve of corrosion of reinforcing steel bars, building designers can set an allowable reliability to discuss the durability of code-suggested minimal thicknesses of concrete covers for reinforced concrete (RC) members in Taiwan. Based on the simulation results, when a RC member is located within 0.3 km from the nearest coastline, along with the concrete cover, the concrete mix and surface coatings should be used as barriers to mitigate the corrosion risk for reinforcing steel bars. Additionally, considering the corrosion risk induced by carbonation and chloride ingress for a RC member with a specified service life of 50 years, which is most common setting in the building design, the minimal required thickness of concrete covers can be set as 7.5 cm when the member is located at 0.3–1.0 km from the nearest coastline. For a RC member located father than 1.0 km from the nearest coastline, its minimal required thickness of concrete covers can be set as 4 cm for the same required durable reliability. Although this work used a specified corrosion degree to calculate reliability of RC members with a specified concrete-cover thickness, the proposed computational procedures for deriving the corrosion risk of reinforcing steel bars can be applied to evaluate the effectiveness of various concrete-cover thicknesses on the mitigation of the corrosion risk.
Keywords
Corrosion Risk Chloride ingress Carbonation Reinforcing steelNotes
Acknowledgments
The authors would like to thank the National Science Council of the Republic of China, Taiwan, for financially supporting this research under Contract NSC 101-2221-E-011 -130 -MY3.
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