| Summary: | 碩士 === 國立臺灣海洋大學 === 河海工程學系 === 98 === The chloride-induced corrosion of the steel reinforcement in concrete is identifies as the main cause of deterioration of reinforced concrete (RC) structures under marine environment and deicing salt. A reliable prediction of service life such as the time to corrosion initiation of RC structures exposed to chlorides is very important for the selection of evaluation model techniques. Existing models are mostly based on the diffusion-based or diffusion-convection transport model for predicting the time and space variation of chloride content in concrete. These transport models have the governing parameters such as concrete cover depth, chloride diffusion coefficient in concrete, surface chloride concentration, chloride threshold level, temperature, time, material constant, and permeability coefficient. A considerable level of uncertainty may be associated with one or more of the above identified parameters. Therefore, carrying out a sensitivity analysis becomes necessary to evaluate the impact of uncertainties from the input parameters on the uncertainty of the model output. The main purpose of this article is carried out sensitivity analyses of the diffusion-convection and diffusion-based models. This article performed firstly sensitivity study of a multimechanistic chloride transport model using nominal range sensitivity analysis and then sensitivity study of corrosion initiations model of RC structures in chloride-laden environment using differential analysis technique. The results of the present study were described as follows:
1. The service life of a RC structure can be drastically under-or overestimated if efforts are not made to set realistically represent the material and environmental properties involved in the situation that is modeled.
2. If the hydraulic conductivity is too small to replace the diffusion-convection corrosion initiation model by the diffusion-based one.
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