Study on Estimation Method of Durability for Reinforced Concrete Structures under Chloride Contaminated Environment

为了对氯离子污染环境下的钢筋混凝土结构进行合理的耐久性设计和正确的诊断，有必要了解气载氯离子的特性，弄清氯离子在混凝土中的渗透过程。此外，重要的是评估钢筋周围的氯离子量与时间的定量关系。因此，本研究对气载氯离子的特性和氯离子在混凝土中的渗透过程进行了实验和分析研究，并对研究结果进行了讨论，主要内容如下：介绍了本研究的背景和相关研究者的概况，以说明本研究的目的.本文提出的气载氯化物的对流扩散方程考虑了表面粗糙度和障碍物的屏蔽作用。用有限元法得到了该方程的解析解，并将结果与现场数据进行比较。证实了它们在定性和定量上都有密切的联系.提出了一种基于神经网络的混凝土氯离子含量的评价方法。神经网络的输出数据被证实是正确的值，这是密切相关的实测数据。最近，过早恶化的既有钢筋混凝土结构已成为公众关注的问题，未来的钢筋混凝土结构的耐久性要求。研究结果可为氯离子污染环境下钢筋混凝土结构的耐久性设计和诊断提供参考。

In order to perform rational durability design and proper diagnosis of reinforced concrete structures under chloride contaminated environment, it is necessary to understand the characteristics of air born chlorides and clarify the penetrating process of chloride ions into concrete. Also, it becomes important to evaluate the amount of chloride ions around steel reinforcement quantitatively relating with time. Therefore, this research presents experimental and analytical studies on the characteristics of air born chlorides and the penetrating process of chloride ions into concrete.The outline of the discussion about research result is as following;The background of this research and wide survey of related researchers are presented in order to show the purpose of this research.1. The advection and diffusion equation of air born chlorides proposed here takes account of the surface roughness and the shielding effect due to barriers. The analytical results of the proposed equation are obtained by using the finite element method (F.E.M.), and the results are compared to the field data. It is confirmed that they are closely related each other qualitatively and quantitatively.2. This paper proposes an evaluating method of chloride ion content in concrete by the Neural-Network. Output data from the Neural-Network are confirmed to present proper values which are closely related to the measured data.Recently, premature deterioration of existing reinforced concrete structures has become a public concern and future reinforced concrete structures are required to have durability. Therefore, the results from this research are believed to give valuable information for durability design and diagnosis of reinforced concrete structures under chloride contaminated environment.