Study on Evaluation of Chloride Attack Environment and Deterioration for RC Buildings at Marine Zones under Subtropical Weather

氯离子附着环境的评价：为了量化空气中的氯离子，这是氯离子附着在混凝土结构上的主要原因，在不同的海岸线上测量了氯离子及其垂直分布。此外，从冲绳气象局的天气数据被用来调查氯离子和风速的关系。以空气中氯化物的含量和分布为边界条件，对氯化物的输运方程进行了有限元分析。通过对试验结果的评价，提出了估算沿海不同位置空气中氯离子含量的新方法，以氯离子分布作为混凝土劣化的评价指标，研究了氯离子渗透过程及氯离子在混凝土中的分布。这些都被认为对钢铁腐蚀及其发展产生了重大影响。两个测试结构暴露7年和12年用于调查的退化特性。通过对试验结果的评价，提出了考虑含气氯离子、混凝土碳化、水灰比和时间等因素影响的扩散方程解析方法。利用所提出的方法，估算了氯离子环境下不同位置的氯离子含量分布。分析结果与现场实测数据进行了比较，表明该方法具有良好的效果，能反映真实的现象特征。

Evaluation on chloride attach environment.In order to quantify air-laden chloride which are the main cause of chloride attach to concrete structures, chloride ions and their vertical distributions are measured at various sea-shores. Also, the weather data from the Okinawa Weather Bureau are used to investigate relation between chloride ions and wind velocity. The quantify and the distributions of air-laden chlorides are considered as boundary conditions, and the transportation equation of chlorides are analyzed by F.E.M.. Evaluating the results, new technique for estimating air-laden chlorides at different locations from seashore is proposed.Distribution of chloride ions indicating evaluation index of deterioration.The process of chloride penetration and distribution of chlorides in concrete are investigated. These are considered to give the great influence on steel corrosion and its development. Two test structures exposed for 7 and 12 years are used for investigating the characteristics of deterioration. Evaluation the test results, new analytical method for the diffusion equation is proposed, where the influences from air-laden chlorides, carbonation of concrete, water cement ratio (w/c) and time are considered. By using the proposed method, the distributions of chloride content at various locations under chloride environment are estimated. The analytical results are compared with the filed data and it is concluded that the proposed method gives the excellent results and represents characteristics of real phenomenon.