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

氯离子附着环境评价。空气中的氯离子是导致混凝土结构中氯离子附着的主要原因，为了定量分析空气中的氯离子及其垂直分布，在不同的海岸进行了测量。同时，利用冲绳气象局的气象资料，研究了氯离子与风速的关系。以空气中氯化物的数量和分布为边界条件，用有限元法分析了氯化物的输运方程。通过对结果的评价，提出了一种估算海滨不同地点空气中氯化物含量的新方法。指示变质评价指标的氯离子分布。研究了氯化物在混凝土中的渗透过程和分布。这些因素对钢的腐蚀及其发展有很大的影响。两个试验结构分别暴露了7年和12年，用于研究老化特性。在对试验结果进行评价的基础上，提出了一种考虑空气氯化物、混凝土碳化、水灰比（w/c）和时间影响的扩散方程解析方法。利用该方法估算了氯化物环境下不同位置氯化物含量的分布。将分析结果与现场数据进行了比较，结果表明所提出的方法具有较好的结果，反映了实际现象的特征。

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.