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：为了对混凝土结构物上氯离子附着的主要原因--空气中的氯离子进行定量化，对不同海岸的氯离子及其垂直分布进行了测量。此外，还利用冲绳气象局的气象资料研究了氯离子与风速的关系。以气载氯化物的数量和分布为边界条件，用有限元方法分析了氯化物的输运方程。对评价结果进行了评价，提出了估算海边不同地点空气中氯化物的新方法。氯离子的分布指示了劣化的评价指标。研究了氯离子在混凝土中的渗透过程和分布。这些都被认为对钢的腐蚀及其发展产生了巨大的影响。使用两个暴露了7年和12年的试验结构来研究其劣化特征。对试验结果进行了评价，提出了考虑含气氯化物、混凝土碳化、水灰比(w/c)和时间等因素对扩散方程影响的新的分析方法。利用该方法对氯离子环境下不同位置的氯离子含量分布进行了估算。将分析结果与现场数据进行了比较，结果表明，该方法具有较好的计算结果，能较好地反映实际现象。

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.