Continued from the previous paper，the results of investigation of the reinforced concrete bridges in Naha-City and Ishigaki-Island are reported in this paper. Some other reinforced concrete structures are also examined. Carbonation tests and Chrolide content tests of the samples from existing reinforced concrete structures throughout Okinawa have been carried on. Based on this and the previous site investigations, including the above room test results, the followings are to be mentioned: 1. The deteriorations of reinforced concrete structures in Okinawa-prefecture due to steel bar corrosion are so prevailing, their degrees so serious and their speeds so rapid, that some protective measures must be taken promptly. 2. The great majority of existing bridges in this prefecture has been injured in some degree, and half of them are deteriorated hadly. 3. The main cause of the deterioration is salt included in concrete. 4. There are three major origins of the salt above: sand from seashore and sea, mixing water, and direct intrusion of salt water into concrete. 5. Direct intrusion of salt water into concrete after setting is most prominent effect on the salt content and consequently the deterioration of reinforced concrete structure.
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