1985 Volume 23 Issue 12 Pages 21-27
The island of Okinawa is located in the most southern part of Japan is sole prefecture which belongs to the sub-tropical zone amongst all other Japanese prefectures. It is surrounded by ocean on all sides and atmospheric temperature as well as humidity is relatively very high throughout the year. In addition, numerous typhoons (tropical cyclones) hit the island almost every year. Under these circumstances, concrete structure in this area is perpetually affected by the particle of salinity, thus, put it under grave conditions in terms of saline water-deterioration surroundings. In order to cope with such situation as above, JHPC has prepared“Guideline for Design and Construction of Concrete Structure on Okinawa Expressway (Ishikawa-Naha)-Draft Version”in 1983 for the purpose of securing sufficient durability of concrete structure against deterioration caused by saline water. Construction of the Okinawa Expressway is now under processing in accordance with this Guideline. This Report shows surroundings of deterioration by saline water and some examples of saline water-deteriorated structure. On the other hand, some countermeasures for deterioration are also provided for the reader's reference in this Report.
