Crushed stone and sea sand are generally used for concrete in Okinawa. The properties of these aggregates are inferior to those of ordinal river aggregates.
　The paper discusses the durability of concrete in marine environment with aggregates of Okinawa.
　In this exposure test, the exposure peirod is 10 years, and the main testing items are compressive strength, and corrosion of embedded steel bars.
　The main conclusions are as follows;
(1) With ordinary portland cement, the strength reduction of concrete with aggregates of Okinawa is a little more compared with that of concrete with ordinal ones. Also, the corrosion of embedded bars in concrete with aggregates of Okinawa is a little more than that in concrete with ordinal ones. The corrosion, however, is not so severe as to crack the concrete.
(2) Using blast furnace slag cement instead of ordinay portland cement, the strength reduction is not recognized.