As part of a durability study, this paper describes the mixing and curing effect of sea water on setting time, compressive strength of cement-sand mortar and corresponding concrete, rebar corrosion, chloride content and variation of alkalinity over a period of 18 months in a laboratory simulated splash/tidal zone of marine environment. The test results indicate that sea water is not suitable for the mixing and curing of both plain and reinforced concrete in such marine conditions.