Abstract: Problems such as corrosion of reinforced concrete, lack of river sand and fresh water cause difficulties in the construction of offshore projects. Due to the rich resources of seawater and sea-sand, experts and scholars at home and abroad put forward to use seawater and sea-sand instead of fresh water and river sand to prepare concrete. Workability, mechanical properties and durability of seawater and sea-sand concrete were studied. Chlorine salts of seawater and sea-sand accelerate the setting and hydration of cement, leading to early setting and increasing the early strength of the concrete. However, the strength of seawater and sea-sand concrete grows slowly in the later period, and its final strength is similar to that of ordinary concrete. A small amount of shells in sea-sand has little effect on the workability and mechanical properties of concrete. Different from doped chloride ion, the mechanisms of chloride transmission and binding capabilities of seawater and sea-sand concrete are more complex. As a result, the mechanism of reinforcement corrosion in seawater and sea-sand concrete is changed. However, supplementary cementitious materials, compound rust inhibitor and fiber reinforced polymer bar provide guarantee for the application of seawater and sea-sand concrete structures.

Key words: seawater and sea-sand concrete, mechanical property, durability, chloride binding, reinforcement corrosion