Sea sand cannot be directly used in buildings, because the high chloride content in sea sand, whether used in mortar or concrete, seriously affects the durability of structures.

According to the specification JGJ206-20 10 Technical Specification for the Application of Sea Sand Concrete, the sea sand must meet the following four conditions: 1. Sea sand used for concrete must be purified; 2. Sea sand shall not be used for prestressed concrete; 3. Sea sand for concrete should use seabed sand; 4. Sea sand should be mixed with natural sand or artificial sand.

Therefore, the purified sea sand can be used in buildings.