ON CHLORIDE EXTRACTION FROM CONCRETE STRUCTURES AND ITS APPLICATION

Based on the electrochemical principle of steel corrosion in concrete structures, the principle of chloride ion extraction from concrete is studied. Sixty cylinder specimen and three slab specimen with admixed chloride ion concentration varying from 1.5-3%, by weightof cement, were tested to study the coefficients which affect the efficiency of desalination process, bond strength and mechanical behavior of bending slabs after desalination. It is found that the option of anode mesh, electrolytes and current in desalination is the key to sufficient desalination. The side effectof desalination is impairmentof bond strength. It is shown that the impairmentof bond strength is up to 30-35% for rod rebars. But partof bond strength can be recovered for a time after desalination. It is also shown that desalination cannot significantly change the load carrying capacity and load-deflection relationship of bending members.