Corrosion Resistance Behavior of Cr–Cu Alloyed Thermo-Mechanically Treated Reinforced Bars in 3.5% NaCl Solution

The corrosion resistance of reinforcing steels are of interest to the building and construction industry as it decides the durability of structures. These steels passivates under very high alkaline pore solution (leached solution from concrete). However, they corrode once they come in direct contact with chlorides ions (near sea coast and/or de-icing material) causing premature deterioration of the entire concrete structure. To protect steel bar from corrosion, they are alloyed with chromium (up to 0.50%) in steps to steel and their corrosion resistance behavior are compared with unalloyed rebar in chloride environment. In general, chromium addition in steel provides better corrosion protection through surface passivation than unalloyed one. However, in the present study, increase in chromium content in steel did not show a direct relationship to the corrosion protection of thermo mechanically treated (TMT) rebars. To ensure the corrosion protection of TMT rebars, the critical limit of chromium addition should be 0.3%. The corrosion resistance of the TMT with varying chromium content followed the following trends: TMT-0.5Cr > TMT-0.3Cr > TMT > TMT-0.1Cr.