Corrosion of steel bars embedded in concrete having compressive strengths of 20, 30 and 46 MPa was
investigated. Reinforced concrete specimens were immersed in a 3% NaCl solution by weight for 1, 7
and 15 days. In order to accelerate the chemical reactions, an external current of 0.4 A was applied using
portable power supply. Corrosion rate was measured by retrieving electrochemical information of polarization
technique. Pull-out tests of reinforced concrete specimens were then conducted to assess the corroded
steel/concrete bond characteristics.
Experimental results showed that corrosion rate of steel bars and bond strength between corroded
steel/concrete were dependent on concrete strength and accelerated corrosion period. As concrete
strength increased from 20 to 46 MPa, corrosion rate of embedded steel decreased. First day of corrosion
acceleration caused a slight increase in steel/concrete bond strength, whereas sever corrosion after 7 and
15 days of corrosion acceleration significantly reduced steel/concrete bond strength. Visual and metallographic
observation of steel bars removed from concrete samples after testing revealed that the severity
of corrosion reactions and reduction of steel bar diameter increased as the corrosion acceleration period
increased. Presence of localized corrosion pits as well as severe corrosion grooves of steel bars was con-
firmed after 7 and 15 days of corrosion acceleration, respectively