Inspection of Buildings in Rio de Janeiro-Brazil: Proving the greater tendency of corrosion at the base of reinforced concrete columns using potential corrosion technique

Monitoring the corrosion of steel embedded in concrete is a way to assess the degradation of civil structures. A technique used for this is the measurement of corrosion potential, which includes the use of a reference electrode, connected to a high input impedance voltmeter. There are many factors influencing the measurement of corrosion potential, such as: degree of concrete moisture content, the oxygen access, existence of micro fissures, chloride penetration, carbonation and concrete cover thickness. This study aims to analyze the measurement of corrosion potential for the copper/copper sulfate (Cu/CuSO4) electrode obtained in the inspection work of four residential buildings located in Barra da Tijuca, Rio de Janeiro, Brazil. The evaluation aims to investigate the difference in measurements of corrosion potential in the middle and bottom of each inspected column. The reason for the research is to explain a practical realization: the reinforcement corrosion can be seen more often at the columns base than in the remaining of this type of structural element. General data for all the 4 buildings inspected indicates that 77% of all 109 inspected columns have more negative corrosion potential values at the base. The reasons for this discovery are discussed throughout this paper