EFFECT OF CURRENT DISTRIBUTION ON CORROSION RATE MEASUREMENTS IN REINFORCED-CONCRETE

The effect of current distribution on corrosion rate measurements was studied for the case of reinforcing bars (rebar) in concrete. The mann er in which the current that is applied during electrochemical determi nation is distributed around the rebar circumference was considered th eoretically and by using an electrical analyzer. The ratio between the maximum and minimum current density (i(max) and i(min), respectively) at opposite points on the surface of the cylindrical electrode indica ted the lack of uniformity in the current distribution. This index fir st was estimated for the primary distribution of the current, which re presented a situation of less uniformity. Subsequently, an electrical resistance model was used to determine the additional effect of polari zation on the secondary distribution. Finally, an attempt was made to quantify the influence of a nonuniform current distribution around the rebar circumference on corrosion rate values obtained from the Stern- Geary equation.