The paper discusses the results of potential measurements on concrete reinforcements in presence of stray currents. To eliminate the spurious ohmic drop contribution, the “lateral gradient technique” has been used, This technique, formerly introduced for interfered steel structures, such as buried pipelines, has been investigated for reinforced concrete structures and then proved to be applicable also to the reinforcements, with or without cathodic protection, leading to potential readings not affected by the ohmic drop contribution. The interpretation of field measurements for concrete structures is discussed on the basis of laboratory test results for passive and active steel rebar,
Kevwords: stray current, cathodic protection, potential measurement, lateral gradient technique, polarisation resistance, Stern-Geary equation.