The simplest way to assess the severity of steel corrosion is to measure the corrosion potential, since it is qualitatively associated with the steel corrosion rate. One can measure the potential difference between a standard portable half-cell, normally a copper/ copper sulphate (Cu/CuSO4) standard reference electrode placed on the surface of the concrete with the steel reinforcement underneath. The reference electrode is connected to the positive end of the voltmeter and the steel reinforcement to the negative. This test can give the probability of corrosion activity taking place at the point where the measurement of potentials is taken from a half-cell, typically a copper-copper sulphate half-cell. An electrical contact is established with the exposed steel & the half-cell is moved across the surface of concrete for measuring the potentials.
Half Cell Potential Meter Testing Method
The use of this method of Gamma Radiography is not allowed in some countries due to the issues concerning human safety because of its high reactivity & volatility.