Influence of environmental parameters on application of standard ASTM C876-91: half cell potential measurements

Abstract Since the potential of corrosion of any metal in contact with concrete is a function of a large number of variables related to the composition of pore solution, degree of polarisation, temperature and cover depth, no quantitative (corrosion rate) conclusion can be drawn from it. Potentials do not provide relevant information on the amount of corrosion. The validity of these interpretations has been questioned in some situations such as saturated structures, or when carbonation is the cause of the corrosion or cathodic processes are modified. Half cell potential technique (ASTM C 876) is however a useful tool widely used for in situ assessment of the corrosion state of rebars. Some applications of the ASTM C 876 standard are presented and it has been shown that this standard cannot be used under all conditions. Finally, some recommendations are provided in an attempt to optimise the application of the ASTM C 876 standard.