Physico-chemical behaviour of concrete cover and reinforcing steel under cathodic protection

摘要: Steel in reinforced concrete structures is normally protected against corrosion by the alkalinity and the physical barrier of the surrounding concrete. Nevertheless, carbonation or chloride contamination can cause depassivation and hence corrosion of steel. A valuable technique which will stop further deterioration is cathodic protection. The objective of this experimental investigation was to study the influence of cathodic protection on the soundness of reinforcing steel and concrete cover. The test pieces were six concrete slabs manufactured with three cements and with and without silica fumes. Cathodic protection with impressed current system had been applied to the reinforcements for three years. To accelerate ageing, the slabs were subjected to freezing and thawing cycles and sprayed with sodium chloride solution. A first part of the study, concerning electrochemical measurements, was presented in 1994. ¹ After cathodic protection testing, the slabs underwent physico-chemical analysis in order to show the final condition of steel and concrete.