Effectiveness and Throwing Power of Hybrid Anode Cathodic Protection in Chloride Contaminated Reinforced Concrete
摘要
Hybrid cathodic protection (HCP) of steel in concrete works by combining impressed current cathodic protection (ICCP) and galvanic cathodic protection (GCP) into two consecutive phases. Hereby, the first phase (ICCP) aims to realize pit-realkalisation, while the second phase (GCP) aims to keep the passivity of the reinforcement. In this research, the influence of chloride concentration, cement type, charge density during first phase and type of anode on the throwing power and protection degree of HCP with discrete anodes is investigated for concrete slab elements. Results show a comparable throwing power (around 250 ± 30 mm) of the HCP system for concrete with no or a limited mixed-in chloride concentration and a varying cement type, charge density during 1st phase or type of anode. For concrete with a severe contamination of chlorides (2 m% Cl− ~ cement mass), the throwing power is greatly reduced to only 50 mm. Consequently, based on the 100 mV depolarization criterium (EN ISO 12696:2022), HCP was found to be most effective for concrete with a relatively limited mixed-in chloride content and with discrete anodes containing an integrated DC power source.