Structural shape effect on rehabilitation of vertical concrete structures by ECE technique

Electro-migration of ionic species due to cathodic polarization is used to extract chloride ions from reinforced concrete, hence, the name electrochemical chloride extraction, (ECE). The embedded reinforcing steel is made cathodic with respect to an externally placed anode blanketed within suitable electrolyte-holding fibre material. In the present study, an examination has been made of the effect of structural (design) requirements and the geometric configurations of different reinforced concrete (r.c.) column specimens. Also of practical concern was the fate of the chloride ions within the r.c. column hoop and opposite face of the anode during the ECE application. This is because the extraction application is from one face of the column structure, and secondly, the chloride ions must pass between negatively charged rebars in order to exit the structure. It is observed that circular columns containing spiral reinforcements show better ECE performance than structures with planar surfaces. In most cases, the geometrical curvatures in candidate systems will require (structurally), a more closely spaced reinforcing steel and ties. Hence, the proximity of such reinforcing steel and ties, as well as the greater total steel quantity means an efficient ECE system.