Electrochemical repair techniques in carbonated concrete. Part II: cathodic protection

The role of several factors such as concrete composition, exposure condition and pre-corrosion of steel reinforcement in concrete on the effectiveness of the electrochemical realkalisation (ER) technique was discussed in Part I of this article (Bertolini and Redaelli in J Appl Electrochem, doi:10.1007/s10800-011-0301-4, 2011). Here the same factors will be considered in the case of cathodic protection (CP). CP differs from ER since it is a permanent technique with much lower applied current density. It was originally introduced to protect steel from corrosion in chloride-contaminated concrete; however, it can be advantageous even in carbonated concrete, in particular compared to conventional repair. CP tests were carried out on reinforced specimens made with six different types of concrete, subjected to accelerated carbonation. CP was applied with a current density of 10 mA m(-2) of steel preceded by a start-up current density of 100 mA m(-2) for 3 weeks. Reference specimens in the same conditions were also considered.