Implementation of non-destructive techniques for the monitoring of rebar corrosion of concretes developed for nuclear applications

摘要

There are many mechanisms associated to the degradation of reinforced concrete and, among them; the corrosion of the reinforcing bars is the most frequently degradation mechanism found. It is worth mentioning that the annual worldwide cost of maintaining and repairing of reinforced concrete structures is approximately eight thousand million dollars. So, the monitoring of the corrosion state of a reinforcing concrete structure is mandatory for economical (among others) reasons. In the present work, the rebar corrosion was studied by mean of different parameters such as: corrosion potential, corrosion rate, electrical resistivity, oxygen availability and temperature of the concrete and environment. The measurements were carried out by non-destructive electrochemical techniques, implemented with corrosion sensors embedded in the concrete. The sensor design involves an appropriate electrodes system. Besides, some of these parameters were measured directly from the structure by mean of a commercial instrument, which allows the confinement of the electrochemical signals in a selected zone. Two different reinforced concretes, designed for nuclear applications and whose durability must be higher than three hundred years, where compared from the rebar corrosion point of view. The work was carried out on prototypes, but focuses in the implementation of these techniques in real structures.