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The present work shows the study of the distribution of current and electrochemical potential in the reinforcing steel by using as anode a layer of cement paste added with graphite powder and carbon fiber. The research was carried out on concrete slabs with w / c ratio of 0.5. Each slab is placed 12 steel rods. One of the slabs was contaminated with Cl- added in the mixing water 5% NaCl by weight. Was applied on each slab a layer thickness of 1cm conductive cement paste. Was measured current draw of each rod as well as the polarized potential. The use of a cement material conductive paste shows a good performance as anode in the PCCI reinforcing steel to achieve maintain polarized potential of-800mV.

The transport of ions such as chloride ion through the concrete has been the subject of study, because the entrance of these, affects the useful life of the structure. The mechanism of ionic transport is described by the Nernst-Planck equation and to solve the problem numerical techniques such as the Finite Difference Method (MDF) or Finite Element (MEF) are used which require a meshing process and a higher cost Computational. In this work, relatively new methods such as the Radial Base Functions (FBR) method and the Fundamental Solution Method (MSF) were applied, which do not require a mesh to solve the ion transport problem.

In this paper is presented the application of the Method of Fundamental Solution (MFS) to obtain the solution of Laplace equation with linear boundary conditions to describe the distribution of potentials in corrosion cells. The results obtained by this method are compared with another numerical method, in this case finite element. As case of study takes the interior problem analyzed by McCafferty (1). In which two concentric electrodes placed in bottom of a cylindrical container, creating a galvanic cell. The results obtained by the MFS present a good agreement with the calculated by finite element.

In this work, the degradation of bond between steel and concrete under cathodic protection conditions (-1000mV≤ E ≤ -850mV vs. Ag/AgCl) and cathodic overprotection ((E < -1000 mV vs Ag/AgCl) by impressed current applied in two mixtures submerged in a solution of 3.5% wt. NaCl was evaluated; the first fabricated from ordinary Portland cement (OPC) and the second by substituting 15% of the cement with fly ash(OPCFA). According to the results of chemical analysis and Electrochemical impedance spectroscopy on the steel-concrete interface, was found an increase in the concentration of potassium, sodium (K+, Na+) and hydrogen (H+) ions . In addition, was observed that for specimens subjected to overprotection presented a higher bond loss, this based on pull out test results also realized.