New controlled release corrosion inhibitors for reinforced concrete structures

The main cause for RCS degradation is the corrosion of steel reinforcement, due to a pH reduction because of the carbonation process or the penetration of chloride ions leading to the pitting corrosion of steel. Concrete deterioration of reinforced concrete structures (RCS) has become one of the more costly problems, an estimated three to four percent of gross national product for direct and indirect costs in the developed countries, in maintenance and repair operations. The aim of this research work is the use of controlled delivery release corrosion inhibitors as a palliative method to prevent corrosion of RCS. This kind of inhibitors allow a controlled delivery within the concrete matrix or by incorporation in a steel conversion layer, thus enabling a slow and gradual release of the inhibitor compound as a function of the pH environment and selectivity depending on the aggressive agent, such as chloride or carbonates involved in the corrosion process. The inhibitors will be studied the calcium nitrite (as a reference inhibitor) encapsulated in natural rosins by double micro-emulsion method, as a controlled release corrosion inhibitors.