Evaluation of repair in reinforced concrete when only take off the coating layer of de Steel bars.

Abstract

In this investigation, there were used prismatic specimens (CPP) molded with concrete, structural mortar, polymeric mortar and grout, In order to represent the repairs when all concrete is removed around the affected bar. In addition, samples made with repairs only to the steel bar cover layer to represent partial repairs. Each CPP with two CA 60 Ø 5.0 mm steel rods inserted. prepared in three conditions: zinc-based protective paint, nitrite-based protective paint and no protection. The physical properties of the materials, such as compressive strength, water absorption, and electrical resistivity, measured on cylindrical specimens. The CPPs subjected to drying cycles for fivedays in an oven at 50 ° C, followed by two days of wetting by partial immersion in 3.5% NaCl solution. After each cycle, the corrosion potentials measured with equipment with a high impedance voltmeter and a copper / copper sulfate half-cell. Data obtained that allowed to compare the efficiency of the protection as zinc and with nitrites coated with concrete, structural mortar, polymeric mortar and free against the attack of chloride. Thus, it seeks to discover which material has a better performance and which the degree of disadvantage between total and partial repairs. The preliminary analysis found that the protection with nitrites and cementitious grout obtained the best results, that when removing all the concrete around the steel bars the protection is better, however, partial repairs with corrosion inhibitors and coating with polymeric mortar or grout provides good protection, offering less risk to the structure.
Keywords: electrochemical methods, corrosion potential, mortar, concrete, chlorides, nitrites