Análise da viabilidade do uso de compósito de quitosana e do nitrito de sódio como inibidores de corrosão do aço e suas influências na tecnologia do concreto

Abstract

Reinforced concrete structures can present several manifestations that indicate problems capable of compromising the functionality of the elemento. Among these manifestations, the most aggravating in structural elements are those that affect the steel inside the structure, being this the corrosion and degradation of the metal. As a way of increasing the service life of reinforced concrete elements subjected to aggressive agents that degrade steel, corrosion inhibitors are used to retard the corrosive process. In this research, the following substances were used as corrosion inhibitors: sodium nitrite and chitosan composite. Sodium nitrite has already been used in research and commercially as a corrosion inhibitor for concrete structures and chitosan is an organic substance, a polymer of amino glucose, which has already been used as a corrosion inhibitor on steel surfaces, and this research analyzed its viability as a corrosion inhibitor of steel inside concrete elements, an analysis of the efficiency of these substances was measured by reading the corrosion potential in electrochemical tests at different ages, its influence on concrete technology in its physical and mechanical characteristics was also verified. The chitosan composite increased the consistency of the concrete, decreased its specific mass, but did not affect the voids index, in the compression strength and in modulus of elasticity the performance was inferior. Sodium nitrite, on the other hand, had a plasticizing effect on fresh concrete and had intermediate results in most tests, lower performance than reference concrete and higher than concrete with chitosan in the results of compression strength, modulus of elasticity and specific mass, but greater absorption and voids index than the other studied concretes.