Análise da resistência à tração de barras corroídas por meio de ensaios acelerados

Abstract

The corrosion of reinforcement in reinforced concrete is one of the most important problems related to the durability of concrete. Corrosion causes the bar to mostly alter its mechanical performance. The ductility of the steel bar is indispensable, because it makes a structure safe when susceptible to collapse, guaranteeing a warning in case of rupture. Thus, the objective of the work is to perform an analysis of the effects of corrosion on the mechanical properties of corroded reinforcements through accelerated tests. The corrosion of the reinforcement of the present study, occurs by electrochemical action, with punctiform shape, that is, localized wear in the pits-shaped armature. The method used in the study consists basically of 24 cylindrical test specimens with a diameter of 50 mm and a height of 340 mm, the steel bars are 8 mm in diameter and 300 mm in length, the acceleration of corrosion occurred through the use of a solution of 3.5 g / L NaC1, justified because it is similar to the concentration of salt in sea water, current application through a source, in the times of 1,3,5, and 7 days, and finally the tensile test was performed. The mass variation, degree of corrosion, maximum stress and final elongation of the corroded bars were analyzed. The results show that corrosion directly affects the ductility properties. Since the mass variation and the degree of corrosion showed a great variation in the data, even in short periods of time. The final elongation showed a difference of 3 % to 11.5 % when compared to the control group and the mean maximum tension in relation to the control group had a percentage reduction from 5.96 % to 31.81 %, for the times of 1 and 7 days.