Corrosão Acelerada por Imersão Modificada (ensaio CAIM) sobre ação de meio salino e água cinza em barras de aço usadas em concreto armado

Abstract

Clean, potable water is essential for the maintenance of life and for this reason the proper use of this resource is essential for its preservation. In civil construction, drinking water is used to carry out most activities. In the northeastern hinterland of Brazil, the use of water in civil construction contrasts with the absence of water and the basic needs of the country people. Thinking about mitigating this contrast, this work aims to evaluate the effects of corrosion caused by gray water (GW) on carbon steel bars through the ACMI test with the aim of verifying the mechanisms of direct corrosion in concrete reinforcement. Gray water, reused water, contains salts that can influence the corrosion of metals and the control of its constituents can be fundamental for the viability of its use in concrete. The study of accelerated corrosion by the ACMI test on steel bars was carried out by immersion in saline water and gray water. The bars were emerged for a period of 8 hours under a voltage of 15 Volts. The study of corrosion mechanisms on the bar was followed by the evolution of the current over time, corrosion rate and optical microscopy. The results show that the GW with low organic content derived from the washing machine, under study, is a less aggressive electrolyte than saline water, certainly due to the lower divisibility of chlorides and oxygen in the medium. Thus, depending on the composition, the use of this type of water may be an option for use in concrete structures, however, the interaction of GW with other mixing constituents such as cement and aggregates must also be considered, which they can form micropiles, requiring further study of the control mechanisms of the corrosive process.