Macrocell Processes in Reinforced Concrete Structures

Abstract

Corrosion of steel embedded in reinforced concrete is the phenomena that most affects the durability of this type of structures. The control and analysis of the rebars can help detect this problem beforehand, contributing to prevent costly repairs made when the damage is quite advanced. Currently, there are several techniques for measuring the corrosion rate of steel, but they have the disadvantage of being slow or requiring specialized tools. In addition, these techniques need direct connection to the rebars, so removing the concrete cover layer is necessary. This destructive technique is sometimes impossible to do because there are analysis zones which are inaccessible due to they are buried or submerged. Recently, using sensors embedded previously casting and external electrical connections let analyse the corrosion without using invasive techniques. This study presents the complementary technique of analysing macrocell currents in order to know the origin and direction of current in reinforcements. This technique requires less time and non-advanced material, only an ammeter and electrical connection to the rebars, executed before casting. In addition, this parameter provides information about the real corrosion of the different parts of the structure. In this study it is performed the laboratory analysis of this technique by the use of specimens containing one anode and one cathode inside them creating a macrocell. The influence of different environments on macrocell current intensities shall be studied and compared with other studied parameters as corrosion density.

Full document