Corrosion Diagnostics Performed on Cores Drilled from Concrete Structures, Using the Laboratory Simulation of Temperature and Relative Humidity Impact

Abstract

This paper presents an improved procedure for conducting diagnostics tests on corrosion in reinforced concrete structures. This method consists in drilling cylindrical concrete cores with fragments of secondary steel reinforcement (e.g., spacer bars, stirrups, binders) from the selected areas of the structure. Then, a three-electrode system is arranged on those cylindrical cores under laboratory conditions. The fragment of steel rebar with concrete is used as the working electrode. Using the counter electrode in the form of a patented conductive coating applied on the core side wall with painting techniques and the graphite reference electrode placed in an opening made in the core near the reinforcement was the novelty of this method. Following the procedure, the occurrence of minimum and maximum corrosion rates in concrete is simulated in the climate chamber after determining, on the basis of historical weather data, extreme combinations of temperature, and relative humidity for a given structure. This method was verified in the diagnostics testing of two large reinforced concrete tanks for fresh water, and cement storage silos.

Time-Dependency in the Corrosion Process of Reinforced Concrete Subjected to a Chloride Solution

“…Therefore, evaluation and prevention of RC corrosion are crucial for ensuring safety. Many studies have examined the modelling and mechanisms of steel corrosion through the effects of chloride attack and carbonation [4]. However, the studies examining corrosion detection in RC structures have had significant limitations owing to differences in the corrosion behaviour between laboratory experiments and actual structures, nonhomogeneous concrete materials, and local conditions which can influence the results.…”