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.