Analysis of Accelerated Corrosion Experiment on Reinforced Concrete Slabs Using Half-Cell Potential Measurements

Corrosion of steel reinforcement is know to be the primary cause of deterioration for reinforced concrete structures. It is one of the foremost factors that affect the durability of concrete structures. The corrosion of steel reinforcement is most commonly caused by the action of chloride ions on the steel reinforcement. These chloride ions cause the breakdown of the passive film formed around the reinforcement due to the highly alkaline environment of the concrete. Damage to the concrete eventually manifests itself in the form of cracking and eventually spalling of the concrete. End of service life for the corrosion affected structures is characterized by the loss of concrete cover of the reinforcement. At this stage, the reinforcement is no longer protected against further degradation from corrosion. In this research, corrosion in reinforced concrete structures is induced by means of accelerated corrosion experiment. Reinforced concrete slabs were cast with various different cover thickness for the steel reinforcement (1.5-in, 2.0-in and 2.5-in) and the effects of chloride induced corrosion studied and analyzed by means of half-cell potential measurements. A separate accelerated corrosion experiment was performed on an individual steel rebar to measure the anticipated mass loss from corrosion. These results were compared against the analysis of the half-cell potential data and correlated. Furthermore, a cover meter survey was performed on the reinforced concrete slabs to determine the reliability of the cover meter sensor when corrosion is known to be present in the reinforcement. The sampling rate for the half-cell potential measurements was 8 inches while the sampling rate for the cover meter survey was 5 inches.