Evaluation of reinforcement corrosion in repaired concrete bridge slabs - a case study

摘要

Results of a study of reinforcement corrosion in four repaired concrete slab sections taken from an old bridge are presented, as well as results measured on electrochemical cells. Significant evidence is provided to help the inspection engineer to interpret the corrosion survey data taking into account the specifics of the environmental conditions that prevailed during the survey. The measurements comprised half-cell potential, linear polarization, and concrete resistivity, which are known to be sensitive to the ambient environment, especially to oxygen and water in concrete. Some semi-destructive tests, including chloride concentration, chloride permeability, and carbonation depth, were also carried out to assist the analysis and to support the results of the nondestructive corrosion testing techniques. The concrete cover of the slab samples was later removed to assess the actual state of corrosion of the reinforcement and to compare it to the corrosion predicted from the corrosion surveys. This study shows that each corrosion measurement technique has its specific advantages and limitations. Better prediction of corrosion can be obtained by analyzing the data collected from various evaluation methods with careful consideration for the effects of environmental conditions.