Estimating corrosion attack in reinforced concrete by means of crack opening

The corrosion of reinforcement in concrete is the most common degradation phenomenon of reinforced concrete structures. Reinforced concrete elements subjected to corrosion generally crack due to the expansive nature of oxides. One very important task is estimating the corrosion level using a non-destructive method in order to establish both the actual safety of the structure and a priority intervention plan. Many researchers have studied the relationship between the corrosion phenomenon and the corresponding crack openings and their evolution; several statistical analyses, based on test data from experimental campaigns under a wide range of test conditions, are available. The present work attempts to contribute to finding a relationship between the crack opening and the amount of corrosion induced in the reinforcing bars. The result of the analysis is that only a reduced number of tests can be used to establish an empirical model based on a reliable set of test data. A simple relationship between crack opening and corrosion penetration is not recommended, due to the different parameters that are able to influence this correlation. Therefore, two fundamental parameters, the ratio of the concrete cover to the rebar diameter and the concrete strength, have also been considered. The considerations made regarding these parameter test results have been rearranged and the result is a formulation that shows reduced scatter.