The size effect of rebars, on the structural integrity of reinforced concrete structures, which are exposed to corrosive environments

Abstract

Abstract. The goal of the present study is to mention the importance of underestimation of the corrosion damage developed in critical load bearing areas, on the column bases, where formation of plastic hinges is attended, mainly during strong seismic events (Figure 1). In such cases, plastic hinges are expected to absorb the seismic energy, owed to seismic vibration. However, chloride induced corrosion is responsible for significant degradation of concrete infrastructures located in coastal areas. Forecasting the life expectancy of such structures, in corrosive environments, is a challenge in engineering, given the fact that existing internal, external, as well as subcutaneous defects, in combination with the aggressive environmental factors, may be responsible for the development of subcutaneous damage on steel reinforcement [1], which may diminish the tolerance of the critical regions of the structures. Moreover, it is widely known that penetration of chloride ions into reinforced concrete varies according to its porosity and its permeability, however, the major factor for corrosion initiation is the threshold of chloride concentration, which strongly depends on the exposed surface area of steel. In the present experimental study, the variation of corrosion damage, on bare specimens, was evaluated and correlated with the geometry of the exposed surface of steel in corrosion [2]. Finally, a correlation between short bare specimens and the "injured" areas of the long embedded specimens is estimated as well.

The influence of exposed to corrosion length of rebars on fatigue life of RC elements

“…More specific, the differential aeration corrosion refers to each specimen, when different parts of which are exposed to different concentrations of oxygen. In that sense, as already demonstrated in previous work of the authors [26,27], specimens with a shorter exposed length showed greater mass loss in comparison with specimens of the same total length but with longer exposed length, as the corrosion phenomena were bounded to a smaller area. In that manner, the parameter of exposed length affects not only the corrosion rate (percentage mass loss) but also the surface damage of corroded steel bars.…”

Mechanical Behavior Evaluation of Tempcore and Hybrid Reinforcing Steel Bars via a Proposed Fatigue Damage Index in Long Terms

“…In a similar way, as already demonstrated in the previous work of the authors [48,58], specimens with a shorter exposed length showed greater mass loss in comparison with specimens of the same total length but with longer exposed length, as the corrosion phenomenon was limited to a smaller area. Similar to the above mentioned, in the present manuscript, tensile specimens, wherein the parts with an oxygen deficit were larger than those of the fatigue specimens, denoted a higher percentage of mass loss for both categories of steel reinforcement.…”

Critical parameters affecting mass loss of steel reinforcement

“…Equivalent remarks triggered the prosecution of the present study. Specifically, searching in existing literature, the significance of the exposed length of the specimens, has rarely been reported Drakakaki and Apostolopoulos, 2018;. Taking into account a few findings in recent literature Drakakaki, and Apostolopoulos, 2018), it seems that the size of the exposedto the corrosive environmentarea of steel is of major importance for the evaluation of the damage level that has been incurred to the material.…”

“…Specifically, searching in existing literature, the significance of the exposed length of the specimens, has rarely been reported Drakakaki and Apostolopoulos, 2018;. Taking into account a few findings in recent literature Drakakaki, and Apostolopoulos, 2018), it seems that the size of the exposedto the corrosive environmentarea of steel is of major importance for the evaluation of the damage level that has been incurred to the material. However, corrosion damage assessment, without taking into consideration the exposed and the unexposed lengths of steel reinforcement increases the risk for erroneous predictions concerning the mechanical behavior of steel reinforcement (Apostolopoulos et al, 2017;Imperatore et al, 2017).…”