Purpose As it is widely known, corrosion is a major deterioration factor for structures which are located on coastal areas. Corrosion has a great impact on both the durability and seismic performance of reinforced concrete structures. In the present study, two identical reinforced concrete columns were constructed and mechanical tests were organized to simulate seismic conditions. Prior to the initiation of the mechanical tests, the base of one of the two columns was exposed to predetermined accelerated electrochemical corrosion (at a height of 60 cm from the base). After the completion of the experimental loading procedure, the hysteresis curves – for unilateral and bilateral loadings – of the two samples were presented and analyzed (in terms of strength, displacement and dissipated energy). The paper aims to discuss this issue. Design/methodology/approach In the present study, two identical reinforced concrete columns were constructed and mechanical tests were organized to simulate seismic conditions. The tests were executed under the combination of a constant vertical force with horizontal, gradually increasing, cyclic loads. The implemented displacements, of the free end of the column, ranged from 0.2 to 5 percent. Prior to the initiation of the mechanical tests, the base of one of the two columns was exposed to predetermined accelerated electrochemical corrosion (at a height of 60 cm from the base). After the completion of the experimental loading procedure, the hysteresis curves of the two samples were presented and analyzed (in terms of strength, displacement and dissipated energy). Findings Analyzing the results, for both unilateral and bilateral loadings, a significant reduction of the seismic performance of the corroded column was highlighted. The corrosion damage imposed on the reference column resulted in the dramatic decrease of its energy reserves, even though an increase in ductility was recorded. Furthermore, more attention was paid to the consequences of the uneven corrosion damage, recorded on the steel bars examined, on ductility, hysteretic behavior and damping ratio. Originality/value In the present paper, the influence of the corrosion effects on the cyclic response of structural elements was presented and analyzed. The simulation of the seismic conditions was achieved by imposing, at the same time, a constant vertical force and horizontal, gradually increasing, cyclic loads. Finally, an evaluation of the performance of a column, under both unilateral and bilateral loadings, took place before and after corrosion.

Purpose Corrosive agent constitutes a major problem for constructions located in coastal areas, since it keeps affecting their durability. This phenomenon, in synergy with moisture and high temperatures, leads to premature deterioration of the structures. Under these conditions, the need for management of the problem of resistance of steel against corrosion is an issue of paramount importance and a challenge to the structural integrity and reliability. The paper aims to discuss these issues. Design/methodology/approach The need for management of the problem of resistance of steel against corrosion is an issue of paramount importance and a challenge to the structural integrity and reliability. In the present study, an effort was made to increase the corrosion resistance of the high strength and ductility dual-phase steel B500c category, with the use of different shot blasting processes, without any interference in the chemical composition or in the production mode. In particular, shot blasting treatment was used for both cleaning and creating compressive stresses on the surface of steel bars, according to the pertinent protocols. The modified samples were studied via both conventional characterization methods and electrochemical techniques. Findings Through the whole surface treatment process of B500c steel, a positive impact came about not only the corrosion resistance, but also the mechanical performance. Originality/value Shot blasting process aims to increase the corrosion resistance of high ductility dual-phase steel (B500c), without any interference in the chemical composition or in the production mode.

In this work, the effects of chloride-induced corrosion on tempcore B400c and B450c steel grades are evaluated, in terms of corrosion resistance and mechanical characteristics, after the performance of Tensile and Low Cycle Fatigue Tests. Both steel categories, characterized by high strength and high ductility, have been used in existing structures, indicating that they demonstrate different performance against the ascribed corrosion environments. B450c steel grade seems to preserve higher energy reserves, ensuring higher expectancy to the corresponding reinforced concrete structures. Additionally, due to buckling and buckling reversal, both steel grades demonstrate limited ductility at 4%. Finally, when cyclically stresses occur, crack nucleation is taking place, at the areas where sulphides, FeS and MnS can be found, leading to sub-surface crack propagation, interacting with external pits.

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.

Purpose The safety of reinforced concrete structures is generally related to the expected service life of their individual materials. Corrosion damage manifesting on steel reinforcement is usually underestimated, although it greatly affects both load bearing capacity and plastic deformation limits of steel reinforcement. Corrosion damage degree has a great impact on the life expectancy of structures. This paper aims to discuss these issues. Design/methodology/approach In the present study, an effort has been made to examine and present critical parameters, which are significantly responsible for the differentiation of the corrosion damage level, as far as mass loss is concerned. Consequently, the size effect of the exposed – to the aggressive conditions – area of the specimen, as well as the volume of the protected (against corrosion) area, was examined in detail. Findings Differential aeration greatly affects the results of corrosion on the material, given that under both high and low oxygen concentration corrosion process is still ongoing. Originality/value Findings proceeded are worth mentioning, as they may contribute to a more pertinent evaluation of the corrosion damage (as far as mass loss is concerned), restricting the risk of erroneous predictions concerning the mechanical behavior of steel reinforcement.