XPS depth profiling study on the passive oxide film of carbon steel in saturated calcium hydroxide solution and the effect of chloride on the film properties

Although the steel–concrete interface (SCI) is widely recognized to influence the durability of reinforced concrete, a systematic overview and detailed documentation of the various aspects of the SCI are lacking. In this paper, we compiled a comprehensive list of possible local characteristics at the SCI and reviewed available information regarding their properties as well as their occurrence in engineering structures and in the laboratory. Given the complexity of the SCI, we suggested a systematic approach to describe it in terms of local characteristics and their physical and chemical properties. It was found that the SCI exhibits significant spatial inhomogeneity along and around as well as perpendicular to the reinforcing steel. The SCI can differ strongly between different engineering structures and also between different members within a structure; particular differences are expected between structures built before and after the 1970/1980s. A single SCI representing all on-site conditions does not exist. Additionally, SCIs in common laboratory-made specimens exhibit significant differences compared to engineering structures. Thus, results from laboratory studies and from practical experience should be applied to engineering structures with caution. Finally, recommendations for further research are made.

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The steel-concrete interface

The effect of simulated concrete pore solution composition and chlorides on the electronic properties of passive films on carbon steel rebar

Investigation on dispersion of graphene oxide in cement composite using different surfactant treatments

Effect of pH and chloride on the micro-mechanism of pitting corrosion for high strength pipeline steel in aerated NaCl solutions

The effect of concrete pore solution composition on the protective properties of the oxide films that form on black reinforcing steel has been experimentally investigated using anodic polarization and electrochemical impedance spectroscopy (EIS) The tests were conducted on oxide films grown in saturated calcium hydroxide solutions that included different representative amounts of NaOH, KOH, and Ca(SO4), which are compounds that are commonly observed in most ordinary portland cement concrete types The results of both anodic polarization and EIS tests show that pore solution composition has an effect on the protective properties of the passive oxide films and, in particular, sulfate ions ( SO 4 ) 2 - have been shown to have a negative influence on the film quality

The effect of concrete pore solution composition on the quality of passive oxide films on black steel reinforcement

Electrochemical investigation of chloride-induced depassivation of black steel rebar under simulated service conditions

Microscopic investigation of mill scale and its proposed effect on the variability of chloride-induced depassivation of carbon steel rebar

Nano-scale study of passive films and chloride-induced depassivation of carbon steel rebar in simulated concrete pore solutions using FIB/TEM

Rebar in concrete is protected against corrosion by a passive film that is stable due to the high alkalinity of the pore solution Corrosion may start once the protective passive film on the rebar surface breaks down (depassivation) due to the ingress of external ions such as chlorides or processes such as carbonation The main goal of this investigation is to characterize the effect of surface conditions, specifically the presence of mill scale, on chloride-induced depassivation of rebar in concrete pore solution using electrochemical and microscopy techniques To achieve this goal, linear polarization tests were conducted on black steel rebar with and without mill scale in a special corrosion cell that is designed to simulate in-service conditions Both electrochemical and microscopic observations suggest that enhanced corrosion of as-received rebar in concrete occurs in crevices at the interface between the underlying steel surface and the mill scale which are linked to the free surface

G.A. McRae

Papers

The effect of concrete pore solution composition on the quality of passive oxide films on black steel reinforcement

Electrochemical investigation of chloride-induced depassivation of black steel rebar under simulated service conditions

Microscopic investigation of mill scale and its proposed effect on the variability of chloride-induced depassivation of carbon steel rebar

Nano-scale study of passive films and chloride-induced depassivation of carbon steel rebar in simulated concrete pore solutions using FIB/TEM

Effect of surface condition on the chloride-induced depassivation of rebar in concrete