Surface Modification of Rusted Rebar and Enhanced Passivation/Anticorrosion Performance in Simulated Concrete Pore Solutions with Different Alkalinity

Abstract

Naturally exposed rusted rebar has been widely used for the production of reinforced concrete. However, rusted rebar is prone to corrosion under chloride ion (Cl−) contamination and/or at a low alkalinity of concrete. This study employed two surface modification methods, sand blasting and wire brushing, to augment the corrosion resistance of naturally exposed rusted rebar. Electrochemical tests revealed that the surface-modified rebar displayed a significant improvement of passivation in the concrete alkaline environment and anticorrosion performance in both the Cl− free and Cl−-containing simulated concrete pore solutions of different alkalinity. The enhanced performance was mainly due to the elimination of the rust layer and the direct exposure of the fresh metallic surface to the alkaline medium. Moreover, the effect of surface nanograins on the intensified passive film led to the best passivation performance of the wire-brushed rebar. The overall findings demonstrate that the two developed methods were conducive to the passivation and anticorrosion performance of the rusted rebar and thereby hold great promise for improving the service life of the reinforced concrete structures.

Autonomous Corrosion Assessment of Reinforced Concrete Structures: Feasibility Study

“…These environmental loads are also the major factor that are controlling the corrosion rate of rebar. The moisture amount within the concrete governs the corrosion rate through their influence on the electrochemical reactions at the rebar-concrete interface and ions transport between anodes and cathodes [12]. The surrounding temperature controls the rate of rebar corrosion since it influences the electrochemical reactions and the moisture amount that the concrete retains [135].…”

“…Under this amount of alkalinity, rebar persists passivated. However, the passivation of rebar is breakdown due to the presence of Cl − or by the carbonation of the concrete [12][13][14]. Carbonation is a natural physicochemical process triggered by the penetration of CO 2 from the neighboring environment into the concrete through pores in the matrix where the CO 2 reacts with hydrated cement [15,16].…”

Post-Processing Improvements for Mechanical, Microstructure, and Surface Properties of Steel

“…A convolutional neutral network can support the image analysis of corroded surfaces for its precise definition, in order to improve the accuracy of FEM simulation of structural performances of steel structures [6]. On the other hand, in the case of reinforced concrete structures, it has been demonstrated that the rebar corrosion can depend on its surface state and the passivation and anticorrosion behavior can be improved through rebar surface treatments [7]. Finally, in the case of steel, hot work sliding parts specific surface modifications must be developed for guaranteeing corrosion and wear resistance through boriding or yttria-stabilized zirconia thermal spray coating [8].…”

The Useful Life of Reinforced Concrete Structures with Reinforcement Corrosion Due to Carbonation in Non-Aggressive and Normal Exposures in the Spanish Mediterranean

“…However, under aggressive conditions (generally related to carbonation or the presence of chlorides) [1][2][3][4][5][6][7][8], even concrete that has been prepared and applied correctly can lose its protective properties and allow reinforcements to corrode before the minimum of 50 years of its expected useful life have elapsed, sometimes with serious consequences. Therefore, this concept of almost eternal durability is no longer applicable, and indeed the need for continuous maintenance of concrete structures is now recognized, including action and repair on structures with an age of less than 10 years.…”