Cyclic Polarization of Corrugated Austenitic Stainless Steel Rebars in Acid Rain: Effect of Fly Ash, pH and Steel Type

The present work studies the effect of fly ash content (0–25 wt.%), pH (8, 12.5), and steel type (316L, 304L) on the cyclic polarization of stainless steel rebars in electrolytes, simulating fresh concrete exposed to acid rain and corroded concrete cover that has exposed the reinforcement to direct acid rain attack. At the same time, it tries to elucidate the corrosion inhibition activities of a Greek lignite fly ash that is a high-Ca fly ash with a questionable effect on the corrosion resistance of concrete. A higher pH results in lower corrosion rates for both steels and all fly ash content. However, different passivity trends are noted for the two steels as a function of pH. The partial replacement of Ca(OH)2 with fly ash up to 20 wt.% has a beneficial effect on the electrochemical behavior of the stainless steel rebars, in terms of both uniform and localized corrosion resistance. However, this trend is reversed at 25 wt.% FA. The reasons for such trends are explored via microstructural examinations of the steels after polarization and XRD analysis of fly ash, as well as reinforced concrete containing fly ash

Effect of Fly Ash on the Electrochemical Performance of 316L Stainless Steel Concrete Reinforcement in Saline Environments Attacked by Acid Rain

The present study investigates the effect of fly ash (FA) as a corrosion inhibitor on the electrochemical performance of 316L stainless steel concrete reinforcement in a simulating concrete pore solution exposed to a coastal environment that is severely polluted by acid rain (AR). The corrosion behavior of 316L stainless steel is examined by means of cyclic (reverse) polarization in order to evaluate the susceptibility of 316L rebars to localized corrosion. A slightly alkaline solution simulating corroded concrete that has exposed the reinforcement directly to acid rain attack (pH ≈ 8) was chosen as electrolyte. The solution contained Ca(OH)2 partially replaced by FA (0 wt.% - 25 wt.%), an acid rain simulating solution and 3.5 wt% NaCl. The beneficial effect of FA partially replacing Ca(OH)2 (up to 20 wt.% FA) on the corrosion resistance of 316L rebars was manifested by slower corrosion kinetics, nobler corrosion potentials and less susceptibility to localised corrosion. However, these trends were reversed at 25 wt.% FA. The above performance was compared with the corrosion performance in the same electrolyte but without the addition of 3.5 wt.% NaCl

Accelerated corrosion performance of AISI 316L stainless steel concrete reinforcement used in restoration works of ancient monuments

The accelerated corrosion performance of AISI type 316L stainless steel rebars in solutions simulating concrete exposed to various environments was studied by means of cyclic polarization, before and after a four month salt spray test. B500A structural steel rebars were also tested for comparison reasons. Although 316L showed some susceptibility to localized corrosion during polarization in saturated Ca(OH)2 containing 3.5 wt.% NaCl, four months of salt spraying did not significantly affect its polarization behavior. Salt spraying for 4 m did not have any significant effect on the macrostructural state of 316L reinforced concrete

Accelerated corrosion performance of AISI 316L stainless steel concrete reinforcement used in restoration works of ancient monuments

The accelerated corrosion performance of AISI type 316L stainless steel rebars in solutions simulating concrete exposed to various environments was studied by means of cyclic polarization, before and after a four month salt spray test. B500A structural steel rebars were also tested for comparison reasons. Although 316L showed some susceptibility to localized corrosion during polarization in saturated Ca(OH)2 containing 3.5 wt.% NaCl, four months of salt spraying did not significantly affect its polarization behavior. Salt spraying for 4 m did not have any significant effect on the macrostructural state of 316L reinforced concrete

Combined Corrosion Inhibitors and Mechanical Properties of Concrete Embedded Steel (AISI 316L) during Accelerated Saline Corrosion Test

The objective of this effort is to study the effect that the combination of fly ash (FA) with a liquid corrosion inhibitor has on the mechanical degradation of 316L rebars embedded in concrete specimens during salt fog testing for a period of four months, as well as the porosity of concrete. Partial replacement of Ordinary Portland Cement (OPC) by FA (0–25%) did not significantly affect the tensile properties of 316L except a small decrease in the elastic modulus and % elongation with FA increasing. Both FA and FA-liquid inhibitor combination resulted in significant reductions in the porosity of the reinforced concrete after 4 m of salt fog testing