Crevice corrosion of steel rebar in chloride-contaminated concrete

2021 ◽  
Vol 296 ◽  
pp. 123587
Author(s):  
Lei Yan ◽  
Guang-Ling Song ◽  
Ziming Wang ◽  
Dajiang Zheng
Keyword(s):  
Crevice Corrosion ◽  
Steel Rebar ◽  
Corrosion Of Steel ◽  
Chloride Contaminated

Effect of electrochemical chloride extraction treatment on the corrosion of steel rebar in chloride contaminated mortar

2016 ◽  
Vol 63 (5) ◽  
pp. 377-385 ◽  
Author(s):  
The Huyen Nguyen ◽  
Tuan Anh Nguyen ◽  
Van Khu Le ◽  
Thi Mai Thanh Dinh ◽  
Hoang Thai ◽  
...  
Keyword(s):  
Compressive Strength ◽  
Chloride Ions ◽  
Electric Resistivity ◽  
Sodium Borate ◽  
Content Type ◽  
Steel Rebar ◽  
Free Chloride ◽  
Electrochemical Chloride Extraction ◽  
Corrosion Of Steel ◽  
Chloride Contaminated

Purpose This work aims to demonstrate the use of electrochemical chloride extraction (ECE) to remove chloride ions away from the steel rebar in chloride-contaminated mortar and to mitigate the corrosion of the embedded steel. Design/methodology/approach To simulate salt contamination in concrete, sodium chloride was added at 0.5 per cent by weight of cement in the fresh mortar featuring a water-to-cement ratio of 0.45. The ECE treatments were varied at two electrical current densities (1 and 5 A/m2), using two electrolytes (0.1M NaOH and 0.1M Na3BO3 solutions) and for two periods (2 and 4 weeks). The average free chloride concentration in cement mortars before and after ECE treatment was quantified using a customized chloride sensor, whereas the spatial distribution of relevant elements was obtained using energy-dispersive X-ray spectroscopy. The effect of ECE treatment on the electric resistivity of mortar and the corrosion resistance of steel rebar was investigated by electrochemical impedance spectroscopy and potentiodynamic polarization measurements, respectively. Findings The experimental results reveal that the ECE treatment was effective in removing chlorides and in improving electric resistivity and compressive strength of the mortar, when using the sodium borate solution as the electrolyte. In this case, a 4-week ECE treatment at 1 A/m2 decreased the free chloride content in the mortar by 70 per cent, significantly increased the Ca/Si ratio in the mortar near rebar, led to a more refined and less permeable microstructure of the mortar and significantly improved its compressive strength. The ECE treatment was able to halt the chloride-induced corrosion of steel rebar by passivation. A 4-week ECE treatment at 1 A/m2 using sodium hydroxide and sodium borate solutions decreased the corrosion rate of rebar by 36 and 34 per cent, respectively. Originality/value This electrochemical rehabilitation of steel-reinforced concrete under chloride-contaminated condition is very effective in prolonging its service life.

Effect of Migrating Corrosion Inhibitor on Corrosion Rate of Reinforcing Steel in Concrete with Various Admixed Chloride

2012 ◽  
Vol 204-208 ◽  
pp. 3146-3150 ◽  
Author(s):  
Zhi Yong Liu ◽  
Xin Gang Zhou ◽  
Xiu Lin Li
Keyword(s):  
Corrosion Rate ◽  
Electrochemical Impedance ◽  
Corrosion Current ◽  
Cementitious Materials ◽  
Steel Bar ◽  
Average Corrosion Rate ◽  
Corrosion Of Steel ◽  
High Chloride ◽  
Effect Of Surface ◽  
Chloride Contaminated

Effect of surface applied inhibitor on the durability of chloride contaminated reinforced concrete has been investigated in this paper. The C30 concrete samples contaminated with 0.5%,1.0%,1.5% NaCl by mass of the cementitious materials in the mixing process were experienced adequate curing and subjected to 1 months exposure tests after painting with 400 g/m2 MCIs. The corrosion behavior of the steel rebar in concrete samples was monitored by using electrochemical impedance spectroscopy (EIS), linear polarization resistance (LPR) and corrosion currents. The results indicate that, after painting the MCIs for 28d on the surface of concrete samples with 0.5% and 1% NaCl, the average corrosion rate of reinforcements in concrete samples （0.34μA/cm2 ）is lower than that of the control one (No.0, no painted inhibitor), and about 1/4 of the initial corrosion current of the samples with 0.5% and 1% NaCl before painting MCI. But the corrosion current of rebar in No.3 sample with 1.5% NaCl is still higher than that of the control one (No.0). Therefore, painting MCIs on the surface of samples is very effective to inhibit the corrosion of steel bar in concrete at low or middle chloride conditions, but it is not enough to repair severely corroded steel bar in high chloride contaminated concrete.

scholarly journals Ammonium Phosphate as Inhibitor to Mitigate the Corrosion of Steel Rebar in Chloride Contaminated Concrete Pore Solution

Molecules ◽  
2020 ◽  
Vol 25 (17) ◽  
pp. 3785
Author(s):  
Soumen Mandal ◽  
Jitendra Kumar Singh ◽  
Dong-Eun Lee ◽  
Taejoon Park
Keyword(s):  
Passive Film ◽  
Ammonium Phosphate ◽  
Corrosion Current ◽  
Iron Phosphate ◽  
Nacl Solution ◽  
Steel Rebar ◽  
Prolonged Duration ◽  
Corrosion Inhibition Efficiency ◽  
Corrosion Of Steel ◽  
Steel Rebars

In the present study, different amounts, i.e., 1–3 v/v% of 1 M ammonium phosphate monobasic, were used as an eco-friendly corrosion inhibitor to mitigate the corrosion of steel rebar exposed to simulated concrete pore (SCP) + 3.5 wt% NaCl solution at a prolonged duration. Potentiodynamic polarization results show that as the amount of inhibitor is increased, the corrosion resistance of steel rebar is increased. The steel rebar exposed to 3% inhibitor-containing SCP + 3.5 wt% NaCl solution exhibited nobler corrosion potential (Ecorr), the lowest corrosion current density (icorr), and 97.62% corrosion inhibition efficiency after 1 h of exposure. The steel rebars exposed to 3% inhibitor-containing SCP + 3.5 wt% NaCl solution revealed higher polarization resistance (Rp) and film resistance (Ro) with exposure periods compared to other samples owing to the formation of passive film. The scanning electron microscopy (SEM) of steel rebar exposed to 3% inhibitor-containing SCP + 3.5 wt% NaCl solution showed homogenous and uniform dendritic passive film which covers all over the surface, whereas, bare, i.e., SCP + 3.5 wt% NaCl solution exposed samples exhibited pitting and irregular morphology. Raman spectroscopy results confirm the formation of goethite (α-FeOOH), maghemite (γ-Fe2O3), and iron phosphate (FePO4) as a passive film onto the steel rebar surface exposed to 3% inhibitor-containing SCP + 3.5 wt% NaCl solution. These phases are responsible for the corrosion mitigation of steel rebar which are very protective, adherent, and sparingly soluble.

scholarly journals An Electrochemical Study to Evaluate the Effect of Calcium Nitrite Inhibitor to Mitigate the Corrosion of Reinforcement in Sodium Chloride Contaminated Ca(OH)2Solution

2017 ◽  
Vol 2017 ◽  
pp. 1-14 ◽  
Author(s):  
Hwa-Sung Ryu ◽  
Jitendra Kumar Singh ◽  
Han-Seung Lee ◽  
Won-Jun Park
Keyword(s):  
Electrochemical Impedance Spectroscopy ◽  
Sodium Chloride ◽  
Anodic Polarization ◽  
Open Circuit Potential ◽  
Electrochemical Impedance ◽  
Open Circuit ◽  
Nacl Solution ◽  
Steel Rebar ◽  
Calcium Nitrite ◽  
Corrosion Of Steel

The effect of calcium nitrite (Ca(NO2)2) was assessed by electrochemical means such as open circuit potential (OCP), electrochemical impedance spectroscopy (EIS), and potentiodynamic studies in saturated Ca(OH)2solution contaminated with 0.99 and 7.91 g/L NaCl. The preliminary results of OCP showed that the potential is shifted towards positive (noble) side as content of inhibitor increased. The EIS results indicate that Ca(NO2)2works effectively in reduction and initiation of corrosion of steel rebar in NaCl contaminated Ca(OH)2solution. Potentiodynamic studies revealed the pitting tendency of steel rebar exposed in 0.99 g/L NaCl at [Cl−/NO2-] = 1.2 attributed to low conductivity of passive film which causes interference for Cl−ions attack during anodic polarization. The 85.75% efficiency is found in 0.99 g/L at [Cl−/NO2-] = 1.2. The Ca(NO2)2inhibitor transformed the unstable iron oxides/hydroxides into stable and protective oxides/hydroxides due to its strong oxidizing nature. Therefore, this inhibitor is sufficiently and significantly reducing the corrosion of steel rebar at even its low concentration with 0.99 and 7.91 g/L NaCl solution.

scholarly journals Application of Plants Extracts as Green Corrosion Inhibitors for Steel in Concrete - A review

2018 ◽  
Vol 3 (2) ◽  
pp. 158 ◽  
Author(s):  
Yuli Panca Asmara ◽  
Tedi Kurniawan ◽  
Agus Geter Edy Sutjipto ◽  
Jamiluddin Jafar
Keyword(s):  
Corrosion Inhibitor ◽  
Corrosion Inhibitors ◽  
Concrete Strength ◽  
Cost Effective ◽  
Carbon Steels ◽  
Reinforcing Bar ◽  
Steel Rebar ◽  
Corrosion Of Steel ◽  
Green Corrosion Inhibitors

High requirements in protection of steel reinforcing bar (steel rebar) from corrosion are necessary since there are multi interaction of corrosive chemicals which cause early damage of concrete buildings. Corrosion of steel in concrete can destroy the concretes and reduce concrete strength. To protect rebar from corrosion, application of corrosion inhibitor is believed to have higher performance compared to other protection systems. To date, organic inhibitors have promising methods in steel rebar protection as they are environment-friendly, compatible with concrete, cost effective and applicable in any various concrete conditions. Thus, demands in using these inhibitors tend to increase significantly. This paper reviews the applications of green corrosion inhibitor specifically highlighted in protecting mechanisms, typical plants extracted, performance in corrosion protection, and classification of green corrosion inhibitors. The corrosion resistances of carbon steels in concrete protected by green inhibitors are in focus. As summary, it can be confidently notified that green corrosion inhibitors for steel in concrete will have a prospect to be used as corrosion prevention in the future with further improvements.

Sign in / Sign up

Export Citation Format

Share Document