scholarly journals Effect Use of Two Chemical Compounds Sodium Nitrate and Sodium Silicate as Corrosion Inhibitor to Steel Reinforcement

2019 ◽  
Vol 14 (2) ◽  
pp. 123-128
Author(s):  
Sarah Kareem Mohammed

Corrosion of steel reinforcement is one of the biggest problems facing all countries in the world like bridges in the beach area and marine constructions which lead to study these problems and apply some economical solutions. According to the high cost of repair for these constructions, were studied the effect of using kind of chemical compounds sodium nitrite(NaNO2) and sodium silicate(Na2SiO3) as corrosion inhibitors admixture for steel bars that immersed partially in electrolyte solution (water + sodium chloride in 3% conc.) (Approximately similar to the concentration of salt in sea water). The two inhibitors above added each one to the electrolyte solution at concentrations (0.5%, 1% and 2%) for both of them.      The results were  corrosion rate for steel sample that's immersed partially in salt solution was higher than corrosion rate of steel bar that's immersed partially in electrolyte solution with inhibitors  also the two corrosion inhibitors (sodium nitrite and sodium silicate) that added to the electrolyte solution were working successfully to prevent and inhibit the corrosion by using weight loss technique with best percent of 0.5% sodium nitrite ( efficiency 94.1% ) and best percent of 2% sodium silicate ( efficiency 92.5%).

2018 ◽  
Vol 199 ◽  
pp. 04004
Author(s):  
Ze Gyang Zakka ◽  
Mike Otieno

This paper presents results of an ongoing research of the effect of 1D and 2D chloride ingress on concrete resistivity and corrosion rate of steel reinforcement. 12 concrete beams made with concrete of binder blend PC(50)/GGBS(50), w/b = 0.40, 10 mm steel reinforcement rods at concrete cover of 20 mm were used in this laboratory based experiment. The steel reinforcement bars were placed at the middle or at an orthogonal corner of the concrete beams subjected to 1D and 2D chloride ingress respectively. A single crack was induced using 3-point bending on one-half of the beams. The beams were exposed to a repeated cycle of 2 weeks ponding in 5% NaCl and then air drying in ambient laboratory condition for 2 weeks. The corrosion rate of both cracked and uncracked specimens exposed to 2D chloride ingress was significantly higher than that of beams exposed to 1D chloride ingress. The uncracked specimens had lower concrete resistivity values compared to the cracked specimens even though higher corrosion rates were measured.


2013 ◽  
Vol 357-360 ◽  
pp. 876-879
Author(s):  
Luboš Taranza ◽  
Rostislav Drochytka

Corrosion of steel constructions due to the affection of aggressive agents is one of the principal problems affecting reinforced concrete constructions. In critical cases, this phenomenon may cause static destabilisation of the construction and as a result, it is necessary to protect constructions using primary and secondary protection which significantly decreases this risk. This paper addresses the options for evaluating various types of protective anti-corrosion systems which use progressive corrosion inhibitor technology in a laboratory environment. Corrosion inhibitors efficiently slow down the course of corrosive processes on steel reinforcement and prolong the service life of building constructions. The rate of efficiency can be verified with high information capability in the laboratory by a series of testing methods.


2020 ◽  
Vol 35 (1) ◽  
pp. 27-43
Author(s):  
Mahmoud Imam ◽  
Ali El- Agamy ◽  
Mohamed Mahdy ◽  
Ahmed Abdel-Fattah

2020 ◽  
Vol 329 ◽  
pp. 02001
Author(s):  
Viktoriya Konovalova

The influence of phosphate coatings on the corrosion behavior of steel reinforcement in a chloride-containing environment was studied to determine the need for additional protection against corrosion. The main indicators of the corrosion rate of steel reinforcement with phosphate coatings in chloride-containing solutions were determined, confirming the high protective properties of these coatings. It was found that the corrosion rate of steel reinforcement protected by phosphate coatings is reduced by 3 times. The processes of electrochemical corrosion of steel reinforcement of strength class A500S from steel grade St3ps in concrete under the influence of aggressive environments containing chloride ions (2 % MgCl2 solution and HCl solution with pH = 5) were studied. The kinetics of the corrosion process of steel reinforcement with and without protective phosphate coatings in solutions of various compositions has been studied. The change in mass of steel reinforcement protected by phosphate coatings is 3-4 times less than that of samples without coating. The surface potential of steel reinforcement with phosphate films changes significantly more slowly than that of unprotected samples.


2019 ◽  
Vol 4 (3) ◽  
pp. 73-76
Author(s):  
Ghada Mazin Hani ◽  
Sahib M. Mahdi ◽  
Amer H. Majeed

At the present time the use of corrosion inhibitors is a good solution to maintain or reduce the corrosion problems in the equipment, so nowadays the production of inhibitors all non-toxic, natural and cheap is the most important demand. In this study dry olive leaves extraction used as inhibitor in a temperatures similar to the average temperature in Iraq, so as to bring the picture of reality as much as possible, at (25 °C and 45 °C) and solution was prepared in the following concentration to stimulate the field environment for oil extracting 19.2 % of sodium chloride (NaCl), 8% of calcium chloride (CaCl), 1.08 % of magnesium chloride (MgCl) and saturated with Co2 gas, the corrosion rate of steel sample was measured be using a potentiostat device with reference of calomel electrode. The result was, the dry olive leaves extract is an effective inhibitor material. Dry olive leaves extraction inhibitor has a low corrosion rate at 25OC and 45OC and the Corrosion rate decrease with increasing temperature for oil extraction solution, From the EDS test found that high percentage of carbon and oxygen caused to produce many compounds like the phenolic compound of the olive leaves is the responsible of inhabitation effect of the olive leaves.


2021 ◽  
Vol 68 (1) ◽  
pp. 36-43
Author(s):  
Hai Tan ◽  
Yanbao Guo ◽  
Junqiang Wang ◽  
Deguo Wang ◽  
Yongjie Cui

Purpose The purpose of this study is to investigate the influence of additive particle size on the anti-corrosion behaviors of polyurethane (PU) coating. Design/methodology/approach The graphite (Gr) and poly-graphite (PGr) were used as large size additive and small size additive, respectively. The immersion test and electrochemical test were used to study the corrosion behaviors. Findings In the immersion test, the surface of the bare steel sample was corroded uniformly. However, for the steel samples with coatings, the surfaces were corroded locally. This phenomenon showed that the coating can isolate artificial sea-water and samples and then decreased the corrosion rate. Furthermore, the most severe corrosion was observed on the sample with the Gr/PU coating compared with other anti-corrosion coatings. The results of the electrochemical measurements indicated that the corrosion rate of the sample with PGr/PU coating was approximately two times lower than that of the sample with the Gr/PU coating and the sample with PGr/PU coating was hardest to be corroded. Originality/value To have a more objective and direct recognition of the particle size effect on the coating quality.


2019 ◽  
Vol 9 (4) ◽  
pp. 683 ◽  
Author(s):  
María Prieto ◽  
María González ◽  
Ángel Rodríguez ◽  
Alfonso Cobo

The aim of this study is to investigate the corrosion behavior of steel reinforcement embedded in mortar specimens in which both the aggregate and cement are partially replaced by ladle furnace slag (LFS) and different percentages of chloride ions by weight of cement are introduced into the mix at the time of kneading. The corrosion behavior was studied by using electrochemical techniques in order to evaluate the corrosion rate and the symptoms produced in steels of specimens with and without slag LFS. From the analysis of the results, it is concluded that the use of LFS in a partial replacement of aggregate and cement in mortar specimens does not compromise the behavior of the mortar with regard to corrosion of the steel reinforcement; consequently, partial replacement by LFS is fully feasible from this standpoint.


Materials ◽  
2021 ◽  
Vol 14 (10) ◽  
pp. 2491
Author(s):  
Elena Garcia ◽  
Julio Torres ◽  
Nuria Rebolledo ◽  
Raul Arrabal ◽  
Javier Sanchez

The number of reinforced concrete structures subject to anoxic conditions such as offshore platforms and geological storage facilities is growing steadily. This study explored the behaviour of embedded steel reinforcement corrosion under anoxic conditions in the presence of different chloride concentrations. Corrosion rate values were obtained by three electrochemical techniques: Linear polarization resistance, electrochemical impedance spectroscopy, and chronopotenciometry. The corrosion rate ceiling observed was 0.98 µA/cm2, irrespective of the chloride content in the concrete. By means of an Evans diagram, it was possible to estimate the value of the cathodic Tafel constant (bc) to be 180 mV dec−1, and the current limit yielded an ilim value of 0.98 µA/cm2. On the other hand, the corrosion potential would lie most likely in the −900 mVAg/AgCl to −1000 mVAg/AgCl range, whilst the bounds for the most probable corrosion rate were 0.61 µA/cm2 to 0.22 µA/cm2. The experiments conducted revealed clear evidence of corrosion-induced pitting that will be assessed in subsequent research.


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