Evaluating rebar corrosion damage in RC structures exposed to marine environment using neural network

Shokrgozar

J. Electrochem. Sci. Eng.

et al. 2022

In this study, the effect of protection methods regarding the corrosion decrement of steel in concrete was simulated by artificial neural networks (ANNs) and fuzzy logic (FL) approaches. Hot dip galvanizing as a protective coating, Ferrogard 901 corrosion inhibitor, a pozzolanic component, such as fly ash (FA) and micro-silica (MS), and eventually rebar AISI-304 were employed in concrete. Reinforced concrete samples were held under impressed voltage of 30 V in 3.5 % NaCl electrolyte for 350 hours toward a stainless-steel auxiliary electrode. Corrosion currents have been modelled using feed forward back propagation ANNs and FL methods. The results demonstrate good consistency between corrosion data and simulated models. Furthermore, the correlation coefficient criterion clearly indicates using pozzolanic materials, with a combination of MS and FA, can be introduced as one of the best corrosion protection methods, with a 35 % contribution factor in reinforced concrete.

Section: Figure 12 Error Of Corrosion Versus Time Of Fuzzy Logic Modelmentioning

confidence: 99%

Simulation of corrosion protection methods in reinforced concrete by artificial neural networks and fuzzy logic

Shokrgozar

J. Electrochem. Sci. Eng.

et al. 2022

“…Sulfates in groundwater are usually of natural origin but can also come from fertilizers and industrial wastewater. As the author states in [23,24], the progress of sulfate corrosion depends on the type of cation associated with the sulfate anion and on the salt concentration. The most aggressive chemical compounds include the salts of the following types: CaSO 4 , Na 2 SO 4 , K 2 SO 4 , MgSO 4 , (NH 4 ) 2SO 4 , and acid-H 2 SO 4 .…”

Section: Introductionmentioning

confidence: 99%

Experimental Study of the Resistance to Influence of Aggressive Liquids on Lightweight Concrete

Kurpińska

Haustein

2021

Materials

In light of the scientific research, the corrosion of concrete structures is one of the main problems that may reduce their durability due to the negative impact of the natural environment. The paper analyzes the influence of the type of component on the selected properties of lightweight concrete subjected to the influence of aggressive liquids. Four concrete mixes were prepared with a granular aggregate made of foamed glass (GEGA) and aggregate made of sintered fly ash (GAA) with the use of a mineral additive: silica fly ash. The prepared lightweight concrete after one year was exposed for 60 days to the following environments: strong acid—HCl, 1% and 2% concentration, weak acid—CH3COOH, 1% and 2% concentration, and an aqueous salt solution of Na2SO4, 1% and 2% concentration. Then, the compressive strength was tested, and the microstructure analysis of the ready-made lightweight concrete (LWC) was performed. The degree of penetration of aggressive solutions into the cracks of the samples was assessed by means of applying 1% phenolphthalein solution. Changes in the weight of lightweight concrete samples after the test period were estimated. The obtained test results indicate that the decrease in the durability of lightweight concrete can be classified as a long-term process. Concrete with GEGA and GAA showed high resistance to aggressive environments. Moreover, the environment containing chlorides turned out to be the most aggressive, while the environment containing sulfates proved to be the least aggressive. The higher the concentration of the destructive factor was, the faster the corrosion process went. This has been proven by measuring the pH using phenolphthalein and carrying out microscopic examination. Concretes containing aggregates made of foamed glass and sintered fly ash are suitable for use both in traditional construction and in facilities exposed to an aggressive environment (e.g., in the chemical industry and at gas stations).

Advances in Materials Science and Engineering

“…Normally, steel embedded in concrete is protected from corrosion attack by a passive layer of thin oxide film from the highly alkaline, pH of about 12.5∼13, cement hydration products [3,7,8]. Steelrebar corrodes in concrete due to breakdown of the protective oxide film by aggressive agents of the environments, in the form of chloride ingress, from natural marine or artificial saline (deicing salts) [8,9], or sulphate attack, from microbial or industrial environments [7,[10][11][12]. Corroded products from these are expansive within concrete leading to cracks, spalling, delamination, and loss of structural integrity of the reinforced concrete [8,9,13].…”

Section: Introductionmentioning

confidence: 99%

Effect of NaNO₂and C₆H₁₅NO₃Synergistic Admixtures on Steel-Rebar Corrosion in Concrete Immersed in Aggressive Environments

Okeniyi

Popoola

Loto

et al. 2015

This paper studies effect of different combinations of NaNO2(sodium nitrite) and C6H15NO3(triethanolamine (TEA)), as synergistic admixtures in concrete immersed in NaCl and in H2SO4test environments, on the corrosion of the concrete reinforcing steel (rebar). Although statistically analysed electrochemical test results confirmed NaNO2effectiveness, synergistic combinations of 4 g NaNO2+ 4 g C6H15NO3in NaCl medium and of 2 g NaNO2+ 6 g C6H15NO3in H2SO4medium were also highly effective at inhibiting rebar corrosion. Synergistic parameter analyses showed that the effective synergistic admixtures that inhibited concrete steel-rebar corrosion in their respective medium were the NaNO2and C6H15NO3combinations that exhibited synergistic interactions of cooperative adsorption on steel-rebar. These support the suitability of requisite concentration of triethanolamine as additive admixture with sodium nitrite for steel-rebar corrosion mitigation, which is potent with reduced environmental effects, in concrete immersed in NaCl and in H2SO4corrosive media.