corrosion of steel
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2022 ◽  
Vol 12 (1) ◽  
pp. 76-97
Author(s):  
Carlos Fernando Gomes do Nascimento ◽  
Alexandre De Azevedo Demétrio Filho ◽  
Thaís Marques da Silva ◽  
Eliana Cristina Barreto Monteiro

The objective of this study was to understand whether voids intensify the triggering of reinforcement corrosion in cellular concrete, for slabs with light specific masses. The methodology was based on four tests: visual inspection, corrosion potential, electrical resistivity, and mass loss. In relation to the L1 family, the L2 and L3 families (higher air content) were shown to be more susceptible to reinforcement corrosion and mass loss from the steel bars in 90% of cases. However, the behavior of some slabs indicates the possibility of the process being asymptomatic with regard to staining, considering that the influence of the cover on the corrosion of the steel bars was verified


2021 ◽  
Author(s):  
Sergey Leonovich ◽  
Evgeniy Shalyy ◽  
Elena Polonina ◽  
Elena Sadovskaya ◽  
Lev Kim ◽  
...  

Section I of the monograph is devoted to an urgent problem - forecasting the durability of port reinforced concrete structures, the destruction of which is associated with corrosion of steel reinforcement caused by chloride aggression and carbonation of concrete. The analysis of models for calculating the service life of structures and experimental data is carried out, the life cycles for the main degradation processes in concrete and reinforcement, the periods of initiation and propagation of corrosion are considered, the influence of environmental factors (temperature, humidity) and the quality of concrete (In/C, cement consumption, diffusion coefficient) on the kinetics of chloride penetration and the movement of the carbonation front is taken into account. Probabilistic models of basic variables are considered, the limiting states of port reinforced concrete structures for the durability of reinforced concrete structures based on the reliability coefficient for service life are formulated. Sections II and III describe modern methods of restoration and restoration of reinforced concrete port structures subjected to corrosion destruction using nanofibrobeton. The concept of multilevel reinforcement has been implemented. Methods of experimental fracture mechanics were used to evaluate the joint work of exploited concrete and reinforcement nanofibre concrete. It is intended for scientific and engineering staff of universities, research and design organizations.


Materials ◽  
2021 ◽  
Vol 14 (24) ◽  
pp. 7691
Author(s):  
Zhilu Jiang ◽  
Siyao Li ◽  
Chuanqing Fu ◽  
Zheng Dong ◽  
Xuefeng Zhang ◽  
...  

Steel corrosion has become the main reason for the deterioration of reinforced concrete structures. Due to the heterogeneity of concrete and the spatial variation of environmental conditions, macrocell corrosion is often formed by localized corrosion, which is more detrimental if the anode is supported by large numbers of cathodes. The macrocell corrosion caused by concrete carbonation has been seldom studied. Furthermore, the influence of geometrical conditions on cathode-controlled corrosion in the chloride environment needs to be further clarified. In this work, the macrocell corrosion of steel embedded in concrete specimens exposed to accelerated carbonation, chloride contamination, and chloride penetration is studied using a modified ASTM G109 method. Concrete specimens with various binder types, geometrical parameters (i.e., concrete cover thickness and the diameter of embedded steel), and boundary conditions were tested. A simplified mathematical model for the prediction of the steel corrosion rate was developed considering two-dimensional oxygen diffusion. The results showed that, at the same level of anodic potential drops, the corrosion current rate in chloride-induced corrosion is higher than that of carbonation-induced corrosion. Chloride contamination is less detrimental to concrete incorporated with slag and pulverized fly ash than it is to pure ordinary Portland cement (OPC), likely due to enhanced chloride binding capacity. The results also indicated that the model considering two-dimensional diffusion can accurately predict the cathodic reaction process on corroded steel bars, which provides a theoretical basis for considering the correction coefficient of steel bar position in the establishment of a steel bar corrosion rate model.


2021 ◽  
Author(s):  
Raymond Nicholas Burke ◽  
Abdallah Mohd AR Al Tamimi ◽  
Wael Salem Al Shouly ◽  
Mohamed Ali Jaber ◽  
David Erik Baetsen

Abstract Industry-wide, the degradation and corrosion of steel infrastructure and the associated maintenance to prevent or mitigate this, poses a heavy environmental and operational burden across many industry segments. To address these challenges, ADNOC Group Technology, led by our Non-Metallic Steering Committee and ADNOC Upstream, in partnership with several selected specialist product companies, is deploying a range of innovative solutions as pilot trials within a holistic R&D program – which is aiming to transform our production and processing facilities, with a close focus on integrity management – and specifically we are assessing the deployment of non-metallic pipelines, storage and process vessels as well as downhole tubing and casing. Focusing specifically on flowlines and pipelines - traditional steel pipes used in the oil patch are burdensome to store, transport and install, as well as susceptible to degradation, corrosion-driven wall loss in challenging operational environments, such as those found Onshore and Offshore Abu Dhabi. This vulnerability results in increased operating risks as facilities mature, adding cost and time for inspection, maintenance and eventually - replacements that will lead to production deferrals or interruptions. A range of non-metallic pipeline technologies are being assessed and piloted in this program, including stand-alone extruded polymeric pipe and liners, Reinforced Thermoplastic Pipe (RTP) used Onshore and Offshore, specialized non-metallic flexible pipelines for Offshore including Thermoplastic Composite Pipe (TCP) and downhole tubulars. The methodology involves placing segments of RTP into live pipeline systems for a finite duration of operation – usually one year – and then removing sections to assess any degradation in performance, or capability of the RTP during that time. These test results will be the subject of a further publication at the end of this trial period. In this paper, we will focus on RTP piloting Onshore and specifically mention a unique trial in an ultra-sour gas field, where the technology has already delivered the required performance: safely transporting gas with levels of H2S up to 10% by volume. This trial also proves that specifically engineered non-metallic products may be successfully operated at the high temperature and high pressure (HPHT) levels that are characteristic of our reservoirs.


2021 ◽  
Vol 313 ◽  
pp. 125589
Author(s):  
Liang Fan ◽  
Le Teng ◽  
Fujian Tang ◽  
Kamal H. Khayat ◽  
Genda Chen ◽  
...  

2021 ◽  
Vol 2021 ◽  
pp. 1-11
Author(s):  
Longlong Niu ◽  
Shiping Zhang

This paper presents an experimental study on the performance of cracked ultra-high-performance fiber-reinforced concrete (UHPC) exposed to dry-wet cycles of 3.5% NaCl solution under the temperature of 60°C. The results show that the wider the crack, the higher the corrosion degree of steel fibers embedded in UHPC, and the deeper the chloride ion diffusion on both sides of the crack. With the increase of dry-wet cycles, the flexural strength of precracked UHPC first decreases and then increases, and the lowest flexural strength was observed in 60 dry-wet cycles. Although self-healing is hard to cease the corrosion of steel fibers, it can relieve the corrosion of steel fibers and improve the flexural strength exposed to 100 dry-wet cycles.


2021 ◽  
Vol 105 (1) ◽  
pp. 135-142
Author(s):  
Mikhail A. Kamenskii ◽  
Svetlana N. Eliseeva ◽  
Veniamin V. Kondratiev

Electrochemical properties of δ-MnO2-based cathode materials were studied in dependence on current collector used for electrode casting (stainless steel mesh, carbon paper and titanium foil) by galvanostatic charge/discharge measurements and cyclic voltammetry. It was shown that δ-MnO2-based electrodes cast on carbon paper demonstrate the most stable electrochemical performance in comparison with two other current collectors. This can be explained by corrosion of steel and passivation of titanium in mild aqueous electrolytes. Detailed study of carbon paper as current collector shows that pressing of electrodes leads to decreasing the porosity and fast capacity fading.


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