Corrosion In Reinforced Concrete Research Articles

Effect of Recycled Brick Powder on Corrosion of Reinforced Concrete under the Action of Chloride or Carbonation

Effect of Recycled Brick Powder on Corrosion of Reinforced Concrete under the Action of Chloride or Carbonation

Numerical modeling of non-uniform corrosion of concrete reinforcement considering calcium leaching and chloride diffusion coupling effect

A novel numerical model is proposed for characterizing the nonuniform corrosion of steel bars. The proposed model corrects the anodic Tafel slope through the concentration of chloride and accounts for the adsorption-binding impact of chloride. The viability of the presented model is confirmed with regard to chloride diffusion and the distribution of steel corrosion products. The rebar-concrete interface's non-uniform distribution of oxygen and chloride concentrations along the circumferential direction influences the corrosion current density. Calcium leaching influences the migration of oxygen and chloride, and speeds up the electrochemical corrosion of the rebar.

Performance assessment of alko-amine corrosion inhibitors for use as an admixture in reinforced concrete structures: Experimental investigation and mechanism of action

Corrosion in reinforced concrete (RC) is a major issue in the construction industry, giving rise to structural failure, huge repair costs, and safety concerns. To mitigate RC corrosion, chemical corrosion inhibitors (CCI) are commonly used. This study aims to investigate the performance of different alko-amine CCIs for corrosion control in reinforced concrete (RC) structures subjected to chloride-rich conditions. The experimental program was divided into two levels: investigations comprised of quick testing on bare rebars, suitable for industries, and analysis which comprised of electrochemical investigation in simulated concrete pore solution and testing on rebar embedded in concrete, suitable for research labs. The interaction between inhibitors and steel was examined through surface analytical techniques such as AFM and XPS. Finally, the inhibition mechanism for the CCI was proposed. The alko-amines were found to show a strong dependence on their molecular structure for the formed film integrity. Monoethanolamine (MEA) and methyl ethanolamine (MeEA) formed a denser and more uniform film compared to dimethyl ethanolamine (DMeEA) and ethyl monoethanolamine (EMEA). MeEA showed the highest inhibition efficiency in both simulated pore solution environments and when used as an admixture in RC.

Review on Repair and Rehabilitation of Cold Storage

Abstract: The purpose of the project is to gain fundamental and practical understanding on concrete repair and rehabilitation of the structures. Large number of reinforced concrete (RC) structure are deteriorating, often prematurely, and need remedial measures to reinstate their safety and/or serviceability. Consequently, the need for repair and protection has grown considerably in recent years. While costs associated with repair of deteriorating concrete structures can be substantial, costs resulting from poorly designed or executed repairs may be even higher. Repair methods need to be designed with consideration for the anticipated or desired remaining service life of the structure. A distinction must be made between repairs intended to stop deterioration fully and those merely aimed at slowing down deterioration processes for a limited period of time. Then the respective repairs will be studied and classified into cracks, corrosion of concrete reinforcement, seepage and deterioration of surface coating. Detailed study will be done on the causes for each repair and a suitable rehabilitation method will be suggested for each repair site by comparing various methods. This paper presents review of literature available on the repair and rehabilitation of cold storage and presented a complied review report.

Monitoring of Reinforced Concrete Corrosion: Active and Passive Bars Exposed to Climate

The durability of reinforced concrete structures is a significant concern, with corrosion of reinforcement being a leading cause of reduced durability. To ensure accurate models, it is necessary to calibrate or validate them with direct measurements of the structures, specifically monitoring durability-related parameters. The heterogeneity of structures and the dispersion of the parameters considered in models make this calibration or validation essential. To enable the predictive maintenance of structures, it is essential to monitor the parameters related to their durability. This article presents the results of the monitoring of the temperature, corrosion potential, resistivity, and corrosion rate of two structural components, a beam and a tendon, for over 10 months. The obtained values were correlated with the climate to which they were exposed. The corrosion rate can be correlated with the influence of climate, enabling real-time estimation of section loss. This is a necessary step towards the digitization of structures or the development of digital twins that incorporate the effect of corrosion.

X-ray computed tomography to observe the presence of water in macropores of cementitious materials

Corrosion of steel reinforcement in concrete is a common degradation mechanism occurring in infrastructures worldwide. Even though extensive research has been conducted over the last decades to accurately predict the influence of steel corrosion on concrete durability, a comprehensive understanding of several micro-scale processes simultaneously involved in the corrosion mechanism is still lacking. The application of X-ray Computed Tomography (X-ray CT) can contribute to elucidate these processes, since this technique allows observing the internal status of specimens non-destructively, over time, and with a spatial resolution in the range of µm. Nevertheless, the relatively low sensitivity of light elements (e.g., hydrogen and oxygen) to X-ray CT may hinder the observation of solution within the cementitious matrix. This consideration is discussed in this letter. The results of this study show that the detection of solution in macropores (e.g., air voids) through X-ray CT is not limited by the relatively low attenuation coefficient of the fluid per se, but more by the spatial resolution at which acquisitions are performed and by the dimensions of the porous volume where solution penetrates. The observations reported in this letter may open several opportunities to further study the influence of the moisture conditions of air voids on several degradation mechanisms of reinforced cementitious materials (e.g., steel corrosion, freeze-thaw damage), which have been rarely investigated with X-ray CT according to the literature. The application of these findings could significantly deepen the understanding of several micro- scale processes that affect the durability of reinforced cementitious materials which still need to be elucidated, as further discussed in the present letter.

BASIC METHODS OF MONITORING OF CORROSION PROCESSES OF CEMENT STRUCTURES AND THEIR IMPLEMENTATION FOR PROJECTING OF POSSIBLE MINERALOGICAL CHANGES IN MATRIX COMPOSITION: REVIEW

Long time service of concrete constructions is accompanied by continuous impact of environment on its structural integrity and capability to carry project capacity of constructions. This influences are able to change not only chemical composition of cement matrix but itself activates corrosion processes that have place to occur on the joints of metal rebar and cement matrix in reinforced concrete (RC). Chemical initiation in the reinforced concrete begins due to the migration of water with parts of molecular oxygen in the thickness of concrete via porous structure of material. The same can be said about the injected compounds of either SO4 2- or Clcomponents that both can be present either in environment or concrete itself due to the modifications of slurry. Such occurrences usually accompanied by changes of pH of the environment that is crucial for the electrolytic environment to appear. Therefore, the process of the reduction of water/ proton may begin at rebar surface wich is the cause not only of the reinforced concrete rebar corrosion but also are reason of accelerated cement matrix degradation. Also, must be noted, that steel corrosion in RC accompanied by changes in current flow. Thus, by understanding the chemical processes and changes that occur in cement matrix of concrete and basics of steel corrosion initiation under the influence of aggressive solutions, the list of non-destructive methods of monitoring (NDM) based on electrical methods of monitoring are reviewed. Different approaches using electrical methods of corrosion monitoring has shown that the use of any of the technics either measurements of the corrosion potential or concrete resistivity or polarization resistance provides different results in mapping of areas with high corrosion risks, monitoring of the heterogeneity of concrete and insights on transport phenomena (e.g. water and salts ingress) in the material. Moreover, advances in potential monitoring without connection to the rebar as non-destructive measurements have shown their effectiveness. Nevertheless, colligation of the results of both numerical and NDM methods is necessary for assortment the results to provide a better data of the worktime of RC structures.

3D mesoscale investigation of non-uniform steel corrosion in reinforced concrete under chloride environments

Chloride-induced corrosion of steel in reinforced concrete (RC) exhibits complicated mechanisms such as chloride diffusion, oxygen diffusion, electrochemical polarization, dissolution and deposition of steel. This work investigates the 3D non-uniform corrosion behavior of steel in RC by integrating all the possible mechanisms and mesoscale heterogeneities, for the first time. The anodic Tafel slope is used to describe the depassivation of steel induced by chloride, while the dynamic process of oxygen supply and consumption is considered as well as the inhibition of the cathodic reaction caused by oxygen concentration. The coupling of mass transfer and electrochemical corrosion in RC is developed and validated. Mesoscale RC models with realistic aggregate, mortar, steel and interface are generated through a physically-based approach similar to casting procedures. The simulation results show that the 3D mesoscale RC model can simultaneously capture the non-uniform corrosion patterns of steel along the circumferential and longitudinal directions, offering significant application value in accurately predicting steel corrosion morphology. The random distribution of aggregates affects the local non-uniform corrosion of steel, but has little influence on the overall cumulative corrosion level. The local non-uniform corrosion of steel gradually weakens with the increase in chloride erosion time. The non-uniform corrosion of side steel is enhanced with the increase of the steel diameter and the decrease of the protective layer thickness. Bi-directional erosion mainly enhances the uniform corrosion of corner steel.

A review on the effects of cracking and crack width on corrosion of reinforcement in concrete

AbstractIt is widely known that corrosion is one of the main problems that reinforced concrete structures may endure during their life‐cycle. This problem is usually tackled in a prescriptive manner, by limiting the crack width allowed to occur during structures' service life. In an attempt to better understand the effect that cracking and crack width can have on the corrosion process, as well as systematize the existing work in the field, this paper presents a summary of an in‐depth literature review on the topic of reinforcement corrosion in concrete. The main focus is devoted to chloride‐induced corrosion since that is the most widely studied corrosion mechanism, even though carbonation‐induced corrosion is also relatively briefly discussed. The paper also presents an overview of the existing guidelines that have been used in the past to analyze and support decision‐making regarding corrosion in reinforced concrete structures.

Application of Raman Spectroscopy in the study of the corrosion of steel reinforcement in concrete: A critical review

The application of Raman spectroscopy in the study of the corrosion of steel reinforcement in concrete is critically reviewed. The Raman effects of all the possible products formed during passivation and corrosion are individually reviewed first with an attempt to identify the characteristic peaks and corresponding assignments, which could potentially be a useful reference for future application. The capability of Raman spectroscopy in characterising the passivation and corrosion process under real conditions are then demonstrated and critically reviewed. Finally, the challenges and potential solutions of using Raman spectroscopy are discussed together with some perspectives for future work.

Effects of supplementary cementitious materials on concrete reinforcement corrosion in magnesium sulphate

Effects of supplementary cementitious materials on concrete reinforcement corrosion in magnesium sulphate

Exploration of Next-Generation Reinforced Concrete Corrosion Modeling with Interdependent Initiation and Propagation Stages

Most damage prediction models for reinforcing steel in concrete treat the corrosion initiation stage as being nearly independent of the propagation stage elsewhere in the system. A next-generation chloride-induced corrosion interdependent model addresses those interactions by incorporating the corrosion prevention effect of the local potential drop caused by prior active-to-passive transitions in nearby steel portions. The effect of this potential-dependent threshold (PDT) approach was examined in a 3D realization, confirming and expanding conclusions from previous 1D and 2D models. Exploratory analysis was conducted for model result sensitivity to time step duration and activation zone size. It was found that the main outcome—a strongly lowered long-term damage projection when PDT is taken into consideration was reasonably robust to changes in those variables. The precise damage amount forecast was however sensitive to an extent that needs more detailed analysis. Sensitivity to time step choice appears to be resolvable in the limit, but the selection of appropriate activation zone size needs addressing in future work.

Two- and Four-Electrode Configurations for Contactless Reinforced Concrete Corrosion Monitoring

The paper addresses the need for a fast and reliable method for field monitoring reinforced concrete structures. A proof of concept is presented where a noncontact procedure provides quantitative information on the concrete resistivity and reinforcement corrosion rate. A Wenner-type probe is presented, where a combination of two- and four-electrode measurements in a relatively high-frequency domain allows obtaining the information of interest. The method is based on the fact, verified by numerical simulations, that the embedded rebar works as an effective floating counter electrode and, thus, for distances higher than a critical value (1 cm in the simulations done), the ratio of concrete resistivity to the measured impedance at 1 kHz is constant and only dependent on the electrode diameter. The apparent polarization resistance measured with the four-electrode arrangement and normalized to the concrete resistivity allows obtaining the actual polarization resistance without contacting the rebar whose distance to the electrodes shall be known.

Electrochemical investigation on the effect of chloride ion concentration on the corrosion of concrete reinforcement using in-situ nano-Ag/AgCl electrode

In this paper, the reinforcement embedded in concrete is taken as the research object. By measuring the corrosion rate of the reinforcement in concrete, the open circuit potential of the primary battery composed of reinforcement and calomel electrode in concrete is measured. The chloride ion concentration on the surface of reinforced concrete was measured in situ by the nano-Ag/AgCl electrode. The chloride diffusion theory and corrosion electrochemistry theory were used to study the corrosion mechanism of reinforced concrete specimens. The corrosion rate of reinforced concrete increases with the increase of time in the initial stage of corrosion and reached maximum after 15 h. The pitting of concrete reinforcement is positively related to the concentration of chloride ion in the environment.

Non-destructive monitoring of incipient corrosion in reinforced concrete with top-bar defect using a combination of electrochemical and ultrasonic techniques

Top-bar defect in reinforced concrete (RC) leads to the formation of interfacial voids underneath the reinforcements at an elevation of 300 mm or more. Rebars with top-bar defects show earlier corrosion initiation, faster corrosion rate and a different pattern of corrosion, compared to those without. This paper proposes combined electrochemical and ultrasonic methods for monitoring incipient corrosion in RC. An RC wall structure is cast vertically aiming to create top-bar defect. The specimens were subjected to accelerated chloride-induced corrosion. Simultaneously, they have been monitored with half-cell potential method (HCP), linear polarisation resistance method (LPR), ultrasonic guided waves (GW) and ultrasonic imaging (UI). The pros and cons of the four techniques are determined and discussed. The results are correlated and calibrated with the state of corrosion. Key milestones of the corrosion mechanism such as corrosion initiation and crack initiation can be successfully identified and the progression of bar deterioration, steel-concrete interfacial debonding and cracking propagation have been traced.

Effect of Stray Current on Corrosion and Calcium Ion Corrosion of Concrete Reinforcement.

The construction of subways, hydroelectric stations and water substations is exposed to stray currents, which can accelerate concrete corrosion. The influence of stray currents on reinforced concrete structures is unclear. In this paper, the influence of concrete strength grade, reinforcement diameter and stray current intensity on the extent of reinforcement corrosion and calcium ion dissolution were investigated, and the damage of reinforcement and calcium ion corrosion to concrete strength was investigated by simulating a stray current environment and conducting an electrified acceleration test. The test results show that the higher the strength grade of concrete, the lower the stray current intensity and the smaller the corrosion rate and calcium ion dissolution rate of reinforcement; with the increase in the diameter of reinforcement the corrosion rate decreases, but the calcium ion dissolution rate is not affected by reinforcement diameter. The damage effect of reinforcement corrosion on concrete compressive strength is more obvious than that of calcium ion corrosion.

On the corrosion rate measurement of reinforcing steel in chloride induced macrocell corrosion

This study investigates the corrosion rate measurement of reinforcing steel under chloride-induced macrocell corrosion in reinforced concrete (RC). The corrosion rates of RC columns with different cover thicknesses and chloride concentrations were evaluated using different techniques and cathode over anode ratios. The applicability of the Stern-Geary equation on the macrocell corrosion of RC was studied. The results show that the corrosion rate of highly corroding steel can be underestimated by an order of magnitude by the linear polarisation resistance method due to a failure to compensate for diffusion resistance. The effect of macrocell corrosion on the measurement of polarisation resistance is moderate with a relative error less than 2. The galvanostatic polarisation technique can eliminate the influence of diffusion resistance and therefore reliably measure polarisation resistance. A B value of 52 mV is recommended under macrocell corrosion.

Physics-based surrogate model for reinforced concrete corrosion simulation

Computational models have been used in conjunction with field data, such as in reinforcement concrete corrosion monitoring. It typically involves evaluating the physical model of the corrosion process. However, computation of the numerical solution for the PDE can be highly time intensive. In this paper, a surrogate model is developed to substitute the Finite Element (FE) model of reinforced concrete corrosion. The surrogate model is trained to learn from the FE model by querying the boundary conditions configurations that represents corrosion profile on the steel rebar. A corrosion profile describes the length and the number of the corroded parts of steel rebar in one case. The results demonstrate that the surrogate model is in good agreement to the FE model with a standard deviation less than 0.02. The example cases tested include corrosion profiles with various numbers and lengths of the corrosion. The computing time of the FE model is approximately 360 ms, while the surrogate model is 88 ms, a four-fold time improvement. The surrogate model can be used to improve computational model of corrosion for inverse analysis or optimization.

Characterization of ground penetrating radar signal during simulated corrosion of concrete reinforcement

In this paper, the adequacy of the experimental design in the accelerated corrosion process with the impressed current technique (IC) for ground penetrating radar (GPR) inspection was investigated. The aim of the study is to observe how the GPR signal amplitude behaves under different distributions of corrosion products generated by different exposure conditions in the IC technique. To investigate this, two different experimental setups were prepared. The results are summarized, discussed, and supported by visual evidence, other non-destructive techniques, and electromagnetic theory. The main finding is that the position of the sodium chloride solution required to ensure accelerated corrosion of the reinforcement determines the behaviour of the GPR signal, as it affects the position of the corrosion product layer and its distribution in the concrete cover.

Effect of Cementious Materials on Corrsion in Carbonated Concrete

Reinforced Concrete(RC) is an world wide used material than any other man made material in construction. Today civil engineers are facing a major issue with corrosion in RC. The usage of cementious material in concrete prevents the economics loss and damage of structure. Under condition of carbonated concrete, the quantification of corrosion is determined by using condition evaluation methods like galvanostatic method. By using cementious substances like Silica Fume(SF), Ground Granulated Blast Furnace Slag (GGBS), the galvanostatic method will catalyze long lasting and sustainable concrete for the assessment of carbonation induced corrosion. This paper mainly reports on the study of Corrosion Assessment in carbonated and non carbonated specimens. This investigation includes four series (one carbonated and three non-carbonated) of cubes and beams in standard sizes. The reinforcement provided with 12mm diameter as main reinforcement and 8mm diameter as vertical stirrups. The proportions includes M30 Grade of concrete with GGBS (50%), Silica Fume(3%, 5%,10%) as a cement replacements along with superplasticizers. The methodology was adopted by conducting various test like flexural strength, compressive strength, corrosion rate, degree of corrosion, carbonation depth. The results found were effective, as flexural strength and compressive strength were increased due to the addition of cementious materials, where as carbonation depth and corrosion rate decreased.