Corrosion In Reinforced Concrete Research Articles

Monitoring of rebar corrosion in concrete structures using a lens-based plastic optical fiber (LPOF) sensor

Corrosion of reinforcement in concrete is one of the major causes for deterioration of concrete structures. This work presents an approach in the monitoring of concrete structures for damage induced by corrosion of steel in concrete using a lens-based plastic optical fiber (LPOF) strain sensor. The optical fiber sensor offers the advantage of being light weight, small in size, low-cost, immune to electromagnetic interference and it does not pose any spark hazard. The intensity-based optical fiber sensor used in this work consists of an emitter fiber, a ball lens, a receiving fiber and a light detector system. The light from the emitter fiber converges to focal point using the ball lens, before it enters the receiver fiber. A change in distance between the ball lens and the receiver fiber would lead to a change in the light intensity transmitted. The intensity change is correlated to the relative distance using a suitable calibration curve. Following the calibration of the sensor, it was used to monitor response of concrete members subjected to flexural loading. Subsequently, the sensor was tested for its ability to monitor corrosion of steel in concrete using an accelerated corrosion test set-up. The sensor shows promising results for detection of corrosion. The test results were used for identification of the corrosion propagation phase, which can be used for predicting the remaining service life of the structures. The optical fiber sensor strain readings were then correlated to the corrosion penetration depth to estimate the extent of damage during the corrosion of rebar. The test results show that it is possible to monitor concrete structures for damage due to flexural loading and corrosion of rebar using an intensity-based LPOF strain sensor.

A survey of the literature on the relationship between concrete resistivity and corrosion rate

The movement of ions through the concrete microstructure helps to regulate the process of reinforcement corrosion in concrete. Ions are charged, and the electrical resistivity of a substance determines its capacity to withstand charge transfer. As a result, a link between the corrosion process of steel buried in concrete and the electrical resistivity of concrete might be anticipated. The study on the connection between corrosion rate and concrete resistivity is reviewed in this article. In general, the parameters have an inverse proportional relationship. However, the connection between corrosion rate and resistivity varies across research, and no one relationship can be established. To resolve the discrepancy, the paper examines and analyzes the impact of variables such as the experimental setup, concrete mix design, and corrosion cause.

Part A: Advances in tools and techniques for estimating biogas production and treatment in anaerobic-based STPs Technical Note 3 - Biogas desulfurization by microaeration in UASB reactors

The generation of hydrogen sulfide (H2 S) is a typical problem in anaerobic sewage treatment systems, such as UASB reactors. High concentrations of H2 S in biogas are undesirable, as they reduce its quality, cause corrosionofreinforced concrete and steel structures, compromise the energy recovery units, generate odour emissions that are noticeable at low concentrations (0.47 ppbv e 100 ppbv ), can be toxic to humans and generate sulfur dioxide emissions during combustion. Therefore, it is necessary to propose and consolidate technologies, especially those simplified and of low-cost, that allow the use of biogas energy, avoiding or reducing the formation and/or emission of sulfide, such as microaeration. In view of the gaps in the literature on the application of microaeration to UASB reactors and biogas holders, this technical note addressed the following points of interest: (i) applicability and limitations of the technique; (ii) fundamentals of the process; (iii) design criteria; and (iv) operation and maintenance.

Effect of aggregate contamination with pyrite on reinforcement corrosion in concrete

This research aimed to evaluate the chemical and microstructure parameters of cement pastes and electrochemical parameters of concretes, both contaminated with different levels of SO3 (0.0%, 0.5%, 1.0% and 5.0%) due to the presence of pyrite. To evaluate the chemical and microstructural parameters, SEM and XRD tests were carried out in cement pastes, to detect the formation of deleterious products. The electrochemical parameters, such as corrosion potential, current density and electrical resistivity were measured in concrete samples to evaluate the reinforcements immersed in contaminated concretes and the susceptibility of these reinforcement concretes to the corrosion phenomenon. SEM and XRD tests, carried out up to 720 days, confirmed the presence of deleterious products, such as ettringite. The electrochemical analysis, which was performed during 1100 days, indicated significantly lower values of corrosion potential (around −600 mV) and higher values of current density (0.7 µA/cm2) for the reinforcement immersed in concrete with 5.0% of SO3. Finally, the research concludes the greater susceptibility of pyrite contaminated concretes with 5.0 of SO3 to the phenomenon of corrosion and the formation of deleterious products, therefore, being a harmful content for use in reinforced concrete elements.

Evaluation of Concrete Filled Steel Tube Column Confined with FRP

Abstract The main objective of this study was to assess the concrete-filled steel tube column confined with fiber-reinforced polymers (FRP) experimentally and numerically, where it can be used as a composite concrete column with high resistance and ductility. One of the weaknesses of reinforced concrete structures is the corrosion of steel reinforcement in concrete. This weakness can be resolved using FRP I-shaped composite structural sections instead of reinforcing steel bars in concrete. The composite profile was surrounded by the cylindrical concrete column and glass FRP (GFRP). A GFRP cylinder as a template acts in its place. In addition, it can provide a passive confinement for the composite column. Therefore, three columns have been tested in the experimental program under monotonic axial compressive loading. Furthermore, they have been numerically analyzed by means of a finite element method, employing ANSYS software (Ansys, Inc., Canonsburg, Pennsylvania). The ultimate capacity of each tested composite column has been compared to the theoretical capacity of the proposed numerical model. The results demonstrated that there was good compatibility and agreement between the experimental specimens and numerical analysis.

Experimental investigation of Rice Husk Ash on compressive strength, carbonation and corrosion resistance of reinforced concrete

ABSTRACT Reinforcement corrosion in concrete has become a major factor affecting durability of reinforced concrete structures. Corrosion of reinforcement is a continuous process. It cannot be eliminated completely. But its rate can be prevented with the help of corrosion inhibitors, either by acting as a barrier, by forming an adsorbed layer on the reinforcement surface or by retarding the cathodic or anodic processes of corrosion. The hazardous effects of synthetic inhibitors have led to the utilisation of alternative non-toxic, eco-friendly plant extracts, generally known as green corrosion inhibitors. The study aims to investigate the effect of Rice Husk Ash (RHA) as a green corrosion inhibitor on the durability of reinforced concrete. The compressive strength, carbonation depth and corrosion rate of RHA concrete has been studied. The results showed that the compressive strength increased with the increase in percentage of RHA upto 15% replacement of cement. However, a decrease in compressive strength was noticed from 15 to 20% replacement. It was also observed that the carbonation depth gets increased with the increase in percentage of RHA. From the corrosion tests, it was observed that the corrosion rate decreases with the increase in RHA percentage, hence increasing the inhibition efficiency of the concrete.

Characterization of Impressed Current Technique to Model Corrosion of Reinforcement in Concrete

Corrosion of reinforcement is an important durability concern for the structures exposed to coastal regions. Since corrosion of reinforcement involves long periods of time, impressed current technique is usually used to accelerate the corrosion of reinforcement in laboratories. Characterization of impressed current technique was the main focus of this research,which involved determination of optimum chloride content and minimum immersion time of specimens for which the application of Faraday’s law could be efficient. To obtain optimum chloride content, the electrolytes in the corrosion cell were prepared similar to that of concrete pore solutions. Concrete prisms of 200 mm by 200 mm by 300 mm were used to determine the minimum immersion time for saturation. It was found that the optimum chloride content was 35 gm/L and the minimum immersion time for saturation was 140 hours. Accounting the results, a modified expression based on Faraday’s law was proposed to calculate weight loss due to corrosion.
 Journal of Engineering Science 11(1), 2020, 93-99

The Reinforced Concrete Reinforcement Corrosion Degradation Inhibition with Nitrates of Alkali and Alki-Earth Metals

In order to determine the inhibitory additives concentration influence degree on the corrosion degradation rate, we studied the anode behavior of steel reinforcement made of steel grade St3 in a 10% solution NaCl with and without the inhibitors additives of various concentrations. As inhibitory additives, nitrates of potassium, sodium, magnesium, calcium and zinc were introduced into the aggressive environment, since they are often introduced into concrete compositions to accelerate their hardening. Polarization curves have been obtained for steel reinforcement in an aggressive environment, allowing the corrosion rate calculation. It was established that the introduction of potassium and zinc nitrates in an amount of 0.5% into an aggressive environment has the greatest effect on the corrosion processes’ inhibition. When nitrates of alkali and alkali-earth metals are introduced into an aggressive environment, the change in the reinforcing bars mass made of St3 steel occurs 7-8 times slower. Increasing the concentration to 1 and 1.5% is shown to be impractical, due to the small difference in the effect on the reinforcing steel anodic dissolution. A study on the effect of combining inhibitory additives on the corrosion resistance of steel reinforcement in a 10% solution NaCl was made. It was found that the combined action of inhibitors is less effective than the single effect of additives on the corrosion rate.

Study on Corrosion of Steel Reinforcement in Concrete Based on COMSOL

Study on Corrosion of Steel Reinforcement in Concrete Based on COMSOL

Stress distribution in thick‐walled cylinder due to non‐uniform radial pressure on the example of reinforcement corrosion in concrete

AbstractThis paper presents an analytical solution to the non‐uniform pressure on thick‐walled cylinder. The formulation is based on the linear elasticity theory (plain strain) and stress function method. As an example, the proposed solution is used to model the stress distribution due to non‐uniform steel reinforcement corrosion in concrete. The model is formulated considering different scenarios of corrosion pressure distribution. It is validated against the finite element model for different cases of non‐uniform pressure distributions. The results show that the corrosion‐induced cracks are likely to start just beyond the anodic zone. This is confirmed by the experimental tests on concrete cylinder exposed to non‐uniform accelerated corrosion of steel reinforcement. The model can be effectively used to calculate the distribution of corrosion‐induced stresses in concrete.

Research on Magnetic Induction Detection of Steel Bars Corrosion

Reinforced concrete structures are widely used in modern buildings. However, the structural damage caused by the steel bars corrosion seriously affects the building remaining life. The reinforcement corrosion in concrete is slow, so the long-term detection of reinforcement corrosion is very important. The development of reinforcement corrosion detection equipment in China is slow, which cannot meet the application requirements of domestic concrete structures, this paper proposes a non-contact magnetic induction detection method for reinforcement corrosion. Through theoretical analysis and experimental design, a simple model is built and simulated. Simulation results of single and multiple steel bars corrosion to verify the feasibility of the method. This paper provides theoretical support and technical solutions for the operation state detection of non-contact reinforced concrete, and makes contribution to the non-contact magnetic induction detection technology.

Threshold Level of Chloride Ions for Corrosion of SD345 Carbon Steel Reinforcement in Concrete

Threshold Level of Chloride Ions for Corrosion of SD345 Carbon Steel Reinforcement in Concrete

Effect of IR Drop on Reinforced Concrete Corrosion Measurements

The ohmic voltage drop (IR) due to the high resistivity of concrete needs to be considered while monitoring the corrosion performance of rebar embedded in concrete. It helps to evaluate the corrosion condition precisely. Concrete mixes were contaminated with chlorides, sulphates, and a combination of chloride plus sulphate solutions as mix water. To assess the IR drop error in corrosion measurements caused by concrete with different salts, linear polarization resistance values were measured with and without IR compensation. The results indicate that the concrete contaminated with 5% of chloride has shown higher error as compared to 2% of sulphates, due to high corrosion current density. However, from the results of chloride and chloride plus sulphate contaminated concrete, it is also confirmed that the IR drop error is not absolute to determine the solution resistance. The higher corrosion in chloride contaminated concrete as compared to chloride plus sulphate contaminated concrete is also observed due to the availability of high chloride concentration. The results of the present study are suggested that the IR drop compensation should be considered when the reinforced structures are exposed to chloride and sulphate environment.

Kelvin Probe Array for Rapid Survey of Reinforced Concrete Corrosion

First Name is required invalid characters Last Name is required invalid characters Email Address is required Invalid Email Address Invalid Email Address

Chloride Diffusion and Induced Reinforcement Corrosion in Concrete with Fly Ash and Ground‐Granulated Blast‐Furnace Slag Exposed to Marine Submerged Zone

This paper investigates the influence of mineral admixtures fly ash (FA) and ground‐granulated blast‐furnace slag (GGBS), the byproducts of industry, on chloride ions migration and corrosion resistance performance. A novel preparation method of wire beam electrode (WEB) was also introduced to explore the excellent corrosion‐resistant capacity of concrete with mineral admixtures. By comparing concrete specimens with and without FA and GGBS, the test result of wire beam electrode, rapid chloride migration (RCM), and electrochemical tests highlight the positive impact of fly ash and GGBS against chloride ions migration, respectively. Concrete with fly ash and GGBS supplies an advanced protection effect of ordinary Portland cement; meanwhile, CO2 emission amount can be significantly reduced. Moreover, homemade wire beam electrode was proved to be a novel and reliable test method against corrosion, which has agreement with the test result of an electrochemical device.

Influence of Polymer Surfactants on the Corrosion of Steel Reinforcement in Concrete as Part of a Complex Anti-Corrosion Additive

Influence of Polymer Surfactants on the Corrosion of Steel Reinforcement in Concrete as Part of a Complex Anti-Corrosion Additive

Example of analysis of climatic data series with respect to the testing of reinforcement concrete corrosion in a climate chamber

The paper presents a possible statistical evaluation of the climate data, namely temperature and relative humidity, with respect to the rapid evaluation of the risk of reinforced concrete corrosion in the laboratory conditions. Data on temperature and humidity from Leoš Janáček Ostrava Airport over the last ten years are analysed. The processed data will be used as the set up for the climate chamber where the concrete samples with steel rods will be placed.

A Cost‐Benefit Methodology for Selecting Analytical Reinforced Concrete Corrosion Onset Models

This work focuses on predicting corrosion onset induced by concrete carbonation or chloride ingress when using analytical predictive models. The paper proposes a procedure that helps building and infrastructure managers to select an appropriate model depending on the available information and the means granted to auscultation campaigns. The approach proposed combines the costs of input parameters, their relative importance, the benefits brought through obtaining parameters, and the maintenance strategy of the manager. Costs represent the intellectual investment to obtain parameters. This encompasses the time spent to obtain and analyze a result and the required expertise. Relative importance and benefits are obtained from sensitivity analysis. The effect of the maintenance strategy is introduced through a scalar called efficiency of the model. The proposed methodology is illustrated with two case studies where it is supposed that more or less extended information is available. Three concrete qualities are also considered in the case studies. The results highlight that the available data and concrete type have significant impacts on the selection of the most appropriate model.

Reinforced concrete bridge exposed to extreme maritime environmental conditions and mechanical damage: Measurements and numerical simulation

Although the durability mechanics models have been significantly improved in the last four decades, their application on real-life structures is still a challenging task. For their reliable application the verification is required on a real structure accounting for different exposure time and micro-climate conditions. The paper provides a brief overview of in-service performance of the Krk Bridge on the Croatian Adriatic coast, where combination of aggressive maritime environment, inadequate durability design and poor construction quality has led to rapid deterioration of the structure caused by corrosion of steel reinforcement in concrete. Measured values of chloride content in concrete for different structural elements and micro-climate conditions after 14 and 20 years of exposure to sea are presented and discussed. Chloride content in concrete is compared with the results of numerical simulation of transport of chlorides through concrete cover using recently developed 3D chemo-hygro-thermo-mechanical model. The numerical results are in good agreement with the data measured on the bridge. This leads to the conclusion that the model is able to realistically predict service life of reinforced concrete structures exposed to chlorides and mechanical damages. It is shown that the micro-climate parameters, such as wind direction and speed, and cracks in concrete significantly affect the chloride content in concrete.

Effect of polymer modified cementitious coatings on chloride‐induced corrosion of steel in concrete

AbstractThe paper deals with the study of the effect of polymer modified cementitious mortars on chloride‐induced corrosion of steel reinforcement in concrete. Nowadays, many results obtained by standard and short‐term tests are available in the literature. The paper reports more than 15 years exposure testing on two commercial coatings, with different polymer/cement ratio. The effect of coatings on corrosion initiation and propagation has been studied by the monitoring of corrosion potential and corrosion rate of rebars in concrete subjected to chloride ponding; chloride profiles, coating adhesion, water content, and corrosion morphology have been also analyzed. It was demonstrated that polymer modified cementitious mortars can delay corrosion initiation caused by chloride penetration into concrete. Owing to high resistivity of coated concrete, corrosion rate is reduced. The protective effect is more pronounced as the polymer content increases from 0.35 to 0.55. The results have been elaborated to estimate the possible increase of service life gained with this additional protection method, compared with other solutions.