An experimental study on correlation between concrete resistivity and reinforcement corrosion rate

2014 ◽  
Vol 61 (3) ◽  
pp. 158-165 ◽  
Author(s):  
Shamsad Ahmad
Keyword(s):  
Reinforced Concrete ◽  
Corrosion Rate ◽  
Current Density ◽  
Corrosion Current Density ◽  
Corrosion Current ◽  
Empirical Correlation ◽  
Reinforcement Corrosion ◽  
Content Type ◽  
Wide Range ◽  
Concrete Resistivity

Purpose – The purpose of this paper was to explore the possibility of establishing an empirical correlation between concrete resistivity and reinforcement corrosion rate utilizing the experimental data generated by measuring corrosion current density of reinforced concrete specimens subjected to chloride-induced corrosion at different levels of concrete resistivity. Design/methodology/approach – To generate concrete resistivity vs corrosion current density data in a wide range, ten reinforced concrete specimens were prepared and allowed to corrode under severe chloride exposure. After significantly corroding the specimens, they were removed from the chloride exposure and were subjected to different moisture levels for achieving variation in the resistivity of concrete so that reasonably good number of resistivity vs corrosion rate data can be obtained. Resistivity and corrosion current density tests were conducted for all the ten specimens and their values were measured in wide ranges of 0.8-65 kΩ·cm and 0.08-11 μA/cm2, respectively. Findings – Data generated through this study were utilized to obtain an empirical relationship between concrete resistivity and corrosion current density. The trend of results obtained using the empirical correlation model developed in the present study was in close agreement with that obtained using a theoretical model reported in literature. Originality/value – The empirical correlation between concrete resistivity and reinforcement corrosion rate obtained under this work can be used for evaluation of reinforcement corrosion utilizing the resistivity values measured non-destructively.

Prediction of residual flexural strength of corroded reinforced concrete beams

2017 ◽  
Vol 64 (1) ◽  
pp. 69-74 ◽  
Author(s):  
Shamsad Ahmad
Keyword(s):  
Reinforced Concrete ◽  
Flexural Strength ◽  
Current Density ◽  
Empirical Model ◽  
Corrosion Current Density ◽  
Concrete Beams ◽  
Corrosion Current ◽  
Reinforced Concrete Beams ◽  
Content Type ◽  
Rebar Corrosion

Purpose This study aims to make an effort to develop a model to predict the residual flexural strength of reinforced concrete beams subjected to reinforcement corrosion. Design/methodology/approach For generating the required data to develop the model, a set of experimental variables was considered that included corrosion current density, corrosion duration, rebar diameter and thickness of concrete cover. A total of 28 sets of reinforced concrete beams of size 150 × 150 × 1,100 mm were cast, of which 4 sets of un-corroded beams were tested in four-point bend test as control beams and the remaining 24 sets of beams were subjected to accelerated rebar corrosion inducing different levels of corrosion current densities for different durations. Corroded beams were also tested in flexure, and test results of un-corroded and corroded beams were utilized to obtain an empirical model for estimating the residual flexural strength of beams for given corrosion current density, corrosion duration and diameter of the rebars. Findings Comparison of the residual flexural strengths measured experimentally for a set of corroded beams, reported in literature, with that predicted using the model proposed in this study indicates that the proposed model has a reasonably good accuracy. Originality/value The empirical model obtained under this work can be used as a simple tool to predict residual flexural strength of corroded beams using the input data that include rebar corrosion rate, corrosion duration after initiation and diameter of rebars.

scholarly journals Influence of Seawater Salinity on Corrosion of Austenitic Steel

2019 ◽  
Vol 26 (3) ◽  
pp. 219-225
Author(s):  
Robert Starosta
Keyword(s):  
Sodium Chloride ◽  
Corrosion Rate ◽  
Austenitic Steel ◽  
Current Density ◽  
Corrosion Current Density ◽  
Corrosion Potential ◽  
Saturated Calomel Electrode ◽  
Corrosion Current ◽  
Seawater Salinity ◽  
Corrosion Susceptibility

Abstract Due to the paramagnetic properties and the ability to passivation, for the production of hulls of some vessels (mainly warships), corrosion-resistant (stainless) steels with austenitic structure are used. This article describes the influence of seawater salinity on selected corrosion properties of high-alloy steel X5CrNi 18-10 (304). The average salinity of the seas is taken as 3.5% content of sodium chloride. Corrosion rate of the tested material was evaluated in an aqueous solution of sodium chloride was evaluated. The NaCl concentration in corrosive solutions was 0.7%, 1.4%, 2.1%, 2.8%, 3.5%, 4.2%. Corrosion tests were performed using the potentiodynamic method. The range of electrochemical potential changes was Ecorr ±150 mV. Corrosion rate was assessed on the basis of corrosion current density measurements. Corrosion potential values against the saturated calomel electrode were also determined. Based on the obtained measurement results and non-parametric significance tests carried out, a significant influence of seawater salinity on the value of corrosion current density and corrosion potential was found. The highest value of corrosion current density (jcorr), and thus the highest corrosion rate, was recorded for 3.5% NaCl solution. In the concentration range from 0.7 to 3.5% NaCl in solution, the corrosion rate of austenitic steel increases. A further increase in salinity of electrolyte results in the inhibition of corrosion rate of steel. There is almost a full negative, linear correlation between the proportion of sodium chloride in the corrosive solution and the value of corrosion potential. Along with the rise in the salinity of seawater, increase the electrochemical activity, and thus the corrosion susceptibility, thus the corrosion susceptibility, of the austenitic steel X5CrNi 18-10 was observed.

scholarly journals Temperature Impact on the Assessment of Reinforcement Corrosion Risk in Concrete by Galvanostatic Pulse Method

2020 ◽  
Vol 10 (3) ◽  
pp. 1089 ◽  
Author(s):  
Wioletta Raczkiewicz ◽  
Artur Wójcicki
Keyword(s):  
Current Density ◽  
Corrosion Current Density ◽  
Pulse Method ◽  
Corrosion Current ◽  
Concrete Cover ◽  
Effect Of Temperature ◽  
Reinforcement Corrosion ◽  
Stationary Potential ◽  
Corrosion Risk ◽  
The Impact

The electrochemical galvanostatic pulse method (GPM) is used for the evaluation of the degree of corrosion risk of reinforcement in concrete. This non-destructive method enables determining the corrosion promoting conditions through the measurements of reinforcement stationary potential and concrete cover resistivity, and determining the probability of reinforcement corrosion in the tested areas. This method also allows for the estimation of the reinforcement corrosion activity and the prediction of the development of the corrosion process on the basis of corrosion current density measurements. The ambient temperature (and the temperature of the examined element) can significantly affect the values of the measured parameters due to electrochemical character of the processes as well as specific measurement technique. Differences in the obtained results can lead to a wrong interpretation of reinforcement corrosion risk degree in concrete. The article attempts to assess the effect of temperature on the measured parameters while using the galvanostatic pulse method. The GP-5000 GalvaPulseTM set was used. The results of this study confirmed the impact of temperature changes on the values of three measured parameters (reinforcement stationary potential, concrete cover resistivity, and corrosion current density) and contributed to catching the trend of these changes.

Preparation and Performance Evaluation of a Novel Bactericide for Sulfate Reducing Bacteria

2021 ◽  
Vol 1035 ◽  
pp. 624-629
Author(s):  
Xiao Jun Fang ◽  
Li Liu ◽  
Zhi Gang Yang ◽  
Yong Qiang Zhang
Keyword(s):  
Corrosion Rate ◽  
Ammonium Salt ◽  
Current Density ◽  
Quaternary Ammonium ◽  
Quaternary Ammonium Salt ◽  
Corrosion Current Density ◽  
Critical Concentration ◽  
Corrosion Current ◽  
Sulfate Reducing ◽  
Reducing Bacteria

The sulfate reducing bacteria (SRB) bactericide was synthesized using KNO3, isothiazolinone, quaternary ammonium salt, and additives as main components, and the optimal ratio and critical concentration of the bactericide were determined. Weight loss method, potentiodynamic polarization curve, compatibility study were used to investigate the changes of corrosion rate and corrosion current density and compatibility after adding the bactericide. The results showed that the optimal formula ratio of the bactericide was: KNO3: isothiazolinone: quaternary ammonium salt: additive is 20:1:2:3, and the critical concentration of the bactericide was 50 mg/L. The addition of bactericides reduced the corrosion rate of pipes by 67% to 88%, and the electrochemical corrosion current density of pipes was significantly reduced, indicating that the presence of bactericides under the given media conditions significantly slowed down the corrosion process of metals. The bactericide was used in conjunction with commonly used oilfield chemicals such as corrosion inhibitors, scale inhibitors, flocculants, without obvious changes in appearance, no reduction in efficacy. Therefore, it may be concluded that the bactericide has good compatibility.

Corrosion behavior of X80 steel under disbond coating interfered with AC

2019 ◽  
Vol 66 (6) ◽  
pp. 704-718
Author(s):  
Qingmiao Ding ◽  
Zili Li ◽  
Tao Shen ◽  
Gan Cui
Keyword(s):  
Corrosion Behavior ◽  
Current Density ◽  
Corrosion Current Density ◽  
Corrosion Potential ◽  
Corrosion Current ◽  
The Self ◽  
Stray Current ◽  
Content Type ◽  
X80 Steel ◽  
Protection Potential

Purpose This paper aims to research the corrosion behavior of the metal under the disbonded coatings interfered with AC through electrochemical method. Design/methodology/approach The corrosion behavior of the metal under disbond coating interfered with alternate stray current (AC) was studied by electrochemical methods using the rectangular coating disbonded simulator. The obtained data from electrode potential test, electrochemical impedance spectroscopy (EIS) and polarization curves in simulated soil solution indicated that under the natural corrosion condition, the self-corrosion potential and the corrosion current density of the metal at different depths under disbond coating had obviously changed if there was AC interference. Findings The self-corrosion potential of the metal at the same depths under disbond coating shifted negatively with the rising of the AC voltage. Under the condition of cathode polarization, there was still obvious potential gradient with the extension of the deep peeling of the coating gap, and the corrosion current density of the test points was minimum, and the protection effect was best when the cathode protection potential was −1.0 V. When the metal was applied with over-protection, the corrosion rate of the metal increased as AC stray current flowing through it increased. Originality/value This paper used the rectangular aperture device to study the corrosion behavior of X80 steel under the disbonded coatings through electrochemical methods when the AC stray current interference voltage was 0V, 1V, 5V or 10V and the protection potential was 0V, −0.9V, −1.0V, −1.2V or −1.3V, respectively. There is great significance to the safe operation and long-term service of pipeline steel in soil environment.

Anodic Behavior of Pb-Ag-Ca-Sr Alloy in Zinc Electrowinning

2013 ◽  
Vol 790 ◽  
pp. 85-89
Author(s):  
Xue Tao Yuan ◽  
Xu Dong Lv ◽  
Yu Gao Zhou ◽  
Zhi Qiang Hua ◽  
Yang Lei ◽  
...  
Keyword(s):  
Corrosion Rate ◽  
Oxygen Evolution ◽  
Current Density ◽  
Oxygen Evolution Reaction ◽  
Corrosion Current Density ◽  
Corrosion Current ◽  
Zinc Electrowinning ◽  
Anodic Behavior ◽  
Before And After ◽  
Surface Product

Over potentials for oxygen evolution reaction, corrosion rate, surface product after polarization and microstructure before and after polarization of Pb-0.2%Ag-0.08%Ca-0.05%Sr quaternary anode in zinc electrowinning were studied and compared with Pb-0.6%Ag binary anode. The results show that over potentials for oxygen evolution reaction on Pb-0.6%Ag and Pb-0.2%Ag-0.08%Ca-0.05%Sr anodes are 675 mV and 790 mV, respectively, while the corrosion current density are 8.2μAcm-2 and 20.1μAcm-2. The surface structure after experiment of in Pb-Ag anodes is dense and tightly attached to the base, while the surface of Pb-Ag-Ca-Sr is loose and porous. The phases of the surface are PbO2, PbSO4 and MnO2 on both anods.

scholarly journals CORROSION BEHAVIOR OF REINFORCING STEEL IN RC SLAB CONTAINING CHLORIDES WITH PARTIAL REPLACEMENT OF CEMENT AS FLY ASH

2019 ◽  
Vol 31 (3) ◽  
Author(s):  
Sristi Das Gupta ◽  
Takafumi Sugiyama ◽  
Md Shafiqul Islam
Keyword(s):  
Reinforced Concrete ◽  
Fly Ash ◽  
Current Density ◽  
Corrosion Current Density ◽  
Corrosion Current ◽  
Concrete Cover ◽  
Partial Replacement ◽  
Normal Concrete ◽  
Fly Ash Concrete ◽  
Rc Slab

Steel reinforcement in concrete containing fly ash has been practically employed to RC structures in snowy cold region and coastal areas so that the durability of the structures against corrosion can be enhanced. In this research to make the compatibility with RC slab bridge sodium chloride solution of 10[WU1] % in concentration was applied on RC slab and corrosion development was monitored by electrochemical method. Applying fly ash in RC slab at two replacement levels of 15[WU2] % (F15) and 30% (F30) of cement the specimens were observed. The observation result verified that fly ash concrete showed longer period of corrosion initiation (ASTM C876) than normal reinforced concrete. The initiation period of corrosion was 4.5 and 6 times longer for F15 and F30 concrete than normal concrete, as well as 91 days strength of F30 concrete was about 14% higher that of norma concrete. Test result showed that fly ash has better influence on steel corrosion reduction than concrete cover increment. It was observed that fly ash concrete (F15 and F30) with 3 cm concrete cover has better corrosion resistivity than using 4 cm cover of non-fly ash concrete. Furthermore, using the same concrete cover (3 cm) it was found that the actual corrosion rate was decreased about 68 to 82% by adding fly ash 15 to 30% respectively compared to normal reinforced concrete. In addition, a significant attenuation in corrosion area in rebar between fly ash concrete and normal concrete was found. Based on actual corrosion area on rebar surface, actual corrosion current density was larger than corrosion current density found from non-destructive way. Moreover, further analysis was conducted for characterization of different corrosion products using Raman spectroscopy with 532 nm wave length. It revealed that the corrosion product (Oxides and Oxyhydroxides compound) were less in F15 and F30 concrete compared to normal concrete. Considering these results, the possibility of reduction of chloride induced corrosion in reinforced concrete structure using fly ash has confirmed. 

scholarly journals Improving Surface Properties of Inconel 600 Alloy by Electroless Ni-P Deposition

2019 ◽  
Vol 12 (4) ◽  
pp. 254-259 ◽  
Author(s):  
Hassan. H. Masallb ◽  
Kadhim F. Al-Sultani ◽  
Abdul Raheem K. Abid Ali
Keyword(s):  
Heat Treatment ◽  
Current Density ◽  
Electroless Plating ◽  
Corrosion Current Density ◽  
Corrosion Current ◽  
X Ray Diffraction ◽  
X Ray ◽  
Wide Range ◽  
Coating Time ◽  
Electroless Ni

The use of electroless Ni-P plating (EN) coating has attracted a surprising interest in the most recent years. Many useful characteristics of the electroless-plating method have created many benefits in different industries such as oil, gas, electronic, automotive, aerospace, and chemical. Some of the highlighted properties of such a method are superior corrosion resistance, superior mechanical properties, and uniform thickness of the coating as well as good surface finish properties, good adhesion characteristics, and a wide range of thickness. In this paper, electroless plating has been applied in a (Ni-P) bath at two different times of 2 and 3 hr respectively. After the plating, a heat treatment at 400 °C for an hour under vacuum 10-4 torr has been done. The prepared samples were characterized by energy dispersive spectroscopy, X-ray diffraction, and scanning electron microscopy (SEM). In addition, micro-hardness and corrosion rate following Tafel extrapolation in two acidic solutions (1M HCl and 1M H2SO4) were also determined. Vickers hardness values for specimens, coated by Ni -P at 2 and 3 hr have increased by 47 % and 32 % respectively. X-ray diffraction analysis for the coated surfaces showed two phases of Ni3P and NiP, presented before and after heat treatment. The SEM images of the cross sectional coated specimens revealed that the thickness of the coating is 68.43 and 92.71 µm for 2 and 3 hr coating time, respectively. Tafel analysis showed that the coated specimens had a lower corrosion current density compared to that for the bare specimens. The corrosion current density for the coated specimens in 1M H2SO4 increased by 57 % with 2 hr and 69 % at 3 hr coating time. While, the corrosion current density for the coated specimens in 1M HCl increased by 37 % and 83 % at 2 and 3 hr coating time respectively.

Sign in / Sign up

Export Citation Format

Share Document