scholarly journals CORROSION CURRENT DENSITY OF MACROCELL OF HORIZONTAL STEEL BARS IN REINFORCED CONCRETE COLUMN SPECIMEN

2019 ◽  
Vol 16 (54) ◽  
Author(s):  
Nevy Sandra
Keyword(s):  
Reinforced Concrete ◽  
Current Density ◽  
Corrosion Current Density ◽  
Corrosion Current ◽  
Concrete Column ◽  
Reinforced Concrete Column ◽  
Steel Bars

Evaluation on the Addition of Inhibitor and Surface Treatment to Corrosion Behavior of the Reinforced Steel Bar Embedded in Mortar Specimen

2017 ◽  
Vol 744 ◽  
pp. 114-120
Author(s):  
Kyung Man Moon ◽  
Sung Yul Lee ◽  
Jae Hyun Jeong ◽  
Myeong Hoon Lee
Keyword(s):  
Current Density ◽  
Test Specimen ◽  
Corrosion Current Density ◽  
Corrosion Current ◽  
Corrosion Properties ◽  
Mortar Specimen ◽  
Steel Bar ◽  
Steel Bars ◽  
Reinforced Steel ◽  
One Year

In this study, seven types of mortar test specimens were manufactured with parameters, that is, the surface of the reinforced steel bar was treated with hot dip galvanizing (Zn) and the surface of the test specimen was coated with underwater paint, and four types of inhibitors (DAW, MCI, DCI, and Silcon) were added in mortars respectively. And, the seven types of mortar test specimens were immersed in seawater for 4 years. The corrosion properties of the reinforced steel bars embedded in mortar test specimens were investigated using electrochemical methods. The corrosion potentials of the test specimens with painting on the surface of the specimen and Zn coating on the surface of the steel bar exhibited the noblest and lowest values respectively after one year, however, after 4 years, the specimens of underwater painting and of addition of Silcon inhibitor indicated the noblest and lowest values of corrosion potentials respectively. Furthermore, the painting specimen exhibited the smallest values of corrosion probability as welll as of the corrosion current density, while, addition of MCI inhibitor showed the highest values of both corrosion probability and corrosion current density. Moreover, the painting specimen showed the smallest value of neutralization degree among all the specimens, and the largest value of neutralization degree was observed at the specimen of natural condition (no adding of inhibitor, no painting and no Zn coating). As a result, it is considered that the addition of inhibitors, coating with hot dip galvanizing (Zn), and painting on the surface have the effects not only to inhibit the neutralization degree but also to increase the corrosion resistance of the embedded steel bar.

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.

Prediction of Steel Bar Corrosion of RC Members Deteriorated by Pre-Existed Chloride and Concrete Carbonation

2015 ◽  
Vol 723 ◽  
pp. 410-418
Author(s):  
Xin Xue ◽  
Wen Xiong ◽  
Hui Chao Wang ◽  
Cong Zhou Shen
Keyword(s):  
Current Density ◽  
Corrosion Current Density ◽  
Corrosion Current ◽  
Area Ratio ◽  
Concrete Cover ◽  
Total Chloride ◽  
Concrete Carbonation ◽  
Cover Concrete ◽  
Steel Bars ◽  
Combined Action

By simulating solo or combined deterioration action of pre-existed chloride and concrete carbonation, this paper carried out an experimental investigation on the corrosion state of steel bars embedded in concrete with different concrete cover thicknesses and containing different chloride amounts. Comparisons of corrosion current density, corrosion area ratio and corrosion weigh loss of embedded steel bars were made and the effect of combined action was systematically studied. Test results indicated that under the combined action, the corrosion current density measured soon after concrete carbonation test increased with the total chloride amount containing in cover concrete, and the specimens under the combined action exhibited larger value of corrosion current density, corrosion area ratio and mass weight loss than that of the specimens subjected to the solo action. It was further indicated that the mass loss ratio of embedded steel bars at the point of corrosion crack initiation was 1.29% for the specimens with 5mm concrete cover, and the corresponding value of the specimens with 10mm concrete cover was 1.33%.

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 Effects of Bleeding on the Corrosion of Horizontal Steel Bars in Reinforced Concrete Column Specimens

2019 ◽  
Vol 10 (4) ◽  
pp. 741 ◽  
Author(s):  
Nevy Sandra ◽  
Keiyu Kawaai ◽  
Isao Ujike ◽  
Ippei Nakai ◽  
Willick Nsama
Keyword(s):  
Reinforced Concrete ◽  
Concrete Column ◽  
Reinforced Concrete Column ◽  
Steel Bars
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