Theoretical considerations on the supposed linear relationship between concrete resistivity and corrosion rate of steel reinforcement

This paper presents results of an ongoing research of the effect of 1D and 2D chloride ingress on concrete resistivity and corrosion rate of steel reinforcement. 12 concrete beams made with concrete of binder blend PC(50)/GGBS(50), w/b = 0.40, 10 mm steel reinforcement rods at concrete cover of 20 mm were used in this laboratory based experiment. The steel reinforcement bars were placed at the middle or at an orthogonal corner of the concrete beams subjected to 1D and 2D chloride ingress respectively. A single crack was induced using 3-point bending on one-half of the beams. The beams were exposed to a repeated cycle of 2 weeks ponding in 5% NaCl and then air drying in ambient laboratory condition for 2 weeks. The corrosion rate of both cracked and uncracked specimens exposed to 2D chloride ingress was significantly higher than that of beams exposed to 1D chloride ingress. The uncracked specimens had lower concrete resistivity values compared to the cracked specimens even though higher corrosion rates were measured.

Download Full-text

Effect of temperature and concrete resistivity on the corrosion rate of steel in unsaturated concrete

2nd International RILEM Symposium on Advances in Concrete through Science and Engineering ◽

10.1617/2351580028.034 ◽

2006 ◽

Author(s):

Alexandre Maltais

Keyword(s):

Corrosion Rate ◽

Effect Of Temperature ◽

Concrete Resistivity

Download Full-text

Effect Use of Two Chemical Compounds Sodium Nitrate and Sodium Silicate as Corrosion Inhibitor to Steel Reinforcement

Al-Khwarizmi Engineering Journal ◽

10.22153/kej.2018.11.006 ◽

2019 ◽

Vol 14 (2) ◽

pp. 123-128

Author(s):

Sarah Kareem Mohammed

Keyword(s):

Corrosion Rate ◽

Sodium Silicate ◽

Electrolyte Solution ◽

Sodium Nitrite ◽

Corrosion Inhibitors ◽

Sea Water ◽

Chemical Compounds ◽

Steel Sample ◽

Steel Reinforcement ◽

Corrosion Of Steel

Corrosion of steel reinforcement is one of the biggest problems facing all countries in the world like bridges in the beach area and marine constructions which lead to study these problems and apply some economical solutions. According to the high cost of repair for these constructions, were studied the effect of using kind of chemical compounds sodium nitrite(NaNO2) and sodium silicate(Na2SiO3) as corrosion inhibitors admixture for steel bars that immersed partially in electrolyte solution (water + sodium chloride in 3% conc.) (Approximately similar to the concentration of salt in sea water). The two inhibitors above added each one to the electrolyte solution at concentrations (0.5%, 1% and 2%) for both of them. The results were corrosion rate for steel sample that's immersed partially in salt solution was higher than corrosion rate of steel bar that's immersed partially in electrolyte solution with inhibitors also the two corrosion inhibitors (sodium nitrite and sodium silicate) that added to the electrolyte solution were working successfully to prevent and inhibit the corrosion by using weight loss technique with best percent of 0.5% sodium nitrite ( efficiency 94.1% ) and best percent of 2% sodium silicate ( efficiency 92.5%).

Download Full-text

The Effect of Freeze-Thaw Damage on Corrosion in Reinforced Concrete

Advances in Materials Science and Engineering ◽

10.1155/2021/9924869 ◽

2021 ◽

Vol 2021 ◽

pp. 1-13

Author(s):

Xiao-Chun Lu ◽

Bin Guan ◽

Bo-Fu Chen ◽

Xin Zhang ◽

Bo-bo Xiong

Keyword(s):

Reinforced Concrete ◽

Corrosion Rate ◽

Sem Analysis ◽

Steel Reinforcement ◽

Reinforcement Corrosion ◽

Freeze Thaw ◽

Pull Out ◽

Thaw Cycle ◽

Corrosion Reaction ◽

Freeze Thaw Cycle

The existing studies of the corrosion of reinforced concrete have mainly focused on the interface area and chemical ion erosion, ignoring the specific service environment of the reinforced concrete. In this study, the effect of freeze-thaw damage was investigated via corrosion experiments under different freeze-thaw cycle conditions. Steel reinforcement corrosion mass, ultimate pull-out force, corrosion rate, and bond slippage were chosen as characteristic parameters in the experiments, and scanning electron microscopy (SEM) analysis was used to explain the mechanism of action of freeze-thaw damage on corrosion. The results showed that, under identical corrosion conditions, the mass of steel reinforcement corrosion and corrosion rate increased by 39.6% and 39.7% when comparing 200 freeze-thaw cycles to 0 cycles, respectively. The ultimate pull-out force and bond slippage after 200 freeze-thaw cycles decreased by 73% and 31%, respectively, compared with 0 freeze-thaw cycles. In addition, SEM analysis indicated that microstructure damage caused by freeze-thaw cycles accelerated the corrosion reaction and decreased cementitious properties, leading to decreasing ultimate pull-out force and bond slippage. The effect of freeze-thaw cycles and steel reinforcement corrosion on the macro mechanical properties of concrete is not a simple superposition.

Download Full-text

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

Anti-Corrosion Methods and Materials ◽

10.1108/acmm-07-2013-1285 ◽

2014 ◽

Vol 61 (3) ◽

pp. 158-165 ◽

Cited By ~ 8

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.

Download Full-text

Effect on Vibroengineering of Material Deterioration in a Scale-Down Reinforced Concrete Containment Vessel Specimen

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.479-480.13 ◽

2013 ◽

Vol 479-480 ◽

pp. 13-19

Author(s):

Wei Ting Lin ◽

Yuan Chieh Wu ◽

Tung Liang Chu ◽

An Cheng

Keyword(s):

Reinforced Concrete ◽

Corrosion Rate ◽

Natural Frequency ◽

Natural Frequencies ◽

Frequency Variation ◽

Accelerated Corrosion ◽

Containment Vessel ◽

Scale Down ◽

Concrete Resistivity ◽

Natural Frequency Variation

This study is aim to evaluate the natural frequency variation of the scale-down reinforced concrete containment vessel specimen under accelerated corrosion conditions. A plastic ring was sealed around the perimeter of the cylindrical vessel bottom with the 3.5 % NaCl solution to achieve the accelerated corrosion test. Concrete resistivity, open circuit potential, corrosion rate and natural frequencies were tested and discussed in this study. Test results presented that the accelerated corrosion method with a direct 60 voltage applied was a suitable method for estimating and accelerating the concrete vessel specimen. Therefore, the changes in natural frequencies were consistent with the material degradation of the concrete vessel specimen. The natural frequencies decreased with the increasing corrosion rate or decreasing resistivities for the specimen at higher mode, but would be no change for the specimen at the natural frequency of 1stmode.

Download Full-text

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

Materials Science Forum ◽

10.4028/www.scientific.net/msf.1011.72 ◽

2020 ◽

Vol 1011 ◽

pp. 72-78

Author(s):

Varvara Rumyantseva ◽

Viktoriya Konovalova

Keyword(s):

Corrosion Rate ◽

Steel Reinforcement ◽

Reinforcing Bars ◽

Aggressive Environment ◽

Effect Of Additives ◽

Sodium Magnesium ◽

Combined Action ◽

Rate Calculation ◽

Single Effect ◽

Influence Degree

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.

Download Full-text

Effect of Interrupting Electricity Period on Electrochemical Chloride Extraction of Reinforced Concrete

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.754-755.342 ◽

2015 ◽

Vol 754-755 ◽

pp. 342-347

Author(s):

Mien Van Tran ◽

Dong Viet Phuong Tran ◽

Mohd Mustafa Al Bakri Abdullah

Keyword(s):

Reinforced Concrete ◽

Corrosion Rate ◽

Current Density ◽

Concrete Structure ◽

Chloride Concentration ◽

Steel Reinforcement ◽

Reinforced Concrete Structure ◽

Half Cell ◽

Cell Potential ◽

Electrochemical Chloride Extraction

Electrochemical chloride extraction – ECE is an effective method to rehabilitate reinforced concrete structure, which has been corroded. This study investigated concentration of chloride remained in concrete and half-cell potential of the steel reinforcement after ECE using interrupting period of electricity current. Efficiency of ECE using Ca (OH)2was surveyed with two current density of 0.5 and 1A/m2. In this study, ECE treatment was proceeded intermittently in approximately 8 weeks. Results pointed out that chloride concentration decreased to 30 – 60% significantly, especially at in the vicinity of reinforcing steel. Simultaneously, half-cell potential of the steel reinforcement after 4 weeks halted treatment stabilizes in low-corrosion rate.

Download Full-text

Monitoring Method of Steel Reinforcement Corrosion Rate in Concrete

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.334-335.101 ◽

2007 ◽

Vol 334-335 ◽

pp. 101-104

Author(s):

Hiroyuki Saito

Keyword(s):

Corrosion Rate ◽

Measurement Method ◽

Steel Corrosion ◽

Electrochemical Measurement ◽

Steel Reinforcement ◽

Passive State ◽

Reinforcement Corrosion ◽

Monitoring Method ◽

Steel Bars

Steel reinforcement concrete is one of the most widely used composite materials in architectural and civil engineering. The alkaline of concrete makes steel passive state, so the steel bars in conrete are kept in anti-corroded phase. Carbon dioxide in atmosphere, however, chemically reacts to the alkaline components in long term, and the passive state of steel is missing. Steel corrosion in concrete is not visible but it may cause decaying buildings or civil construction. The author developed the electrochemical measurement method of monitoring steel corrosion rate in concrete. With the measurement method, the author measured the variety of corrosion rates of steel reinforcement in several atmospheres, such as indoors, outdoors, in-water, underground, and so on. In this paper, found and analyzed mechanisms of steel corrosion in those atmospheres are mainly shown. For an interesting result, the most corroded sample is not the sample exposed outdoor, nor exposed in water, but the sample exposed in wet room. This may cause the diffusion balance of oxygen and water in concrete.

Download Full-text