scholarly journals Monitoring DIAMOND device for corrosion state evaluation of reinforced concrete structures

2018 ◽  
Vol 199 ◽  
pp. 04007 ◽  
Author(s):  
Gabriel Samson ◽  
Fabrice Deby ◽  
Jean-Luc Garciaz ◽  
Jean-Louis Perrin
Keyword(s):  
Reinforced Concrete ◽  
Linear Polarization ◽  
Concrete Structure ◽  
Polarization Resistance ◽  
Reinforced Concrete Structure ◽  
Linear Polarization Resistance ◽  
Corrosion Evaluation ◽  
Ohmic Drop ◽  
Concrete Resistivity ◽  
Corrosion State

The corrosion of steel rebars is a major issue with respect to the durability of reinforced concrete structure. Several corrosion evaluation methods exist: half-cell potential, concrete resistivity or linear polarization resistance (LPR) measurement. However, these techniques are employed at a given moment and are not suitable for continuous corrosion evaluation. This works belongs to the DIAMOND project which aims to produce a new corrosion state measurement monitoring device. The monitoring probe consists on a cylindrical probe. A ring shape counter-electrode CE is plated on the probe side. At the centre of the CE, a reference electrode (RE) is placed for potential measurement. The device is embedded in concrete at 25 mm of the inspected rebar. The instantaneous ohmic drop observed at the beginning of the polarization measurement is only linked with the concrete resistance which depends on concrete cover and resistivity. A numerical model was developed on Comsol® to create abacuses graph that link concrete resistivity and concrete resistance. Thus, the ohmic drop measure at the beginning of the polarization can now be used to determine regularly concrete average resistivity between the monitoring probe and steel rebar. Two other series of abacus graphs are then introduced in order to determine the polarization resistance of the rebar in front of the monitoring probe (the point of interest (PI)). Two monitoring probes were placed in two types of concrete (one sound concrete and one concrete with chloride). Corrosion potential, concrete resistivity and rebar corrosion rate were monitored over around 200 days. The experimental results obtained with the monitoring probe are finally compared to the results obtained with the surface DIAMOND probe (introduced in the ICCRRR 2018 paper “Alternative methodology for linear polarization resistance assessment of reinforced concrete structure [1]”).

scholarly journals Alternative methodology for linear polarization resistance assessment of reinforced concrete structure

2018 ◽  
Vol 199 ◽  
pp. 06009 ◽  
Author(s):  
Gabriel Samson ◽  
Fabrice Deby ◽  
Jean-Luc Garciaz ◽  
Jean-Louis Perrin
Keyword(s):  
Reinforced Concrete ◽  
Corrosion Rate ◽  
Current Density ◽  
Linear Polarization ◽  
Concrete Structure ◽  
Polarization Resistance ◽  
Concrete Cover ◽  
Reinforced Concrete Structure ◽  
Linear Polarization Resistance ◽  
Steel Rebar

For reinforced concrete structures, several corrosion detection methods exist: concrete resistivity, half-cell potential or linear polarization resistance (LPR) measurement. The LPR value can be linked to the corrosion rate thanks the Stern-Geary equation if strong hypotheses are made. Existing commercial devices use a guard ring to canalize the current on specific steel rebar area and assume that the steel rebar is uniformly polarized. However, recent works reveal that the top part of the steel rebar, right under the counter electrode, is the most polarized point. The particular point is referred as the point of interest (PI). This works belongs to the DIAMOND project which aims to produce a new corrosion rate measurement device. Comsol® software was used to model the influence of concrete cover, resistivity and injected current on the current density at the PI. Moreover, a significant influence of the steel rebars diameter was also demonstrated. Two types of abacus are built. The first one links to polarization measured on the surface to the polarization on the rebar at the PI. The second links the ratio between the current density at the PI and the density of injected current to concrete cover and steel rebar diameter. The Stern-Geary equation can now be used at the PI without using the approximation of a uniformly polarized rebar. The corrosion state of reinforced concrete structure can be controlled more precisely. The methodology is then applied on two concrete slabs in which three metal bars are embedded at different concrete covers. The first slab is prepared with ordinary concrete while the second contain chloride to artificially activate the corrosion process. The results reveal that the rebars embedded on the first slab are not corroding (icorr ≤0.2 μΑ/cm2) while the second rebar are corroding (icorr>0.2 μΑ/cm2).

Investigation on Inhibitor Electromigration Anticorrosion Technology for Reinforced Concrete Structure

2009 ◽  
Vol 79-82 ◽  
pp. 1025-1028
Author(s):  
Jun Wu Tang ◽  
Shu Ang Han ◽  
Chang Hong Huang ◽  
Sen Lin Li
Keyword(s):  
Reinforced Concrete ◽  
Concrete Structure ◽  
Polarization Resistance ◽  
Steel Surface ◽  
Chloride Ion ◽  
Passive State ◽  
Reinforced Concrete Structure ◽  
Technical Parameters ◽  
Chloride Removal ◽  
Effective Component

Based on measuring inhibitor effective component N content, chloride removal efficiency and steel polarization resistance, influences of technical parameters of concrete and electric charge amount on the inhibitor electromigration anticorrosion efficiency were described. The results indicated that inhibitor electromigration anticorrosion technology could remove chloride ion, and inhibitor group could move to steel surface so rapidly that corrosive steel could return into passive state, to meet the anticorrosion aim for steel.

scholarly journals PERBANDINGAN LAJU KOROSI PADA TULANGAN BETON BUSA NORMAL DAN BETON BUSA POZZOLAN

2018 ◽  
Vol 1 (4) ◽  
pp. 885-894
Author(s):  
Zubaidi Amri ◽  
Abdullah Abdullah ◽  
Syarizal Fonna
Keyword(s):  
Reinforced Concrete ◽  
Corrosion Rate ◽  
Linear Polarization ◽  
Polarization Resistance ◽  
Water Immersion ◽  
Half Cell ◽  
Cell Potential ◽  
Linear Polarization Resistance ◽  
Foamed Concrete ◽  
Potential Mapping

Abstract: Reinforced concrete foam is one alternative to replace conventional reinforced concrete on structural elements. This study aims to measure the The media immersion and variation of specific gravity (SG) is a variable of interest in this study. The specimen type used is Normal foamed concrete (BB) and pozzolan foamed concrete (BBP). The test specimens used were 8 x 8 x 50 cm, with single reinforcement Ø10 mm in it. Reinforced placement of the reinforcement so that the test specimen has a thickness of 4 cm concrete cover. The specimen was immersed in freshwater and artificial seawater in the form of a 3.5% sodium chloride solution. The measurements results using half-cell potential mapping (HCPM) technique described the highest corrosion risk location. At this location corrosion rate measurement performed using linear polarization resistance (LPR) method. The corrosion rate calculation result of normal foamed concrete SG 1,2, 1,4, 1,6 with NaCl 3.5% and  fresh water immersion medium ranged from 0,621 mpy up to 0,854 mpy and 0,194 mpy up to 0,304 mpy. The corrosion rate value of pozzolan foamed concrete SG 1,2, 1,4,1,6 with 3.5% NaCl and  fresh water immersion media ranges from 0,429 mpy up to 0,545 mpy and 0,072 mpy up to 0,120 mpy. The larger SG value of the foamed concrete specimen used, the less corrosion rate occurs. Corrosion behavior of pozzolan foamed concrete is better than normal foam concrete, this phenomenon occurs due to the effect of adding 10% pozzolan which causes better foamed concrete permeability, so that the resistance of concrete against corrosion increased. In general the corrosion rate of pozzolan foamed concrete in the freshwater environment and corrosive environment (artificial seawaters of NaCl 3.5%) is smaller than the corrosion rate of normal foamed concrete. Abstrak: Beton busa bertulang merupakan salah satu alternatif untuk menggantikan beton bertulang konvensional pada elemen struktural. Penelitian ini bertujuan untuk mengukur laju korosi pada beton busa bertulang. Media rendaman dan variasi berat jenis (SG) merupakan variabel yang ditinjau dalam penelitian ini. Jenis benda uji yang digunakan berupa beton busa normal (BB) dan beton busa pozzolan (BBP). Benda uji yang digunakan berbentuk balok 8 x 8 x 50 cm, dengan tulangan tunggal Ø10 mm didalamnya. Dilakukan penempatan tulangan sehingga benda uji memiliki ketebalan selimut 4 cm. Benda uji direndam menggunakan air tawar dan air laut buatan berupa larutan Natrium Clorida 3,5%. Hasil pengukuran menggunakan teknik half-cell potential mapping (HCPM) menggambarkan lokasi yang memiliki resiko tertinggi terkorosi. Pada lokasi ini dilakukan pengukuran laju korosi dengan menggunakan metode linear polarization resistance (LPR). Hasil perhitungan laju korosi pada beton busa normal SG 1,2 sampai 1,6 dengan media rendaman larutan NaCl 3,5% dan air tawar berkisar antara 0,621 mpy sampai dengan 0,854 mpy dan  0,194 mpy sampai dengan 0,304 mpy. Nilai laju korosi pada beton busa pozzolan SG 1,2, 1,4, 1,6 dengan media rendaman NaCl 3,5% dan air tawar berkisar antara 0,429 mpy sampai dengan 0,545 mpy dan 0,072 mpy sampai dengan 0,120 mpy. Semakin besar nilai SG benda uji beton busa yang digunakan, maka laju korosi yang terjadi semakin kecil. Perilaku korosi beton busa pozzolan lebih baik dari pada beton busa normal, fenomena ini terjadi akibat pengaruh penambahan 10% pozzolan yang menyebabkan permeabilitas beton busa semakin baik sehingga ketahan beton terhadap korosipun semakin meningkat. Secara umum laju korosi pada beton busa pozzolan dilingkungan air tawar dan lingkungan korosif (air laut buatan NaCl 3,5%) lebih kecil dibandingkan laju korosi beton busa normal.

Error Estimation of Linear Polarization Resistance Measurement Caused by IR Drop for Reinforcement Corrosion in Concrete

2016 ◽  
Vol 866 ◽  
pp. 14-19
Author(s):  
Jin Xia Xu ◽  
Ya Long Cao ◽  
Lin Hua Jiang ◽  
Ying Bin Song ◽  
Wei Feng
Keyword(s):  
Linear Polarization ◽  
Polarization Resistance ◽  
Chloride Content ◽  
Chloride Ions ◽  
Resistance Measurement ◽  
Reinforcing Steel ◽  
Error Level ◽  
Corrosion Condition ◽  
Linear Polarization Resistance ◽  
Ir Drop

In order to evaluate more accurately the corrosion condition of reinforcing steel in chloride contaminated concrete, it is significant to investigate the error level in the linear polarization resistance measurement caused by IR drop. Concretes with eight levels of chloride ions (ranging from 0% to 2.0% by mass of cement) by adding different amounts of sodium chloride in the mixing water were prepared. Linear polarization measurements with and without IR compensation, were applied to determine the error level. Besides, half-cell potential method was employed to detect the corrosion condition of reinforcing steel. The results indicate that the error level is so low (less than 5.0%) that the IR drop can be negligible when the chloride content is relatively lower (0.6% or less by mass of cement). However, the error level is increased with the increase of chloride content. The IR drop is suggested to be compensated when the chloride content is relatively higher (more than 0.6% by mass of cement). At this time, the onset of active corrosion of reinforcing steel is also found.

Test and Study on Impact of Corrosion on Bond Force between Steel and Concrete

2010 ◽  
Vol 36 ◽  
pp. 176-181
Author(s):  
Xian Feng He ◽  
Shou Gang Zhao ◽  
Yuan Bao Leng
Keyword(s):  
Reinforced Concrete ◽  
Corrosion Rate ◽  
Concrete Structure ◽  
Steel Corrosion ◽  
Reinforced Concrete Structure ◽  
Bond Force ◽  
Steel Bars ◽  
Protection Layer ◽  
Corrosion Of Steel ◽  
The Impact

The corrosion of steel will have a bad impact on the safety of reinforced concrete structure. In severe cases, it may even be disastrous. In order to understand the impact of steel corrosion on the structure, tests are carried out to study corrosion and expansion rules of steel bars as well as the impact rules of corrosion on bond force between steel and concrete. The results show that wet and salty environment will result in steel corrosion; relatively minor corrosion will not cause expansion cracks of protection layers; when steel rust to a certain extent, it will cause cracks along the protection layer; when there exists minor corrosion in steel and the protection layer does not have expansion cracks, the bond force is still large and rapidly decreases as the corrosion rate increases.

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