Square Steel Tube Impressed Current Corrosion Rate in Term of Linear Polarization Resistance (LPR) Method

Author(s):  
Ahmed Saleh Alraeeini ◽  
Ehsan Nikbakht ◽  
Mokhtar Che Ismail
2013 ◽  
Vol 3 (3) ◽  
pp. 188-199
Author(s):  
C. Flores ◽  
S. Rodríguez ◽  
A. Cárdenas ◽  
O. Guarneros

RESUMENSe estudió la factibilidad del uso de partículas de neumático reciclado en concreto y morteros. Para evaluar las propiedades mecánicas del concreto endurecido se realizaron pruebas de densidad, resistencia a la compresión y determinación del módulo de elasticidad. Además se determinó la trabajabilidad del concreto en estado fresco mediante la prueba de revenimiento Las muestras se fabricaron con la sustitución de un 5%, 7.5% y 10 % del volumen de la arena por partículas de neumático reciclado. Se determinó mediante la técnica de potencial de corrosión el estado que guardaba en acero revisando de esta manera la probabilidad de corrosión. Para el estudio de la velocidad de corrosión se utilizó la técnica electroquímica de resistencia a la polarización lineal (RPL) en morteros fabricados bajo las mismas condiciones y proporciones que en los concretos. Los resultados mostraron que una mezcla con 7.5% de partículas de neumático reciclado puede ser utilizada en estructuras de resistencia moderada, ligera y ubicadas en ambientes con cloruros.Palabras clave: Concreto; mortero; neumático reciclado; velocidad de corrosión; Propiedades mecánicas.ABSTRACTThe feasibility of using scrap tire particles in the elaboration of concrete and mortar was investigated. To assess the mechanical properties of hardened concrete, tests evaluating of its density, modulus elasticity and compression strength were undertaken. To determine the workability of freshly made concrete, a slump test was also performed. Tests in which 5, 7.5 and 10% of sand were substituted by recycled tire particles were made. The likelihood of corrosion on the steel is determined, using the technique of corrosion potential. To test the velocity of corrosion was used the linear polarization resistance method (LPR method) was utilized under the same conditions as well as fabrication of concrete. It was observed that using 7.5% of recycled tire particles offers satisfactory results in structures of moderate strength and lighter weight located in environments with chlorides.Keywords: Concrete; mortar; recycled tire; corrosion rate; mechanical properties.


2018 ◽  
Vol 199 ◽  
pp. 06009 ◽  
Author(s):  
Gabriel Samson ◽  
Fabrice Deby ◽  
Jean-Luc Garciaz ◽  
Jean-Louis Perrin

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).


2018 ◽  
Vol 1 (4) ◽  
pp. 885-894
Author(s):  
Zubaidi Amri ◽  
Abdullah Abdullah ◽  
Syarizal Fonna

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.


2016 ◽  
Vol 866 ◽  
pp. 14-19
Author(s):  
Jin Xia Xu ◽  
Ya Long Cao ◽  
Lin Hua Jiang ◽  
Ying Bin Song ◽  
Wei Feng

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.


2014 ◽  
Vol 811 ◽  
pp. 23-27 ◽  
Author(s):  
Jan Stoulil ◽  
Tomáš Pfeifer ◽  
Alena Michalcová ◽  
Ivo Marek

This work is focused on lifetime prediction of metallic nanoparticles in heat exchange nanofluids. Copper, nickel and iron nanoparticles were studied in 40 wt.% aqueous solution of potassium formate and propylene glycol. Materials were observed by means of mass loss exposure tests, linear polarization resistance and potentiodynamic measurements. Potassium formate solution is not suitable bearing liquid for metallic nanoparticles. Propylyne glycol seems promising, however additional corrosion prevention needs to be applied.


2016 ◽  
Vol 2016 (11) ◽  
pp. 1035-1041 ◽  
Author(s):  
A. T. Faritov ◽  
Yu. G. Rozhdestvenskii ◽  
S. A. Yamshchikova ◽  
E. R. Minnikhanova ◽  
A. S. Tyusenkov

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