Threshold concentration of chlorides in concrete for stainless steel reinforcement: Classic austenitic and new duplex stainless steel

Pachón-Montaño, A.; Sánchez-Montero, Javier; Andrade, Carmen; Fullea, J.; Moreno, E.; Matres, V.

doi:10.1016/j.conbuildmat.2018.07.081

Cited by 32 publications

(23 citation statements)

References 30 publications

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“…Para el cálculo de este tiempo, ecuación [8], si no se tiene en cuenta el envejecimiento, es decir, considerando un coefi-…”

Section: Cálculo Del Periodo De Iniciaciónunclassified

“…La difusión de cloruros en el hormigón ha sido estudiada desde hace varias décadas (1,2,3,4,5) debido a que la llegada hasta la armadura de una cierta concentración llamada "límite" produce la corrosión del acero y por tanto afecta a la seguridad de la estructura (7,8). Todos los estudios han llevado a que tanto en la Instrucción española, EHE 08 (9) como en el Código Modelo (10) se hayan incorporado modelos de cálculo para establecer el tiempo de "vida útil" (sin corrosión) de una determinada estructura.…”

Section: Introductionunclassified

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Periodo de iniciación de la corrosión por ión cloruro según la EHE 08 en elementos de hormigón fisurados

Torres

Andrade²,

Sánchez

2020

Inf. constr.

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El transporte de cloruro en el hormigón por difusión es un problema extensamente estudiado para determinar la vida útil de las estructuras en ambientes marinos. Sin embargo, cuando el hormigón se encuentra fisurado no existe un procedimiento que permita calcular el transporte de los cloruros. Los Códigos limitan el ancho de las fisuras según el tipo de ambiente de exposición. En este trabajo se estudia la relación del ancho de fisura con el coeficiente de difusión y se estima el periodo de iniciación de la corrosión por cloruros en hormigones fisurados. Se ha obtenido una ley que permite predecir la variación del tiempo de iniciación de la corrosión en función del ancho de la fisura.

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“…Para el cálculo de este tiempo, ecuación [8], si no se tiene en cuenta el envejecimiento, es decir, considerando un coefi-…”

Section: Cálculo Del Periodo De Iniciaciónunclassified

Section: Introductionunclassified

Periodo de iniciación de la corrosión por ión cloruro según la EHE 08 en elementos de hormigón fisurados

Torres

Andrade²,

Sánchez

2020

Inf. constr.

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“…The corrosion current densities (i corr ) are also very similar for the three types of samples (Figure 6a). All the measured i corr are about one order of magnitude higher 0.1 A/cm 2 , which is usually assumed to be the limit value for corrosion of carbon steel reinforcements [30]. The average value for the "Ribbed surface" is higher than for the "Core" (Figure 6a).…”

Section: Resultsmentioning

confidence: 88%

Influence of the microstructure of TMT reinforcing bars on their corrosion behavior in concrete with chlorides

Bautista

Pomares

González

et al. 2019

Construction and Building Materials

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Thermomechanically treated (TMT) carbon steel bars, often known as "TempCore" bars, are commonly used as reinforcements in concrete structures. TMT causes the formation of a martensite case in the outer surface of the bars, increasing their hardness, while the remaining ferritic-perlitic core maintains the typical ductility of hot rolled bars. In this work, the effect of this TMT induced microstructure on the development of pitting attacks in chloride media has been analyzed in depth. Electrochemical impedance spectroscopy (EIS) measurements and polarization curves have been carried out in simulated pore solutions to understand the effect of the presence of different phases in the microstructure and to quantify the strength of the galvanic couple that the outer martensite can form with the inner core. Moreover, accelerated corrosion tests in chloride contaminated concrete slabs have also been performed. Bars from six different slabs where corrosive attack has been forced for different times have been studied. The shape of the main pits in the bars corroded in concrete has been analyzed through optoelectronic microscopy and the results obtained prove that the depth of the attack is related to the microstructure of the TMT bars.

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“…Moreover, in studies carried out in solutions with high-strength bars, the results obtained for the S32304 were also better than those obtained for S30400 and S31600 [19], the lean duplex grade being cheaper than the S31600. The improvement of the durability that can be achieved using S31600 instead of S30400 [14] is foreseeably lower than that achieved using S32304 instead of S30400 [1,20]. On the other hand, the lean duplex grade UNS S32001 has proved to have a similar corrosion resistance to pitting onset than S30400 in tests in simulated concrete solutions [19], the current price of the former being slightly lower.…”

Section: Introductionmentioning

confidence: 94%

“…Stainless steels are increasingly used as reinforcement bars for concrete structures exposed to corrosive environments or with a long design life, as they have already shown high chloride concentration threshold [1] and high chemical durability when they are embedded in mortar [2,3]. Their high corrosion resistance is due to the formation of a passivating layer on their surface, which has a duplex structure [4], and whose protective properties increase with the pH of the media [5].…”

Section: Introductionmentioning

confidence: 99%

Influence of the Alkaline Reserve of Chloride-Contaminated Mortars on the 6-Year Corrosion Behavior of Corrugated UNS S32304 and S32001 Stainless Steels

Bautista

Velasco

Torres-Carrasco

2019

Metals

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The durability of two lean corrugated duplex stainless steel (UNS S32304 and S32001) bars manufactured for concrete reinforcement was studied in four different corrosive conditions. These duplex stainless steels are more economical than the most traditional, well-known duplex grade steels (UNS S32205). The research was carried out in mortar samples for six years. In half of the samples, the alkaline reserve had been previously decreased, and their pH was slightly below 12, while in the other half, the pH close to the bars remained as-manufactured. Moreover, there were samples with modified and non-modified alkaline reserve where chlorides had been previously added to the mortar which were exposed to high relative humidity. In other samples—which were partially immersed in 3.5% NaCl—the chlorides entered through the mortar by natural diffusion. The electrochemical behavior of the reinforcements in these conditions was periodically monitored through corrosion potential (Ecorr) and electrochemical impedance spectroscopy (EIS) measurements during the whole testing period. The samples were anodically polarized at the end of the exposure. The results prove that the decrease in the alkaline reserve of the mortars can affect the corrosion behavior of the studied lean duplex in environments with high chloride concentrations. The duplex microstructure of the reinforcements makes it so that the corrosion proceeds by selective attack of the phases.

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Threshold concentration of chlorides in concrete for stainless steel reinforcement: Classic austenitic and new duplex stainless steel

Cited by 32 publications

References 30 publications

Periodo de iniciación de la corrosión por ión cloruro según la EHE 08 en elementos de hormigón fisurados

Periodo de iniciación de la corrosión por ión cloruro según la EHE 08 en elementos de hormigón fisurados

Influence of the microstructure of TMT reinforcing bars on their corrosion behavior in concrete with chlorides

Influence of the Alkaline Reserve of Chloride-Contaminated Mortars on the 6-Year Corrosion Behavior of Corrugated UNS S32304 and S32001 Stainless Steels

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