Investigations of reinforcement corrosion. 1. The pore electrolyte phase in chloride-contaminated concrete

Page, Christopher; Lambert, Paul; Vassie, P R

doi:10.1007/bf02472078

Cited by 86 publications

(49 citation statements)

References 13 publications

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“…[f a concrete surface is subjected to alternate wetting, with chloride solution, and drying, rather than continuous exposure to chloride solution, the chloride ingress will be at a higher rate [6]. Therefore, in this study a weekly cyclic exposure regime was used to accelerate the chloride ingress.…”

Section: Chloride Exposure Regimementioning

confidence: 99%

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Protection provided by surface treatments against chloride induced corrosion

1998

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A B S T R A C T R I~ S U M I~Corrosion of reinforcement bars due to chloride ingress is a well known problem in reinforced concrete. Several methods have been adopted to protect reinforced concrete, and one of them is to provide added protection to the concrete surface in the form of surface treatments such as silanes and siloxanes. They react with the cement matrix and form a hydrophobic layer on the walls of the pores within the concrete. This protects the concrete from the ingress of water and water-born salts.Moisture is required for reaction of silanes and siloxanes with the hydrated cement matrix. However, too much water in the pores of concrete will prevent the treatments from penetrating deeper into the pores. A study has been carried out to investigate the variation, due to the presence of moisture, on the effectiveness of the protection. It has been found that irrespective of the moisture content at the time of application of treatment, silanes and siloxanes provided good protection against chloride ingress and corrosion of reinforcement bars. However, the depth of penetration and therefore the durability of the treatment is adversely affected when the concrete is near saturation. Dans le b(ton arm(, la corrosion des armatures de renforcement due ~ la p~n~tration du chlorure est un probl~me bien connu. Plusieurs mOthodes ont 8t( adopt(es pour prot(ger le b(ton armO, dont la protection suppl(mentaire au revStement du bOton sous forme de traitement h la surface par des silanes et des siloxanes. Ces produits r(agissent avec la matrice cimentaire et forment une couche hydro-1 mterteur phobe sur les patois des pores ~ '" " " du b(ton, empSchant la p(n~tration de l' eau et des sels v(hicule's par l' eau. L'humiditO est n(cessaire pour obtenir la r(action des silanes et des siloxanes avec la matrice cimentaire hydrat(e. Cependant, trop d'eau dans les pores du bOton empSche les traitements de p(n~trer plus profond(ment dans les pores.Une (tude a (t( men8e sur l'efficacit( de la

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Section: Chloride Exposure Regimementioning

confidence: 99%

“…It is known that the ingress of chloride into the concrete will vary depending on the mechanism by which it is transported [5,6]. [f a concrete surface is subjected to alternate wetting, with chloride solution, and drying, rather than continuous exposure to chloride solution, the chloride ingress will be at a higher rate [6].…”

Section: Chloride Exposure Regimementioning

confidence: 99%

Protection provided by surface treatments against chloride induced corrosion

1998

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“…The pore solutions of hardened ordinary Portland cement pastes [5,8,19] and concretes [29][30][31] have physico-chemical characteristics (pH and composition) similar to those of third and fourth solutions series in this work, i.e., KOH 0.3 m + NaCl and KOH 0.5 m + NaCl, respectively. Thus the relevant values of LOD for Cr ions in these solutions are between 3 x 10~3m, and 7 x 10~3m, i.e., approximately below 0.01 m Cr.…”

Section: N -mentioning

confidence: 99%

“…being present in muchlower concentrations [5,6]. The OH~ concentration of the expressed pore solutions of cement mortars and concretes is high (0.04-0.55 M) [29][30][31], while this concentration maybe even higher, up to 0.7 M, for pore solutions obtained from pure Portland cement pastes [5]. Given all these facts we have chosen four fixed levels of OH~ concentration to measure the fccr.otr of the Cr ISE: 0.035 m, 0.1 m, 0.3 m and 0.5 m. For the sake of simplicity the alkaline solutions were prepared using only KOH.…”

Section: Test Solutions and Measuring Proceduresmentioning

confidence: 99%

Determination of the selectivity coefficient of a chloride ion selective electrode in alkaline media simulating the cement paste pore solution

Almenar

Climent

Antón

et al. 2010

Journal of Electroanalytical Chemistry

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Keywords:Potentiometry Ionic selective electrode Sensor Selectivity coefficient Chloride Cement paste pore solutionThe measurement of the free chloride concentration in the pore solution of cement paste or concrete is of interest for assessing the probability of corrosion of the steel reinforcements embedded in concrete. This determination is performed through leaching or pore-pressing methods or through embedded potentiometric sensors into the hardened cementitious material. The potentiometric determination of chloride in cement paste pore solutions is limited by hydroxide ion interference, due to the high alkalinity of such media. The potentiometric selectivity coefficients, ka-,OH-, are determined for a chloride ionic selective electrode in alkaline solutions simulating the electrolyte present within the pore network of cement paste and concrete. This is done using a fixed interference methodology, with least-squares non-linear curve fitting for obtaining the selectivity coefficients together with other relevant electrode parameters. The limit of detection of the CI ISE, due to OH interference, varies with pH. For the pore solution corresponding to an ordinary Portland cement paste or concrete, this limit can be set between 3 x 1CT 3 m, and 7 x 1CT 3 m, i.e., approximately below a chloride concentration value of 1 x 1CT 2 molal. Taking into account these limits of detection the free CI concentrations able to depassivate the steel, can be adequately determined by potentiometric measurements with calibrated ISEs in the expressed pore solutions of Portland cement concretes, without significant influence of OH interference. Nevertheless, this effect can prevent the adequate measurement of low free CI concentrations, below the corresponding limit of detection value.

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“…Andrade e Alonso (1996) especificam o valor de B igual a 52 mV para armaduras em estado passivo e 26 mV para armaduras em estado de corrosão, já Page et al (1991) adotam B igual 52 mV para ambos os casos.…”

Section: Resistência De Polarização (R P )unclassified

"Estudo de concretos de alto desempenho frente à ação de cloretos"

Silva¹

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Aos meus pais, Vera e Jesus, e aos meus irmãos, Fabiana e Rodrigo. AGRADECIMENTOSPrimeiramente gostaria de agradecer ao meu orientador Jefferson Liborio, pela valiosa oportunidade que me foi concedida no início desta pesquisa, pela dedicação, apoio, incentivo, confiança e, claro, pela amizade estabelecida durante esses anos.Aos professores Ênio Pazini Figueiredo (UFG), Sebastião Elias Kuri (UFSCar) e Silvia Selmo, (EPUSP) pela extrema competência e auxílio na escolha e análise dos métodos experimentais na área de corrosão de armaduras.Ao professor Mário Morio Isa, que foi quem me iniciou na pesquisa, com quem muito aprendi e por quem tenho eterna gratidão, e a dois outros amigos e professores da UNESP (Bauru): Rita David e Luttgardes de Oliveira, pelo grande incentivo.Aos amigos que fizeram e fazem parte do Grupo LMABC: Fernanda Costenaro, Alessandra, José Américo, Valdirene, Vanessa, Samir, Marcelo, Rafaelle, Sandra, Gerusa, Tiago e Giuliano, pelos conselhos técnicos, auxílios experimentais e, principalmente, pela força que me deram durante esses anos. Foram muitos os momentos de descontração e alegria que compartilhamos e que, sem dúvida, deixarão saudades.Aos amigos do Departamento de Estruturas -EESC, especialmente à Regiane, Isabella, ao Júlio, Alexandre, André e Serginho pelos bons momentos vividos. À amiga Lizandra, além da grande amizade, pela dedicação e auxílio no início do desenvolvimento experimental desta pesquisa.Aos amigos do Laboratório de Construção Civil -EESC e da UFSCar, em especial à amiga Cida, cuja ajuda foi fundamental no entendimento e na aplicação dos conceitos de impedância eletroquímica, que só vieram a enriquecer tecnicamente o trabalho. Ao grande amigo, Adriano, pelo incentivo e apoio dado nos bons anos de convívio juntos.À professora Regina Santos e ao Paulo, do IQSC, que me auxiliaram na determinação do teor de cloretos. Ao professor Hernandez e ao Ezequiel, do IFSC, pela ajuda na análise dos resultados de impedância eletroquímica.Às secretárias da Interunidades: Wladerez e Cristiane, aos funcionários do Departamento de Estruturas: Luiz, Amauri, Mario, Fabiano, Rosi, Nadir, Toninho, Junior, Massaki, Sr. Wilson e ao nosso técnico Jorge, pelo grande auxílio prestado no desenvolvimento dessa pesquisa.Aos meus pais, Vera e Jesus, e meus irmãos, Fabiana e Rodrigo, um imenso obrigado, por absolutamente tudo, sem restrições. Com certeza não teria conseguido chegar até aqui sem o apoio e carinho de vocês.Ao meu amor Luciano, pelo apoio, incentivo, compreensão, confiança, carinho e companheirismo em todos os momentos. À Fapesp, pela concessão do apoio financeiro no desenvolvimento desta tese e a todos que, direta ou indiretamente, colaboraram e torceram para a realização desta pesquisa. Representação esquemática do processo de carbonatação. 43 FIGURA 3. 6 Representação esquemática da corrosão na presença de cloretos: mecanismo de formação e propagação. 44 FIGURA 3. 7 Dimensão dos poros relacionados com os principais mecanismos de transporte. 47 FIGURA 3. 8 Esquema dos fatores que inf...

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Investigations of reinforcement corrosion. 1. The pore electrolyte phase in chloride-contaminated concrete

Cited by 86 publications

References 13 publications

Protection provided by surface treatments against chloride induced corrosion

Protection provided by surface treatments against chloride induced corrosion

Determination of the selectivity coefficient of a chloride ion selective electrode in alkaline media simulating the cement paste pore solution

"Estudo de concretos de alto desempenho frente à ação de cloretos"

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