Methodology of calculating required chloride diffusion coefficient for intended service life as function of concrete cover in reinforced marine structures

Justnes, Harald; Kim, Min Ook; Ng, Serina; Qian, Xinlei

doi:10.1016/j.cemconcomp.2016.08.006

Cited by 46 publications

(20 citation statements)

References 23 publications

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“…This approach leads to the possibility to derive a closed analytical solution, which is also known from the DuraCrete approach. In this case it results in the well known equation [7][8]: (4) where C(x,t) is the local concentration of chlorides that diffuse into the concrete cover zone, Cs the surface chloride concentration (constant), and Ci the initial chloride concentration in the concrete. The parameter x is the distance inside the cover, t the time and Dapp(t) the so-called apparent diffusion coefficient, not considering the bound chlorides.…”

Section: Free Chloridesmentioning

confidence: 99%

“…When applying this formula in the way it is written in (4), with a time dependent Dapp(t), it is important to know that all other boundary conditions are considered to be constant in time and space. The time dependence of the diffusion coefficient is based on a simple formulation introduced also in the DuraCrete model and is denoted as [7][8]: (5) This well-known formula for the apparent diffusion of concrete represents the apparent diffusion at 28 days of hardening Dapp(t0), multiplied with a time factor (t0/t) to the power m, which is called ageing factor. With this ageing factor the influence of several uncertainties of the behaviour of the concrete pore structure with time are taken into account.…”

Section: Free Chloridesmentioning

confidence: 99%

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Modelling of chloride ingress in concrete based on benchmarking field results

Koenders

2018

MATEC Web Conf.

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Modelling the ingress of chloride ions into the cover of a concrete structure is a phenomenon that is gaining an increasing attention of the research community, but even more, from the engineering practice. As the mechanism that drives the ingress of chlorides is implicitly responsible for the service-life of concrete structures, its input parameters are a major issue whenever predicting the service-life of new concrete structures. In this paper most relevant parameters involved in the evaluation of chloride ingress models are discussed and related to the benchmark activities that currently run in RILEM TC 270-CIM on benchmarking Chloride Ingress Models. The results provide an overview of the models used in the structural design stage, mostly analytical models, and in the rehabilitation stage, mostly numerical models.

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Section: Free Chloridesmentioning

confidence: 99%

Section: Free Chloridesmentioning

confidence: 99%

Modelling of chloride ingress in concrete based on benchmarking field results

Koenders

2018

MATEC Web Conf.

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“…Some scholars have establishing models about diffusion coefficient. Nicola et al used external sulfate to attack concrete structures under partially or fully saturated conditions and established a diffusion model to account for chemical and mechanical damage [15,16]. In order to calculate the chloride diffusion coefficient (D) in concrete, 3 factors (chloride concentration, curing, and environment temperature) were considered and used to predict concrete's life of service [17,18].…”

Section: Introductionmentioning

confidence: 99%

Experimental Study on Diffusion Process of Sulfate Ion in Cemented Gangue Backfill Material

Yao

Wang

Feng

et al. 2020

Advances in Civil Engineering

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Cemented gangue backfill material (CGBM) is made of coal gangue, fly ash, cement, and water. The backfill body will be corroded by mine water that contains different kinds of corrosive ions. The paper mainly aimed to study the diffusion process of sulfate ion (SO42−) in CGBM. Soluble salt solutions with different concentrations are prepared to simulate various mine water. The SO42− concentration was measured by layered sampling method and chemical analyzing method. The diffusion coefficient was calculated according to the second Fick’s law. Scanning electron microscope (SEM) and X-ray diffraction (XRD) were used to analyze the degradation mechanisms. The experimental results showed that the SO42− concentration increases in CGBM when the external sulfate solutions concentration increases. With the increasing of magnesium ion (Mg2+) concentration and bicarbonate ion (HCO3−) concentration in the external corrosion solutions, the diffusion coefficient of SO42− was increased, and HCO3− has more significant effects than Mg2+. SO42− reacting with CGBM produced ettringite and gypsum. The ettringite and gypsum changed the pore structure of hardened CGBM and affected the compressive strength of hardened CGBM. Studying the diffusion of SO42− can contribute to predicting the service life of CGBM.

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“…Segundo Ollivier e Torrenti [6], quanto maior for a dificuldade imposta ao ingresso de agentes nocivos na estrutura de poros do concreto, mais durável este será. O fenômeno que governa o ingresso de cloretos em estruturas de concreto em ambientes marinhos é a difusão [7] e a difusividade do concreto pode ser tomada como um indicador da qualidade do mesmo, estando a ela associados o tipo de aglomerante, relação água/cimento, uso de aditivos químicos e outros fatores.…”

Section: Introductionunclassified

Ensaios acelerados de penetração de cloretos aplicados à estimativa do coeficiente de difusão do concreto e à vida útil de estruturas em ambiente marinho

Wally

Sell

Magalhães

2019

Simpósio Paranaense De Patologia Das Construções

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A durabilidade e a vida útil das estruturas em concreto armado são atualmente uma preocupação generalizada entre os envolvidos com a construção civil. A corrosão das armaduras causada pela ação de cloretos tem recebido atenção especial visto que há elevada concentração desses íons em zonas costeiras. Neste trabalho são avaliados os coeficientes de difusão de três dosagens de concreto utilizando o método prescrito pela NT Build 492 e também através de uma relação com a carga passante determinada pela ASTM C 1202. É também realizada uma avaliação da correlação dos resultados de ambos os métodos. Por fim é determinado o cobrimento da armadura necessário ao atendimento de diferentes vidas úteis de serviço. Os resultados mostram que existem divergências entre os resultados apresentados por ambos os métodos e que essas podem ser influenciadas pela qualidade do concreto avaliado.

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Methodology of calculating required chloride diffusion coefficient for intended service life as function of concrete cover in reinforced marine structures

Cited by 46 publications

References 23 publications

Modelling of chloride ingress in concrete based on benchmarking field results

Modelling of chloride ingress in concrete based on benchmarking field results

Experimental Study on Diffusion Process of Sulfate Ion in Cemented Gangue Backfill Material

Ensaios acelerados de penetração de cloretos aplicados à estimativa do coeficiente de difusão do concreto e à vida útil de estruturas em ambiente marinho

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