Diffusion behavior of chloride ions in concrete

Tie-wei, Zhang; Gjørv, Odd E.

doi:10.1016/0008-8846(96)00069-5

Cited by 87 publications

(38 citation statements)

References 7 publications

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“…This would suggest that during the transport of chlorides, there is a potential for significant binding of the accompanying sodium cations by the hydrates to occur in the AAS concretes. Such binding could retard the further ingress of chlorides in such concretes and reduce their chloride diffusivity [6]. The lower pH for the AAS concretes (refer to Table 4) could also have enhanced their chloride binding capacity due to a competition in absorption between Cl -and OH - [9], which also could reduce the D nssd .…”

Section: Slump and Compressive Strengthmentioning

confidence: 99%

“…Apart from diffusion of chloride ions from external environment into the concrete, cations accompanying the chloride ions, such as sodium ions, will diffuse into the concrete [5]. Together with the cations originally present in the pore solution of the concrete, they may form a counter electrical field to drag further ingress of chlorides as the mobility of cations is smaller than that of anions [5][6][7]; II. Ions originally present in the pore solution may also diffuse out to the external environment as a result of the chemical concentration gradient and electro-neutrality constraints [5].…”

Section: Introductionmentioning

confidence: 99%

“…The outward diffusion of hydroxyl ions will empty the sites for chlorides to enter into the concrete to re-occupy the empty sites, thus increasing the amount of chlorides in concrete, especially in the near surface zone [5]; III. Hydrated cement may react with both chlorides and the accompanying cations to slow down further ingress of chlorides [4,6]. The orientation and the degree of such interactions are significantly influenced by the surface charge of the hydrated cement (strongly related to the composition of pore solution) and the alkalinity of pore solution [8,9].…”

Section: Introductionmentioning

confidence: 99%

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Chloride transport and the resulting corrosion of steel bars in alkali activated slag concretes

et al. 2015

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As the relative performance of alkali activated slag (AAS) concretes in comparison to portland cement (PC) counterparts for chloride transport and resulting corrosion of steel bars is not clear, an investigation was carried out and the results are reported in this paper. The effect of alkali concentration and modulus of sodium silicate solution used in AAS was studied. Chloride transport and corrosion properties were assessed with the help of electrical resistivity, non-steady state chloride diffusivity, onset of corrosion, rate of corrosion and pore solution chemistry. It was found that: (i) although chloride content at surface was higher for the AAS concretes, they had lower chloride diffusivity than PC concrete; (ii) pore structure, ionic exchange and interaction effect of hydrates strongly influenced the chloride transport in the AAS concretes; (iii) steel corrosion resistance of the AAS concretes was comparable to that of PC concrete under intermittent chloride ponding regime, with the exception of 6 % Na 2 O and Ms of 1.5; (iv) the corrosion behaviour of the AAS concretes was significantly influenced by ionic exchange, carbonation and sulphide concentration; (v) the increase of alkali concentration of the activator generally increased the resistance of AAS concretes to chloride transport and reduced its resulting corrosion, and a value of 1.5 was found to be an optimum modulus for the activator for improving the chloride transport and the corrosion resistance.

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Section: Slump and Compressive Strengthmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Chloride transport and the resulting corrosion of steel bars in alkali activated slag concretes

et al. 2015

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“…Cations also get adsorbed in the concrete. Some studies [5,6] have reported that diffusion of chloride ions must be accompanied by diffusion of cations, although the cations mostly diffuse at a slower rate compared to anions, which eventually may slow down the diffusion rate of anions. De Weerdt et al [7] highlighted that cations have important role regarding the chloride binding.…”

Section: Introductionmentioning

confidence: 99%

Rebar corrosion due to chlorides in synergy with sodium, potassium, and magnesium

Sharma

Deo

Kumar

et al. 2018

Construction and Building Materials

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“…Moreover, interactions between chloride ions in the pore solution and solid phase of cement matrix form the Friedel's salt [32] and present a typical concentration dependency [33,11,10,42] and are quite difficult to be described by the traditional models. Although the Nernst-Planck flux equation model [13,12,2] can well depict such diffusion processes with clear physical significance, its complicated expressions and many parameters severely impede its applicability.…”

Section: Introductionmentioning

confidence: 99%

A variable-order time-fractional derivative model for chloride ions sub-diffusion in concrete structures

Chen

Zhang

2013

fcaa

104

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This study proposes a new variable-order fractional diffusion equation model to describe the coupled chloride diffusion-binding processes in reinforced concrete, in which the order of fractional derivative term is a variable function instead of a constant in the standard fractional model. The concentration influence coefficient k is introduced to capture the effect of concentration dependency on chloride transport due to the chloride binding behavior. The two parameters in the proposed model can be determined directly by a statistical analysis of measurement data. Four test cases illustrate that the proposed variable-order fractional derivative model agrees significantly better with experimental data than the most commonly used traditional model governed by the classical Fick's second law, especially when a large concentration coefficient k is involved. That proposed model is also verified by accurately predicting chloride concentration profiles in a period of 200 days.MSC 2010 : 74H15, 74S20, 76R50, 81T80

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Diffusion behavior of chloride ions in concrete

Cited by 87 publications

References 7 publications

Chloride transport and the resulting corrosion of steel bars in alkali activated slag concretes

Chloride transport and the resulting corrosion of steel bars in alkali activated slag concretes

Rebar corrosion due to chlorides in synergy with sodium, potassium, and magnesium

A variable-order time-fractional derivative model for chloride ions sub-diffusion in concrete structures

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