Concentration Distribution of Chloride Ion under the Influence of the Convection-Diffusion Coupling

Zhao, Qingli; Zhang, Y. Z.

doi:10.1155/2017/2076986

Cited by 5 publications

(3 citation statements)

References 20 publications

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“…is was because that the effect of water convection on the chloride distribution was obvious when the chloride penetration depths were below 6 mm, whereas the effect of chloride migration by the concentration gradient on chloride distribution was significant in the inner concrete. e intensity by convection was higher than that by a concentration gradient, and the continuous convection resulted in the chloride gathering around the surface layer with water evaporation, which led to the chloride content by convection was higher than that by concentration gradient [35]. However, the water convection was feeble in the inner layer of concrete, and thus there was no obvious difference on the inner chloride content in various concrete after the same duration.…”

Section: Chloride Migration In Concrete With the Coupling Of Watermentioning

confidence: 91%

Chloride Penetration into Concrete under the Coupling Effects of Internal and External Relative Humidity

Fang

Ming-min

2020

Advances in Civil Engineering

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Chloride penetration frequently happens in an unsaturated concrete; in this case, the chloride migration is under the coupling effects of internal moisture and external relative humidity (RH). Various chloride attack tests were designed in this paper to investigate the effects of internal moisture and external RH (50–100%) on the chloride penetration into an unsaturated concrete, and the chloride content was determined to quantify the chloride migration in concrete. The results highlighted that there was a good correlation between the chloride penetration into concrete and its internal RH. The chloride ion was difficult to penetrate into concrete when its internal RH was below 50%; however, the chloride penetration rate increased when the internal RH of concrete was above 75%, and the chloride migration increased with increasing RH and exposure duration. Water evaporation in concrete increased with decreasing external RH, and an obvious increase in the surface chloride content may be observed when external RH was 50%; however, when external RH was above 75%, the inner chloride content increased and surface chloride content decreased with increasing exposure duration. Simulating the chloride penetration under wet-dry cycling, the water migration resulted in an increase in the surface chloride content and a decrease in the inner chloride content, and the chloride crystal precipitated on the surface of concrete with a high w/c ratio.

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Section: Chloride Migration In Concrete With the Coupling Of Watermentioning

confidence: 91%

Chloride Penetration into Concrete under the Coupling Effects of Internal and External Relative Humidity

Fang

Ming-min

2020

Advances in Civil Engineering

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“…To simplify the calculation, it is assumed that the convection velocity of the pore fluid linearly decreases over time. The convection velocity under the effect of space and time [23] can be calculated using Equation (5)…”

Section: Convection Velocitymentioning

confidence: 99%

“…σ y = P For inner surface : σ y = 0 (23) where P is the total compressive force caused by the surrounding water and soil.…”

Section: Normal Stress Of the Lining Section Caused By The Surroundinmentioning

confidence: 99%

Durability of Subsea Tunnels under the Coupled Action of Stress and Chloride Ions

Zhao

2019

Applied Sciences

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The durability of subsea tunnels under the coupled action of stress and chloride ions was analyzed to estimate the service life and provide a theoretical foundation for durability design. The influence coefficient of the stress on chloride ion transmission at lower stress levels was discussed according to the material mechanics, and was verified by experimental data. A stress calculation model of a subsea tunnel’s lining section is proposed based on the plane-section assumption. Considering the space-time effect of the convection velocity, a partial differential equation was constructed to calculate the chloride ion transfer condition under the coupled action of stress-convection-diffusion. The numerical solution of the partial differential equation was solved and the sensitivity of the parameters was analyzed. The subsea tunnel’s time-varying reliability index was calculated following the Monte Carlo method, and was used to predict the service life. The results show that the chloride ion concentration calculated by considering the coupled action is larger and the reliability index is lower than calculated only considering diffusion. Our findings contribute to the conclusion that durability designs of subsea tunnels should consider the coupled action of stress-convection-diffusion. An effective method to improve the service life of a subsea tunnel is to reduce the water–binder ratio or increase the thickness of protective cover.

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Comparisons of instantaneous chloride diffusion coefficients determined by RCM method and chloride natural diffusion test

Wang

2019

Construction and Building Materials

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Concentration Distribution of Chloride Ion under the Influence of the Convection-Diffusion Coupling

Cited by 5 publications

References 20 publications

Chloride Penetration into Concrete under the Coupling Effects of Internal and External Relative Humidity

Chloride Penetration into Concrete under the Coupling Effects of Internal and External Relative Humidity

Durability of Subsea Tunnels under the Coupled Action of Stress and Chloride Ions

Comparisons of instantaneous chloride diffusion coefficients determined by RCM method and chloride natural diffusion test

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