Similarities in Accelerated Chloride Ion Transport Tests for Concrete in Tidal Zones

Zhang, Qing-Zhang; Gu, Xiaoqiang; Jiang, Zhilu; Zhang, Weiping

doi:10.14359/51702007

Cited by 6 publications

(5 citation statements)

References 24 publications

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“…The areal porosity,

, can be defined as

where

is the water-absorption area. The areal porosity,

, and volumetric porosity,

, are related to each other, as shown by the following [ 7 ]:

where

is the tortuosity and is equal to

for a uniformly random porous medium.…”

Section: Analytical Analysismentioning

confidence: 99%

“…Thus, more physically based moisture transport models have been developed by further studying transport mechanisms and composite theory. For example, to consider the influence of saturation degree and microstructural characteristics, Zhang et al [ 7 ] introduced two empirical parameters, i.e., the relative permeability of water and the hindrance diffusion coefficient of water vapor, into macroscopic transport equations. Maekawa et al [ 8 ], Ishida et al [ 9 ], and Huang et al [ 10 ] first obtained the transport equation for a single cylindrical pore based on the basic theories of thermodynamics, and then integrated all the pores of an assumed pore size distribution to obtain the moisture diffusivity of cementitious materials.…”

Section: Introductionmentioning

confidence: 99%

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Moisture Transport of Axial-Compression-Damaged Mortar and Concrete in Atmospheric Environment

et al. 2022

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The moisture transport of axial-compression-damaged mortar and concrete was experimentally and analytically studied in this paper. Five stress levels, i.e., 25%, 40%, 55%, 70%, and 85%, of the corresponding ultimate compressive strengths were selected for mortar and concrete specimens with the water cement ratio (w/c) of 0.5. Porosities and sorptivities of mortar or concrete before and after axial compression were measured and compared. Based on the Lucas–Washburn equation on absorption, the relationship between sorptivity and pore size distribution as well as porosity was established. A damage-representative radius was proposed to simply quantify the variation of pore characteristics of damaged mortar and concrete, and the moisture transport of axial-compression-damaged mortar and concrete could be predicted by summing the contributions to water absorption from the original pore system and the pore-equivalent microcrack system. It is shown that the porosities of mortar and concrete only slightly increase with the damage level, but the sorptivities are sensitive to axial compression damage, i.e., increasing nearly monotonically with the stress level from 0.3326 to 0.3533 mm/min0.5 for damaged mortar specimens (w/c = 0.5) and from 0.1970 to 0.2226 mm/min0.5 for damaged concrete specimens (w/c = 0.5). The increase trend became more apparent for both materials after a threshold of 40–55% of the corresponding ultimate compressive strengths, which is within the service load of structures, indicating that damage should be considered for chloride ions and water transport in concrete in the tidal zone. The predicted moisture diffusivities of damaged mortar and concrete show marginal difference from those of sound materials because the damage-representative radius could be underestimated due to elastic recovery of materials after unloading.

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“…The areal porosity,

, can be defined as

where

is the water-absorption area. The areal porosity,

, and volumetric porosity,

, are related to each other, as shown by the following [ 7 ]:

where

is the tortuosity and is equal to

for a uniformly random porous medium.…”

Section: Analytical Analysismentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Moisture Transport of Axial-Compression-Damaged Mortar and Concrete in Atmospheric Environment

et al. 2022

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“…According to the hydrostatic pressure equation P = ρ•g•H, then the Darcy velocity v can be expressed by the water head H (m), Equation ( 5) can be converted to Equation (6).…”

Section: Theoretical Derivation Of Diffusion and Convection Coupling Equationmentioning

confidence: 99%

“…Reinforced concrete in underground and marine engineering are not only corroded by seawater corrosive medium but also subjected to seawater pressure. Seawater and underground water are rich in a variety of ions [ 6 , 7 ], such as Cl − , Na + , SO 4 2− , K + , Mg 2+ , Ca 2+ , etc. Chloride has been recognized as the main cause of corrosion of reinforced concrete [ 8 , 9 , 10 , 11 , 12 , 13 ], and it is an important aspect of the durability research of marine and underground engineering.…”

Section: Introductionmentioning

confidence: 99%

Influence of Hydrostatic Pressure and Cationic Type on the Diffusion Behavior of Chloride in Concrete

Liu

Jiang

2021

Materials

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The durability of the concrete in underground and marine engineering is affected by the underground and ocean environment. Chloride diffusion coefficient under hydrostatic pressure is a key parameter of concrete durability design under corresponding conditions. Therefore, this paper studies the diffusion behavior of chloride in different diffusion source solutions by experiment and simulation. Based on the experimental results, this paper proposes a new chloride diffusion model under the coupling effect of diffusion and convection. The interaction of ions and compounds in the diffusion source solutions, concrete pore fluid, and concrete material are considered in the new chloride diffusion model. The experimental results show that chloride diffusion rate is significantly affected by hydrostatic pressure, which increases with the increase of hydrostatic pressure. The chloride diffusion coefficient shows a certain difference in difference diffusion source solutions. The chloride diffusion coefficient in divalent cationic diffusion source solutions is the largest, the chloride diffusion coefficient in the divalent and monovalent cationic compound ones is in the middle, and the chloride diffusion coefficient in the monovalent cationic ones is the smallest. There is a linear relationship between the chloride diffusion coefficient and the hydrostatic pressure whether in single or combined cationic diffusion source solutions.

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“…Type 2 explicitly describes the coupled pore water convection and chloride diffusion mechanisms using a water infiltration model together with Fick's law [15]. The environmental and the material factors, which link to the two transport mechanisms, can be specified in the modelling [16] (for example, the influence of cylic wetting and drying conditions [17][18][19], the effect of the electrical double layer at the pore surfaces [20], the osmotic effect [21], and the effect of double-porosity in concrete [22]).…”

Section: Introductionmentioning

confidence: 99%

The characterization of chloride effect on concrete water sorption and its application in the modelling of concrete conditions in tidal zones

Wang

Oleiwi

Wang

et al. 2020

Construction and Building Materials

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Concrete exposed to cyclic wetting and drying in salty water conditions is thought to be subjected to an accelerated ingress of chloride from the outside environment, and prone to a worsening deterioration process inside. Additionally, there is an osmotic effect on salty water flow in porous concrete. However, so far, a fully profound understanding of the coupled cyclic wetting-drying and osmosis effects on the chloride movement in concrete is still limited. This paper reports on a comprehensive study on the topic. A series of experimental tests was conducted initially for the vapour-water sorption isotherm (VWSI) of normal concrete of different porosity and chloride content. Thereafter, a novel mathematical model was proposed and validated to characterise the effect of chloride salt on the vapour absorption and water retention behaviour of concrete. Finally, the proposed characteristic model was implemented in a numerical model to simulate chloride ingress in concrete in tidal zones. The vapour-water sorption isotherm model successfully provides an effective tool to quantify the coupled influence of cyclic wetting-drying and osmosis on chloride transportation in concrete.

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Similarities in Accelerated Chloride Ion Transport Tests for Concrete in Tidal Zones

Cited by 6 publications

References 24 publications

Moisture Transport of Axial-Compression-Damaged Mortar and Concrete in Atmospheric Environment

Moisture Transport of Axial-Compression-Damaged Mortar and Concrete in Atmospheric Environment

Influence of Hydrostatic Pressure and Cationic Type on the Diffusion Behavior of Chloride in Concrete

The characterization of chloride effect on concrete water sorption and its application in the modelling of concrete conditions in tidal zones

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