Modelling of two-dimensional chloride diffusion concentrations considering the heterogeneity of concrete materials

Wu, Linjian; Wang, Yuanzhan; Wang, Yuchi; Ju, Xueli; Li, Qingmei

doi:10.1016/j.conbuildmat.2020.118213

Cited by 47 publications

(14 citation statements)

References 55 publications

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“…In addition, Wu et al [34] have also conducted a host of experiments to characterize the distribution of Cl − concentration in 2D direction. In the test, the w/c is 0.54; the size of the sample is 100 mm × 100 mm×400 mm, the NaCl concentration is 3.5% in the environment, and the distribution of Cl − concentration is measured after soaking for 180 days in concrete.…”

Section: Verification Of the Chloride Concentration Distribution Modelmentioning

confidence: 99%

Multi-Scale Simulation of Two-Dimensional Chloride Transport Under the Effect of Bending Load in Concrete

Zhang

Sun

et al. 2021

Front. Phys.

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Chloride transport in marine concrete under loading is the main cause of its structural deterioration. The traditional numerical simulation assumes that the coefficient of chloride transport is constant, resulting in a large deviation in the prediction results. Based on the porous medium theory, micromechanics theory, and the idea of equivalent homogenization, a multi-scale model of the effective diffusion variable coefficient of chloride transport under bending load was established, which was calculated and programmed by the numerical analysis. The results show that the prediction values of the two-dimensional variable coefficient model are basically consistent with those in the literature, and the prediction accuracy is significantly improved. In addition, the theoretical simulation proves that the bending load affects the porosity of the cement matrix, and then the diffusion coefficient of chloride is changed in concrete. The compression zone can slow down the chloride transport process, while tension zone will accelerate it. The chloride concentration under tension zone is 42.1% higher than that under compression zone when the diffusion time is 200 days and the concrete depth is 15 mm.

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Section: Verification Of the Chloride Concentration Distribution Modelmentioning

confidence: 99%

Multi-Scale Simulation of Two-Dimensional Chloride Transport Under the Effect of Bending Load in Concrete

Zhang

Sun

et al. 2021

Front. Phys.

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“…When the chloride diffusivity of concrete is determined, Fick’s second law can be used to compute the chloride profiles in concrete analytically or numerically [ 39 , 40 , 41 ] and the time for the reinforcement surface to reach the critical chloride content [ 42 , 43 ], which is beyond the scope of this paper.…”

Section: Experimental Verificationmentioning

confidence: 99%

A Three-Dimensional Random Walk Algorithm for Estimating the Chloride Diffusivity of Concrete

et al. 2020

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The chloride diffusivity of concrete is an important parameter for assessing the long-term durability of coastal concrete structures. The purpose of this paper is to present a three-dimensional random walk algorithm (RWA) for estimating the chloride diffusivity of concrete. By analyzing the size distribution of aggregates, the equivalent interfacial transition zone (ITZ) thickness is derived in an analytical manner. Each aggregate is combined with the surrounding ITZ to construct an equivalent aggregate model (EAM) and the chloride diffusivity is formulated. It is found that the equivalent ITZ thickness decreases with the increase of practical ITZ thickness and aggregate volume fraction. The aggregate gradation influences the equivalent ITZ thickness to a certain extent. The relative chloride diffusivity of the equivalent aggregate is almost directly and inversely proportional to the equivalent ITZ thickness and the aggregate radius, respectively. The numerical results show that, when the EAM is adopted, the computational time is greatly reduced. With the EAM, concrete can be modeled as a two-phase material and the chloride diffusivity is estimated by applying the RWA. It is shown that, with the increase of mean square displacement and number of Brownian particles, the average chloride diffusivity of concrete approaches a stable value. Finally, through comparison with experimental data, the validation of the RWA is preliminarily verified.

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“…The penetration of aggressive external agents such as carbon dioxide or chlorides is what is mainly responsible for the deterioration of reinforced-concrete structures [5][6][7]. For new buildings, the durability of concrete elements can be guaranteed with proper mix design and construction details; in the case of existing structures with durability deficiency, these problems must be solved in a different way, such as cathodic protection/prevention, electrochemical-based techniques, migrant corrosion inhibitors and surface treatments.…”

Section: Introductionmentioning

confidence: 99%

Protection of Concrete Structures: Performance Analysis of Different Commercial Products and Systems

et al. 2021

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The increasing demand for reconstructions of concrete structures and the wide availability on the market of surface protective products and systems could lead to misunderstandings in the decision of the most effective solution. Surface protectors have become increasingly widespread in recent years in concrete restoration interventions thanks to their properties: they are able to protect the substrate from aggressive agents and consequently extend the useful life of the structures. The aim of this article is first of all to present the surface protective treatments available on the market, outlining their strengths and weaknesses. Subsequently, a characterization of seven different commercial coatings for reinforced-concrete structures is provided, taking into account chemical nature, fields of use and effectiveness, both in terms of physic and elastic performance and resistance to aggressive agents that undermine the durability of the treated concrete elements.

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Modelling of two-dimensional chloride diffusion concentrations considering the heterogeneity of concrete materials

Cited by 47 publications

References 55 publications

Multi-Scale Simulation of Two-Dimensional Chloride Transport Under the Effect of Bending Load in Concrete

Multi-Scale Simulation of Two-Dimensional Chloride Transport Under the Effect of Bending Load in Concrete

A Three-Dimensional Random Walk Algorithm for Estimating the Chloride Diffusivity of Concrete

Protection of Concrete Structures: Performance Analysis of Different Commercial Products and Systems

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