Influence of calcium leaching on chloride diffusivity in cement-based materials

Tang, Yu-Juan; Zuo, Xiao-Bao; Yin, Guang-Ji; Davoudi, Hadi; Li, Xiangnan

doi:10.1016/j.conbuildmat.2018.04.112

Cited by 37 publications

(10 citation statements)

References 43 publications

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“…The pH of a CEM I paste is generally between 13 and 14 whereas the pH of seawater varies between 7.5 and 9.0, with an average of around 8.2 [78,79]. Alkali metals such as potassium, as well as calcium and hydroxide ions will leach out of the cement paste which will lead to a decrease in the pH of the material [80]. However, the pH of the surface of the cement paste remained almost constant throughout our test.…”

Section: Tablementioning

confidence: 99%

See 1 more Smart Citation

In vitro and in situ tests to evaluate the bacterial colonization of cementitious materials in the marine environment

Hayek¹,

Salgues²,

Habouzit³

et al. 2020

Cement and Concrete Composites

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Civil engineers have a responsibility to take measures to protect marine biodiversity by selecting more bioreceptive construction materials in the design of marine infrastructure, for better biodiversity conservation. In this study, it was shown that pre-carbonation of cementitious materials accelerates their bacterial colorization by lowering the pH of their surface. It has been shown both in the laboratory and in-situ tests that the bacterial colonization of cementitious materials is influenced by the pH and the type of cement. By comparing the bacterial colonization of Portland cement mortars, CEM I, and slag cement, CEM III, mortars, it was found that the CEM III mortars are more bioreceptive than the CEM I mortars. This study presented and verified a novel experimental laboratory approach which can be used to evaluate the bacterial colonization (bioreceptivity) of cementitious materials in marine environment. The approach could be taken up in future recommendations to enable engineers to eco-design more eco-friendly marine infrastructure and develop green-engineering projects.

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Section: Tablementioning

confidence: 99%

“…Upon immersion, leaching and colonization by bacteria [80,90] lead to a gradually decrease of the pH of the carbonated and non-carbonated surfaces and reaching a value of 6.5 after 15 days of immersion. Upon further immersion the pH remains almost constant until the end of the experiment (Fig.…”

Section: Ph Of Concrete Surfacesmentioning

confidence: 99%

In vitro and in situ tests to evaluate the bacterial colonization of cementitious materials in the marine environment

Hayek¹,

Salgues²,

Habouzit³

et al. 2020

Cement and Concrete Composites

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show abstract

“…According to Forster et al [ 6 ], smaller leaching coefficient (k) indicated slower leaching process. In addition, Tang et al [ 40 ] reported that the leaching coefficient can represent the leaching rate of a sample. Therefore, the leaching rate of R0 was the highest, followed by G1, G2, G3, and G4.…”

Section: Resultsmentioning

confidence: 99%

Electrochemical Characterization and Inhibiting Mechanism on Calcium Leaching of Graphene Oxide Reinforced Cement Composites

Long

et al. 2019

Nanomaterials

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Calcium leaching is a degradation progress inside hardened cement composites, where Ca2+ ions in cement pore solution can migrate into the aggressive solution. In this work, calcium leaching of graphene oxide (GO) reinforced cement composites was effectively characterized by combined techniques of electrochemical impedance spectroscopy (EIS) and scanning electron microscope (SEM). Inhibiting mechanism of GO on calcium leaching of the composites was also examined. The obtained results show that the diameter of the semi-circle of the Nyquist curves of leached samples with GO addition decreased less than that of controlled samples. After leaching for 35 days, loss rate of model impedance RCCP of leached samples with 0, 0.05, 0.1, 0.15, and 0.2 wt.% GO addition was 94.85%, 84.07%, 79.66%, 75.34%, and 68.75%, respectively. Therefore, GO addition can significantly mitigate calcium leaching of cement composites, since it can absorb Ca2+ ions in cement pore solution, as well as improve the microstructure of the composites. In addition, coupling leaching depth and compressive strength loss were accurately predicted by using the impedance RCCP.

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“…This drop in pH can be explained by the action of the leaching reaction in seawater. In contact with water, alkali metals such as potassium, calcium and hydroxide ions will leach out of the mortar specimens and thus reduce the pH of the surface [107,108].…”

Section: Ph Of Mortar Surfacesmentioning

confidence: 99%

Influence of the Intrinsic Characteristics of Cementitious Materials on Biofouling in the Marine Environment

et al. 2021

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Coastal marine ecosystems provide essential benefits and services to humanity, but many are rapidly degrading. Human activities are leading to significant land take along coastlines and to major changes in ecosystems. Ecological engineering tools capable of promoting large-scale restoration of coastal ecosystems are needed today in the face of intensifying climatic stress and human activities. Concrete is one of the materials most commonly used in the construction of coastal and marine infrastructure. Immersed in seawater, concretes are rapidly colonized by microorganisms and macroorganisms. Surface colonization and subsequent biofilm and biofouling formation provide numerous advantages to these organisms and support critical ecological and biogeochemical functions in the changing marine environment. The new challenge of the 21st century is to develop innovative concretes that, in addition to their usual properties, provide improved bioreceptivity in order to enhance marine biodiversity. The aim of this study is to master and clarify the intrinsic parameters that influence the bioreceptivity (biocolonization) of cementitious materials in the marine environment. By coupling biofilm (culture-based methods) and biofouling (image-analysis-based method and wet-/dry-weight biomass measurement) quantification techniques, this study showed that the application of a curing compound to the concrete surface reduced the biocolonization of cementitious materials in seawater, whereas green formwork oil had the opposite effect. This study also found that certain surface conditions (faceted and patterned surface, rough surface) promote the bacterial and macroorganism colonization of cementitious materials. Among the parameters examined, surface roughness proved to be the factor that promotes biocolonization most effectively. These results could be taken up in future recommendations to enable engineers to eco-design more eco-friendly marine infrastructure and develop green-engineering projects.

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Influence of calcium leaching on chloride diffusivity in cement-based materials

Cited by 37 publications

References 43 publications

In vitro and in situ tests to evaluate the bacterial colonization of cementitious materials in the marine environment

In vitro and in situ tests to evaluate the bacterial colonization of cementitious materials in the marine environment

Electrochemical Characterization and Inhibiting Mechanism on Calcium Leaching of Graphene Oxide Reinforced Cement Composites

Influence of the Intrinsic Characteristics of Cementitious Materials on Biofouling in the Marine Environment

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