Mechanism of Carbonation and Prediction of Carbonation Process of Concrete

Saeki, Tatsuhiko; Ohga, Hiroyuki; Nagataki, Shigeyoshi

doi:10.2208/jscej.1990.414_99

Cited by 26 publications

(14 citation statements)

References 3 publications

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“…Due to the lack of experimental results for moderate level of carbonation (not fully carbonated), the porosity reduction factor for this level is simply modeled as a linear function of the remaining calcium hydroxide to its initial value which also coincides with the experimental work of Saeki et al (1991) as initially modeled by Ishida and Maekawa (2001). The proposed bi-linear porosity reduction function is expressed as,…”

Section: Changes In Micropore Structures Due To Carbonationmentioning

confidence: 90%

Theoretically Identified Strong Coupling of Carbonation Rate and Thermodynamic Moisture States in Micropores of Concrete

Ishida¹,

Maekawa²,

Soltani

2004

ACT

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In order to predict the chemo-physical process of carbonation, a finite element based computational method is implemented based upon multi-phase/scale governing equations of moisture and flux of both heat and carbon dioxide. Influencing parameters of carbonation involving reaction rate, CO 2 diffusivity and the reduction of porosity are discussed. It is found that such modeling can accurately show high nonlinearity among carbonation reaction, pore structure development and moisture distribution in micropore structures. By using the proposed assumptions, the reliability of the predictive method of the carbonation mechanism in cementitious materials under arbitrary environmental and curing conditions is examined by comparing available experimental results with theoretical ones. Through sensitivity analyses that focus on the nonlinearity of the moisture profile and local carbonation, it is clarified that different moisture distribution may bring the opposite trend of the carbonation depth under low and high CO 2 concentrations.

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Section: Changes In Micropore Structures Due To Carbonationmentioning

confidence: 90%

Theoretically Identified Strong Coupling of Carbonation Rate and Thermodynamic Moisture States in Micropores of Concrete

Ishida¹,

Maekawa²,

Soltani

2004

ACT

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“…It has been validated by Hukujima [30] and Saeki [31] that the key factor affecting the diffusion of Ca 2+ is the moisture in concrete. Furthermore, Hukujima accepted that the diffusion coefficient of Ca 2+ conforms to exponential functions of the water content in concrete.…”

Section: Mass Transfer Of Carbon Dioxide In Concretementioning

confidence: 99%

Influence of Wind Pressure on the Carbonation of Concrete

Zou

Liu

et al. 2015

Materials

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Carbonation is one of the major deteriorations that accelerate steel corrosion in reinforced concrete structures. Many mathematical/numerical models of the carbonation process, primarily diffusion-reaction models, have been established to predict the carbonation depth. However, the mass transfer of carbon dioxide in porous concrete includes molecular diffusion and convection mass transfer. In particular, the convection mass transfer induced by pressure difference is called penetration mass transfer. This paper presents the influence of penetration mass transfer on the carbonation. A penetration-reaction carbonation model was constructed and validated by accelerated test results under high pressure. Then the characteristics of wind pressure on the carbonation were investigated through finite element analysis considering steady and fluctuating wind flows. The results indicate that the wind pressure on the surface of concrete buildings results in deeper carbonation depth than that just considering the diffusion of carbon dioxide. In addition, the influence of wind pressure on carbonation tends to increase significantly with carbonation depth.

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“…Various researches exist about the relation between pore diameter range and mass transfer in concrete (Shigeru et al 1983) (Uchikawa 1987). In the authors' research on carbonation, the diffusion coefficients of moisture and carbon dioxide could be estimated by the pore volume in the range of 15 nm to 15000 nm (Saeki et al 1991b). Although the range of pore size related to chloride diffusion was not examined, the pore volume in the range of 15nm to 15000 nm was applied in this study.…”

Section: Properties Of Synthesized C-s-hmentioning

confidence: 99%

Estimation of Chloride Diffusion Coefficent of Concrete Using Mineral Admixtures

Saeki

Sasaki

Shinada

2006

ACT

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It is well known that mineral admixtures, such as granulated blast-furnace slag and fly ash, control the ingress of chloride ions into concrete. However, the effects of the qualities and the replacement ratios of these admixtures on the diffusivity of chloride ions are not clear. Moreover, the micro-structure of concrete is changed by carbonation and change in microstructure affects mass transfer in concrete. This effect on the chloride diffusivity of concrete using mineral admixtures has not been clarified sufficiently. Therefore, in this study, the chloride ion diffusion coefficients of mortar specimens containing mineral admixtures were measured, and the influences of the kind of mineral admixture, replacement ratio, and carbonation on the chloride diffusion coefficient were estimated, and the relation between the microstructure and diffusion coefficient was studied. Furthermore, an estimation method of the diffusion coefficient using the pore volume and surface area of the pore system as parameters was proposed.

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Mechanism of Carbonation and Prediction of Carbonation Process of Concrete

Cited by 26 publications

References 3 publications

Theoretically Identified Strong Coupling of Carbonation Rate and Thermodynamic Moisture States in Micropores of Concrete

Theoretically Identified Strong Coupling of Carbonation Rate and Thermodynamic Moisture States in Micropores of Concrete

Influence of Wind Pressure on the Carbonation of Concrete

Estimation of Chloride Diffusion Coefficent of Concrete Using Mineral Admixtures

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