Microstructural changes caused by carbonation of cement mortar

Johannesson, Björn; Utgenannt, Peter

doi:10.1016/s0008-8846(01)00498-7

Cited by 313 publications

(138 citation statements)

References 2 publications

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“…During the carbonation, portlandite crystals, Ca(OH) 2 , reacts with CO 2 and forms calcite crystals, CaCO 3 . Since calcite crystals have different crystal structure and molar volume, the microstructure of the lime and lime-cement pastes changes, such as, crystals join to each other creating a net and the strength of the material increases.…”

Section: Carbonation Processmentioning

confidence: 99%

“…Even though mass factor has not been found in the previous papers studied the changes in microstructure properties produced by the carbonation [1][2][3], it seems adequate to use this mass factor in order to take into account the change of mass produced as consequence of the carbonation process. Table 4 shows the intrudable porosity results of the carbonated and non-carbonated pastes, obtained by mercury intrusion porosimeter.…”

Section: Mass Factormentioning

confidence: 99%

“…Johannesson and Utgenannt [2] studied the effect of carbonation on the specific surface area of cement mortar using BET theory. They concluded that the specific surface area of the non-carbonated mortar is higher than that of the well-carbonated one.…”

Section: Specific Surface Areamentioning

confidence: 99%

“…As it is well known, carbonation, a consequence of the transformation of Ca(OH) 2 to CaCO 3 , causes variation of the microstructure of mortars and concretes by decreasing their porosity. Carbonation also causes the change of material properties that are closely related to the microstructure, such as permeability, diffusivity of gases, capillarity, etc... Several authors have studied the variation of material properties with carbonation process: Ngala [1] investigated the effects of carbonation on pore structure and diffusional properties of hydrated cement pastes.…”

Section: Introductionmentioning

confidence: 99%

“…Carbonation also causes the change of material properties that are closely related to the microstructure, such as permeability, diffusivity of gases, capillarity, etc... Several authors have studied the variation of material properties with carbonation process: Ngala [1] investigated the effects of carbonation on pore structure and diffusional properties of hydrated cement pastes. Johannesson and Utgenannt [2] studied the change of specific surface area of cement mortar using BET theory. As a result of comparing carbonated and non-carbonated cement pastes, Houst [3] observed that the amount of water adsorbed decreased with carbonation.…”

Section: Introductionmentioning

confidence: 99%

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Variation of microstructure with carbonation in lime and blended pastes

Arandigoyen

Biçer-Şimşir

Álvarez

et al. 2006

Applied Surface Science

132

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ABSTRACT:Carbonation, as a reaction of the curing process of both, cement and lime binders, modifies the microstructure. Several microstructure properties, namely, porosity, pore size distribution, surface fractal dimension and specific surface area have been investigated in this study to describe the effect of carbonation on microstructure. Both carbonated and non-carbonated pastes of lime and blended pastes of lime and cement having varying W/B (water/binder) ratios are studied. Results show that carbonation decreases the porosity, but not with the same intensity in all pore size ranges. The highest modification is between 0.03 and 0.01 µm in lime pastes and between 0.2 and 0.02 µm in 50% lime pastes, while in 80% lime pastes the modification is very small. It is also observed that carbonation is a function of the binder composition but not of the W/B ratio. Moreover, surface fractal dimension decreases during the carbonation process, while the specific surface area varies depending of the binder composition.

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Section: Carbonation Processmentioning

confidence: 99%

Section: Mass Factormentioning

confidence: 99%

Section: Specific Surface Areamentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Variation of microstructure with carbonation in lime and blended pastes

Arandigoyen

Biçer-Şimşir

Álvarez

et al. 2006

Applied Surface Science

132

View full text Add to dashboard Cite

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Influence of a biopolymer admixture on corrosion behaviour of steel rebars in concrete

Roux¹,

Bur²,

Ferrari³

et al. 2010

Materials & Corrosion

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International audienceAmong the multitude of concrete structure pathologies, corrosion of rebars is one of the most important problems of concrete durability. In the context of sustainable development, it appears of primary importance to develop new means to protect the rebars against corrosion. This study aims to develop a new eco-friendly and corrosion-inhibiting admixture based on EPS 180 exopolysaccharides, biopolymers used in coatings already studied for the corrosion inhibition on steel in seawater. C15 rebars embedded in CEMI and CEMV cement paste containing EPS 180 were immersed in natural seawater and their electrochemical behaviour was studied using open circuit potential measurements and electrochemical impedance spectroscopy. These tests highlight the decrease of the cathodic reaction kinetics due to the EPS 180 action at the rebars surface, and the absence of effect on the passive layer. Capillary imbibition tests carried out on cement paste and mortars showed that although limiting the imbibition kinetics for cement pastes, the EPS 180 did not influence the water imbibition of mortars. Tests comparing capillary imbibition of soaked cement pastes and mortars with EPS 180 solution and the same samples containing the EPS 180 admixture highlight that the corrosion inhibition induced by EPS 180 admixture is more due to the modification of the cement - rebars interface than to the clogging of the cement porous network

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Machine learning approach in investigating carbonation depth of concrete containing Fly ash

Tran

Thi

et al. 2022

Structural Concrete

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Understanding and predicting concrete carbonation are significant in designing durability and maintaining the service life of reinforced concrete structures. However, this purpose can hardly be reached because of complex carbonation mechanisms depending on various variables such as cement content (C), fly ash content (FA), water content (W), concentration of CO 2 , relative humidity (RH), temperature (T C), and exposition time (Time). This investigation proposes a machine learning (ML) approach including eight ML algorithms such as four single ML models: XGB, GB, RF, and SVM, and four hybrid ML models: XGB_RRHC, GB_RRHC, RF_RRHC, and SVM_RRHC for investigating and predicting concrete carbonation depth containing fly ash. To achieve this purpose, a dedicated database consisting of 688 samples and seven input variables is built, and the performance of eight machine learning models is compared. Single ML model Extreme Gradient Boosting (XGB) using the default hyperparameters exhibited the highest performance with R 2 = 0.9770, RMSE = 2.2725 and MAE = 1.5218. Shapley Additive exPlanations (SHAP) identifies the most influential feature and order of feature effect on concrete carbonation depth. The first four important features can be sorted in order: time of exposition > cement content > water content > CO 2 concentration. Moreover, at a higher value of exposition time, water content, CO 2 concentration, fly ash content, temperature and relative humidity, the carbonation depth of concrete increases. Using high content of cement can reduce the carbonation depth of concrete.

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Microstructural changes caused by carbonation of cement mortar

Cited by 313 publications

References 2 publications

Variation of microstructure with carbonation in lime and blended pastes

Variation of microstructure with carbonation in lime and blended pastes

Influence of a biopolymer admixture on corrosion behaviour of steel rebars in concrete

Machine learning approach in investigating carbonation depth of concrete containing Fly ash

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