Microstructural changes induced in Portland cement-based materials due to natural and supercritical carbonation

Hidalgo, Antonio Vásquez; Domingo, Concepción; Garcia, Carlos B. W.; Petit, Sabine; Andrade, Carmen; Alonso, C.

doi:10.1007/s10853-008-2521-5

Cited by 126 publications

(57 citation statements)

References 35 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…This would mainly be due to the fact that the degree of carbonation is generally not high enough to observe the formation of metastable forms of CC and amorphous CC. Note that Hidalgo et al [44] have verified similar TGA patterns with three peaks above 550…”

Section: Tga-dtg-ms and Xrd Characterizationmentioning

confidence: 62%

“…Since CC polymorphs have different molar volume, different variations of porosity according to the carbonation conditions are expected. The difference between air-carbonation and accelerated carbonation conditions is even higher if mineral admixtures are added in the cement [30,31,44]. Regarding microstructure aspects, results of the literature suggest that accelerated carbonation at high CO 2 leads to a preferential formation of CC crystals on the surface of CH particles, and thereby inhibits further dissolution of this phase [45].…”

Section: Pretreatmentmentioning

confidence: 99%

See 1 more Smart Citation

Investigation of the carbonation mechanism of CH and C-S-H in terms of kinetics, microstructure changes and moisture properties

Morandeau

Thiéry

Dangla

2014

Cement and Concrete Research

650

278

View full text Add to dashboard Cite

The purpose of this article is to investigate the carbonation mechanism of CH and C-S-H within type-I cement-based materials in terms of kinetics, microstructure changes and water released from hydrates during carbonation. Carbonation tests were performed under accelerated conditions (10% CO 2 , 25• C and 65± 5% RH). Carbonation profiles were assessed by destructive and non-destructive methods such as phenolphthalein spray test, thermogravimetric analysis, and mercury intrusion porosimetry (destructive), as well as gamma-ray attenuation (non-destructive). Carbonation penetration was carried out at different ages from 1 to 16 weeks of CO 2 exposure on cement pastes of 0.45 and 0.6 w/c, as well as on mortar specimens (w/c = 0.50 and s/c = 2). Combining experimental results allowed us to improve the understanding of C-S-H and CH carbonation mechanism. The variation of molar volume of C-S-H during carbonation was identified and a quantification of the amount of water released during CH and C-S-H carbonation was performed.

show abstract

Section: Tga-dtg-ms and Xrd Characterizationmentioning

confidence: 62%

Section: Pretreatmentmentioning

confidence: 99%

Investigation of the carbonation mechanism of CH and C-S-H in terms of kinetics, microstructure changes and moisture properties

Morandeau

Thiéry

Dangla

2014

Cement and Concrete Research

650

278

View full text Add to dashboard Cite

show abstract

“…due to a densification of the pore structure over time [4], and possibly due to changes in cement paste microstructure during carbonation [32], at least in Portland Cement. This may result into slower diffusion of CO 2 and longer times to reach pH 12.5.…”

Section: Discussion 4 Ph Evolution During Carbonation Process-41 Thementioning

confidence: 99%

PH-monitoring in mortar with thermally-oxidized iridium electrodes

2017

View full text Add to dashboard Cite

The pH of the concrete pore solution plays a vital role in protecting the reinforcing steel from corrosion. Here, we present results from embeddable pH sensors that permit the continuous, in-situ monitoring of the pH in the concrete pore solution. These are potentiometric sensors, based on thermallyoxidized iridium/iridium oxide (IrO x ) electrodes. We propose an iterative calculation algorithm taking into account diffusion potentials arising from pH changes, thus permitting the reliable, non-destructive determination of the pore solution pH over time. This calculation algorithm forms an essential part of the method using IrO x electrodes. Mortar samples were exposed to accelerated carbonation and the pH was monitored at different depths over time. Comparative tests were also performed using thymolphthalein pH-indicator. The results from the pH sensors give insight in the carbonation process, and can, in contrast to thermodynamic modelling and titration experiments, provide insight in kinetic processes such as transport and phases transformations. It was found that the front at which the pH is decreased from initially 13-14 down to 12.5 can be significantly ahead of the common carbonation front corresponding to pH 9-10. This has major implications for laboratory testing and engineering practice.

show abstract

“…Carbon dioxide (CO 2 ) present in the atmosphere diffuses through concrete and reacts with different constituents of the cementing matrix, which yields mostly calcium carbonate (CaCO 3 ) from its reaction with portlandite [CaðOHÞ 2 ]. 1 The carbonation of portlandite takes place in the presence of moisture, so the actual reaction occurs with carbonic acid (HCO 3 ) as 2 E Q -T A R G E T ; t e m p : i n t r a l i n k -; e 0 0 1 ; 6 3 ; 2 6 4 CaðOHÞ 2 þ CO 2 → CaCO 3 þ H 2 O:…”

Section: Introductionmentioning

confidence: 99%

Effect of carbonation on the linear and nonlinear dynamic properties of cement-based materials

et al. 2015

View full text Add to dashboard Cite

Abstract. Carbonation causes a physicochemical alteration of cement-based materials, leading to a decrease of porosity and an increase of material hardness and strength. However, carbonation will decrease the pH of the internal pore water solution, which may depassivate the internal reinforcing steel, giving rise to structural durability concerns. Therefore, the proper selection of materials informed by parameters sensitive to the carbonation process is crucial to ensure the durability of concrete structures. The authors investigate the feasibility of using linear and nonlinear dynamic vibration response data to monitor the progression of the carbonation process in cement-based materials. Mortar samples with dimensions of 40 × 40 × 160 mm were subjected to an accelerated carbonation process through a carbonation chamber with 55% relative humidity and >95% of CO 2 atmosphere. The progress of carbonation in the material was monitored using data obtained with the test setup of the standard resonant frequency test (ASTM C215-14), from a pristine state until an almost fully carbonated state. Linear dynamic modulus, quality factor, and a material nonlinear response, evaluated through the upward resonant frequency shift during the signal ring-down, were investigated. The compressive strength and the depth of carbonation were also measured. Carbonation resulted in a modest increase in the dynamic modulus, but a substantive increase in the quality factor (inverse attenuation) and a decrease in the material nonlinearity parameter. The combined measurement of the vibration quality factor and nonlinear parameter shows potential as a sensitive measure of material changes brought about by carbonation.

show abstract

Microstructural changes induced in Portland cement-based materials due to natural and supercritical carbonation

Cited by 126 publications

References 35 publications

Investigation of the carbonation mechanism of CH and C-S-H in terms of kinetics, microstructure changes and moisture properties

Investigation of the carbonation mechanism of CH and C-S-H in terms of kinetics, microstructure changes and moisture properties

PH-monitoring in mortar with thermally-oxidized iridium electrodes

Effect of carbonation on the linear and nonlinear dynamic properties of cement-based materials

Contact Info

Product

Resources

About