Changes in microstructure characteristics of cement paste on carbonation

Shah, Vineet; Scrivener, Karen; Bhattacharjee, Bishwajit; Bishnoi, Shashank

doi:10.1016/j.cemconres.2018.04.016

Cited by 330 publications

(122 citation statements)

References 33 publications

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“…is shows significant mineralogical changes in the specimen after carbonation. Compared to the results of noncarbonated zones, Ca(OH) 2 disappears and CaCO 3 emerges in the fully carbonated zone with almost constant amount of C-S-H. Castellote et al [43], Ho et al [31], and Shah et al [40] reported that the formation of CaCO 3 was mostly due to the carbonation of the hydration products including Ca(OH) 2 and C-S-H gel, which resulted in different volumetric characteristics during carbonation. It is evident that the conversion of Ca(OH) 2 into CaCO 3 is the main mechanism that controls the carbonation behavior in lime-stabilized expansive soils.…”

Section: Microstructural Analysis Of Carbonation Mechanismmentioning

confidence: 92%

“…Samples with dimensions of approximately 3 mm × 3 mm × 3 mm and masses between 1.5 and 2.0 g in fully carbonated, partly carbonated, and noncarbonated zones were adopted to analyze the pore size distribution using mercury intrusion porosimetry (MIP). e referred testing procedures related to XRD, MIP, and SEM are described in detail by Du et al [9] and Shah et al [40]. As shown in Figure 6, the carbonation depth of the limestabilized expansive soil increases with time elapsing.…”

Section: Microstructural Analysismentioning

confidence: 99%

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Experimental Investigation on Carbonation Behavior in Lime‐Stabilized Expansive Soil

Zha

Liu

et al. 2020

Advances in Civil Engineering

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e carbonation behavior of lime-stabilized expansive soil is important for assessing the stabilization efficiency from the perspective of durability. In this study, the accelerated carbonation tests, measurement of pH value distribution, and the free swell ratio tests were conducted to investigate the evolutions of carbonation depth, carbonation extent, and expansive potential of limestabilized expansive soil. XRD, MIP, and SEM techniques were adopted as supplements to reveal the carbonation mechanism. Results demonstrated that the carbonation depth of lime-stabilized expansive soil increased significantly as time elapsed; however, the rate of increase reduced when the carbonation time increased. Higher carbonation depth was obtained at higher temperature and CO 2 concentration and lower relative humidity, which was described by an empirical model. Fully, partly, and noncarbonated zones were subsequently presented with an increase in the depth of the soil. e expansive potential of lime-stabilized expansive soil was partially recovered during carbonation. e obtained linear relationships between the free swell ratio and pH value were adopted to describe the evolution of expansive behavior with carbonation time and depth. In microstructural analysis, the conversion of portlandite into calcium carbonate was significant, which resulted in changes in microstructure and controlled the carbonation behavior.

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Section: Microstructural Analysis Of Carbonation Mechanismmentioning

confidence: 92%

Section: Microstructural Analysismentioning

confidence: 99%

Experimental Investigation on Carbonation Behavior in Lime‐Stabilized Expansive Soil

Zha

Liu

et al. 2020

Advances in Civil Engineering

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“…After further research using XRD, TGA and 29 Si NMR the authors confirmed that the carbonation products formed at 3% CO 2 were representative of the products formed at long term natural carbonation [5]. In agreement, Shah et al using XRD, TGA and SEM-EDS point analysis found that the products formed at 60% RH, 3% CO 2 compared to products formed at natural carbonation [6]. No results on carbonation at relative humidity higher than 75% were found.…”

Section: Introductionmentioning

confidence: 59%

Impact of Accelerated Carbonation on Microstructure and Phase Assemblage

Revert

Weerdt

Jakobsen

2018

Nordic Concrete Research

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The paper summarizes preliminary results on characterization of the microstructure and phase assemblage of mortar and concrete samples containing Portland and Portland-fly ash cement carbonated at either natural conditions, 60% RH and 1% CO2, 90% RH and 5% CO2 or 60% RH and 100% CO2. Different characterization techniques were used: thermogravimetric analysis to study the solid phases, SEM-EDS point analysis to investigate the chemical composition of the solid phases, optical microscopy to investigate the microstructure, and cold water extraction to characterize the chemical composition of the pore solution. The combined results on microstructure and phase assemblage indicate that carbonation up to 5% CO2 appears representative for natural carbonation. Pore solution analysis revealed similar trends for the three accelerated carbonation conditions.

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“…e time for absolute ethyl alcohol to stop cement hydration was 1 d and 7 d for XRD analysis, respectively. XRD was used to quantify the crystalline phases present in the cement paste [22]. e data were collected using by using a Bruker D8 Advance Diffractometer (CuKα,λ � 1.54Å) operating in the Bragg-Brentano geometry on 40 kV and 40 mA.…”

Section: Xrdmentioning

confidence: 99%

The Effect of Sodium Gluconate on Pastes’ Performance and Hydration Behavior of Ordinary Portland Cement

Lü

et al. 2020

Advances in Materials Science and Engineering

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The goal of this paper provides better understanding of the effect of sodium gluconate (SG) on ordinary Portland cement (OPC) hydration behavior. Pastes’ performances of ordinary Portland cement, including setting time at 20°C and 35°C curing temperature, mechanical strength, fluidity, and zeta potential are studied. Furthermore, the effects of SG on cement hydration behaviors are investigated by the means of isothermal calorimetry measurements, X-ray diffraction (XRD), and thermogravimetric analysis (TGA). The results show that SG is difficult to maintain significant retarding effect at the temperature of 35°C compared to that at the temperature of 20°C. SG is able to reduce the cement cumulative hydration heat and delay the occurrence time of heat evolution peak in a certain extent, but it has little impact on reducing the cement evolution rate peak. The effects of SG on mechanical properties and dispersion properties of cement depend on its dosages. Specifically, the positive effect occurs when the addition dosage is less than 0.15% (i.e., by cement weight), but the negative effect emerges if the addition dosages exceed this limitation. Similarly, SG plays different roles on cement hydration at different hydration periods. It inhibits the hydration of C3S and the formation of portlandite (CH) at the early hydration period. On the contrary, it promotes the C3S hydration when hydration time is beyond 1 d. Meanwhile, SG also plays different roles on cement hydration at different dosage additions. Specifically, SG promotes ettringite (AFt) formation at the dosage less than 0.06%, but it inhibits AFt formation at the dosage more than 0.06%.

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Changes in microstructure characteristics of cement paste on carbonation

Cited by 330 publications

References 33 publications

Experimental Investigation on Carbonation Behavior in Lime‐Stabilized Expansive Soil

Experimental Investigation on Carbonation Behavior in Lime‐Stabilized Expansive Soil

Impact of Accelerated Carbonation on Microstructure and Phase Assemblage

The Effect of Sodium Gluconate on Pastes’ Performance and Hydration Behavior of Ordinary Portland Cement

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