Carbonation of γ-Ca&lt;sub&gt;2&lt;/sub&gt;SiO&lt;sub&gt;4&lt;/sub&gt; and the Mechanism of Vaterite Formation

Saito, Tsuyoshi; Sakai, Etsuo; Morioka, Minoru; Otsuki, Nobuaki

doi:10.3151/jact.8.273

Cited by 47 publications

(13 citation statements)

References 6 publications

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“…In Kerisi's study, it was confirmed that c-C 2 S had the strongest water absorption capacity than the other four different types of olivine group minerals [17]. Additionally, different from the carbonation mechanism of other calcium silicates, such as C 3 S and β-C 2 S, which have a hydrate activity, very few Ca ions of c-C 2 S are dissolved in water, so the intermediate product, such as Ca(OH) 2 , is not formed during carbonation [18]. e direct reaction between c-C 2 S and CO 2 also results in a high carbonation reaction rate.…”

Section: Introductionmentioning

confidence: 81%

“…Calcite was the main calcium carbonate phase formed in all specimens. Vaterite is considered to be the main carbonation product of c-C 2 S. Saito reported that the crystallinity of C 2 S is associated with the crystallinity of the carbonation products [18]. c-C 2 S and vaterite have a similar crystalline structure in which Ca 2+ ions occupy a six-coordinate position of hexagonally close packed O 2− , and their Ca-O bond lengths are also similar.…”

Section: Pore Structure Analysismentioning

confidence: 99%

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Improvement in Carbonation Resistance of Portland Cement Mortar Incorporating γ-Dicalcium Silicate

Chen

Lee

Cho

et al. 2019

Advances in Materials Science and Engineering

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In this study, γ-dicalcium silicate (γ-C2S) was incorporated into ordinary Portland cement (OPC) to sequester CO2 to enhance the carbonation resistance of cement-based composite materials. γ-C2S can react with CO2 rapidly to form vaterite and high dense SiO2 gel which could block the pores off and then inhibit further diffusion of CO2 into the system. Cement mortar specimens containing 0%, 5%, 10%, 20%, and 40% γ-C2S as cement replacement were prepared. After water curing for 28 days followed by curing in an environmental chamber for 28 days, the specimens were then exposed to an accelerated carbonation with 5% CO2 concentration for 28 days. The carbonation depth of the cement mortar with a low replacement rate (5% and 10%) was lower than that of the OPC mortar at all ages due to the sequestration of CO2 by γ-C2S. However, the cement mortar with a high replacement rate (20% and 40%) showed less carbonation resistance due to the dilution effect of γ-C2S replacement and increase in initial porosity caused by nonhydraulic characteristic of γ-C2S.

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Section: Introductionmentioning

confidence: 81%

Section: Pore Structure Analysismentioning

confidence: 99%

Improvement in Carbonation Resistance of Portland Cement Mortar Incorporating γ-Dicalcium Silicate

Chen

Lee

Cho

et al. 2019

Advances in Materials Science and Engineering

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“…However, during investigations of rapid strength development in Portland cement by an accelerated carbonation treatment with CO2 gas at ambient temperature and pressure, gamma-C2S has been found to carbonate as readily as Portland cement (Bukovsky & Berger 1979, Saito 2010). This finding has been supported by more recent work on self-pulverised stainless steel slag (Johnson 2003).…”

Section: An Energy-saving Opportunitymentioning

confidence: 99%

Low-energy CO2-activated self-pulverising cement for sustainable concrete construction

Maries¹,

Hills²,

Carey³

2019

Sustainable Construction Materials and Technologies (SCMT)

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In order to achieve an efficient and sustainable concrete industry, there is an urgent need to reduce CO2 emissions from cement manufacture. The innovative scheme described here for the linked production of cement and concrete with low carbon footprint follows a three-stage process. Firstly, a Portland-like cement composition is calcined at reduced temperature and cooled under controlled conditions so that it selfpulverises spontaneously to a powder of normal fineness without grinding. Secondly, CO2-rich gas is extracted direct from the cement kiln flue and used to activate this poorly hydraulic cement in the third stage for making precast concrete products. Considerable energy savings are anticipated, and the challenges of process enhancements and scale-up are currently being addressed. In addition to its use in precast concrete items such as blocks, roof tiles, and pipes, other potential on-site applications are foreseen for this cement where low-energy concrete or controlled setting are required.

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“…Therefore, the application potential of γ-C 2 S in cement-based materials directly determines the applicability of AODS. γ-C 2 S can be easily carbonated without hydration when in contact with CO 2 and water [18]. Using carbonation properties, many researchers have found that γ-C 2 S can be used as a durability modifier for a cement-based product.…”

Section: Introductionmentioning

confidence: 99%

Cementitious Behavior of Argon Oxygen Decarburization Stainless Steel Slag and Its Stabilization on Chromium

Wang

Zeng

et al. 2020

Crystals

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The study mainly aims at the potential of Argon Oxygen Decarburization Slag (AODS) as a supplementary cementitious material and explores the mechanisms of stabilization/solidification (S/S) of chromium in cement-based composite pastes. The basic cementitious parameters, such as water requirement, setting time, soundness, hydration characteristics, and strength indexes of composite binders, were examined through standard methods. The results showed that the most beneficial mineral phase in AODS for cementitious behavior was beta dicalcium silicate (β-C2S). The utilization of a higher AODS dosage in composite binders increased the water requirement and the setting time, while it decreased the hydration heat and the strength indexes. Although the AODS possessed limited cementitious properties, it conformed the Grade II steel slag powder qualified for concrete and cement. Sequential leaching tests were conducted targeting the leachability of chromium in the pastes with different AODS dosage and curing time. Results showed that with the lower AODS dosage and the longer curing time, the S/S efficiency for chromium leaching from the composite paste was better. Utilization of AODS as a cement substitute not only can recycle this solid waste and decrease the emission of CO2 concerning cement production, but also helps to effectively reduce the chromium leaching risk.

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Carbonation of γ-Ca<sub>2</sub>SiO<sub>4</sub> and the Mechanism of Vaterite Formation

Cited by 47 publications

References 6 publications

Improvement in Carbonation Resistance of Portland Cement Mortar Incorporating γ-Dicalcium Silicate

Improvement in Carbonation Resistance of Portland Cement Mortar Incorporating γ-Dicalcium Silicate

Low-energy CO2-activated self-pulverising cement for sustainable concrete construction

Cementitious Behavior of Argon Oxygen Decarburization Stainless Steel Slag and Its Stabilization on Chromium

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