Effects of carbohydrates and sulfonates during CaO hydration on portlandite microstructure

Pesce, Cecilia; Ball, Richard J.; Molinari, Marco; Reeksting, Shaun; Pesce, Giovanni Luca

doi:10.1016/j.cemconres.2023.107372

Cited by 3 publications

(1 citation statement)

References 69 publications

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“…Moreover, at temperatures exceeding 720 • C, it is demonstrated in Equations ( 3) and ( 4) that the minerals of CS and CaCO 3 decomposed into β-C 2 S and CaO. These compounds can then participate in the process of cement hydration [46]. Previous studies have demonstrated similar results [30][31][32].…”

Section: Discussionmentioning

confidence: 66%

Effect of the Pretreatment on the Properties of Cement-Based Recycled Powder

Li,

Feng,

Zhong

et al. 2024

Coatings

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Three pretreatment methods including calcination, carbonization, and a carbonization-calcination combined pretreatment were studied to understand the pretreatment mechanisms for cement-based recycled powder (CRP). The mineral and microstructure of the CRP sample were investigated through X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), thermal gravity (TG) analysis, and scanning electron microscopy (SEM) after exposure to different thermal temperatures (400 °C, 600 °C, and 800 °C), carbonization times (6 h, 1 d, and 3 d), and pre-carbonization for 1 d followed by heating at 800 °C. The results showed that the optimal thermal pretreatment temperature was approximately 720–800 °C. Through the process of calcination, the C-S-H, Ca(OH)2, and CaCO3 minerals in the CRP sample underwent decomposition to produce CaO or C2S. During carbonation, the pretreatment not only results in the increased production of CaCO3 owing to the reaction of the C-S-H gel and Ca(OH)2 with CO2, but also enhances its properties and the strength of chemical bond between CaCO3 and the post-hydration products. Both CaCO3 and CaO were present after the combined pretreatment, which indicates that the CaCO3 mineral formed superior stability after it had been pre-carbonated. Due to fewer impurities in CRP, the positive effect of the pretreatment on CRP was significantly better than that on recycled powder derived from construction and demolition waste.

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Section: Discussionmentioning

confidence: 66%

Effect of the Pretreatment on the Properties of Cement-Based Recycled Powder

Li,

Feng,

Zhong

et al. 2024

Coatings

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Impact of in-situ CO2 injection on natural and accelerated carbonation performance of aerial lime mortar

Hwang,

Park,

Moon

et al. 2024

Construction and Building Materials

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Effects of Organic Additives on Portlandite Microstructure during CaO Hydration

Pesce,

Molinari

2024

MATEC Web Conf.

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This study evaluates the effect of various organic additives on the microstructure of portlandite crystals during the hydration of CaO. Calcium hydroxide mixed with selected additives was prepared and characterised in terms of crystal size and habit, platelets abundance, and particle size distribution using various techniques such as XRD, SEM and Particle Size Analysis. The results suggest that the microstructure of portlandite is altered by the presence of carbohydrates and sulfonates, showing higher platelets abundance, smaller crystallite size, and higher specific surface area. The presence of hydroxyl-rich carbohydrates induces more marked effects compared to sulfonates. These results show that it is possible to tailor the properties of lime to specific applications in both, the conservation and the construction industry. Furthermore, the results show that it is possible to enable the development of materials specifically dedicated to other applications such as the synthesis of precipitated calcium carbonate and the design of CO2 sorbents, all of which will have the added value of reducing the global anthropogenic CO2 emissions.

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Effects of carbohydrates and sulfonates during CaO hydration on portlandite microstructure

Cited by 3 publications

References 69 publications

Effect of the Pretreatment on the Properties of Cement-Based Recycled Powder

Effect of the Pretreatment on the Properties of Cement-Based Recycled Powder

Impact of in-situ CO2 injection on natural and accelerated carbonation performance of aerial lime mortar

Effects of Organic Additives on Portlandite Microstructure during CaO Hydration

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