Preparation of new cementitious system using fly ash and dehydrated autoclaved aerated concrete

Shui, Zhonghe; Lü, Jianxin; Tian, Sufang; Shen, Peiliang; Ding, Sha

doi:10.1007/s11595-014-0987-3

Cited by 17 publications

(10 citation statements)

References 19 publications

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“…Combining X-ray diffraction analysis (XRD) with 29 Si-NMR, Lü et al [ 12 ] inferred that, above 650 °C, β-C 2 S was formed, and at 900 °C, this polymorph became highly crystalline and had low reactivity. Serpell and Zunino [ 11 ] reported that β-C 2 S and a more reactive C 2 S polymorph, α’ H -C 2 S, were identified above 740 °C, though, up to 800 °C, the predominant C 2 S polymorph was α’ H -C 2 S, and, at 900 °C, the main C 2 S polymorph was β-C 2 S. Shui et al [ 25 ] identified α-C 2 S, as well as β-C 2 S, above 800 °C. Through XRD analysis, Carriço et al [ 22 ] detected that, above 600 °C, a new C 2 S polymorph was created, with a similar structure to α’ L -C 2 S. Furthermore, the microstructure and hydration mechanism of RC has yet to be completely figured out, especially taking into account the influence of the treatment temperature.…”

Section: Introductionmentioning

confidence: 99%

Influence of the Treatment Temperature on the Microstructure and Hydration Behavior of Thermoactivated Recycled Cement

et al. 2020

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This paper intends to contribute to a better knowledge of the production and rehydration of thermoactivated recycled cement and its incorporation in cement-based materials. To this end, the influence of the treatment temperature on the properties of recycled cements and recycled cement pastes was assessed by means of a wide array of tests. Anhydrous recycled cement as well as the resulting pastes were characterized through density and particle size, water demand and setting time, thermogravimetry, X-ray diffraction, field emission gun scanning electron microscopy, isothermal calorimetry, 29Si nuclear magnetic resonance spectroscopy, flowability, mechanical strength, mercury intrusion porosimetry and scanning electron microscopy. The treatment temperature had a significant influence on the dehydration and hydration of recycled cement, essentially resulting in the formation of C2S polymorphs of varying reactivity, which led to pastes of different fresh and hardened behaviors. The high water demand and the pre-hydration of recycled cement resulted in high setting times and low compressive strengths. The highest mechanical strength was obtained for a treatment temperature of 650 °C.

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Section: Introductionmentioning

confidence: 99%

Influence of the Treatment Temperature on the Microstructure and Hydration Behavior of Thermoactivated Recycled Cement

et al. 2020

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“…In a second stage of RC production, waste cement is subjected to gridding, usually by means of ball milling as done in the cement industry [42,43]. Some authors opt to previously oven dry the waste cement before gridding, since it reduces the baling phenomenon and wall mill adhesion [36,44,45]. In other studies, the RC grinding was performed after thermal activation [42,[46][47][48][49], however this turns the thermal process less effective and may lead to less homogeneous RC.…”

Section: Figurementioning

confidence: 99%

“…Optimal treatment temperatures have been reported to be in the range of 600-700°C, ensuring high rehydration ability and low thermal energy consumption [2]. The residence time has ranged from 1 to 8 hours in literature, although 2-3 hours is most often adopted [44,46,48,49,54,55,60]. The influence of the residence time and treated temperature on the mechanical strength of mortars produced with 25% of RC from the cement fraction of waste Thermoactivated Recycled Cement DOI: http://dx.doi.org/10.5772/intechopen.98488 mortar was analyzed by Kalinowska-Wichrowska et al [63].…”

Section: Figurementioning

confidence: 99%

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Thermoactivated Recycled Cement

Bogas¹,

Carriço²,

Real³

2022

Sustainability of Concrete With Synthetic and Recycled Aggregates

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The cement industry is currently faced by the great challenge of reducing its vast carbon footprint, due to being the second highest industrial greenhouse gases (GHG) emitter. This value is expected to further increase, since cement production is foreseen to rise by about 20% until 2050. Therefore, more eco-efficient alternatives to ordinary Portland cement have been developed towards a sustainable concrete industry. This chapter presents some of the latest advances in low-carbon thermoactivated recycled cements (RC) obtained from old waste concrete, leading to a significant reduction of the GHG emissions, while also encouraging the valorization reuse of waste materials and the reduction of natural resource depletion. The manufacture and general performance of RC, including the main production issues, rehydration behavior and phase and microstructure development, as well as its incorporation in cement-based materials are discussed. Some of the most recent research, main challenges and future perspective of RC are addressed.

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“…Research indicates that the hydration product Ca(OH) 2 in DCP can react with aluminum oxide and silicon oxide in pozzolanic materials, leading to the fracture of Si-O and Al-O bonds. This makes it a favorable raw material for enhancing the reaction of pozzolanic materials [13][14][15][16][17][18][19]. Currently, fly ash (FA) and slag powder (SL) are the most widely used admixtures for the preparation of composite cementitious materials [4,10,[14][15][16][17]20].…”

Section: Introductionmentioning

confidence: 99%

Mechanical properties and hydration behavior of dehydrated cement paste-slag based composite cementitious material

Zhang,

Tang,

et al. 2024

Eng. Res. Express

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Mechanical properties are critical in engineering applications involving cementitious materials. While dehydrated cement paste-based materials are considered environmentally friendly, they suffer from poor mechanical properties, limiting their engineering applications. Therefore, enhancing the mechanical properties of these materials is crucial to overcoming their limitations in engineering and supporting the development of sustainable building engineering. Based on the pozzolanic reaction mechanism and alkali activation theory, a composite cementitious material was created by combining dehydrated cement paste with slag. Na2SiO3 and NaAlO2 were used as alkali activators. The study investigated the effects of the ratio of dehydrated cement paste to slag, alkali activator dosage, water-binder ratio, and calcination temperature on the material's mechanical properties through an orthogonal test. The optimized ratio, determined through the orthogonal test and mathematical model, resulted in a compressive strength of 37.33 MPa (7d) and 46.89 MPa (28d), surpassing the compressive strength of the original Portland cement paste. Hydration products of the composite cementitious material primarily comprised C-(A)-S-H, C-A-H, and CaCO3, with no observed presence of AFt, AFm, and Ca(OH)2. Notably, the hydration products of the composite material exhibited clear distinctions from those of Portland cement.

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Preparation of new cementitious system using fly ash and dehydrated autoclaved aerated concrete

Cited by 17 publications

References 19 publications

Influence of the Treatment Temperature on the Microstructure and Hydration Behavior of Thermoactivated Recycled Cement

Influence of the Treatment Temperature on the Microstructure and Hydration Behavior of Thermoactivated Recycled Cement

Thermoactivated Recycled Cement

Mechanical properties and hydration behavior of dehydrated cement paste-slag based composite cementitious material

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