Binding materials of dehydrated phases of waste hardened cement paste and pozzolanic admixture

Lü, Linnü; He, Yongjia; Hu, Shuguang

doi:10.1007/s11595-009-1140-6

Cited by 20 publications

(7 citation statements)

References 7 publications

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“…The content of calcium oxide in RCP is higher, which makes RCP more active and helps to improve the performance of concrete. Based on the experimental results of XRD, it is found that new active calcium silicate (Ca 3 SiO 5 and Ca 2 SiO 4 ) can hydrate with water at 800 • C, which further shows the SEM and XRD images of RCP before and after heat treatment, as show in Figure 6 [45][46][47].…”

Section: Heat Treatmentmentioning

confidence: 77%

Short Review on the Application of Recycled Powder in Cement-Based Materials: Preparation, Performance and Activity Excitation

et al. 2022

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Recycled powder is a kind of powder particle with a particle size of less than 75 μm produced in the process of preparing recycled aggregate from construction waste with concrete and brick as the main components. It has the potential to replace part of cement as an auxiliary cementitious material. This has important engineering application value for promoting the full-component and high-quality utilization of construction waste, which meets the needs of national sustainable development. Based on the physical and chemical characteristics of recycled powder, the preparation process and basic properties of the recycled powder were systematically analyzed. Based on the low activity of recycled powder, different methods of its activity excitation were described in detail. In addition, some existing problems in the current research were also prospected.

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Section: Heat Treatmentmentioning

confidence: 77%

Short Review on the Application of Recycled Powder in Cement-Based Materials: Preparation, Performance and Activity Excitation

et al. 2022

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“…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%

“…The first studies in this domain considered a wide range of thermoactivation temperatures, from as low as 200°C to over 900°C [46,49,60]. Later research has been focused on a narrower range, between 500 and 800°C [19,33,35,43,47,61,62], in order to comprise the phases of C-S-H dehydration and CH dehydroxylation, without relevant decarbonation. 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].…”

Section: Figurementioning

confidence: 99%

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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“…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%

“…Lü et al [20] employed FA to partially replace DCP in the preparation of composite cementitious materials. However, with the dosage increasing from 20% to 50%, the long-term compressive strength decreased from 21.2MPa to 13MPa.…”

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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Binding materials of dehydrated phases of waste hardened cement paste and pozzolanic admixture

Cited by 20 publications

References 7 publications

Short Review on the Application of Recycled Powder in Cement-Based Materials: Preparation, Performance and Activity Excitation

Short Review on the Application of Recycled Powder in Cement-Based Materials: Preparation, Performance and Activity Excitation

Thermoactivated Recycled Cement

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

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