Particle characteristics of calcined clays and limestone and their impact on early hydration and sulfate demand of blended cement

Maier, Matthias; Sposito, Ricarda; Beuntner, Nancy; Thienel, Karl‐Christian

doi:10.1016/j.cemconres.2022.106736

Cited by 43 publications

(24 citation statements)

References 61 publications

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“…Despite considerable differences, the physical filler effect seemed to be comparable for all NCCs. Maier et al [ 24 ] assumed the agglomeration effects of CC particles as one of the reasons for the different behavior of CC compared to limestone powders. Such agglomerations could also be a reason for the small differences in silicate reaction among the NCCs.…”

Section: Resultsmentioning

confidence: 99%

“…The great potential of CC is based on physical effects such as the filler effect [ 22 , 23 ] and the adsorption of ions from the pore solution [ 24 ], as well as on the release of silicon and aluminum ions at an early time of hydration [ 15 , 25 ]. This is evidenced by a strong influence of the early clinker hydration in CC blended systems [ 26 , 27 , 28 ].…”

Section: Introductionmentioning

confidence: 99%

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Calcined Clays from Nigeria—Properties and Performance of Supplementary Cementitious Materials Suitable for Producing Level 1 Concrete

2023

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In this work, four naturally occurring (two kaolinite-rich and two smectite-rich) clay samples were collected from different areas around the Ashaka cement production plant, located in Gombe State, Nigeria and calcined in a laboratory. The mineralogical characterization of the clays was carried out by XRD. The hydration kinetics of the calcined clay–cement systems were monitored by isothermal calorimetry. Workability was determined using the flow table method. The reactivity of the calcined clays was determined from the solubility of Si and Al ions and the strength activity index. All calcined clays studied met the requirements of ASTM C618 for the use of natural pozzolans as a partial replacement for hydraulic cement. The metasmectite clays yielded a higher specific surface area, increased water demand, and less reactive Si and Al ions compared to the metakaolin clays. The two calcined clay groups require the addition of superplasticizer to achieve a workability class similar to the Portland cement mortar system. They can be used to replace Portland cement at replacement levels of up to 45%, in combination with limestone powder to form an LC3 cement, thereby achieving at least a “Level 1” reduction in greenhouse gas emissions.

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Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Calcined Clays from Nigeria—Properties and Performance of Supplementary Cementitious Materials Suitable for Producing Level 1 Concrete

2023

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“…This difference is attributed to the physical action (filling effect) produced by the nano-CaCO 3 . Generally, this filling effect is divided into three different mechanisms: dilution, accelerated dissolution, and nucleation. , First, when nano-CaCO 3 is added, the cementitious material content in the UHPC decreases correspondingly, thereby increasing the effective water–cement ratio of the mixture. Second, the particle size of the nano-CaCO 3 is smaller, and the spacing between the cementitious material particles decreases with the presence of the nano-CaCO 3 .…”

Section: Discussionmentioning

confidence: 99%

Preparation of Nano Calcite by the Carbon Capture Technology to Improve the Performance of Ultrahigh-Performance Concrete Containing Calcined Clay

Han

Lin

Wang

2023

ACS Sustainable Chem. Eng.

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Ultrahigh-performance concrete (UHPC) has been widely used because of its outstanding mechanical properties and durability. However, the high demand for cement leads to higher carbon dioxide emissions. In this study, solid nano-calcium carbonate (nano-CaCO3) derived from gaseous carbon dioxide is used as an admixture to UHPC, which indirectly realizes the capture and storage of carbon dioxide by UHPC. This study investigated the effect of the nano-CaCO3 on the macroscopic and hydration properties of the UHPC, characterized its microstructure, and calculated the carbon dioxide emission. The experimental and analytical results show that the mechanical properties and durability of the UHPC are significantly improved with the nano-CaCO3 addition. Microscopic experimental analysis reveals that the presence of nano-CaCO3 significantly increases the hydration rate of the mixture. During the middle and late stages, the nano-CaCO3 reacted with the aluminum in Hwangtoh clay to form monocarboaluminate, which made the UHPC internal structure denser. Furthermore, the calculation results show that the nano-CaCO3 has a significant effect on reducing the UHPC CO2 emission, owing to the CO2 capture and sequestration during the conversion of gaseous CO2 into solid nano-CaCO3.

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“…Álvarez-Pinazo et al [17] used GSAS to conduct the QPA of in-situ synchrotron XRD of sulfobelitic cements. Maier et al [106] used Profex-BGMN to evaluate laboratory in-situ XRD data for LC 3 systems. However, most software only refine individual XRD patterns, making the QPA very time-consuming.…”

Section: Refinement Strategiesmentioning

confidence: 99%

In-situ laboratory X-ray diffraction applied to assess cement hydration

Matos

Neto

Jansen

et al. 2022

Cement and Concrete Research

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Particle characteristics of calcined clays and limestone and their impact on early hydration and sulfate demand of blended cement

Cited by 43 publications

References 61 publications

Calcined Clays from Nigeria—Properties and Performance of Supplementary Cementitious Materials Suitable for Producing Level 1 Concrete

Calcined Clays from Nigeria—Properties and Performance of Supplementary Cementitious Materials Suitable for Producing Level 1 Concrete

Preparation of Nano Calcite by the Carbon Capture Technology to Improve the Performance of Ultrahigh-Performance Concrete Containing Calcined Clay

In-situ laboratory X-ray diffraction applied to assess cement hydration

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