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Showing 1 to 20 of 52 for “"C-S-H"”.
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Synthesis and nano-mechanical characterization of calcium silicate hydrate (C-S-H)
Calcium Silicate Hydrate (C-S-H) constitutes two-thirds of hydrated cement paste by volume. Having a better understanding of the mechanical properties of C-S-H will significantly aid in future effort for making concrete by design' for specific applications such as blast resistance. C-S-H is an …
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The nanostructure and degradation of C-S-H in Portland and blended cements
The microstructure and composition of water and KOH activated hardened pastes of commercial neat white Portland cement (WPC) and blends with 30% fly ash (PFA) have been characterised using a multi-technique approach, With particular emphasis on the nature of the C-S-H phase. The neat and fly ash …
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Struktur, Eigenschaften und quantitative Rietveldanalyse von hydrothermal kristallisierten Calciumsilikathydraten (C-S-H-Phasen)
In der vorliegenden Arbeit wurden die Synthese, Die Kristallisation und die auftretenden Paragenesen technisch wichtiger, kristalliner Verbindungen im System CaO-SiO2-H2O untersucht. Damit wurde eine Grundlage für sysstematische Entwicklung bzw. Verwertung von auf C-S-H-Phasen basierenden …
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Chemomechanics of calcium leaching of cement-based materials at different scales : the role of CH-dissolution and C-S-H degradation on strength and durability performance of materials and structures
Calcium leaching is a durability threat for cement-based materials employed in critical infrastructures, such as Nuclear Waste Storage Systems. This thesis presents a comprehensive study of the material and structural consequences of calcium leaching on the strength and deformation behavior of …
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Synthesis and Multi-Scale Characterization of Calcium Silicate Hydrate at Multiple CaO/SiO2 Mixture Ratios
Calcium Silicate Hydrate (C-S-H) is the primary binding agent that is responsible for setting and hardening, strength, dimensional stability, and durability of Portland cement paste. Although Portland cement hydration produces C-S-H, Calcium hydroxide (CH), ettringite, and other hydration products …
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The nanogranular origin of concrete creep : a nanoindentation investigation of microstructure and fundamental properties of calcium-silicate-hydrates
With an annual per capita consumption of one cubic meter, concrete is the most manufactured material on Earth. But concrete subject to sustained load creeps, like chewing gum, at a rate that deteriorates the durability and lifespan of concrete infrastructure. While it is generally agreed that …
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Molecular Crosslinking of Calcium-Silicate-Hydrate with Organosilanes: Toward Engineering of Cementitious Matrices with High Thermal Resistance
This research work is focused on the development of a novel approach aiming at improving the thermal resistance of cementitious matrices. The proposed approach utilizes the molecular scale crosslinking phenomena in which the galleries of inorganic calcium-silicate-hydrate (C-S-H), the main product …
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Hierarchical modeling of structure and mechanics of cement hydrate
With an annual production of more than 20 billion tons a year, concrete continues to be the world's dominating manufacturing material for a foreseeable future. However, this ubiquity comes with a large ecological price as concrete stands as the third largest culprit to the torrent of CO2 after …
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Investigation of microstructure of disordered colloidal systems by small-angle scattering
Small-angle scattering (SAS) has been widely applied to study the microstructure of colloidal systems. Although colloids cover a wide range of materials, in general they can simply be viewed as basic building particles arranging themselves, according to their interaction, in a continuous medium. In …
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Silicon-29 and oxygen-17 nuclear magnetic resonance investigation of the structure of calcium-silicate-hydrate
This thesis investigates the structure of calcium-silicate-hydrate (C-S-H), a major hydration product of Portland cement, using primarily $\sp{29}$Si and $\sp{17}$O MAS and $\sp1$H-$\sp{29}$Si CPMAS NMR, XRD, chemical and thermal analysis. It presents a comprehensive defect-tobermorite structural …
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Characterization of calcium-silicate-hydrate and calcium-alumino-silicate-hydrate
The primary objectives of this thesis were to synthesize calcium silicate hydrate (C-S-H) and calcium aluminosilicate hydrate (C-A-S-H) and characterize their structures with varying Ca/Si ratios and aluminum content. As a secondary objective, carbonation behavior in synthesized C-S-H was studied. …
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Calcium-Silicate-Hydrate in cementitious systems : chemomechanical correlations, extreme temperature behavior, and kinetics and morphology of in-situ formation
Concrete, the second most used material on the planet, is a multi-scale heterogeneous material. A fundamental component known as Calcium-Silicate-Hydrate which forms from the reaction between cement and water is the binding phase in concrete. Curiously, this is the least understood component of …
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Studies on hydration water dynamics and microstructure of synthetic cement
The mechanical properties of cement pastes depend strongly on their porosities. In a wet paste, the porosity links to the free water volume after hydration. Structural water which presents in the solid phase, constrained water absorbed on the surface of the pores and free water in the center of the …
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Investigation of Shrinkage Mechanisms in Hydrated and Carbonated Tricalcium Silicate Systems
Shrinkage-weight loss measurements, together with microstructural determinations, were obtained on fully hydrated tricalcium silicate (C(,3)S) paste that had original water/cement (w/c) ratios of 0.4 and 0.6. The surface area of the calcium silicate hydrate (C-S-H) phase determined by water is …
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Influence of calcium-(alumino)-silicate-hydrate nanostructure on viscoelastic behavior
Viscoelasticity in concrete has been studied since the early 20th century with continuously advancing technology and methods. Currently, calcium-silicate-hydrate (C-S-H) is thought to be the phase responsible for viscoelasticity in concrete. Advances in small-scale mechanical testing in the past …
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Scaling the rock : a micromechanical model for the elastic properties of hydrated cement pastes
Cement is the most widely produced material worldwide. However, the understanding on how its nanoscale composition affect its microscale mechanical properties is limited. In this thesis, a micromechanical model for the purpose of cement hydration simulation was developed and tested using …
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Probing water properties and cationic exchange in calcium-silicate-hydrate : an atomistic modeling study
Two problems related to the assessment of the performance of cementitious materials in the nuclear fuel cycle are investigated by means of atomistic simulations. The first is the structural and dynamic nature of water confined in the nano-pores of the highly disordered calcium-silicate-hydrate …
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Možnosti využití látek s možnou pucolánovou aktivitou pro přípravu směsných cementů
Směsný cement; kalcinace; dehydroxylace, břidlice, vápenec, pucolánová aktivita, modifikovaný Chapelle test, metakaolinit, fylosilikáty, jílové minerály, kaolinit, C–S–H gel
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Investigation on the Mechanical, Microstructural, and Electrical Properties of Graphene Oxide-Cement Composite
Nanotechnology refers to the use of the materials or particles ranging from a few nanometers (nm) to 100 nanometers (nm) in a wide range of applications. Use of nanomaterials in cement composite to enhance the mechanical properties, fracture toughness and other functionalities has been studied for …
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Étude de la formation de l'ettringite secondaire avec divers types de sulfates alcalins et dosages en gypse
Dans cette étude, nous avons étudié la formation de l'ettringite secondaire selon divers types de sulfates alcalins et dosages en gypse sur des mélanges effectués avec des ciments broyés en laboratoire. Les mélanges avec de l'aphtitalite produisent dans la majorité des cas moins d'expansion et ceux …
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