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Concept

Sodium silicate

Publications associées (25)

The role of Zn in C-S-H atomic structure, nucleation and growth

Anna Morales Melgares

The most promising solution towards cementitious materials with a lower carbon footprint is the partial substitution of the clinker by supplementary cementitious materials (SCMs) such as fly ash, blast furnace slag, limestone and calcined clays. The produc ...

EPFL2023

A method for the reliable and reproducible precipitation of phase pure high Ca/Si ratio (>1.5) synthetic calcium silicate hydrates (C-S-H)

Karen Scrivener, Paul Bowen, Maya Nicole Harris

Various methods have been developed to synthesize C-S-H; however, these methods have only allowed for the successful production of pure-phase C-S-H with Ca:Si of 1.5 or less. Attempts to form higher Ca:Si ratios by these methods gives C-S-H (Ca:Si 1.5 or l ...

Pergamon-Elsevier Science Ltd2022

Insights on chemical and physical chloride binding in blended cement pastes

Karen Scrivener, Fabien Jacques Michel Georget, William Wilson

This study investigates chloride binding in blended cement pastes exposed to 0.5 M NaCl solutions (with and without pH adjustment) using X-ray diffraction and energy-dispersive X-ray spectroscopy image analysis (edxia). The aim is to better understand the ...

Pergamon-Elsevier Science Ltd2022

Liquid metal infiltration of silicon based alloys into porous carbonaceous materials. Part I: Modelling of channel filling and reaction phase formation

Ludger Weber, Manoj Kondibhau Naikade

A relation for an adequate pore fraction needed to obtain residual Si and C free composites via reactive Si-X alloy infiltration is presented. The volume ratio of SiC and carbonaceous phase, the composition of the infiltrating liquid and the apparent densi ...

ELSEVIER SCI LTD2022

Effect of alkali hydroxide on calcium silicate hydrate (C-S-H)

Karen Scrivener, Émilie Michèle L'Hôpital, Yu Yan

This paper investigates the effect of KOH and NaOH on C-S-H structure and solubility. Both KOH and NaOH have a similar effect, they increase pH values and silicon concentrations, and decrease calcium concentrations. At higher alkali hydroxide concentration ...

Pergamon-Elsevier Science Ltd2022

Iron incorporation in synthetic precipitated calcium silicate hydrates

David Lyndon Emsley, Paul Bowen, Brennan James Walder, Jirawan Siramanont

Effect of Fe3+ on the precipitation of synthetic calcium silicate hydrates (C-S-H) under controlled conditions has been evaluated. Using extremely basic either initial calcium nitrate or sodium silicate solutions (pH > 11), incipient formation of ferrihydr ...

Pergamon-Elsevier Science Ltd2021

The effect of alkali hydroxides and equilibration time on Al uptake by calcium silicate hydrates (C-S-H)

Sonya Barzgar

Cement production accounts for approximately 8% of man-made CO2 emissions. Lowering these CO2 emissions is currently one of the most important and urgent research topics within the cement community. To reduce these emissions, the Portland cement (PC) is pa ...

EPFL2021

Kinetic processes in the high-temperature pressure-infiltration of Al into Al2O3

Andreas Mortensen, Ludger Weber, Marta Fornabaio, Gionata Schneider

We explore the influence (i) of the interaction between aluminium and alumina, and (ii) of sodium impurities present in Bayer alumina, on the pressure infiltration of alumina particle preforms with molten aluminium. At 1000°C or above, although the alumini ...

2020

Nanoparticles and method for producing uniform silicate-based nanoparticles

Paul Bowen, Abhishek Kumar

Nanoparticles and method for producing uniform silicate-based nanoparticles are disclosed. The method comprises a step of injecting into tubular branched elements comprising static mixers a first aqueous solution comprising a water-soluble silicate compoun ...

2018

Hardening acceleration/hardening retardation composition for building materials

Paul Bowen, Abhishek Kumar

Provided herein is a composition for use as a hardening regulator, e.g. hardening accelerator or hardening retarder, for building materials, as well as methods for producing thereof. The composition is characterized by a biphasic nature in which solid calc ...

2018

Investigating Earth's Formation History Through Copper and Sulfur Metal-Silicate Partitioning During Core-Mantle Differentiation

James Badro

Identifying extant materials that act as compositional proxies for Earth is key to understanding its accretion. Copper and sulfur are both moderately volatile elements; however, they display different geochemical behavior (e.g., phase affinities). Thus, in ...

AMER GEOPHYSICAL UNION2018

Active apolar doping determines routes to colloidal clusters and gels

Ignacio Pagonabarraga Mora

Collections of interacting active particles, self-propelling or not, have shown remarkable phenomena including the emergence of dynamic patterns across different length scales, from animal groups to vibrated grains, microtubules, bacteria, and chemicalor f ...

National Academy of Sciences2018

Alkali uptake in calcium alumina silicate hydrate (C-A-S-H)

Karen Scrivener, Émilie Michèle L'Hôpital

Uptake of the alkalis K and Na by calcium silicate hydrate (C-S-H) and calcium alumina silicate hydrate (C-A-S-H) of molar Ca/Si ratios = 0.6 to 1.6 and molar Al/Si ratio = 0 or 0.05 has been studied at 20 degrees C. Alkalis are thought to be bound in the ...

Pergamon-Elsevier Science Ltd2016

Influence of calcium to silica ratio on aluminium uptake in calcium silicate hydrate

Karen Scrivener, Émilie Michèle L'Hôpital

Aluminium uptake in calcium silicate hydrate (C-S-H) was studied at different Ca/Si ratios from 0.6 to 1.6 at 20 degrees C. Aluminium incorporation in C-S-H depends on the total amount of aluminium present in the sample. At low Al/Si ratio (

Pergamon-Elsevier Science Ltd2016

A new quantification method based on SEM-EDS to assess fly ash composition and study the reaction of its individual components in hydrating cement paste

Karen Scrivener, Cyrille Dunant, Mohsen Ben Haha, Pawel Tadeusz Durdzinski

Calcareous fly ashes are high-potential reactive residues for blended cements, but their qualification and use in concrete are hindered by heterogeneity and variability. Current characterization often fails to identify the dominant, most reactive, amorphou ...

Pergamon-Elsevier Science Ltd2015

Alkali Activation of AOD Stainless Steel Slag Under Steam Curing Conditions

Ruben Anton Snellings

Crystalline argon oxygen decarburization slag, in powdery form, was investigated for its hydration potential by alkali activation and curing at 80 degrees C. Na-silicate and K-silicate of the same modulus were used as activators. Isothermal calorimetry at ...

Wiley-Blackwell2015

The influence of sodium salts and gypsum on alite hydration

Karen Scrivener, Berta Mota Gassó

This work aims to clarify the impact of alkali and sulfate on the hydration kinetics and microstructural development of alite. The plain alite system is compared to systems with addition of: i) gypsum, ii) Na2SO4, iii) NaOH plus gypsum and iv) NaOH. In all ...

Pergamon-Elsevier Science Ltd2015

Control of groundwater pH during bioremediation: Improvement and validation of a geochemical model to assess the buffering potential of ground silicate minerals

David Andrew Barry, Christof Holliger, Alessandro Brovelli, Elsa Marina Lacroix

Accurate control of groundwater pH is of critical importance for in situ biological treatment of chlorinated solvents. The use of ground silicate minerals mixed with groundwater is an appealing buffering strategy as silicate minerals may act as long-term s ...

Elsevier2014

Use of silicate minerals for pH control during reductive dechlorination of chloroethenes in batch cultures of different microbial consortia

David Andrew Barry, Christof Holliger, Alessandro Brovelli, Elsa Marina Lacroix

In chloroethene-contaminated sites undergoing in situ bioremediation, groundwater acidification is a frequent problem in the source zone, and buffering strategies have to be implemented to maintain the pH in the neutral range. An alternative to conventiona ...

American Society for Microbiology2014

Aluminium and alkali uptake in calcium silicate hydrates (C-S-H)

Émilie Michèle L'Hôpital

Calcium silicate hydrate (C-S-H) is the main hydrate phase in Portland cements. Its composition varies depending on the Ca/Si ratio and on the presence of other ions such as aluminium (called CA- S-H) or alkalis. This thesis aimed to study the compositi ...

EPFL2014