Concept

Sulfate de sodium

Publications associées (27)

Contradict mechanism of long-term magnesium and sodium sulfate attacks of nano silica-modified cement mortars - Experimental and thermodynamic modeling

The mechanisms of external sulfate attack on cement mortars containing nano silica have been studied under full immersion conditions after 3 years. The sulfate degradation processes were compared between sodium sulfate and magnesium sulfate solutions with ...

Elsevier Sci Ltd2024

Crystal, defect, and morphology engineering of porous two-dimensional materials for ionic separation

Heng-Yu Chi

Ordered two-dimensional (2D) materials hosting Å-scale pores are highly promising for enabling challenging separation, thanks to well-defined pore geometry resulting in tight confinement of ions when hosted inside the pore. In addition, the 2D nature of th ...

EPFL2024

Effect of different ions on dissolution rates of silica and feldspars at high pH

Karen Scrivener, Mahsa Bagheri

The dissolution kinetics of silica-containing minerals in aggregates influences strongly the process of ASR in concrete. In this paper, the effect of different ions on the dissolution rates of SiO2 (amorphous and quartz) and feldspars at high pH values was ...

Pergamon-Elsevier Science Ltd2022

Insights on the role of alumina content and the filler effect on the sulfate requirement of PC and blended cements

Karen Scrivener, Franco Alberto Zunino Sommariva

Understanding the mechanism controlling the sulfate requirement of blended cements is crucial for a successful deployment of these technologies towards a more sustainable industry. Particularly, clarification regarding the role of alumina content on the su ...

Pergamon-Elsevier Science Ltd2022

Strength-promoting mechanism of alkanolamines on limestone-calcined clay cement and the role of sulfate

Karen Scrivener, François Henri Avet, Xuerun Li, Wilasinee Hanpongpun, Hong Huang

This paper reports the strength-promoting mechanism of alkanolamines on limestone-calcined clay cement (LC3). The hydration kinetics, phase formation and microstructure of LC3 with triethanolamine (TEA) or triisopropanolamine (TIPA) were investigated. TEA ...

Pergamon-Elsevier Science Ltd2021

Factors influencing the sulfate balance in pure phase C3S/C(3)A systems

Karen Scrivener, Franco Alberto Zunino Sommariva

Understanding the sulfate balance mechanism of cement is needed for an effective use of sustainable blended cements. Pure phase systems allow to study the interaction between sulfate and each of the phases involved in early age hydration separately. This p ...

Pergamon-Elsevier Science Ltd2020

Limestone calcined clay cements (LC3): raw material processing, sulfate balance and hydration kinetics

Franco Alberto Zunino Sommariva

Limestone calcined clay cements (LC3) are blended cements that combine clinker, limestone, calcined clay and gypsum. The availability of the materials required to produce LC3 and the good performance that it achieves, makes LC3 suitable as a sustainable re ...

EPFL2020

Ultrafast carbothermal reduction of silica to silicon using a CO2 laser beam

Jaeki Jeong

We report the extraction of silicon via a carbothermal reduction process using a CO2 laser beam as a heat source. The surface of a mixture of silica and carbon black powder became brown after laser beam irradiation for a few tens of seconds, and clear peak ...

NATURE RESEARCH2020

Biogeochemical Cycling by a Low-Diversity Microbial Community in Deep Groundwater

Rizlan Bernier-Latmani, Manon Frutschi, Emma Bell

Olkiluoto, an island on the south-west coast of Finland, will host a deep geological repository for the storage of spent nuclear fuel. Microbially induced corrosion from the generation of sulphide is therefore a concern as it could potentially compromise t ...

Frontiers Media SA2018

Room temperature C(sp(2))-H oxidative chlorination via photoredox catalysis

Xile Hu, Lei Zhang

Photoredox catalysis has been developed to achieve oxidative C-H chlorination of aromatic compounds using NaCl as the chlorine source and Na2S2O8 as the oxidant. The reactions occur at room temperature and exhibit exclusive selectivity for C(sp(2))-H bonds ...

Royal Soc Chemistry2017

Methane Production from Microalgae via Continuous Catalytic Supercritical Water Gasification: Development of Catalysts and Sulfur Removal Techniques

Gaël Peng

This doctoral thesis aims at demonstrating the technical feasibility of methane production from microalgae via continuous catalytic supercritical water gasification (CSCWG). This work focuses on three different research approaches: (i) assessment and impro ...

EPFL2015

Degradation mechanism of slag blended mortars immersed in sodium sulfate solution

Wei Sun, Karen Scrivener

Additions of slag are usually considered to give cementitious materials which perform well in sulfate bearing environments. This paper compares the deterioration of slag cement blends to those of plain Portland cement and demonstrates that this occurs more ...

Pergamon-Elsevier Science Ltd2015

Methods to determine hydration states of minerals and cement hydrates

Karen Scrivener

This paper describes a novel approach to the quantitative investigation of the impact of varying relative humidity (RH) and temperature on the structure and thermodynamic properties of salts and crystalline cement hydrates in different hydration states (i. ...

Pergamon-Elsevier Science Ltd2014

Application of Image Analysis Based on SEM and Chemical Mapping on PC Mortars under Sulfate Attack

Wei Sun

The degradation mechanisms of cementitious materials exposed to sulfate solutions have been controversial, despite considerable research. In this paper, two methodologies of image analysis based on scanning electron microscope and chemical mapping are used ...

Journal Wuhan Univ Technology2014

Enzyme and Acid Deconjugation of Plasma Sulfated Metanephrines

Sandrine Gerber

Background: Total (i.e. free + sulfated) metanephrines in plasma is a biomarker for the diagnosis of pheochromocytoma/paraganglioma. Sulfated metanephrines must be completely deconjugated by perchloric acid hydrolysis or sulfatase treatment prior to analyt ...

Elsevier2014

Mechanism of expansion of mortars immersed in sodium sulfate solutions

Wei Sun, Karen Scrivener

The mechanisms behind the expansion of samples immersed in solutions containing sulfate ions have been controversial. Expansion is believed to originate in the formation of ettringite, but it is not possible to find any direct correlation between these two ...

Pergamon-Elsevier Science Ltd2013

Influence of bicarbonate ions on the deterioration of mortar bars in sulfate solutions

Karen Scrivener

This work investigates the influence of bicarbonate ions on the deterioration of cementitious material exposed to sulfate ions. Mortars based on a CEM I and on a CEM III/B cement were investigated. Experimental investigations were compared to thermodynamic ...

Pergamon-Elsevier Science Ltd2013

On the relevance of volume increase for the length changes of mortar bars in sulfate solutions

Karen Scrivener

The ingress of sulfate ions into cementitious materials leads to the formation of ettringite, gypsum and other phases. The increase in solid volume through the formation of these phases is often assumed to be the only reason for expansion. In this paper we ...

Pergamon-Elsevier Science Ltd2013

Deterioration of mortar bars immersed in magnesium containing sulfate solutions

Karen Scrivener

Mortars prepared with a CEM I and a CEM III/B binder were investigated in different magnesium sulfate solutions. The main deterioration mechanism for the CEM I was expansion, while surface erosion was dominant for CEM III/B. The presence of sodium, potassi ...

Springer Verlag2013

Modelling Hydration Kinetics of Cementitous Systems

Aditya Kumar

The modeling platform µic has been extended to study the hydration of cement based systems. It is shown that the hydration kinetics of alite can be described through the implementation of two mechanisms: a solution controlled dissolution (SCD) mechanism fo ...

EPFL2012