Emmanuel Gallucci

Sika Technology AG · Central Research

The impact of substitution of cement paste with uncalcined clay (bentonite and kaolinite) in the range of 5% by volume of paste on the development of hydration and properties of mortar was investigated. Two issues were addressed, the expected filler effect of the dispersed sub-micron clay particles, and the possible chemical reactivity of the clay....

Recent advances in bridging kinetics and thermodynamics of mineral dissolution have opened new horizons in our understanding of the role of dissolution in cement hydration. Indeed most hydration kinetic regimes of alite can be rationally envisioned from a dissolution perspective. This short note reviews some key findings on dissolution mechanisms a...

The impact of organic compounds on the processing and reactivity of inorganic materials has been a source of inspiration for materials scientists for decades and continues to trigger novel and innovative applications in a broad range of disciplines. However, molecular design of such compounds to reach targeted properties remains challenging, partic...

In this study, a new method to assess early properties of cementitious materials by water-solvent replacement is investigated. Isopropanol was used to replace a part of mixing water of binder paste, limiting the maximum degree of hydration it can achieve. Results of four independent methods (calorimetry, thermo-gravimetric analysis, back-scattered...

We present a multi-model simulation approach, targeted at understanding the behavior of comminution and the effect of grinding aids (GAs) in industrial cement mills. On the atomistic scale we use Molecular Dynamics (MD) simulations with validated force field models to quantify elastic and structural properties, cleavage energies as well as the orga...

Temperature affects the properties of concrete through its effect on the hydration of cement and its associated microstructural development. This paper focuses on the modifications to C-S-H induced by isothermal curing between 5 and 60 degrees C. The results show that as the temperature increases (within the range studied) the C/S ratio of C-S-H ch...

Morphological and topological quantification of complex pore networks is of great relevance for environmental engineering, earth science and industry. Recent developments of 3D imaging techniques such as X-ray microtomography or X-ray microscopy provide an opportunity to perform a comprehensive analysis of the pore network topology. Such an analysi...

Keywords: Mineral Dissolution ; Kinetics Note: Export Date: 1 June 2011, Source: Scopus Reference EPFL-ARTICLE-166447doi:10.1016/j.cemconres.2011.01.021View record in Web of ScienceView record in Scopus Record created on 2011-06-06, modified on 2016-08-09

The microstructural aspects of iron sulfide degradation in dam concrete were investigated by scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS) in both dam concrete samples and laboratory concrete. The results show that iron sulfide inclusions with a diameter of a few micrometers in the aggregates are reactive and appear to...

A BaCO3 slurry, containing radioactive 14C, is produced during the reprocessing of spent nuclear fuel. This slurry is encapsulated in a Portland-blastfurnace slag composite cement. The effect of BaCO3 on the hydration of OPC and Portland-blastfurnace slag cements has been studied in this work. Samples containing a simulant BaCO3 slurry were cured f...

Alkali aggregate reaction (AAR) is known leading to great damage in concrete, both in compressive strength and in durability. In this study, a backscattered scanning electron microscopy with energy dispersive spectroscopy is adopted to diagnose AAR reaction. The results show that the type of AAR reaction and reaction products can be easily identifi...

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

Hydrated Calcium Aluminate Cement (CAC) is known to have a complex microstructure involving different phase assemblages strongly dependant on the temperature. This work presents an experimental approach to study the microstructure of CAC pastes from the first minute of hydration with controlled time–temperature histories up to several months of cur...

The early hydration of alite, in particular the reason for the onset of the induction period, has been a subject of controversy for many decades. Several theories have been proposed, principally the formation of a protective phase inhibiting dissolution or delayed nucleation and growth, but none have successfully taken into account all the experime...

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

An important microstructural aspect of the early hydration of Portland cement (PC) is the formation of a shell of hydration products around cement grains. There is, at present, limited information on the mechanism of formation of the shell and of the chemistry of the phases that constitute the shells. Through the use of STEM imaging of early age hy...

The kinetics of hydration of cementitious materials is sensitive to the mixing procedure. High shear mixing conditions lead to an increase in the kinetics of hydration at early age compared to low shearing conditions such as hand mixing. In this study the effect of mixing speed and procedure was studied on alite and Portland cement in the presence...

An image analysis method has been developed, tested and validated by the Laboratory of Maintenance and Safety of structures and Groupe de Compétences en Traitment de 1'Image et du Signal (MCS-CTIS) for determining the fiber orientation and distribution within fiber cementitious materials. The determination of the fiber orientation and distribution...

The influence of the presence of limestone on the hydration of Portland cement was investigated. Blending of Portland cement with limestone was found to influence the hydrate assemblage of the hydrated cement. Thermodynamic calculations as well as experimental observations indicated that in the presence of limestone, monocarbonate instead of monosu...

The durability of structures made of blended cements lacks of field data (especially sulfate attack), which makes it difficult to fit these new concretes with existing test methods and performance criteria. Most results on sulfate resistance are derived macro-properties (expansion) to the detriment of micro-characteristics (phase assemblage). This...

Deterioration of cementitious materials by sulfate ions is a concern for concrete in contact with ground water (and in a lesser extent sea water) in many parts of Europe, and is an important issue for underground construction identified as a major area for progress in the construction industry. Sulfate resistance relates closely to testing and stan...

This paper presents an in situ study of the hydration of cement pastes in the SEM, made possible by the development of a radical new technology for the investigation of wet samples: the QX capsule from QuantomiX, based on the WETSEM technology, consists of an electron transparent but water and air tight membrane, which allows the examination of cem...

Scanning Electron Microscopy Image Analysis (SEM-IA) was used to quantify the degree of alkali silica reaction in affected microbars, mortar and concrete prisms. It was found that the degree of reaction gave a unique correlation with the macroscopic expansion for three different aggregates, stored at three temperatures and with two levels of alkali...

The distribution and morphology of CH particles in various cementitious systems was investigated to determine which parameters influence their nucleation and growth. Morphological image analysis of SEM-BSE images of polished cross-sections was used to measure CH distribution, particle size and shape within the microstructure. It was observed that C...

Cement pastes aged from 1 to 60 days were studied using synchrotron microtomography on the MS-X04SA beam line at the Swiss Light Source. This allowed three dimensional images to be obtained with a resolution approaching that of backscattered electron images in the SEM. From these images, several features can be extracted and studied, both quantitat...

Cement is used to condition waste materials and for the construction and backfilling of repositories for low-and intermediate-level radioactive waste. In this study, Ni uptake by hardened cement paste has been investigated with the aim of improving our understanding of the immobilization process of Ni(ll) in cement on the microscale. Information on...

X-ray diffraction (XRD) is a powerful technique for the study of crystalline materials. The technique of Rietveld refinement now enables the amounts of different phases in anhydrous cementitious materials to be determined to a good degree of precision. This paper describes the extension of this technique to a pilot study of the hydration of a typic...

Although tungstates are now well known as laser Raman shifters, their physicochemical properties (especially the vibrational ones) were not often studied. We have carried out a comprehensive and systematic study of tungstate Raman spectra, thanks to which, structural and vibrational properties could be correlated. It was shown that the Raman scatte...

KY(WO4)2 single crystals are studied for their civilian applications as laser host materials. In order to determinate the best growth conditions and their reproducibility, the investigation of the K2O-Y2O3-WO3 ternary system was undertaken. It was shown that the compound is not stoichiometric: its stability domain and crystallization field were def...

Pure and Yb3+-doped Al2(WO4)3 single crystals of good quality and purity were grown using the Bridgman–Stockbarger method. This is the first time that Al3+ is substituted with big cations such as lanthanide ones. Undoped, this compound has attractive properties as a non-linear χ(3) material (ν1=1049 cm−1). When doped with Yb3+, it also has interest...

A neutron diffraction investigation of the non-stoichiometric α-KYW2O8 phase was carried out in order to study the influence of the compound composition on its structural properties. Three samples were analysed and refined using the Rietveld method. The best agreement factors were obtained for the composition at the center of the solid solution fie...

KY(WO4)2 single crystals were grown by the Bridgman–Stockbarger method. Due to the existence of two polymorphic forms the elaboration was performed below the transition line using different fluxes chosen in the WO3–Y2O3–K2O ternary system. The compound is not stoichiometric and the crystal composition depends on the flux. We verified that these dif...

In order to determinate the best crystal growth conditions for KY(WO4)2 single-crystals, the investigation of the K2O-Y2O3-WO3 ternary system was undertaken by the study of three isoplethic sections (K2W4O13-Y2O3, K2WO4-KY(WO4)2, K2W2O7-KY(WO4)2). The stability domain and the crystallisation field of the compound were then defined: KY(WO4)2 is not...

KY(WO4)(2) is known as the most popular third order optically non linear tungstate. Although it is said to be stoichiometric and to melt congruently, single-crystals couldn't be obtained by the Laser Heated Pedestal Growth method. In order to determine the best conditions of crystallization of this compound, the study of its stability domain was un...

RÉSUMÉ : La température de cure a un rôle majeur sur le développement des propriétés mécaniques du béton. A jeune age, tout semble montrer que c'est simplement l'augmentation du degré de réaction qui est responsable des résistances plus élevées à haute température. Les résultats obtenus dans le cadre de cette étude montrent clairement que les mécan...