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Peysson, Sandrine. "Contribution à l'étude de la Stabilisation de Déchets par du Ciment Sulfo-alumineux". Lyon, INSA, 2005. http://theses.insa-lyon.fr/publication/2005ISAL0008/these.pdf.
Pełny tekst źródłaCalcium sulfoaluminate cement is mainly composed of yeelimite known to be a precursor of ettringite formation. Ettringite is able to incorporate several heavy metals by isomorphous substitutions without altering its crystalline structure. The design of a binder required for immobilising heavy metals was undertaken. The hydration study of clinker, and cement containing 4 amounts of gypsum has been carried out by means of XRD, DTA and IR spectrometry. It was pointed out that the addition of gypsum enhances hydration. Two binders were selected : 80/20 and 70/30. The immobilisation of 7 pollutants was very successfull. Nevertheless, damages appeared with the binder 70/30 containing sodium chromate and dichromate : sodium caused activation of yeelimite reactivity and important dissolution of gypsum leading to important ettringite production. With a great amount of gypsum (30 %), dissolution led to secondary ettringite formation which damaged the hardened paste. Adding polyol enhances the retention of sodium chromate. On the other hand, the immobilisation of two types of weakly radioactive wastes supplied by CEA has been made. Results obtained in terms of setting time, compressive strength and leaching were excellent
Peysson, Sandrine Pera Jean Ambroise Jean. "Contribution à l'étude de la Stabilisation de Déchets par du Ciment Sulfo-alumineux". Villeurbanne : Doc'INSA, 2005. http://docinsa.insa-lyon.fr/these/pont.php?id=peysson.
Pełny tekst źródłaBerger, Stéphane. "Étude des potentialités des ciments sulfo-alumineux bélitiques pour le conditionnement du zinc : de l’hydratation à la durabilité". Thesis, Lille 1, 2009. http://www.theses.fr/2009LIL10140/document.
Pełny tekst źródłaCalcium silicate cements are widely used for low- and intermediate-level radioactive waste conditioning. However, wastes produced by nuclear activities are very diverse and some of their components may chemically react with cement phases. For instance, ashes resulting from the incineration of technological wastes including neoprene and polyvinylchloride may contain substantial amounts of soluble zinc chloride. This compound is known to strongly delay or inhibit Portland cement setting. One approach to limit adverse cement-waste interactions is to select a binder showing a better compatibility with the waste while keeping cement matrix advantages (low cost, simple process, hydration with water provided by the waste…).This work thus investigates the potential of calcium sulfoaluminate cement for zinc ZnII immobilization. Four aspects were considered: hydration (kinetics and products formed), properties of hydrated binders, mechanisms of zinc retention and durability of the cement pastes (based on leaching experiments and modelling). The influence of three main parameters was assessed: the gypsum content of the cement, the concentration of ZnCl2 and the thermal evolution at early age.It follows that materials based on a calcium sulfoaluminate cement containing 20% gypsum are interesting candidates for zinc ZnII stabilization/solidification: there is no delay in hydration, mineralogy of the hydrated phases is slightly dependent on thermal history, mechanical strength is high, dimensional changes are limited and zinc ZnII is well immobilized, even if the cement paste is leached by pure water during a long period (90 d)
Berger, Stéphane. "Etude des potentialités des ciments sulfo-alumineux bélitiques pour le conditionnement du zinc De l'hydratation à la durabilité". Phd thesis, Université des Sciences et Technologie de Lille - Lille I, 2009. http://tel.archives-ouvertes.fr/tel-00595609.
Pełny tekst źródłaChampenois, Jean-Baptiste. "Etude de l’hydratation des ciments sulfo-alumineux par des solutions de borate de sodium : de la spéciation du bore au retard à l'hydratation". Thesis, Montpellier 2, 2012. http://www.theses.fr/2012MON20252/document.
Pełny tekst źródłaIn the primary circuit of pressurized water reactors, boron helps controlling the fission reactions. The treatment of this solution produces aqueous low-level or intermediate-level and short lived radioactive with a high boron concentration (up to 1 to 3 mol/L). Stabilization/solidification of such wastes with calcium silicate cement is complicated by the strong retarding effect of borate ions on cement hydration. A calcium hydroxide addition is required to precipitate borate ions into hexahydroborite. With this approach, the hydration delay is limited, but not suppressed. Besides, hexahydroborite is unstable in the cement paste and is progressively converted into a hydrated calcium boroaluminate phase. Another strategy may consist in using belite calcium sulfoaluminate cement with high ye'elimite content. During hydration, this binder forms indeed large amounts of AFm and/or AFt phases which can incorporate borate ions into their structure.In this work, hydration of calcium sulfoaluminate cement by borated solutions was investigated at early age, and over a 2-year period, in order to determine the influence of a set of parameters (boron concentration and pH of the waste, gypsum content of the cement) on the hydration rate of the binder, on the phase assemblage formed, and on the properties of the resulting material (mechanical strength, volume change). An analytical approach was adopted, based on a progressive increase in the complexity of the investigated systems. The focus was successively placed on the speciation of boron in alkaline solution, on the study of the phases formed within the {CaO, B2O3, Na2O, H2O}, {CaO, B2O3, Al2O3, H2O} and {CaO, Al2O3, B2O3, SO3, H2O} systems, and on the characterization of cement pastes prepared with a borate solution which mimicked the waste. The experimental approach was completed by thermodynamic modelling using a database specially developed for the needs of the study. Gypsum appears to play a key role in controlling the reactivity of cement. The gypsum addition sets, by an indirect mechanism, the interstitial solution pH at a value close to 11, which promotes the precipitation of a poorly crystallized borated compound, ulexite. Dissolution of the anhydrous phases is strongly slowed down until the exhaustion of gypsum, and major delays are observed. Without any gypsum, the hydration delay is shorter. Under these conditions, the pore solution pH reaches higher values after mixing. Ulexite is consequently quickly destabilized. Borate anions are then incorporated into a mixed borate/sulphate AFt type phase. It appears that calcium sulfoaluminate cements with low gypsum contents should be recommended to solidify borated solutions
Dhoury, Mélanie. "Influence des ions lithium et borate sur l'hydratation de ciments sulfo-alumineux : application au conditionnement de résines échangeuses d'ions boratées". Thesis, Montpellier, 2015. http://www.theses.fr/2015MONTS014/document.
Pełny tekst źródłaIn pressurized water reactors, a solution of boric acid, the pH of which is controlled by the addition of lithium hydroxide, is injected in the primary circuit. Boron acts as a neutron moderator and helps controlling the fission reactions. The primary coolant is purified by flowing through columns of ion exchange resins. These resins are periodically renewed and constitute a low-level radioactive waste. In addition to radionuclides, they mainly contain borate and lithium ions. They are currently encapsulated in an organic matrix before being stored in a near-surface repository. An evolution of the process is considered, involving the replacement of the organic matrix by a mineral one.In this PhD study, the potential of calcium sulfoaluminate cements (CSAC) to solidify / stabilize borated resins in the presence of lithium is investigated. These binders have the advantage to form hydrates which can incorporate borate ions in their structure, and their hydration is less retarded than that of Portland cement.An analytical approach is adopted, based on a progressive increase in the complexity of the investigated systems. Hydration of ye'elimite-rich CSAC is thus successively investigated in the presence of (i) lithium salts, (ii) lithium hydroxide and sodium borate, and (iii) lithium hydroxide and borated ion exchange resins. The experimental investigation is supplemented by thermodynamic modelling using a database specially developed for the needs of the study.Lithium ions are shown to accelerate CSAC hydration by decreasing the duration of the period of low thermal activity. The postulated mechanism involves the precipitation of lithium-containing aluminum hydroxide. On the contrary, sodium borate retards CSAC hydration by increasing the duration of the period of low thermal activity. Ulexite, a poorly crystallized mineral containing sodium and borates, transiently precipitates at early age. As long as ulexite is present, dissolution of ye'elimite is strongly slowed down. When sodium borate and lithium hydroxide are simultaneously introduced in the mixing solution, these two mechanisms are superimposed. With a gypsum-free cement, a third process is additionally observed: lithium promotes the initial precipitation of a borated AFm phase which is later converted into a borated AFt phase when hydration accelerates.Finally, based on the achieved results, a cement-based formulation is designed for the encapsulation of borated resins. Its properties fulfill the requirements for a conditioning matrix over the duration of the study
Sawadogo, Awa. "Biodétérioration des ciments Portland et sulfoalumineux dans les réseaux d’assainissement urbains". Electronic Thesis or Diss., Université de Lorraine, 2021. http://www.theses.fr/2021LORR0146.
Pełny tekst źródłaTraditional cements contain Portland clinker, which causes high greenhouse gas emissions. For this reason, new more environmentally friendly cements, such as sulpho-aluminous cements, are being developed. This study investigates the biodegradation process of two of these cements (CSA B and CSA F), in comparison with two Portland clinker-based cements (CEM I and CEM III). Pastes of these four cement grades with the same initial porosity, as well as mortars, were exposed at four different sites in the Nancy agglomeration's sewage network. These samples were monitored and characterised (physico-chemical properties, surface mineralogy) at regular intervals for 18 months. The environmental conditions (temperature, precipitation) of the agglomeration were also recorded during this period.A direct sulphuric acid attack test carried out on the 4 cement grades enabled the majority of gypsum to be detected on their surface. It was found that gypsum was the main degradation product obtained for both Portland clinker cements and CSA. The analysis of the surfaces of the samples taken from the sites revealed the characteristic elements of the first phases of biodeterioration: deposition of sulphur, formation of gypsum and ettringite. Bacterial colonisation thus appears from the first months of exposure of the samples on all sites. Nevertheless, some sites show much higher densities, especially when seasonal environmental conditions are optimal (humidity and temperature), and the presence of H₂S favourable to bacterial development is likely. In this context, sulphur and then gypsum in particular appear on the surface of the samples. The iron-rich CSA is the least bioreceptive, apparently due to the appearance of gibbsite on the surface, which acts as a buffer to inhibit bacterial succession
Michel, Marie. "Accélération de ciment au laitier par du ciment sulfo-alumineux". Lyon, INSA, 2008. http://theses.insa-lyon.fr/publication/2008ISAL0115/these.pdf.
Pełny tekst źródłaThe use of supplementary cementing materials such as blast furnace slag, in cements contributes to reduce their environmental impact. The industrial development of slag cements is slowed down by their limited early-age mechanical performances and high drying shrinkage. The present study deals with the acceleration of two slag cements: a slag cement CEM III A and a slag cement containing 83,5% blast furnace slag and 15,5% anhydrite. The acceleration results of the partial replacement of slag cement by calcium sulfoaluminate cement. The hydration of calcium sulfoaluminate cement yields ettringite which allows the cement to develop high early strength. Furthermore, drying shrinkage is limited. The presence of Portland clinker in the slag cements is responsible of quick setting time and quick hardening of the mortar due to the activation of yeelimite, the main component of calcium sulfoaluminate clinker, by portlandite yielded by the hydration of calcium silicate phases. To compensate the limited time of workability, some setting time retarders are introduced but they reduce the medium-term mechanical performances. The presence of Portland clinker has detrimental effect at early age, but increases the medium-term activation of slag and therefore leads to an important improvement of strength. The content of each component (slag cement, calcium sulfoaluminate cement and Portland clinker, and calcium sulphate) is optimized by the evaluation of mechanical performances. To follow the process of hydration of binders, XRD and DTA-TGA analyses have been carried out on cement pastes
Antoun, Marc. "Vers une meilleure compatibilité ciment/mâchefer (MIDND) dans la formulation de matériaux cimentaires intégrant un ciment sulfo-alumineux". Thesis, Ecole nationale supérieure Mines-Télécom Lille Douai, 2019. http://www.theses.fr/2019MTLD0002.
Pełny tekst źródłaIn a world where circular economy and the valorization of raw materials is taking a greater importance, municipal solid waste incineration (MSWI) bottom ash is identified as potentially renewable resource in the construction field and more specifically in cementitious materials like mortar and concrete. Given the origin of the bottom ash and in order to have a better cement/MSWI bottom ash compatibility, the fraction used was as refined as possible by removing ferrous, non-ferrous and unwanted materials. The choice of the cement used is a critical factor as well because it affects the quality of the end product since MSWI bottom ash has particular physicochemical properties. The work in this PhD studies the advantages of using a sulfo-aluminate cement to valorize an improved 0/2 mm fraction of bottom ash that has been developed to be used in cementitious matrices. The first part presents the results of the mortar sample mixes containing bottom ash in a substitution by volume of the standard sand. To better highlight the effect of using a sulfo-aluminate (CSA), CSA mortars containing bottom ash were compared to a Portland cement (OPC) mortars, with substitution rates of 25 %, 50 %, 75 % and 100 % were used. A study of the porosity was then conducted at 90 days ; it shows that the pores larger to 50 nm are remarkably less present for CSA mortars. This thesis brings forward a major and innovative result : the level of alkalinity of the mortar plays an important role in the release of hydrogen gas after mixing and before setting. The presence of these gases creates large porosity in the hardened mortar samples. The second part studies the physical and microstructural aspects of the mortars after being immersed in aggressive environments : pure water and sulfate solution. The substitution rates used in this experiment were 50 % and 100 % by volume as well as the reference mortars with no bottom ash. These samples were then studied in the SEM which showed that CSA/bottom ash mortars were clearly less affected than the OPC/bottom ash mortars. This was highlighted by the porosity, the cracking and the depth of degraded zone
Le, Bihan Tina. "Etude du comportement des chapes autonivelantes en ciment sulfo-alumineux : outils expérimentaux et de modélisation". Lyon, INSA, 2010. http://theses.insa-lyon.fr/publication/2010ISAL0056/these.pdf.
Pełny tekst źródłaIn the area of the construction, the development of floating screeds in building is slowed down because of a lifting of angles, also called curling, which leads to disorders in hard coatings. The aim of the work is to link the physical characteristics of the formulated material of the screed and the volume variations that occur, whether in endogenous configuration or not, to minimize curling. The determination of these parameters allows on an experimental level to characterize the screed right from its casting and to give data for a modelling approach. This one is based on the theory of porous environments, where the hydro-mechanical coupling is based on the mechanism of coupling between capillary pressure and the degree of saturation of the material. A self-levelling and liquid screed of calcium sulfo-aluminate cement is studied. The development and the adaptation of techniques of characterizing during the very early age (during the first 24 hours) are a key point of the study. We will follow the vertical movements of the surface of the screed before 24 hours (measured by stereo-correlation), the lineic deformations right since the beginning, the hydration and its consequences on the physical properties of the material. The experimental and numerical studies show that the hydration of the material, the modulus of elasticity and the porous distributions play a major role on the kinetics of evolution of the dimensional variations. A swelling component has been showed. The driving force of the swelling is related to the crystallization pressure according to the observations in the environmental SEM and in the evolution of the solid phase according to the modelling