Дисертації з теми "Pâte de ciment hydratées"
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Hoeun, Sela. "Influence de l'adhésion entre les principales phases cimentaires sur le comportement mécanique de la pâte de ciment hydratée." Electronic Thesis or Diss., Ecole centrale de Nantes, 2023. http://www.theses.fr/2023ECDN0049.
This PhD thesis focuses on the multi-scale modelling of mechanical properties of cementitious materials. The aim of this PhD thesis is to obtain the mechanical properties of hydrated cement paste phases at nano-scale using Molecular Dynamics (MD) simulations. Mechanical properties of hardened cement paste at micro-scale were then calculated with homogenization scheme and Discrete Element Method (DEM). Indeed, properties obtained at the lower scale are considered as the input data at the upper scale. At nano-scale, tensile test and shear test were performed with main hydrated cement paste phases (i.e., calcium-silicate-hydrates, portlandite and ettringite) via MD simulations. As a result, mechanical properties at nano-scale were obtained. Another approach to obtain Young’s modulus and Poisson ratio was done via Voigt-Reuss-Hill approximation. With homogenization scheme (i.e., Mori-Tanaka scheme), Young’s modulus and Poisson’s ratio of a simplified hardened cement paste were calculated. Finally, DEM simulation was done with tensile test of a simplified hardened cement paste by taking into account the mechanical properties at the nano-scale. This PhD thesis contributes to create the bridge of achieving the transition from the molecular scale to the continuous microscopic scale
Zhu, Xiaodong. "Étude à l'échelle nanométrique du nano-revêtement organique efficace sur la surface de la pâte de ciment dans un environnement agressif pour des matériaux de construction durables." Electronic Thesis or Diss., Université de Lille (2022-....), 2023. https://pepite-depot.univ-lille.fr/ToutIDP/EDENGSYS/2023/2023ULILN035.pdf.
Improving the life-time of cement paste is a significant challenge in construction sector. Surface treatment approaches, such as surface coating, surface pore sealing, and surface impregnation, have been playing a significant role to improve the durability of cement-based structures especially in preventing surface deterioration and damage. Experimental investigations indicate that surface coating, acting as a physical barrier, is an effective way for enhancing the durability of materials by avoiding the penetration either of water or hazards substances. Due to the experimental observation limitations, there is an urgency need to deeper delve the atomic level to understand the mechanism behind the success hydrophobic behavior of cement surface modified with a nano-coating treatment.Therefore, this dissertation adopts a nano-scale level study to understand and control the nano-coating process to engineer an impermeable hydrophobic Calcium-Silicate-Hydrate (CSH) surface through nano-coating of epoxy and rubber films under aggressive environment. To this end, Molecular Dynamics (MD) simulations based on a combination potential of a general force field (CLAYFF) and the consistent-valence force field (CVFF) have been employed to represent the interatomic interactions between CSH and epoxy or rubber films. A developed realistic model has been used to represent the CSH nanostructure.The thesis is dedicated, first, to study deeply the hydrated surface properties of CSH paste in order to thoroughly understand the hydrophilic nature of the (001) CSH surface. Then, a fully investigation has been performed on the interfacial interaction and adhesion properties between epoxy resins nano-coating and CSH surface. For that, we use diglycidyl ether of bisphenol A (DGEBA) as epoxy monomer and m-phenylenediamine (MPD) as hardener. Thereafter, an in-depth analysis of a hydrophobic rubber nano-coating process onto CSH surface is explored. Four types of rubber are employed, as TPI (1,4-trans-Polyisoprene), CPI (1,4-cis-Polyisoprene), TPB (1,4-trans-Polybutadiene), and CPB (1,4-cis-Polybutadiene). Finally, the present work is devoted to analyze the interfacial deterioration process between epoxy/rubber nano-coating of CSH surfaces under aggressive environment, like a salty water (4 wt.% of NaCl).Results obtained indicate that epoxy and rubber coated CSH surface energy are drastically dropped to the range of 33.7 mJ/m2- 48.4 mJ/m2, which extremely reduces the hydrophilicity of the CSH surface. The averaged contact angle between water-nanodroplet and rubber coated CSH surface is found in range of 92.85° and 98.11°. The calculated interfacial adhesion between organic-coatings (epoxy and rubber) and CSH is in range of 49.42 mJ/m2 to 102.81 mJ/m2. Additionally, m-phenylenediamine (MPD) would highly improve the epoxy nano-coating efficiency. Regarding rubber nano-coating, it is found that coating process with TPI (1,4-trans-Polyisoprene) and CPB (1,4-cis-Polybutadiene) than CPI (1,4-cis-Polyisoprene) and TPB (1,4-trans-Polybutadiene) will enhance efficiently the impermeability of CSH paste. Under aggressive conditions, non-fully epoxy nano-coating is detached more distorted in 4 wt.% of NaCl solution due to the chlorine ions, which are responsible to attack the CSH surface. A continuous well-distributed rubber nano-coating is capable to make CSH impermeable under harsh environment leading to a promising future for sustainable cementitious materials.The doctoral thesis concludes the feasibility and reliability of nano-coating by rubber film to prevent the interfacial deterioration of CSH surfaces in aggressive environment and to improve the impermeability of nano-coated CSH surfaces for more durable cementitious materials
Zajac, Maciej. "Etude des relations entre vitesse d'hydratation, texturation des hydrates et résistance mécanique finale des pâtes et micro-mortiers de ciment Portland." Dijon, 2007. http://www.theses.fr/2007DIJOS006.
This work is dedicated to the study of the influence of curing temperature on hydration of Portland cement in the range 5–45°C. The effects of the temperature on the evolution of compressive strength have been correlated separately with the evolution of the hydration degree and the microstructure of the hydrates. We show that the origin of the temperature effects is related to the hydration of tricalcium silicate of cement (C3S). The initial hydration of C3S is more rapid as the temperature is high but it is more decelerated as soon as the hydration is limited by the diffusion of water and the ions through the layer of hydrates (C-S-H) formed around the grains during the early period. Under these conditions, the barrier is denser, consequently, the evolution of the long-term hydration is slower. The temperature alters the density and repartition of C-S-H as well, giving a more porous material. These phenomena are responsible for the lower final resistance at higher temperature
Feneuil, Blandine. "Stabilité des mousses de ciment : lien avec les propriétés rhéologiques de la pâte de ciment." Thesis, Paris Est, 2018. http://www.theses.fr/2018PESC1045/document.
Cement foams advantages compared to normal concrete is their low density, low material need and thermal insulation properties. To better understand how the morphology of the cement foam affects its properties, we create solid cement foam with well controlled structure. This involves two steps: the creation of the fresh cement foam with chosen structure, and the stability of this structure up to cement hardening. Our cement foam fabrication protocol allows us to obtain fresh cement foams samples with very well controlled parameters. For each sample, all the bubbles have the same size, and we can select the content of air, water, cement and surfactant. This technique consists in mixing a well-controlled precursor aqueous foam stabilized by surfactant, with a cement paste prepared separately. First, we study the interaction of surfactants and cement paste. Some surfactants cannot stabilize foam in cement paste highly alkaline solution. Some others, mainly anionic surfactants, adsorb on cement grains surface, which modifies interactions between cement grains and consequently the yield stress of the cement paste. At low surfactant concentration, cement grain surface becomes hydrophobic and yield stress increases due to hydrophobic attraction between cement grains. At high surfactant concentration, adsorbed micelles create a steric repulsion between cement grains and make yield stress of cement paste drop. In a second chapter, we study the effect of bubbles on the yield stress of aerated cement paste. To compare the results with the literature, the measured yield stress is normalized by the yield stress of the suspending cement paste, i.e. taking into account the effect of surfactant. For a surfactant with low affinity to cement grains surface, results are consistent with literature, whereas reduced yield stress is much higher than expected when surfactant strongly adsorb on cement grain surface. This effect is attributed to the change of the bubble surface properties due to the adsorption of hydrophobic cement grains at the air-liquid interface. Then, we focus on cement foam stability, at air content 83%. We first study three series of experiments at given water-to-cement ratio and bubble size. For each series, the yield stress of the cement paste is changed by addition of superplasticizer or high amount of anionic surfactant. Unexpectedly, the best foam stability is obtained for relatively low yield stress. Rheological measurements on the fresh cement foams allowed us to understand this improved stability as a consequence of the reorganization of cement grains into denser packing. In a second part on stability, we study the influence of bubble size, water-to-cement ratio and surfactant content. A stability criterion is defined from the bubble size and the interstitial cement paste yield stress. Eventually, we observe that cement foam structure affects water imbibition velocity and mechanical resistance to compression of hardened cement foams
Soltani, Fethi. "Caractérisation de la pâte de ciment par des méthodes ultrasonores." Phd thesis, Ecole Centrale de Lille, 2010. http://tel.archives-ouvertes.fr/tel-00685879.
Brisard, Sébastien. "Analyse morphologique et homogénéisation numérique : application à la pâte de ciment." Phd thesis, Université Paris-Est, 2011. http://tel.archives-ouvertes.fr/tel-00617356.
Regnaud, Laure. "Evolution temporelle au jeune âge de la fluidité de la pâte de ciment adjuvantée de superplastifiants type polycarboxylate." Dijon, 2006. http://www.theses.fr/2006DIJOS039.
Bessaies-Bey, Hela. "Polymères et propriétés rhéologiques d'une pâte de ciment : une approche physique générique." Thesis, Paris Est, 2015. http://www.theses.fr/2015PEST1042/document.
To fulfil the rheological requirements of cementitious materials, mix designer engineers use various polymers. Theses admixtures either stay in the suspending fluid modifying its viscosity or adsorb at the surface of cement particles modifying their surface properties and their interactions. In this work, we propose a general physical frame allowing for the description of the consequences of the addition of one or various polymers on the rheology of cement paste. We identify two main parameters affecting the rheology of cement paste, which can be modified by chemical admixtures. These parameters are the inter-particle distance and the viscosity of the suspending fluid. Our solution viscosity and hydrodynamic radii measurements in synthetic cement pore solution suggest that the volume fraction of polymers is the main parameter enhancing the viscosity of the suspending fluid. By means of rheological and adsorption measurements, we study the effects of polymers on the inter-particle distance and the rheological behavior of the suspension. Finally, we study the competitive adsorption between polymers at the surface of cement particles. We propose a technique based on dynamic light scattering measurements allowing for the measurement of the respective adsorption of two polymers at the surface of cement particles. We then study the competitive adsorption between a super-plasticizer and sulfate ions, retarder or viscosity enhancing admixtures
Hermida, German. "Influence du volume de pâte et de la concentration en ciment sur la performance du béton : vers le développement d'un béton à contenu minimal en pâte." Phd thesis, École normale supérieure de Cachan - ENS Cachan, 2008. http://tel.archives-ouvertes.fr/tel-00572748.
Hermida, Germán. "Influence du volume de pâte et de la concentration en ciment sur la performance du béton : vers le développement d'un béton à contenu minimal en pâte." Cachan, Ecole normale supérieure, 2008. http://tel.archives-ouvertes.fr/tel-00572748/fr/.
The paste volume or the cement content is a parameter still not well studied regarding the performance of concrete. Actually the majority of the investigations were focused on the quality of the paste and not its quantity. However there is a permanently growing interest to reduce the paste volume in concrete, for environmental and economical reasons. Nowadays some standards define a minimum paste or cement content for certain W/C ratios, but improvements in admixtures and better grading models allow reducing of the cement content/paste volume below these limits. The collection and processing of the bibliography data allowed identifying the effects of the paste volume on some of the principal concrete properties. This research proofed through experiments some of the identified tendencies in the data analysis and it helped to comprehend other still unclear tendencies. When the paste volume is reduced, while maintaining its quality, compressive strength, abrasion, and elastic module grow and workability, bleeding, shrinkage, porosity, capillary absorption and penetration of the chloride ion are reduced. In the evaluated ranges, the reduction of the paste volume did not show effects on the concrete setting times, flexural strength and the progression of carbonation. The use of admixtures of the last generation (polycarboxilate) and an optimal granulate progression using the MEC model, allowed to produce concretes with paste volumes and cement contents below the limits defined by the codes. They have a better workability, mechanic behavior and durability than the conventional concretes
Gallias, Jean-Louis. "Etude des caractéristiques physiques et chimiques de la liaison acier corrodé-pâte de ciment." Toulouse 3, 1992. http://www.theses.fr/1992TOU30131.
Bach, Quoc Tien. "Influence du remplacement du ciment par des cendres volantes à faible teneur en calcium sur la cinétique de prise de pâtes de ciment au jeune âge." Nantes, 2015. http://archive.bu.univ-nantes.fr/pollux/show.action?id=28eb329d-8730-4b1d-b074-94eb36f39570.
This work deals with the influence of the replacement of CEM I type cement by low calcium fly ash on the hydration kinetics of cement pastes at early-age. Different cement paste compositions are tested. They are characterized by different replacement rates (0%, 40% and 80%) and different water to binder ratios (0. 25 and 0. 50). The study of hydration is based on the experimental measurement of the released heat of hydration (isothermal microcalorimetry), of the amount of portlandite and chemically bounded water (thermogravimetric analysis) and of the evolution of the mechanical properties during the hydration (compressive strength Rc and tensile strength Rt). The results are then used to determine the parameters of the models describing the composed cement paste evolution (Lacarriere 2007) , (Meinhard & Lackner 2008) et (Baert et al. 2010). The second part is dedicated to the study of heat and moisture transfers in the cement paste at early-age. The numerical simulations are carried out to determine the influence of the aggregate thermophysical properties, concentration and shape on the hydration kinetics. These parameters, either physical, composition related ot morphological may have an influence on the medium temperature evolution and consequently on its chemical evolution since the hydration reactions are thermoactivated. The numerical implementation is based on the model by (Di Luzio & Cusatis 2009) discretized by means of the finite difference method (bidimensionnal problem)
Roosz, Cédric. "Propriétés thermodynamiques des phases cimentaires hydratées : C-S-H, C-A-S-H et M-S-H." Thesis, Poitiers, 2016. http://www.theses.fr/2016POIT2264/document.
Concrete is one of the most widely used building materials in the world. Durability, mechanical and chemical properties have made it a material of choice in storage concepts proposed by the French National Agency for Radioactive Waste Management (Andra), including the achievement of retaining structures, cell plugs, massive supports or conditioning waste. The study of the stability of the constituent phases of cementitious materials is needed in view of the planned quantities and the durability of the structures, andmust consider (i) temperature ranges suitable for cement matrices containment in contact with exothermic waste (25-80°C), and (ii) a representative time scale of the lifetime of the storage.The Andra ThermoChimie project therefore aims to develop a consistent thermodynamic database, to model the chemical evolution of cement materials in the environment of radioactive waste. However, in the present state, the database offers only thermodynamic data of cementitious crystalline phases, as well as a limited data set of three different chemical compositions for nanocrystalline C-S-H. This does not allow to reproduce the degradation of cementitious materials, or model the degradation of the new formulations, such as "Low pH" concretes.The objective is therefore to acquire a thermodynamic complementary data set on phases such as C-S-H (Calcium Silicate Hydrates) C-A-S-H (Calcium Aluminate Silicate Hydrates) and M-S-H (Magnesium Silicate Hydrates), to complete the ThermoChimie database. This study is based on experimental, analytical and digital work, in order to obtain a set of thermodynamic data (ΔfG0, ΔfH0, Cp(T), S0) sufficiently representative of the chemical variability of these phases. Finally, this set of data allows the development of a thermodynamic predictive model in extended spaces of compositions and temperatures.Development of this predictive model requires (i) The acquisition of thermodynamic properties on representative phases of the studied chemical system, and (ii) a precise knowledge of the structure and chemical formulas of these phases. Three types of hydrates were therefore synthesized and characterized: C-S-H, C-A-S-H and M-S-H. Analytical methods such as XRD, TGA and solid state NMR (29Si, 27Al) are used to ascertain similarities between the structure of C-(A-)S-H and that of tobermorite, and between the structure of M-S-H and that of Mg-Si phyllosilicates 2:1. Hydrates, however, have a lower crystallinity, with defects in the polymerization of silica chains, and random stacking faults (turbostratism).A multi-technique approach is also used, combining adsorption isotherm (water and nitrogen) and 1HNMR with XRDand TGA, and allows characterization of different types of water more or less bound to the structure of C-(A-)S-H.This study allowed to highlight and quantify the different types of water in the C-(A-)S-H structure. The impact of the drying process was also highlighted on the quantification of different types of water, including interlayer water. The acquisition of thermodynamic parameters of the synthesized phases is carried out from the analysis of equilibrium solutions for the calculation of log K and ΔfG0, while calorimetric acquisitions permit obtaining heat capacities and the calculation of S0. Finally, enthalpy of formation of these phases is calculated from the Gibbs free energy of formation and entropies.The predictive model is developed fromthe acquired thermodynamic properties.The Gibbs free energy of formation ΔfG0 is predicted from an electronegativity model, while Cp and S0 are predicted through polyhedral decomposition model. Finally, a comparison of data obtained with those published in the literature, and the realization of predominance diagrams generalized to the whole CaO-MgO-Al2O3-SiO2-H2O system assess the reliability of the proposed model
Saada, Ridha. "Caractérisation bidimensionnelle d'arrangements granulaires par analyse d'image : application à la pâte fraiche de ciment cryosublimée." Toulouse, INSA, 1992. http://www.theses.fr/1992ISAT0016.
Lombois-Burger, Hélène. "Malaxage et comportement rhéologique des pâtes granulaires en présence de polymère : application à l'extrusion de formulations cimentaires." Paris 6, 2003. http://www.theses.fr/2003PA066545.
Zhang, Yan. "Modélisation du comportement élastoplastique d'une pâte cimentaire soumise à la dégradation chimique." Thesis, Lille 1, 2008. http://www.theses.fr/2008LIL10005/document.
Thesis presents elastoplastic modelling of cement-based materials coupledwith chemical degradation and mechanical damage. The emphasis is put on cementpaste subjected to compressive stresses. A short literature review is first presented on the mineralogical composition, chemical degradation mechanisms, basic mechanical behaviour and chemical-mechanical coupling. Based on this analyses and a series of experimental data obtained from uncoupled and coupled tests, an elastoplastic constitutive model coupled with chemical damage is first formulated. Two plastic mechanisms are taken into account; respectivelyrelated to deviatoric shearing and pore collapse. The chemical damage is identified as relative variation of porosity. Elastic and plastic properties are affected by chemical damage. Numerical simulations are compared with experimental data and good agreements have been obtained. The evolution of the chemical damage has been described by the generalized diffusion equation which is based on the mass balance equation and a phenomenological chemistry model. We have used finite element method to solve the generalized diffusion equation. Coupled chemical-mechanical tests have been simulated by the proposed model and we have also obtained satisfactory concordance. An extension of the model is finally proposed by including mechanical damage due to microcracks in order to describe brittle responses of material under tensile stresses and low confining pressures. An example of application to structural analysis with chemical degradation is presented. It has been shown that the proposed model describes correctly the main features of the mechanical behaviours of cement-based materials at different stress conditions with chemical degradation
Alrifai, Amjad. "Influences des paramètres de formulation sur les retraits des bétons auto-plaçants (BAP) : étude de la pâte et du MBE." Cergy-Pontoise, 2010. http://www.theses.fr/2010CERG0462.
Shrinkage behaviour of self-compacting concrete (SCC) can be different from that of traditional vibrated concrete, because of different paste and aggregate volumes. For traditional concrete, shrinkage can be estimated based on shrinkage results obtained on cement paste level. Based on homogenization techniques, Le Roy developed a model relating the shrinkage of concrete to the shrinkage of the representative cement paste, considering a granular coefficient taking into account the elastic properties and the aggregates concentration. The objective of this work is to predict the shrinkage of SCC from that of the cement paste and / or mortars. The ‘trisphere’ model of Le Roy was adapted to SCC. We worked on cement paste and concrete equivalent mortar (CEM) of two SCC. The results show that autogenous shrinkage increases with decreasing of W/C and A/C ratios contrary to drying shrinkage which increases with higher ratios. These results have been confirmed and can be explained by porosity results. Furthermore, it is shown that the Le Roy model which is used to predict vibrated concrete shrinkage can be adapted to self-compacting concrete
Pasquero, Daniela. "Contribution à l'étude de la déshydratation dans les pâtes de ciment soumises à haute température." Marne-la-vallée, ENPC, 2005. http://www.theses.fr/2005ENPC0040.
Jebli, Mouad. "Caractérisation à l'échelle locale des propriétés mécaniques de l'interphase pâte de ciment-granulat : application à la lixiviation." Thesis, Montpellier, 2016. http://www.theses.fr/2016MONTT339/document.
In this work, we presents an experimental study to characterize the mechanical properties at the local scale of the cement paste-aggregate interface during hydration and during chemical degradation by leaching.It is generally accepted that the microstructure of the interface between the aggregates and the cement paste is characterized by a higher porosity than that of cement paste. This makes this zone a weak point in the concrete. The particular properties of this zone strongly influence the mechanical behavior of concrete. In this work, the mechanical properties of the cement paste-aggregate composite, are experimentally studied. The experimental tests are performed on composites at classical aggregate scale (one centimeter of section). These composite are composed by and Portland cement paste and aggregate. The cement paste is prepared with a water/cement ratio of 0.5. The shape of the prepared composites makes them convenient for direct tensile and shear tests. At different stages of hydration, we performed direct tensile and shear tests on the composites by means of specific devices. The same tests were carried out on the cement paste in order to compare with composites results. The shape of the prepared composites makes them convenient to characterize the cement paste-aggregate interface. At different stages of hydration, the composites are subjected to compression tests, direct tensile tests or shear tests. The study of the mechanical properties of the cement-aggregates interface revealed that the cement paste-aggregate interface is the weakest zone in the composite.An experimental protocol was developed to study the effects of calcium leaching mechanism at the cement paste-aggregate interface on the mechanical properties of the concrete. As the process of leaching with the deionised water occurs very slowly, the experimental study in the laboratory is accelerated by replacing the water by ammonium nitrate solution. To quantify the development and kinetics of degradation at the cemented bond, the concrete leaching fronts are characterized at different levels of degradation by using phenolphthalein. Local mechanical tests (compression, tensile and shear) are performed on composite and cement paste at different stages of degradation. The experimental results show that there is a leaching effect on the alteration of the mechanical properties at the cement paste-aggregate interface
Bresciani, Christophe. "Simulation numérique de l'hydratation et du développement des propriétés physiques et mécaniques d'une pâte de ciment afin de sélectionner de nouveaux ajouts minéraux." Phd thesis, École Nationale Supérieure des Mines de Paris, 2008. http://pastel.archives-ouvertes.fr/pastel-00005221.
Macé, Nathalie. "Influence de la température sur la rétention du sélénite par une pâte de ciment altérée et par ses phases pures constitutives." Paris 11, 2006. https://hal-cea.archives-ouvertes.fr/tel-01697604.
In the French design of a deep repository for radioactive waste, cementitious materials are considered as container or buffer and backfill materials in the engineered barrier system. The temperature would temporally increase from ambient to a maximum value of 70°C, due to cement hydration exothermic reactions and to the heat generation of radioactive waste. Such temperature changes could affect the cement paste mineralogy and could therefore impact radionuclides retention properties. Selenium has been chosen for the retention study, since the radioisotope 79Se (T1/2 = 6. 5 105 years) contributes to the long term hazard of radioactive waste disposal. The main objective is to study the effect of temperature on selenite sorption with thermally altered cement pastes (CEM I) and relative individual cement phases (portlandite, C-S-H, ettringite and hydrogarnet). Results show that increasing of temperature affects: 1) the mineralogical composition of thermally altered cement pastes and the ionic activity products of pure cement phases. This effect has been predicted with a thermodynamic calculation 2) the sorption properties of selenite affinity. Decreasing Rd values with temperature can not be explained only by mineralogical modification, but also by the modification of equilibrium solution composition (particularly with calcium and sulphate concentrations). The construction of a predictive and mechanistic model to describe Se(IV) sorption onto cementitious phases as a function of temperature was not possible because of a lack of sufficient data, but the present work can be considered as a step in this direction
Nguyen-Tat, Tam. "Application de la technique d'émission acoustique pour évaluer l'endommagement mécanique dans le béton." Thesis, Toulouse 3, 2018. http://www.theses.fr/2018TOU30119.
In concrete, Acoustic Emission Technique (AET) has been used to characterize the different fracture modes in flexural beams by RA method (described in RILEM TC 212 ACD recommendation). On the one hand, the RILEM concludes that AE signals which are generated from tensile mode (mode I) exhibit lower Amplitude and higher Frequency than those from shear mode (mode II). Moreover, in the most recent bending tests, authors concluded that the cracks begin with the damage mode I, whereas the mode II just appears before the final failure of specimens. However, no specific rule to determine the typical RA and the AF value associated with each crack type is given by the RILEM recommendation. On the other hand, RA classification method is determined by two parameters which are the RA (Rise-time per Amplitude) and the AF (Average Frequency) value without considering the position of the sensors in conjunction with location of the cracks. In this thesis it was demonstrated that the distance from the sensor to the source of events significantly affects both RA and AF parameters. Different types of mechanical tests (three-point-bending, flexural-induced shear, compression-induced shear and uniaxial tensile) have been conducted on cement-based specimens (concrete, mortar and cement-paste) to promote tensile mode and/or shear mode in these specimens. Acoustic Emission (AE) raw data were filtered to remove noise from signals. Then, k-means algorithm, as a Pattern Recognition Analysis (PRA) method, was used to identify the similarities within the recorded signals, to deduce the characteristics of the source mechanism and to classify the filtered-signals into groups. Clustering results by k-means according to a proposed process have proven efficiency in providing information on RA, AF, Rise-time, Duration and Absolute Energy (ABEN) related to mode I and mode II. Then, two damage classification techniques were used, in which RA method was applied to filtered signals. By these techniques, the proportion of mode I and II was specified and the location of demarcation line also fixed. Finally, the evolution of AE signals versus travelling distance has been clarified by conducting the experiments on concrete and mortar blocks. The conclusion showed that sensors which have further distance from the source gave higher RA values than the nearer ones. Therefore, users may be confused about the original source of high RA signals and to classify them to mode II, while actually they were generated from mode I. Furthermore, the burst-shape of AE signal waveforms must be distinguished from other waveforms that may results from other sources (mechanical vibration due to the loading system, electromagnetic noise and etc.), especially at the final periods of the tests. These exceptional waveforms have significant higher RA value than those in AE signals, thus users may mislead that they were born from shear damages. In addition to three-point-bending tests, based on the variation of the elastic modulus of the material and the released AE energy, the relation of the Damage variable and Index Damage was established. And, to assess the degree of damage versus loading in concrete beams, Kaiser's effect was observed and the CALM ratio and LOAD ratio were proposed. Thirdly, aiming to examine the influences of the material inhomogeneity (e.g. aggregate) to the shapes of waveform of AE signals, the Cross-Correlation (CC) value have been implemented to three specimens as concrete, mortar and cement-paste beams. As conclusion, although coming from the same event, the waveforms of signals that obtained at different sensors which are placed at different distances were quite incompatible and the further sensors produced higher RA value than the nearer ones. This phenomenon reaffirms the increase of RA values as the signal travelling paths increase
Boulay, Vincent. "Valorisation des matériaux granulaires recyclés dans le béton de ciment pour usage résidentiel." Mémoire, Université de Sherbrooke, 2014. http://hdl.handle.net/11143/5917.
Nguyen, Hai Trung. "Transfert hydrique dans le milieu poreux réactif : Application à l’étude de séchage d’une pâte pure ettringitique au jeune âge." Thesis, Lyon, 2018. http://www.theses.fr/2018LYSEI124/document.
Self-leveling flooring compounds (SLC) are often composed of calcium aluminate cements (CAC) and calcium sulfate to ensure rapid setting. The mineral composition of calcium aluminate cements is usually designed around monocalcium aluminate (CA). Recently, a new cement with the main compound of mayenite (C12A7) has been designed to optimize the application of SLC by increasing the amount of ettringite in the hydration product. However, there is a lack of knowledge related to early-age hydration (during the first 24 hours) of this type of product. The main objective of this study is to evaluate the interaction between early-age hydration and natural drying through a coupling model. This model is applied to the study of an ettringite binder composed of cement rich in C12A7 and plaster First, a kinetic model of hydration, initially developed in a diluted system, has been proposed to study the hydration of an ettringite paste under endogenous conditions. It allows to describe the evolution as a function of time of the porosity, the water content, and the quantities of phases (reactants and hydrates). A model of pore size distribution has also been proposed. This model allows us to obtain the capillary pressure curve at early-age, which is necessary for the modeling of moisture transport. Then, a complete modeling of water transfers was presented. It has shown that the assumption of constant gas pressure leads to an overestimation of mass loss for weakly permeable materials. However, for the case of CAC, this hypothesis can be retained to simplify the coupling with the kinetic model of hydration. Finally, a modeling of the coupling between hydration and desiccation has been developed. The originality of this model concerns the integration of the isothermal curve resulting from the pore size distribution model in the modeling of water transfers via a Matlab function. The model was able to reproduce the kinetics of mass loss of a sample of ettringite binder subjected to early drying. The role of temperature was also elucidated. In addition, the model predicted an early stop of hydration on the drying surface after 10 hours of hydration. The effect of desiccation reaches a depth of 5 mm on a sample with a thickness of 3 cm
Sharman, Jeff. "Mode d'action des agents viscosants dans les pâtes de ciment et les pâtes de carbonate de calcium." Mémoire, Université de Sherbrooke, 2013. http://hdl.handle.net/11143/6605.
Ghabezloo, Siavash. "Comportement thermo-poro-mécanique d'un ciment pétrolier." Phd thesis, Ecole des Ponts ParisTech, 2008. http://tel.archives-ouvertes.fr/tel-00403940.
Benard, Philippe. "Etude de l'action des phosphates présents dans l'eau de gâchage sur l'hydratation d'un ciment Portland." Phd thesis, Université de Bourgogne, 2005. http://tel.archives-ouvertes.fr/hal-00015367.
Sanahuja, Julien. "Impact de la morphologie structurale sur les performances mécaniques des matériaux de construction : application au plâtre et à la pâte de ciment." Phd thesis, Ecole des Ponts ParisTech, 2008. http://pastel.archives-ouvertes.fr/pastel-00004039.
Maalej, Sirine. "Micromecanical model : correlation between hydraulic and acoustic parameters of cement-based materials." Phd thesis, Ecole Centrale de Lille, 2010. http://tel.archives-ouvertes.fr/tel-00590429.
Nguyen, Thi Bich Hau. "Valorisation du verre dans le béton : étude expérimentale du comportement de pâte de ciment et du mortier : rhéologie, mécanique et durabilité." Thesis, Aix-Marseille, 2013. http://www.theses.fr/2013AIXM4793/document.
The aim of this work is the valorisation of recycled waste materials in cement paste and mortar in order to reuse these resources for replacing natural aggregates in concrete. Our study concerns the use of a microsphere glass powder (MGP) with a particle size from 1 to 50 m into the cement matrix. This experimental work first focuses on the effect of the MGP on the workability properties of fresh cement paste and fresh mortar and on the physical, mechanical and durability properties of mortar. Many standard tests have been conducted for the characterisation of the behavior of the fresh cement paste i.e the consistency and the setting of fresh cement paste. The durability properties at early age (from 3 to 28 days) and at long time (from 28 days to 112 days) have been also quantified. We employed the scanning electron microscopy for the mortar microstructure analysis. Some supplementary tests like the ultrasonic wave propagation, the segregation and the flow properties on the vibrated table have been also used. The primary results have proved the effect of the MGP on the behaviour of the fresh cement paste, fresh mortar and mortar. The presence of MGP showed interesting modifications on the rheology, mechanical and durability properties of the cement system
Mercado, Mendoza Hugo Ramiro. "Transferts aqueux à travers les matériaux cimentaires partiellement saturés." Toulouse 3, 2012. http://thesesups.ups-tlse.fr/1722/.
The diffusivity properties are of great importance as far as the durability of a construction made of cement-based materials, such as a particular solution for radioactive waste disposal, is concerned. Besides, the influence of material microstructure on transfer properties is recognized and ensues both from the characteristics of the material itself as well as from its history and environment conditions. In service conditions, cement-based materials are seldom at a fully saturated state. The scientific community has long since ascertained the lack of experimental data on aqueous diffusion in non-saturated medium. The main purpose of this work is to determine de diffusion coefficient of an ionic species through partially saturated cement-based materials. An approach has been proposed on the basis of the analogy between ionic diffusion and electrical conductivity - given by the Nernst-Einstein relationship - and the formation factor concept. Accordingly, an experimental programme based on the electrochemical impedance spectroscopy test, together with a data analysis procedure using an electrical model of material microstructure, have been developed. A first validation study has been carried out by means of an electrokinetic test on saturated materials. The geometric character of the formation factor, reflecting the pore network configuration whatever the pore solution ionic force or composition, has been shown. As a consequence, the diffusion coefficient of chloride ion has been calculated, highlighting the suitability of the proposed method. This method has allowed to determine the diffusion coefficient of an ionic species through several partially saturated materials. It has been observed that the formation factor depends also on the material saturation level. Thus, the diffusion coefficient turns out to be an intrinsic parameter of the material, through its pore network and its solution content. The shapes of evolution of the diffusion coefficient as a function of saturation level have shown the existence of leading paths for ionic species transfer through materials. In a logical way, these paths seem to be related to the main pore modes, but also to the total open porosity of the material
Bernard, Ellina. "Magnesium silicate hydrate (M-S-H) characterization : temperature, calcium, aluminium and alkali." Thesis, Bourgogne Franche-Comté, 2017. http://www.theses.fr/2017UBFCK025/document.
The various options to store radioactive wastes in deep geological strata considered in France or Switzerland include the use of large volumes of cementitious materials for infrastructure in contact with argillaceous rocks. So-called low-pH binders were developed to minimize disruption to the surrounding rock by the alkaline plume. Studies conducted on the interaction zone between concrete and clay systematically highlighted the formation of magnesium silicate phases including magnesium silicate hydrate (M-S-H) at the interfaces, which can presently be modeled only partially due to incomplete thermodynamic data. The purpose of this study was to characterize these phases in temperature, aluminum, calcium, and alkali conditions in order to provide the thermodynamic data and improve the calculations on physicochemical evolutions of low-pH concretes and possibly Portland concretes.M-S-H phases were synthesized from magnesium oxide and silica fume in batch experiments at different temperatures, for various times and varying Mg/Si. A large number of different techniques such as chemical solid characterizations coupled with suspension investigations and liquid analyses were used to characterize the phases synthesized. Initially a M-S-H phase with Mg/Si equal to 1 was precipitated in addition to amorphous silica and brucite whatever the total Mg/Si used for the synthesis. After long equilibration times, 2 to 3 years at 20°C or 1 year at 50 and 70°C, the Mg/Si in M-S-H ranged from ~0.8 to ~1.4. The temperature had little influence on the M-S-H formed even if the M-S-H formation occurred faster and M-S-H was thermodynamically slightly less stable when the temperature was increased. At or near to equilibrium, M-S-H phases were characterized with ill-defined structure comparable to nano-crystallite, hydrated phyllosilicates with a surface area greater than 200 m2/g. A M-S-H solid-solution model was calculated and implemented in the thermodynamic database.It was observed that M-S-H also form from calcium silicate hydrate (C-S-H) with a Ca/Si = 0.8 in the presence of additional magnesium. In batch experiments, a low pH of the suspensions (pH ≤ 10) destabilized C-S-H or prevented its formation and favored the precipitation of M-S-H. Detailed investigations showed that small amounts of calcium could be incorporated in M-S-H (Ca/Si ≤0.10), such that also calcium containing end-members were added to the M-S-H solid-solution. At pH ≥ 10-10.5, two separate silicate phases coexist: C-S-H and M-S-H. The interface between a simplified “low-pH” binder mimicked by C-S-H with Ca/Si = 0.8 and a magnesium-rich environment mimicked by M-S-H with Mg/Si = 0.8 confirmed these phenomena. SEM-EDS observations and reactive transport modelling using the thermodynamic data derived in the batch experiments showed the fast deterioration of the C-S-H and the precipitation of M-S-H in the C-S-H disk at the interface and a homogeneous uptake of calcium in the M-S-H disk.The increase of pH favors the sorption. M-S-H with a sodium uptake up to Na/Si ~ 0.20 and without brucite formation were observed at high pH (12.5). The sorption on M-S-H was favored in the order Na+ < Mg2+ < Ca2+. Finally, aluminum was incorporated into M-S-H to form magnesium alumino-silicate hydrate (M-A-S-H). An Al/Si ratio up to 0.2 was observed in presence of sodium aluminate or metakaolin. 27Al MAS NMR data showed that aluminum was present in both tetrahedral and octahedral sites of M-(A-)S-H. The M-(A-)S-H formed had a similar structure as M-S-H with a comparable polymerization degree of the tetrahedral silicates and a similar surface charge
Seigneur, Nicolas. "A coupled experimental, numerical and statistical homogenization approach towards an accurate feedback relationship between porosity and diffusive properties of model cementitious materials in the field of reactive transport modelling." Doctoral thesis, Universite Libre de Bruxelles, 2016. https://dipot.ulb.ac.be/dspace/bitstream/2013/237928/3/TDM.pdf.
Doctorat en Sciences de l'ingénieur et technologie
info:eu-repo/semantics/nonPublished
Bresciani, Christophe. "Transcrire en toutes lettres les symboles spéciaux : simulation numérique de l'hydratation et du développement des propriétés physiques et mécaniques d'une pâte de ciment afin de sélectionner de nouveaux ajouts minéraux." Paris, ENMP, 2008. http://www.theses.fr/2008ENMP1605.
The desire to preserve the environment is becoming more and more important in our societies. The setting up of the search for the so-called sustainable development reflects this commitment. To follow this way of sustainable development, governments are putting the industries under an ever-increasing pressure to reduce the various pollutions they generate. In the case of the cement industry, CO2 emissions and consumption of raw materials are mainly referred to reduce its environmental impact. The development of cement with mineral additions, mostly spawned from industrial processes, is a way of reducing the amount of clinker in Portland cement and therefore decreasing emissions. Such cements already exist and use industrial by-products such as blast furnace slag, silica fume or fly ash. Moreover, these cements with additions are interesting because they have specific properties, very different from CEM I type Portland cements. This last point of the specific properties of cement with additions associated with the increasing pressure of sustainable development constitutes the basement on which is built the thesis. Our work aims at developing a methodology for development of cement with mineral additions. Such a methodology would allow cement manufacturers to develop new products while walking the line of sustainable development by promoting by-products of other industries. The originality of our methodology rely on maximum use of numerical tools and simulation as a replacement of experimental works that are the main part of studies that aim at developing such cements. The main interests of our approach are cost and time reductions for cement development. Development times can be very long when they include durability studies. The work done for the thesis has first consisted in giving the methodology a functional realty. This methodology is split in three successive steps for testing the relevance of an industrial by-product as a potential addition in cement. To do this, three softwares were selected : • CHESS, a geochemical computing code, used for the first step, • VCCTL, cement paste microstructure generating code, used for the second step, • HYTEC, reactive transport simulation code, used for the third step. We had to adapt those softwares to their use in the field of the methodology in order to establish a synergy of operation between them. This adaptation has led us to perform a significant modification of the VCCTL source code in order to expand its capacity to take into account unknown additions. The work has then focused on the practical validation of the methodology by its confrontation with the results of experimental studies. This practical validation was initially focused on an OPC and then on blends of OPC with either blast furnace slag or fly ash circulating fluidized bed (CVLFC). The results achieved confirm the interest of the approach but they are also letting foresee the current limitations mostly linked to the numerical tools
Auroy, Martin. "Impact de la carbonatation sur les propriétés de transport d'eau des matériaux cimentaires." Thesis, Paris Est, 2014. http://www.theses.fr/2014PEST1058/document.
The French design of deep geological repository involves the use of cement-based materials (vault cell and containers). The durability assessment over the operational phase (supply 100 years) is decisive. In operating conditions, a ventilation system would maintain the CO2 partial pressure within the disposal, subjecting concrete to drying and carbonation. The temperature (due to the waste thermal output) and drying effects on carbonation have been studied in the past. The data acquired must however be complemented. In this sense, taking into account the water transfers simultaneously to carbonation is essential. On the one hand, because carbonation is a common pathology of reinforced concrete that leads to rebar corrosion. On the other hand, because the durability of reinforced concrete structures is dependent on their water content evolution all along their service life. The assessment of water transport properties in carbonated materials, under unsaturated conditions, is an important issue for Andra in charge of the management of radioactive waste in France.Accelerated carbonation test are performed on four hardened cement pastes (CEM I, CEM III/A, CEM V/A and a Low-pH mix) at 3% CO2 content. The water transport properties of carbonated materials are evaluated using a simplified approach, requiring the knowledge of 3 physical parameters, accessible through experimental way: (i) porosity, (ii) water vapour desorption isotherm and (iii) permeability.The results highlight mineralogical and microstructural changes induced by carbonation: hydrates decomposition and calcium carbonate precipitation (CaCO3) according to various polymorphs. The high decalcification of C-S-H and the polymerisation of silicates chains, leading to the formation of a calcium-enriched silica gel, are found. This results in carbonation shrinkage, responsible of microcracking. On the other hand, the reduction of porosity and specific surface area are observed. The formed carbonates fill the pores, reducing the total porosity. In this sense, the higher the initial portlandite content, the higher the amount of CaCO3 and, consequently, the more the porosity decrease. The structure of the carbonated materials is totally different from the initial state. These changes result into a significant reduction of the water content at the equilibrium and a modification of the isotherms morphology, directly related to the microstructure evolutions. The permeability is found to decrease in the case of Portland cement (CEM I), due to porosity clogging. By contrast, it was found to increase significantly for blended cements (CEM III/A, CEM V/A and Low-pH mix), this is directly attributed to the microcracking effect which is more significant compared to porosity clogging. The initial mineralogy (portlandite and C-S-H contents) therefore plays a determinant role regarding to the carbonation impact on the cementitious materials behaviour. Furthermore, the representativeness of accelerated carbonation compared to natural one was verified. The data set acquired during this work can be extended and, applied confidently under real carbonation conditions
Nguyen, Tien Dung. "Étude de la zone d'interphase " granulats calcaires poreux-pâte de ciment" : Influence des propriétés physico-mécaniques des granulats; Conséquence sur les propriétés mécaniques du mortier." Phd thesis, Ecole Nationale Supérieure des Mines de Saint-Etienne, 2013. http://tel.archives-ouvertes.fr/tel-00849595.
El, Barrak Maher. "Contribution à l'étude de l'aptitude à l'écoulement des bétons autoplaçants à l'état frais." Toulouse 3, 2005. http://www.theses.fr/2005TOU30080.
Platel, David. "Impact de l'architecture macromoléculaire des polymères sur les propriétés physico-chimiques des coulis de ciment." Phd thesis, Université Pierre et Marie Curie - Paris VI, 2005. http://pastel.archives-ouvertes.fr/pastel-00001497.
Boher, Cedric. "Etude expérimentale et modélisation de la diffusion gazeuse à travers des milieux poreux partiellement saturés en eau. Application aux verres Vycor, géopolymères et pâte de ciment CEM V." Thesis, Toulouse, INSA, 2012. http://www.theses.fr/2012ISAT0014/document.
This work documents the relationship that exists between the transfer properties of a material (pore size distribution, total porosity accessible to water, water saturation degree), and its diffusion coefficient. For this sake, materials having a quasi mono modal porosity are used: Vycor® glasses and geopolymers. We also use materials having a complex porosity: CEM V cement pastes. The use of Vycor® glasses and geopolymers allows quantifying the gas diffusion coefficient through materials having known pores size, as a function of their water saturation degree. The use of cement pastes allows checking if it is possible to decompose the diffusion coefficient of a complex porosity material, in an assembling of diffusion coefficients of quasi mono modal porosity materials. For this sake, the impact of pore network arrangement on the diffusion coefficient is studied in great details. This study is divided into three parts:• Measurement of the geometric characteristics of materials porous network by means of the mercury intrusion porosimetry, water porosimetry, isotherms of nitrogen sorption / desorption, and water desorption tests.• Measurement of the materials diffusion coefficient, as a function of their relative humidity storage, and their water saturation degree.• Modeling the diffusion coefficient of the materials, and study the impact of the pore network (tortuosity, pores connection)
Nguyen, Dac Loi. "Nouvelle méthodologie d'identification des propriétés mécaniques locales d'un matériau hétérogène par nanoindentation : application aux matériaux du génie civil." Thesis, Paris Est, 2017. http://www.theses.fr/2017PESC1028/document.
The present work proposes and develops a complete methodology for identifying the local mechanical properties of a heterogeneous material at the scale of the constitutive phases. It is a combination of very diverse skills in theory, in numerical simulation and in experimentation. More precisely, the theoretical part concerns the determination of the nano-micro relations for the indentation module; the numerical part based on the yield design theory is carried out to find the last relations applicable for the hardness; and the last part is performed to obtain homogenized properties by the experimental way using the nano-indentation technique. The experimental study of the thesis is for the purpose of determining indentation properties of different cement paste samples. A complete experimental program, is developed, which allows characterizing the main phases at the micrometric scale of this material, among which we are mainly interested in the C-S-H matrix phases. The modeling of the problem related to the penetration of an indentation point into a material is studied. For this, the first way, based on the kinematic approach of the yield design theory, consists in trying to construct ruin mechanisms analytically, then to make them evolve according to the change of the initial geometry, in order to obtain the corresponding ultimate load. The second way is then to follow the same approach, but by building numerically these ruin mechanisms. The obtained load depends naturally on the retained criteria parameters, which are determined by the combination with the experimental results. The Von-Mises and Tresca strength criteria for purely coherent materials as well as the elliptical one are examined in this work
Baroghel-Bouny, Véronique. "Caractérisation microstructurale et hydrique des pâtes de ciment et des bétons ordinaires et à très hautes performances." Phd thesis, Ecole Nationale des Ponts et Chaussées, 1994. http://tel.archives-ouvertes.fr/tel-00523299.
Mitani, Husam. "Variations volumiques des matrices cimentaires aux très jeunes âges : approche expérimentale des aspects physiques et microstructuraux." Phd thesis, Ecole des Ponts ParisTech, 2003. http://tel.archives-ouvertes.fr/tel-00005721.
dans les structures en béton. Dans le cadre de cette étude nous nous sommes intéressés
uniquement à létude du retrait endogène aux jeunes âges, ses effets sur la microstructure, les
paramètres qui influencent sa cinétique, lamplitude et lorigine de ce type de retrait.
Le retrait endogène, conséquence de la contraction « Le Chatelier », est un phénomène bien
connu de lindustrie cimentière. Dans les bétons confectionnés avec un rapport E/C de lordre
de 0.5, les effets de ce retrait sont inexistants. Le développement et lutilisation de plus en
plus fréquente des bétons à hautes et à très hautes performances posent de nouveaux
problèmes sur lapparition et la mesure du retrait endogène.
Dans les premier et second chapitres, nous avons examiné la littérature concernant la
structuration de la pâte de ciment à différentes étapes, les mécanismes dhydratation, les
différents types de retraits, les techniques de mesure associées et les facteurs qui influencent
ce dernier.
Dans le troisième chapitre, nous avons présenté une méthode que nous avons mise au point.
Elle permet de mesurer les variations volumiques dès la fin du gâchage et sur une période de
temps allant jusqu'à trois jours. Dans ce mémoire, nous présentons les résultats obtenus à
partir dune formulation de mortier à ultra hautes performances (UHP) et des résultats obtenus
à partir de pâtes de ciment et de mortiers.
Dans le quatrième chapitre, des analyses microstructurales, chimiques, minéralogiques, et
physiques sont également présentées. Elles permettent de donner quelques indices sur
lorigine du retrait endogène. Parallèlement nous avons présenté des résultats obtenus sur
leffet dajout de C3A dans un clinker, leffet de la finesse Blaine et finalement les résultats de
létude comparative entre différentes catégories de ciment.
MENOU, Abdellah. "Etude du comprtement thermomécanique des bétons à haute température: Approche multi échelles de l'endommagement thermique." Phd thesis, Université de Pau et des Pays de l'Adour, 2004. http://tel.archives-ouvertes.fr/tel-00008986.
Stefan, Lavinia. "Étude expérimentale et modélisation de l'évolution des propriétés mécaniques au jeune âge dans les matériaux cimentaires." Phd thesis, École normale supérieure de Cachan - ENS Cachan, 2009. http://tel.archives-ouvertes.fr/tel-00624989.
Chabil, Fatima Zohra. "Carbonatation de bétons adjuvantés à base de ressources locales algériennes." Phd thesis, Université d'Orléans, 2009. http://tel.archives-ouvertes.fr/tel-00797822.
Autier, Caroline. "Etude de l’adjuvantation de pâtes cimentaires par différents polycarboxylates : la mésostructure : un lien entre interactions organo-minérales et propriétés macroscopiques." Thesis, Montpellier 2, 2013. http://www.theses.fr/2013MON20061/document.
Superplasticizers are admixtures developed to give the cementitious materials greater fluidity for the same water to cement ratio (w/c), promoting the particles dispersion. Many studies were conducted to deepen the understanding of their mode of action. Usually, they connect directly the amount adsorbed with the rheological behavior of the materials in which they are incorporated. However, at an intermediate scale, mesostructurale organization of the cement paste controls not only its fluidity, but also its homogeneity and physicochemical stability.This work focuses on a new generation of superplasticizers: polycarboxylates (PCE). A multi-scale experimental approach has been developed by integrating mesostructural characteristics of cement paste to make the link between the organo-mineral interactions, particularly PCE adsorption, and the macroscopic properties (sedimentation and rheological behavior). Identification and granular characterization of cement paste was discussed, at the level of the particle, by a morpho-granulometric approach. Dispersion indices were defined to quantify the influence of PCE on mesostructural organization of particles (unit particles or agglomerates). In a second step, the evolution of this organization has been studied by analysis of sedimentation columns. A phase separation index has been defined, highlighting the existence of stability ranges as a function of the dosage and molecular structure of the PCE incorporated.Linking these observations with study of organo-mineral interactions has allowed to deepen the understanding of the mode of action and influence of PCE. This analytical approach is a potential tool to the development of innovative superplasticizers
Coussy, Samuel. "Stabilisation de rejets miniers pollués à l'arsenic à l'aide de sous-produits cimentaires : étude de l'influence de la cristallochimie sur le risque de mobilisation des polluants." Phd thesis, INSA de Lyon, 2011. http://tel.archives-ouvertes.fr/tel-00740233.
Dakhmouche, Chabil Fatima-Zohra. "Carbonatation de bétons adjuvantés à base de ressources locales algériennes." Thesis, Orléans, 2009. http://www.theses.fr/2009ORLE2084/document.
The carbonation is a pathology which affects cement-based materials such as concretes and mortars.The carbonated skin of material becomes brittle and losses the protection of inner steels againstcorrosion. The corrosion products generate a degradation of the concrete which may lead to thecollapse of the structure.Six types of adjuvant concretes and two cement pastes have been designed by a rheological study inorder to study the effect of accelerated and natural carbonation on the sustainability of concretes andcement pastes based on algerian resources. For this purpose, several investigation methods were usedwith both macroscopic and microscopic scales.In conclusion, the empirical rheological model developed herein can be used to formulate concretesresistant to carbonation. The study of carbonation shows that the accelerated protocol may be lessaggressive than the natural one, especially for dense cement pastes. In this case, the acceleratedcarbonation of the surface tends to fill up the superficial microporosity of the concrete, slowing downthe production of carbon dioxide, contrary to the natural carbonation which acts more diffusely withoutcompletely obstructing the pores. The lesser compact is the concrete, the more effective is theaccelerated protocol
Le, Roy Robert. "Déformations instantanées et différées des bétons à hautes performances." Phd thesis, Ecole Nationale des Ponts et Chaussées, 1995. http://tel.archives-ouvertes.fr/tel-00529739.
Hamdaoui, Ons. "Caractérisation thermique et mécanique de fibres naturelles d'origine marine en vue de leur utilisation dans les matériaux de l'habitat." Thesis, Paris Est, 2018. http://www.theses.fr/2018PESC1152/document.
In this work, we have firstly studied the use of fibers extracted from the marine plant Posidonia-Oceanica as loose-fill thermal insulation material for buildings. Measurements were conducted and allowed the determination of the effect of fibers density and chemical treatments on thermal properties. Thermal conductivities were lying between 0.04 and 0.07 W.m-1.K-1, whereas the heat capacity is about 2500 J.kg-1.K-1. Thus, it was found that fibers thermal conductivity is close to the one of commonly used thermal insulation materials and that their heat capacity is significantly higher. It was also found that the influence of chemical treatment on the thermal properties is not significant. Measurement results showed that these fibers could be a promising ecological loose-fill insulation material in the construction field. Secondly, fibers were used as reinforcement for cement paste. A set of composite samples were formulated by varying fibers volume fractions from 0 to 20%. Their hygroscopic, thermal and mechanical properties were evaluated. Composites were analyzed by Fourier transform infrared spectroscopy (FTIR) and their thermophysical properties were measured with a Hot Disk thermal constants analyzer during the drying cycle. Sensitivity of these materials to relative humidity was examined by measuring the water content variation in controlled humidity environments. These measurements allowed the quantification of the water diffusion coefficient. This coefficient increased slightly with the increase of fibers content in composite samples. Concerning thermal properties, the addition of Posidonia-Oceanica fibers improved the material insulating properties. In fact, a decrease of about 22% on thermal conductivity values was found with the introduction of 20% of fibers compared to the unfilled cement paste. For Posidonia-Oceanica fibers volume fractions considered in this study (0 to 20 Vol.%), the effect of the presence of fibers on thermal diffusivity and on heat capacity is not significant, regarding the measurement uncertainties. Concerning mechanical properties, flexural and compressive strengths increased for about fiber volume fractions in the range of 5 to 10%. Moreover, a noticeable increase of toughness was observed with increasing fibers amount: for instance, an increase of about 65% was observed with the introduction of 20% of fibers in the composite. Based on the experimental observations, simplified analytical models were developed to predict thermal conductivity, flexural strength, compressive strength and toughness as a function of fibers volume fraction in the material