3D-printing, också känt som additiv tillverkning, är en tillverkningsmetod som har revolutionerat många branscher och har växt stort både inom industrin och för privat användning. Tekniken använder sig utav en lager-på-lager metod för att tillverka olika objekt. Med dagens teknik går det att printa ut föremål av exempelvis metall, plast, betong och ett flertal andra material. Additiv tillverkning av betong ger möjligheten att skapa nya smarta konstruktionslösningar, vilket medför stora materialbesparingar och minskat materialspill. Produktionskostnader och hastighet kan också dra nytta av metoden genom att minska arbetskraft och eliminera kostnader för tillverkning och montering av gjutformar. Den här studien bidrar till en ökad förståelse för vad som krävs för att utveckla ett fungerande betongmaterial för additiv tillverkning. För att additiv tillverkning ska kunna standardiseras, bli mer kommersiellt och få en bredare användning krävs en djupare förståelse av betongens materialegenskaper. Detta eftersom materialet skiljer sig från konventionell betong. Syftet med detta projekt är att utveckla en betongblandning anpassad för additiv tillverkning. En undersökning görs för att hitta (i) en betongblandning med lämpliga mekaniska materialegenskaper och (ii) en betongblandning som är väl anpassad till 3Dskrivare. Det viktigaste för att en betongblandning ska kunna användas för additiv tillverkning är att blandningen kan pumpas genom systemet och extraheras genom munstycket vid tillverkning samt att slutmaterialet visar bra byggbarhet. Pumpbarhet är förutsättningen för att betongen ska kunna användas i en 3D-skrivare. Betongen ska vara tillräckligt smidig för att kunna pumpas ut genom ett munstycke, men även ha en tillräckligt god inre sammanhållning för att inte deformeras efter att den har pumpats ut. Pumpbarhet påverkas till stor del av vilken sorts pumpsystem som används. Resultaten varierar beroende på vilken pump, munstycke och slang som används vid materialtesterna. Det förefaller att en generell blandning anpassad för flera olika pumpsystem är svårt att uppnå. I det här arbetet har sex olika blandningar med olika variationer testats. Detta ledde till 38 blandningar som genomgått olika tester. De blandningarna med bäst resultat efter finjusteringar var blandning 4.1 och 5.1, de visade hög kvalité för pumpbarhet och byggbarhet. Blandning 4.1 innehåller vatten, anläggningscement, starvis 3040, glenium, CERW, krossballast och glasfibrer och blandning 5.1 är likadant fast med flygaska istället för CERW. / 3D printing, also known as additive manufacturing, is a manufacturing method that has revolutionized many industries and has grown widely both in industry and private use. The technique means using a layer-upon-layer method to manufacture different objects. With today's technology, it is possible to print objects of, for example, metal, plastic, concrete and several other materials. Additive manufacturing of concrete structures can be used to create new smart design solutions, which means significant material savings and reduced material waste. Production costs and time reduction may also be achieved using the method due to lower labor requirements and reduced costs for manufacturing and assembling of molds. This study contributes to an increased understanding of what is required to develop a functioning concrete material for additive manufacturing. In order for additive manufacturing to be standardized, become commercial and be broadly used, a deeper understanding of the concrete properties is required. This is because the material used in 3D printing differs from conventional concrete. The purpose of this project is to develop a concrete mixture adapted for additive manufacturing. A survey is made to find (i) a concrete mixture with suitable mechanical material properties, and (ii) a concrete mixture well adapted to 3D printers. The most important thing for a concrete mix to be used for additive production is that the mixture can be pumped through the system and extracted through the nozzle during manufacture and that the final material shows good buildability. Pumpability is a prerequisite for the concrete to be used in a 3D printer. The concrete must be sufficiently flexible to be pumped out through a nozzle, but also have a sufficiently good internal cohesion so as not to deform after it has been pumped out. Pumpability is largely affected by the type of pump system used. The results vary depending on the pump, nozzle and hose used in the material tests. It seems that a general mix adapted to several different pump systems is difficult to achieve. In this work, six different mixtures with different variations have been tested. This led to 38 mixtures that underwent various tests. The mixtures with the best results after fine adjustments were mix 4.1 and 5.1, they showed high quality for pumpability and buildability. Mixture 4.1 contains water, plant cement, starvis 3040, glenium, CERW, crush ballast and glass fibers and mixture 5.1 is similarly fixed with fly ash instead of CERW.

Yes / Understanding the structure-property relationships of drug delivery system (DDS) components is critical for their development and the prediction of bodily performance. This study investigates the effects of introducing polyethylene oxide (PEO) homopolymers, over a wide range of molecular weights, into Pluronic injectable smart hydrogel formulations. These smart DDSs promise to enhance patient compliance, reduce adverse effects and dosing frequency. Pharmaceutically, Pluronic systems are attractive due to their unique sol-gel phase transition in the body, biocompatibility, safety and ease of injectability as solutions before transforming into gel matrices at body temperature. This paper presents a systematic and comprehensive evaluation of gelation and the interplay of microscopic and macroscopic properties under both equilibrium and non-equilibrium conditions in controlled environments, as measured by rheology in conjunction with time-resolved Small Angle Neutron Scattering (SANS). The non-equilibrium conditions investigated in this work offer a better understanding of the two polymeric systems’ complex interactions affecting the matrix thermo-rheological behaviour and structure and therefore the future release of an active pharmaceutical ingredient from the injectable DDS.

yes / This paper investigates the effect of cement based grout rheology on the injection process through coarse aggregate for producing preplaced aggregate concrete. Four different sands were used in the grout production at different water-cement ratios and cement-sand ratios. Superplasticiers and pulverised fuel ash were also employed in the grout production. Coarse aggregate of known weight was compacted into 150 mm cubic forms, and then the grout was injected through a plastic pipe under self weight into the stone ‘skeleton’. It has been found that there are threshold values of the rheological parameters beyond which full injection is not possible. In particular, all grout mixes with and without additives and admixtures exhibited the same yield stress threshold value for full injection, whereas the threshold values for other rheological properties including the grout plastic viscosity, flow time and speed were different according to the materials added to the mix.

No / Rheological characterisation of hydroxyapatite -high density polyethylene (HA-HDPE) composites has been performed in terms of isothermal compressibility and wall slip. Addition of HA to the polymer melt decreases the compressibility of the melt. The unfilled HDPE was found to exhibit wall slip at shear stresses as low as 0.10 MPa. The flow curves of the composites showed three distinct regions: a gradient at low shear rates; a plateau region; and a gradient at higher shear rate. An increase in rheometer pressure seems to suppress the slip in composites. The 40 vol.-% HA-HDPE composite exhibited two critical shear stresses, one corresponding to wall slip, which occurs in the lower shear rate region of the flow curve, and the other corresponding to a plateau, which is identified with the stick-slip behaviour of unfilled HDPE reported in the literature. The plateau shear stress increased with filler volume fraction and this effect is attributed to the decreased compressibility of the melt. A good correlation with a negative correlation coefficient was found to exist between compressibility and shear stress in the plateau region. The slip observed in unfilled HDPE and at low shear rates in the 40 vol.-% HA- HDPE systems has been explained in terms of a low molecular weight polymer layer formed at the melt/wall interface. The large interfacial slip observed in the plateau region is attributed to complete disentanglement of adsorbed chains from free chains at the melt/wall interface at and beyond the plateau region.

<p>U okviru disertacije su razvijeni postupci za iskori&scaron;ćenje sporednog produkta prerade paradajza (tropa) kao polazne sirovine za proizvodnju prehrambenih proizvoda sa dodatom vredno&scaron;ću. Sprovedena istraživanja kretala su se u dva smera: proizvodnja lipofilnih i hidrofilnih ekstrakata od liofilizovanog tropa paradajza, primenom rastvarača koji su dozvoljeni za upotrebu u prehrambenoj industriji (n-heksana i 95% etanola) i njihova karakterizacija u pogledu sadržaja i sastava fitohemikalija i biolo&scaron;ke aktivnosti in vitro; razvoj formulacija i tehnolo&scaron;kih postupaka za kreiranje gotovih proizvoda sa povećanim sadržajem prehrambenih vlakana i njihova karakterizacija u smislu nutritivnih, reolo&scaron;kih i senzorskih svojstava. Proizvedena su tri proizvoda sa povećanim sadržajem prehrambenih vlakana: kečap od svežeg tropa paradajza, kečap od liofilizovanog tropa paradajza u prahu i marmelada od liofilizovanog tropa paradajza u prahu.<br />Proizvedeni lipofilni i hidrofilni ekstrakti pokazali su sposobnost redukcije jona gvožđa, kao i antiradikalsku aktivnost na DPPH, azot (II)-oksid i superoksid-anjon radikale. Karotenoidi detektovani u lipofilnim ekstraktima (likopen i &beta;-karoten) povezani su sa vi&scaron;om antiradikalskom aktivno&scaron;ću na superoksid-anjon radikal, dok su fenolna jedinjenja detektovana u hidrofilnim ekstraktima (hidroksicinamati, flavonoli i dihidrohalkoni) bila efikasnija u redukciji jona gvožđa. Etanolni ekstrakt tropa paradajza pokazao je inhibitornu aktivnost na angiotenzin-konvertujući enzim pri koncentraciji ekstrakta od 10 mg/ml.<br />Kečap proizveden od svežeg tropa paradajza, kečap proizveden od liofilizata tropa paradajza i marmelada proizvedena od liofilizata tropa paradajza su bili okarakterisani povećanim sadržajem prehrambenih vlakana (preko 3 g na 100 g proizvoda), na osnovu kog mogu da se deklari&scaron;u kao izvor vlakana. Marmelada je proizvedena od liofilizovanog tropa paradajza bez dodatka hidrokoloida, sa 20% manjim sadržajem &scaron;ećera u odnosu na komercijalne proizvode.<br />Reolo&scaron;ka svojstva kečapa proizvedenog od svežeg tropa paradajza su prevashodno zavisila od koncentracije nerastvorljivih čestica. Rezultati senzorske ocene sprovedene uz primenu panela treniranih ocenjivača, ukazuju da su miris na paradajz i aroma paradajza bili najvažniji za jasno razlikovanje kečapa proizvedenog od svežeg tropa paradajza od komercijalnih proizvoda.<br />Kečap i marmelada proizvedeni od liofilizovanog tropa paradajza se, kao reolo&scaron;ki sistemi, mogu opisati modifikovanom frakcionom Kelvin-Voigt-ovom jednačinom kao viskoelastična tela. Ispitivanje model sistema sastavljenih od različitih odnosa liofilizata tropa paradajza i vode tretiranih na temperaturi od 60&deg;C i 100&deg;C ukazalo je da su vrednosti modula elastičnosti (G&rsquo;) zavisile od koncentracije liofilizata tropa i da su G&rsquo; vrednosti niže na 100&deg;C u odnosu na 60&deg;C. Test dopadljivosti kečapa i marmelade od liofilizovanog tropa paradajza, sproveden primenom hedonske skale od 1 do 7, ukazuje da su oba proizvoda prihvaćena od strane potro&scaron;ača (prosečna ocena za ukupnu dopadljivost veća od 4).</p> / <p>This dissertation describes processes for utilization of tomato processing byproduct (tomato pomace) as raw material for value-added food products. Research was conducted in two directions: one is production of lipophilic and hydrophilic tomato pomace extracts using solvents that are allowed for use in the food industry (n-hexane and 95% ethanol) and their characterization in terms of content and composition of phytochemicals and their in vitro biological activity; the other one is development of formulations and technological processes for the creation of tomato pomace based products with increased content of dietary fiber and their characterization in terms of nutritional, rheological and sensory properties. Three products with increased dietary fiber content were produced: ketchup was produced from fresh tomato pomace, and ketchup and jam were produced from lyophilized tomato pomace powder.<br />Produced lipophilic and hydrophilic extracts showed ferric ion reducing ability, as well as DPPH, nitric oxide and superoxide anion radical scavenging activity. Carotenoids detected in lipophilic extracts (lycopene and &beta;-carotene) were correlated with higher superoxide anion radical scavenging activity, while phenolic compounds detected in hydrophilic extracts (hydroxycinnamates, flavonols and dihydrochalcones) were more effective in ferric ion reduction.<br />Ketchup produced from fresh tomato pomace, ketchup produced from lyophilized tomato pomace, and jam produced from lyophilized tomato pomace were characterized by increased content of dietary fiber (more than 3 g per 100 g of product). Jam was produced from the lyophilized tomato pomace without addition of hydrocolloids, with 20% lower sugar content in comparison with commercial products. Rheological properties of ketchup produced from fresh tomato pomace primarily depended on the insoluble particles content. The results of sensory analysis indicate that tomato odor and flavor were the most important for clear separation of ketchup produced from fresh tomato pomace from commercial products.<br />Ketchup and jam produced from lyophilized tomato pomace could be described, as rheological systems, by the application of modified fractional Kelvin-Voigt model as viscoelastic solids. The examination of model systems comprised of different lyophilized tomato pomace:water ratios heat treated at 60&deg;C and 100&deg;C indicated that storage modulus (G&rsquo;) values depended on the concentration of lyophilized tomato pomace and that G&rsquo; values were lower at 100&deg;C than at 60&deg;C. Preference test for ketchup and jam, conducted by application of 7-point hedonic scale, indicated that both products were accepted by the consumers (average score for overall acceptability higher than 4).</p>

L’amidon, biopolymère de réserve, composant majeur des céréales et des plantes de grande culture, trouve de nombreuses applications industrielles après transformation hydrothermique. L’objectif de la thèse est d’étudier les modifications des propriétés structurales et fonctionnelles de l’amidon de maïs standard modifié par traitement physique, de type hydrothermique à l’aide de trois procédés. L’intensification des traitements, dans un contexte où le développement durable apparaît comme une priorité majeure, s’inscrit dans la large thématique de la valorisation des agro-ressources et du développement des procédés de transformation consacrés aux ressources carbonées renouvelables. La caractérisation des modifications des propriétés physicochimiques de l’amidon,générées par les traitements a été réalisée, dans l’objectif de relier les différences aux comportements thermique(transitions de phase, empesage) et rhéologique (comportement à l’écoulement et viscoélasticité) des amidons hydrotraités. Les traitements physiques appliqués aux amidons ont conduit à des modifications plus ou moins importantes de leurs structures. La maîtrise de l’utilisation de l'amidon nécessite la bonne connaissance des transitions de phase impliquées et des structures résultantes, fonction principalement de la teneur en eau et de la température. Dans cet objectif, une partie des travaux de thèse a été consacrée à la compréhension des phénomènes physiques à l’origine des transferts de matière et de chaleur dans le matériau amylacé pendant son hydrotraitement, ainsi que les équations régissant ces transferts. Un modèle phénomènologique de transfert couplé de masse et de chaleur a été développé, tenant compte des réactions biochimiques qui ont lieux simultanément dans le matériau, en présence d’eau et de chaleur. Les résultats de la modélisation numérique, à l’aide de la méthode des éléments finis, a permis de définir la répartition spatiale, des paramètres variables(température, teneur en eau,…), dont l’influence est déterminante sur la progression des réactions de fusion. / Starch, biopolymer of reserve, is the major component of cereals and of crop plants, has many industrial applications after hydrothermal processes. The objective of this work is to study the structural and function almodifications of standard maize starch by physical processes, as hydrothermal treatments (action of heat and moisture). The intensification of treatments, in a context of sustainable development, is nowadays a major challenge. This action belongs to the themes linked to the agri-resources valorisation and the development of the transformation processes devoted to the renewable carbonaceous resources. The impact of hydrothermaltreatments on starch physicochemical properties is extensively studied with the aim to connect the modificationof hydrotreated starches to their thermal (phase transitions, pasting) and rheological (flow and viscoelasticity)behaviours. The physical treatments applied to starches lead to important modifications of their structures,according to the processing conditions. The mastering of starch use requires the knowledge of implied phase transitions and resulting structures, which are mainly function of water content and temperature. In this aim, apart of this work was devoted to the comprehension of the physical phenomena responsible of the heat and mass transfer in the starch layer, during the treatment. A coupled heat and mass transfer model was developed, taking into account the biochemical reactions, which take place in the material simultaneously in presence of water and heat. Using the finite element method, the numerical simulation allowed to define the space distribution of the variable parameters (temperature, water content,…), which have a great influence on the progression of fusion reactions.

Ligante asfáltico e borracha moída de pneus são materiais, na maioria das vezes, de difícil compatibilização, exigindo a adição de produtos químicos que facilitem a dispersão e a incorporação da borracha, como, por exemplo, os óleos extensores. A presente pesquisa tem por objetivo verificar a hipótese de que o resíduo de óleo de xisto, por se tratar de um óleo aromático, presta-se bem como óleo extensor de borracha, permitindo, inclusive, a adição de teores de borracha maiores que os normalmente incorporados aos ligantes asfálticos na ausência de óleos extensores. A tentativa de verificação de tais hipóteses foi efetuada por meio de uma programação laboratorial dividida em duas etapas. A primeira englobou uma investigação sobre o efeito da borracha moída e do resíduo de óleo de xisto sobre características físicas de 27 ligantes asfálticos, a fim de modelar diversas propriedades reológicas desses materiais, tendo como variáveis previsoras as porcentagens de componentes e as variáveis de processo. Na segunda etapa, foram estudados 8 ligantes asfálticos, a fim de obter dados para a validação dos modelos definidos na primeira etapa e também para a modelagem de propriedades não contempladas na primeira fase. Em ambas as fases, o planejamento dos experimentos foi efetuado empregando a técnica estatística de experimentos com misturas. A caracterização física dos ligantes asfálticos foi efetuada por meio de ensaios tradicionais (ponto de amolecimento, penetração e resiliência) e da especificação Superpave (viscosidade aparente, balanço de massa, cisalhamento dinâmico e fluência na flexão), em ligantes virgens e submetidos às práticas de envelhecimento a curto e longo prazos indicadas pela especificação Superpave (RTFOT e PAV). Ensaios de estabilidade à estocagem também foram realizados. Há evidências de que o resíduo de óleo de xisto pode ser empregado como óleo extensor em ligantes asfalto borracha, porém a seleção das concentrações adequadas dos componentes (asfalto, borracha e resíduo de óleo de xisto) depende do monitoramento de propriedades reológicas nas temperaturas de ocorrência dos principais defeitos do pavimento na região de implantação da rodovia. / Asphalt binder and crumb rubber from discarded tires are materials that, most of time, are not compatible, requiring the addition of chemical products to facilitate the dispersion and incorporation of rubber particles as, for example, the extender oils. This research aims at evaluating the hypothesis that the shale-oil residue, once it is an aromatic oil, may be used as an extender oil for asphalt-rubber binders, allowing the incorporation of crumb-rubber proportions even higher than those usually added to asphalt binders without extender oils. The effort to verify these hypotheses was made by means of a laboratorial program divided in two steps. In the first step an investigation was carried out to assess the effects of crumb rubber and shale-oil residue on physical characteristics of twenty seven asphalt binders, in order to model rheological properties of these materials, using the component proportions and the process variables as predictor variables. In the second step, eight asphalt binders were studied, to obtain data to validate the original models and to model some properties that were not monitored in the first step. In both steps, the experiment was designed using the statistical technique of experiments with mixtures. The physical characterization of the asphalt binders was performed using traditional tests (softening point, penetration and resilience) and those of Superpave specification (apparent viscosity, mass loss, dynamic shear and flexural creep), with materials in three conditions: virgin, short-term aged (RTFOT) and long-term aged (PAV). Storage stability tests were also performed. There are evidences that the shale-oil residue can be used as an extender oil in asphalt-rubber binders, but the selection of the adequate concentrations of the components (asphalt, rubber and oil) depends on the measurement of rheological properties in the temperatures at which the main pavements distresses occurs in the place the road will be constructed.

This work studied the rheological and mechanical properties of polyamide 12 modified montmorillonite clays and bentonita (the organo-modified commercial montmorillonite and a bentonite modified by various routes. Two polyamides 12 were used for the polyamide matrix, a virgin and another reprocessed. The polyamide 12 reprocessed was derived from tailings lines of fluid transport in automotive vehicles. Ten different compositions were prepared in single-screw extruder, and subsequently molded test specimens by injection. For formulations reprocessed polyamide 12, were added 5 to 7 wt.% of a commercial organo-modified montmorillonite ( I44P ) and the virgin polyamide 12 , 3 and 5 wt.%. For virgin polyamide matrix, also formulations were studied with 3 and 5% by weight of bentonite treated with Agent Titanate. The nanocomposite structure formation was evaluated by X-ray diffraction. For all developed formulations, mechanical and rheological tests, and their results were correlated performed: polyamide matrices, the content and the treatments of the clays. Clay dispersion and morphology of the fracture surface were analyzed by SEM. The analysis results showed distinct mechanical and rheological behaviors depending on the type of matrix, the degree of dispersion of clay, content and type of treatment of clays. There was formation of nanocomposites for polyamide 12 modified with I44P clay and composites for polyamide 12 modified bentonite. The rheological properties confirm the increase of the elastic properties of the nanocomposites due to the restriction to macromolecular mobility. The addition of organophilic commercial montmorillonite (I44P) promoted the increased stiffness of the nanocomposites without significant loss of toughness. / Este trabalho estudou as propriedades reológicas e mecânicas de poliamida 12 modificadas com montmorilonitas, sendo uma montmorilonita organofilica comercial (I44P) e montmorilonita sódica (bentonita) modificada por diversas rotas. Para a matriz de poliamida, foram utilizadas duas poliamidas 12, sendo uma virgem e a outra reprocessada oriunda de rejeito de linhas de transporte de fluídos em veículos automotores. Foram preparadas dez composições diferentes em extrusora monorrosca e, posteriormente, moldados corpos de prova por injeção. Para as formulações de poliamida 12 reprocessada, foram adicionados 5 e 7% em massa de montmorilonita organofílica comercial e para a poliamida 12 virgem, 3 e 5%. Para esta mesma matriz de poliamida virgem, também foram estudadas formulações com 3 e 5% em massa das bentonitas tratadas com agente titanato. A formação de estrutura de nanocompósitos foi avaliada por difração de raios-X. Para todas as formulações desenvolvidas, foram realizados ensaios mecânicos e reológicos, e seus resultados correlacionados com: as matrizes de poliamida, o teor e os tratamentos das argilas. A dispersão da argila e a morfologia da superfície de fratura foram avaliadas por MEV. Os resultados das análises mostraram comportamentos mecânicos e reológicos distintos em função do tipo de matriz, grau de dispersão das argilas, o teor e o tipo de tratamento das argilas. Houve formação de nanocompósitos para poliamida 12 modificada com a argila I44P e de compósitos para poliamida 12 modificada com bentonitas. As propriedades reológicas confirmam o aumento das propriedades elásticas dos nanocompósitos devido à restrição a mobilidade macromolecular. A adição da montmorilonita organofilica comercial (I44P) promoveu o aumento da rigidez dos nanocompósitos sem perdas significativas da tenacidade.

Ligante asfáltico e borracha moída de pneus são materiais, na maioria das vezes, de difícil compatibilização, exigindo a adição de produtos químicos que facilitem a dispersão e a incorporação da borracha, como, por exemplo, os óleos extensores. A presente pesquisa tem por objetivo verificar a hipótese de que o resíduo de óleo de xisto, por se tratar de um óleo aromático, presta-se bem como óleo extensor de borracha, permitindo, inclusive, a adição de teores de borracha maiores que os normalmente incorporados aos ligantes asfálticos na ausência de óleos extensores. A tentativa de verificação de tais hipóteses foi efetuada por meio de uma programação laboratorial dividida em duas etapas. A primeira englobou uma investigação sobre o efeito da borracha moída e do resíduo de óleo de xisto sobre características físicas de 27 ligantes asfálticos, a fim de modelar diversas propriedades reológicas desses materiais, tendo como variáveis previsoras as porcentagens de componentes e as variáveis de processo. Na segunda etapa, foram estudados 8 ligantes asfálticos, a fim de obter dados para a validação dos modelos definidos na primeira etapa e também para a modelagem de propriedades não contempladas na primeira fase. Em ambas as fases, o planejamento dos experimentos foi efetuado empregando a técnica estatística de experimentos com misturas. A caracterização física dos ligantes asfálticos foi efetuada por meio de ensaios tradicionais (ponto de amolecimento, penetração e resiliência) e da especificação Superpave (viscosidade aparente, balanço de massa, cisalhamento dinâmico e fluência na flexão), em ligantes virgens e submetidos às práticas de envelhecimento a curto e longo prazos indicadas pela especificação Superpave (RTFOT e PAV). Ensaios de estabilidade à estocagem também foram realizados. Há evidências de que o resíduo de óleo de xisto pode ser empregado como óleo extensor em ligantes asfalto borracha, porém a seleção das concentrações adequadas dos componentes (asfalto, borracha e resíduo de óleo de xisto) depende do monitoramento de propriedades reológicas nas temperaturas de ocorrência dos principais defeitos do pavimento na região de implantação da rodovia. / Asphalt binder and crumb rubber from discarded tires are materials that, most of time, are not compatible, requiring the addition of chemical products to facilitate the dispersion and incorporation of rubber particles as, for example, the extender oils. This research aims at evaluating the hypothesis that the shale-oil residue, once it is an aromatic oil, may be used as an extender oil for asphalt-rubber binders, allowing the incorporation of crumb-rubber proportions even higher than those usually added to asphalt binders without extender oils. The effort to verify these hypotheses was made by means of a laboratorial program divided in two steps. In the first step an investigation was carried out to assess the effects of crumb rubber and shale-oil residue on physical characteristics of twenty seven asphalt binders, in order to model rheological properties of these materials, using the component proportions and the process variables as predictor variables. In the second step, eight asphalt binders were studied, to obtain data to validate the original models and to model some properties that were not monitored in the first step. In both steps, the experiment was designed using the statistical technique of experiments with mixtures. The physical characterization of the asphalt binders was performed using traditional tests (softening point, penetration and resilience) and those of Superpave specification (apparent viscosity, mass loss, dynamic shear and flexural creep), with materials in three conditions: virgin, short-term aged (RTFOT) and long-term aged (PAV). Storage stability tests were also performed. There are evidences that the shale-oil residue can be used as an extender oil in asphalt-rubber binders, but the selection of the adequate concentrations of the components (asphalt, rubber and oil) depends on the measurement of rheological properties in the temperatures at which the main pavements distresses occurs in the place the road will be constructed.

Statics, dynamics, rheology and scission-recombination kinetics of self-assembling linear micelles are investigated at equlibrium state and under shear flow by computer simulations using a newly proposed mesoscopic model. We model the micelles as linear sequences of Brownian beads whose space-time evolution is governed by Langevin dynamics. A Monte Carlo algorithm controls the opening of a bond or the chain-end fusion. A kinetic parameter omega modelling the effect of a potential barrier along a kinetic path, is introduced in our model.<p>For equilibrium state we focus on the analysis of short and long time behaviors of the scission and recombination mechanisms. Our results show that at time scales larger than the life time of the average chain length, the kinetics is in agreement with the mean-field kinetics model of Cates. By studying macroscopic relaxation phenomena such as the average micelle length evolution after a T-jump, the monomer diffusion, and the zero shear relaxation function, we confirm that the effective kinetic constants found are indeed the relevant parameters when macroscopic relaxation is coupled to the kinetics of micelles.<p>For the non-equilibrium situation, we study the coupled effects of the shear flow and the scission-recombination kinetics, on the structural and rheological properties of this micellar system. Our study is performed in semi-dilute and dynamically unentangled regime conditions. The explored parameter omega range is chosen in order for the life time of the average size chain to remain shorter than its intrinsic (Rouse) longest relaxation time. Central to our analysis is the concept of dynamical unit of size Lambda, the chain fragment for which the life time tau_Lambda and the Rouse time are equal. Shear thinning, chain gyration tensor anisotropy, chain orientation and bond stretching are found to depend upon the reduced shear rate Beta_Lambda=gamma dot*tau_Lambda while the average micelle size is found to decrease with increasing shear rate, independently of the height of the barrier of the scission-recombination process. / Doctorat en sciences, Spécialisation physique / info:eu-repo/semantics/nonPublished