Nesta dissertação de mestrado analisa-se e compara-se, através de ensaios laboratoriais, o comportamento mecânico e de adesividade de misturas em concreto asfáltico, confeccionadas a partir de ligantes asfálticos modificados e convencionais. O conhecimento e entendimento destas características são de extrema importância, pois refletem diretamente no desempenho do pavimento em serviço. Foram estudadas misturas elaboradas com um ligante convencional e três ligantes modificados por polímeros. Todas as misturas foram dosadas segundo a metodologia Marshall, e submetidas a ensaios laboratoriais de módulo de resiliência e resistência à tração por compressão diametral, resistência à fadiga com tensão controlada, fluência por compressão uniaxial dinâmico e dano por umidade induzida. Para uma avaliação combinada entre a rigidez e os modelos de fadiga das misturas, também realizou-se uma análise paramétrica de estruturas hipotéticas de pavimentos. Os resultados obtidos mostraram, na maioria dos casos, o melhor comportamento à fadiga das misturas elaboradas a partir de ligantes modificados. Embora pouco consistentes, os resultados de resistência à deformação permanente também indicam a superioridade das misturas modificadas. Entretanto, a mistura com ligante convencional foi a que se mostrou menos suscetível à temperatura nos ensaios de módulo de resiliência. Já os resultados do ensaio de dano por umidade induzida mostraram bom desempenho de todas as misturas, ainda que não se possa quantificar a influência do tipo de ligante sobre eles. / This research analyses and compares, trough laboratory tests, the mechanical and the stripping behavior of asphalt concrete mixtures, prepared with traditional and modified binders. The understanding of these characteristics is extremely important, since they reflect directly on pavements performance. Mixtures prepared with one traditional binder and three polymers modified binders. All mixtures were prepared following the Marshall methodology, and submitted to laboratory tests of resilient modulus, tensile strength, fatigue life (stress controlled), dynamic creep and resistance to moisture damage. In order to assess a combination of fatigue and stiffness modulus of the mixtures, a parametric analysis of hypothetical pavement structures was also done. The results obtained showed, in most cases, best behavior regarding fatigue of the mixtures prepared with modified binders. Although not very consistent, the results of permanent deformations resistance also indicate the superiority of the modified mixtures. However, the conventional binder mixture showed the lowest thermal susceptibility in the resilient modulus tests. The results of moisture damage resistance tests showed good performance for all mixtures, but it is not possible to quantify the influence of the binder type on then.

Artigos de couro estão associados com tendências de moda e sofisticação em produtos de consumo. No processamento do couro, a fase de acabamento consiste de um conjunto de operações e tratamentos, essencialmente de superfície, que conferem características finais ao produto. Os objetivos do acabamento são reduzir defeitos visíveis, modificar as propriedades superficiais e melhorar os atributos de uso. Nesta fase final, são aplicadas, dentre outros produtos, resinas, geralmente, poliacrilatos e poliuretanos, e algumas vezes caseínas e outros polímeros que formam filmes de recobrimento protetores sobre o couro. Nesse contexto, este trabalho visa a uma avaliação dos filmes formados com resinas comerciais utilizadas industrialmente no acabamento de couros, relacionando a composição destes materiais com características sensoriais, com resistência mecânica, através de testes de tração, com estabilidade à água ou a solvente orgânico, com análise de dureza, e através de caracterizações por infravermelho e DSC. Ensaios de tração mostraram que as resinas poliuretânicas, no geral, apresentam uma maior resistência à tração quando comparadas com resinas acrílicas, assim como os valores de tenacidade, indicando que esses filmes suportam um maior impacto para levar o material à ruptura. A adição de pigmentos diminui essa resistência, tanto em resinas acrílicas quanto em resinas poliuretânicas, enquanto que a produção de filmes compactos apresenta características intermediárias com relação aos componentes puros. Todos os filmes acrílicos testados apresentaram uma maior capacidade de alongamento. Com relação à dureza, as resinas que se mostraram mais flexíveis e com maior alongamento, foram as que apresentaram menor dureza. A estabilidade dos filmes com relação à água e solventes mostrou que os componentes solúveis em água e em solvente aumentam com a presença de pigmento e que a absorção de água é maior e de solvente é menor em filmes com pigmento, tanto para acrilatos quanto para poliuretanos. As caracterizações a partir de análise por FTIR e DSC indicaram os grupamentos químicos e picos de temperaturas característicos dos acrilatos e poliuretanos, respectivamente. / Leather goods are associated with fashion trends and sophistication in consumer products. In the leather processing, the finishing phase consists of a series of operations and treatments, essentially in surface, conferring its final characteristics. The objectives are to reduce visible defects, modify surface properties and improve the usage attributes In this final stage are applied, among other products, resins, generally polyacrylates and polyurethanes, sometimes casein and other polymers, which form protective coating films on leather. In this context, this paper evaluates the films formed with commercial polymeric resins used industrially in finishing leather, relating the composition of these materials with their sensory characteristics, with their strength by tensile testing, with its stability to water or organic solvent, with analysis of hardness and characterizations by IR and DSC. Tensile tests showed that the polyurethane resins in general have a higher tensile strength when compared with acrylic resins, as well as the toughness values, indicating that these films support a greater impact to bring the material to rupture. The addition of pigments decreases this resistance, for acrylic resins and polyurethane resins, while the production of compact film has intermediate characteristics with respect to the pure components. All acrylic films tested had a higher elongation. With respect to hardness, the resins that were more flexible and more stretching, showed the lowest hardness. The stability of the films with respect to water and solvents has shown that water soluble solvent components increased by the presence of pigment and the water absorption is higher and the solvent is lower in pigmented films to acrylates and polyurethanes. The characterizations from IR and DSC analysis indicated the chemical groups and characteristic temperatures peaks of acrylates and polyurethanes, respectively.

This master’s thesis is focused on preparation of the mortar mixtures inspired by roman cement with a great resistivity against the corrosion environment, especially a seawater. There were prepared samples of a roman cement containing of pure lime and various artificial pozzolans and natural tuff which were used as pozzolan admixtures. The task of this work is to explore possibility of using pure lime and for example pozzolan admixture which can resist against the corrosive environment like a roman cement. There were prepared a lot of various samples which were tested separately on their mechanical characteristics before and after their exposure of the influence of the corrosive environment. There were used X-ray diffraction analysis for the characterization of a phase composition of the raw materials and some selected samples.

Diploma thesis studies historical bonding agents on the base of geopolymers. The aim of the thesis is to find a proper material composition, especially made of natural clay materials (kaolinite, bentinite) and their modifications (metakaoline). These bonding agents have to have a suitable type of an activator that guarantees good bonding properties. Therefore testing of various kinds of alkaline activating ingredients on the same mineral composition was done. Except of usual hydroxides and a water glass, ancient natrons (mixtures of alkaline carbonate with addition of appropriate chlorides) and a lime mash were used as the activators. From the above mentioned mixtures, series of samples (columns 20 x 20 x 100 mm) stored at the laboratory temperature were prepared. In the prepared mashes, their workableness and moulding were investigated. In the developed samples, their surface appearance was observed together with a number of efflorescence and its types. An indivisible part of the research was formed by determination of mechanical properties of the experimental columns such as a compressive strength and a tensile strength in bending. Furthermore, phase composition of the samples and its changes with a temperature increase were investigated. For these tests, XRD and TG – DTA methods were used. A multi-seat isoperbolic calorimeter was used to study hydratation that was also the important part of the general evaluation of designed mixtures.

Evaluation of physical and chemical properties of geopolymer composites based on alkali aktivated metakaoline and silicate oxide.

Abstract: Oil pollution and spills cause serious damage to marine ecosystems and coastal environments. Currently, oily waters recuperated form a spill must be shipped onshore for treatment. This limits the volume of water that can be treated during a spill. There is a need to develop technologies to treat oily waters below 15 ppm (parts per million) at the site of the spill. Synthetic membrane technologies are widely used in water treatment and purification. They can offer an on-site solution to contaminated oily water treatment in oil production and spills. The suitability of a membrane for use in this application is determined by the type of material used in its fabrication. Compared to polymeric membranes, inorganic membranes are inert to microbiological degradation, offer high chemical and thermal resistance, and can easily be backflushed and cleaned once fouled. However, inorganic membranes consisting of metal oxides are heavier and more expensive than polymeric membranes, due to their bulky and brittle ceramic support layers. This limits their application when the overall weight of a process unit is of concern. A newly developed 2D/3D material, named twinned alumina nanosheets (TAN), has recently been used to make dynamic membranes. The nanoplatelets forming TAN have a length of 4 µm, a width of 1 µm, and a thickness of 100 nm. They have a very high permeability, a 0.2 µm-pore size and a porosity up to 88% due to their low nanosheet volume. These unique characteristics make TAN a very promising material to form membrane selective layers. However, they must be supported on a very open layer in order to take advantage of their high porosity. In this work, a composite membrane was produced with a selective layer of 2D/3D alumina nanoplatelets deposited onto stainless steel meshes and ceramic supports. The structure of the TAN in the selective layer was reinforced with binders. The main objective of this work was to verify the adhesion of the TANs onto the support. The crystallization of TAN was optimized to obtain an open 2D/3D structure. This structure was then deposited on a stainless-steel mesh. The mesh was pretreated by electrochemical etching to achieve a re-entrant surface. The mesh was immersed in an etching solution and placed parallel to a conductive graphite plate under a constant electric potential of 5V for 4 min. Aqueous solutions of silica sol and colloidal silver were tested as binding agents. They were deposited on the mesh with TAN and sintered for 4 hrs. Experiments were performed on testing stainless steel meshes with different opening sizes and comparing different calcination temperatures. The best sintering temperature was 800°C for a mesh with an opening size of 35µm. The synthesized membrane was challenged with a suspension of 10 ppm bentonite clay at a constant pressure of 100 mbar. The integral structure of a TAN membrane produced with a 2.5wt% silica binder was maintained after backflushing. The 2.5wt% silica membrane had a high flux and the particle filtration process for this membrane was modelled as pore constriction and intermediate blocking, indicating that backflushing provided the deep cleaning of pores. According to the SEM images, the 2.5wt% silica membrane preserved the integral structure of the TAN, while the pores tended to fill with silica at higher silica concentrations. The effective pore size of the 2.5wt% silica membrane was estimated to be the smallest, which is approximately 0.53 μm. The 7.5wt% silica membrane had half the permeate flux of the other membranes, because of the high concentration of binder filling the pores of the TAN selective layer. The SiO 2 binder had a positive effect in reinforcing the TAN particles. The flux of the membrane did not increase after backflushing indicating that the selective layer of the membrane was securely bound to the stainless steel mesh. The membrane exhibited flux decline between backflushings indicating that particles were retained on its surface. SEM images taken after the filtration showed that this membrane completely released bentonite particles form its pores. Tests were also performed with a membrane having two TAN coatings on the wire mesh. This reduced the flux but did not improve the retention of fine particles. Colloidal silver was found to be a poor binding agent as particles were released particles from its selective layer. Silica was a highly successful binding agent while colloidal silver was not. TAN was also successfully deposited onto ceramic supports. It was also retained on top of the membrane after backflushing. The results of this work demonstrate that TANs reinforced and bound with silica are a promising type of material to form membrane selective layers. These layers have an open pore structure with a three-dimensional channel connectivity on both stainless steel and ceramic supports. The selective layer was successfully bound to the stainless steel supports. If the pore size of this membrane were to be reduced, it would meet the requirements for use at the site of an oil spill to treat contaminated waters as it does not need the heavier supports found in traditional ceramic membranes. Résumé: La pollution et les déversements d'hydrocarbures causent de graves dommages aux écosystèmes marins et aux environnements côtiers. À l'heure actuelle, les eaux huileuses récupérées d'un déversement doivent être expédiées à terre pour leur décontamination. Ceci limite le volume d’eau contaminé qui peut être traité. Il est nécessaire de développer des technologies permettant de traiter les eaux huileuses en dessous de 15 ppm (parties par million) sur le site du déversement. Les technologies membranaires sont largement utilisées dans le traitement et la purification de l'eau. La possibilité de se servir d’une membrane dans cette application est déterminée par les matériaux utilisés dans sa fabrication. Comparées aux membranes polymères, les membranes inorganiques sont inertes vis-à-vis de la dégradation microbiologique, offrent une résistance chimique et thermique élevée et peuvent facilement être rincées et nettoyées une fois encrassées. Cependant, les membranes inorganiques constituées d'oxydes métalliques sont plus lourdes et plus coûteuses que les membranes polymères, en raison de leurs couches de support en céramique volumineuses et cassantes. Cela limite leur application lorsque le poids total d'une unité de traitement est préoccupant. Un matériau 2D/3D récemment développé, appelé TAN (Twinned Alumina Nanosheets), a récemment été utilisé dans la formation de membranes dynamiques. Les nano-plaquettes formant les TAN ont une longueur de 4 µm, une largeur de 1 µm et une épaisseur de 100 nm. Ils ont une très haute perméabilité, une taille de pores de 0,2 µm et une porosité allant jusqu'à 88% en raison du faible volume des nanofeuilles. Ces caractéristiques uniques font du TAN un matériau très prometteur pour la formation de couches sélectives de membranes. Cependant, ils doivent être déposes sur une couche très ouverte afin de tirer parti de leur grande porosité. Au cours de ce travail, une membrane composite a été réalisée avec une couche sélective de nanoplaques d’alumine 2D / 3D (TAN) déposées sur deux types de supports; des mailles en acier inoxydable et des supports en céramique. La structure du TAN dans la couche sélective a été renforcée avec des liants. L'objectif principal de ce travail était de vérifier l'adhérence des TAN sur le support. La cristallisation des TAN a été optimisée pour obtenir une structure 2D/3D ouverte. Cette structure a ensuite été déposée sur un treillis en acier inoxydable. Les mailles ont été prétraitées pour obtenir une surface réentrante. Le maillage a été immergé dans une solution de gravure et placé parallèlement à une plaque de graphite conductrice sous un potentiel électrique constant de 5 V pendant 4 min. Des solutions aqueuses de sol de silice et d’argent colloïdal ont été testées en tant que liants. Ils ont été déposés sur la maille et frittés pendant 4 heures. Des expériences ont été effectuées sur des mailles en acier inoxydable avec différentes tailles d’ouverture et températures de calcination. La meilleure température de frittage était de 800 ° C pour un treillis ayant une taille d'ouverture de 35 µm. La membrane synthétisée a été mise à l’essai avec une suspension de 10 ppm d'argile bentonite à une pression constante de 100 mbar. La structure intégrale de la membrane couche de TAN produite avec un liant à 2,5wt% de silice a été maintenue après les tests de perméabilité. La structure 3D poreuse a tendance à se remplir de silice à des concentrations de silice supérieures à 2,5wt%. La taille effective des pores de la membrane produite avec 2,5wt% de liant de silice a été estimée à 0,53 µm. Le flux de la membrane n'a pas augmenté après le rinçage, indiquant que la couche sélective de la membrane était liée de manière sûre au maillage en acier inoxydable. La membrane présentait un déclin de flux entre les rinçages indiquant que des particules étaient retenues à sa surface. Les images au microscope à balayage prises après la filtration ont montré que cette membrane libère complètement les particules de bentonite de ses pores. Des essais ont également été réalisés avec une membrane comportant deux revêtements TAN sur le treillis métallique. Cela réduit le flux mais n'améliore pas la rétention des particules fines. L'argent colloïdal s'est avéré être un agent de liaison médiocre car des particules sont libérées de sa couche sélective. La silice était un liant très efficace, contrairement à l'argent colloïdal. Le TAN a également été déposé avec succès sur des supports en céramique. Il est également resté sur la membrane après le rinçage à contre-courant. Les résultats de ce travail démontrent que les TAN renforcés avec un liant de silice sont un type de matériau prometteur pour former des couches sélectives, avec des structures à pores ouverts possédant une connectivité de canal tridimensionnelle, sur des supports en acier inoxydable et en céramique. La couche sélective a été liée avec succès au support en acier inoxydable. Si la taille des pores de cette membrane devait être réduite, elle pourrait être utilisée sur le site d'un déversement d'hydrocarbures pour traiter les eaux contaminées car elle ne nécessite pas les supports plus lourds que l'on trouve dans les membranes de céramique traditionnelles.

The current interest in energy saving asphalt production techniques is great and several new processes have been developed to reduce the mixing and compaction temperatures for hot mix asphalt. In particular, mastic asphalt products (Gussasphalt) require high working temperatures, and harder requirements concerning bitumen fumes and carbon dioxide emissions have been introduced for such products. Consequently, the need of a new means of producing and placing mastic asphalt at lower temperatures is particularly large. One way of reducing asphalt mixture temperature is by using special flow improving additives like wax. This technique has successively been tried in several studies for polymer modified mastic asphalt used for bridge decks and parking areas in Sweden. However, there still are uncertainties about possible negative impact on crack susceptibility at lower temperatures due to the addition of wax. In this study, 4% montan wax (Asphaltan A) was used for one particular polymer modified mastic asphalt product. Type and amount of wax additive was selected based on results from earlier studies. The impact on binder, binder/filler mixtures and mastic asphalt from production was tested in the laboratory, focusing on low temperature performance. The bending beam rheometer (BBR) was used for determining low temperature creep compliance and the tensile stress restrained specimen test (TSRST) for determining fracture temperatures. Binder properties were determined using dynamic mechanical analysis (DMA), Fourier transform infrared (FTIR) spectroscopy and conventional tests (softening point, penetration, elastic recovery, Fraass breaking point, viscosity and storage stability). Aging was performed using the rolling thin film oven test (RTFOT) at 200°C. As expected, the addition of wax to the polymer modified binder showed a viscosity reduction at higher temperatures, corresponding to a similar positive effect of more than 10°C on production and laying temperature for the mastic asphalt. DMA and BBR results showed some increase in stiffness and a more elastic response of the wax modified binder at medium and low temperatures. The TSRST fracture temperature was 5 °C higher for the mastic asphalt containing 4% wax, indicating however no dramatic negative impact on crack susceptibility.

Finding innovative technologies for building our roads has always been of paramount importance. From moving to warm mix asphalt to decrease our indulgence in high energy consumption to substituting fly ash for asphalt binders to reduce dependence on pure asphalt binders from petroleum, engineers have painstakingly tried to develop new ways to improve the ways that flexible pavements are made. The major problem facing the next generation of civil engineers is sustainable practices on the field. Over the years, significant progress has been made in this regard on the impacts of building pavements on the environment. Characterizing these improvements tends to be difficult, and that is where Life Cycle Assessment (LCA) comes in. LCA is a technique used to analyze and quantify the environmental impacts of a product, system, or process. LCA shows where the significant impacts occur and how improvements can be made while recommending better practices. Even with its many advantages, its use is very constrained, especially in the United States, as it is still a very novel approach in design coupled with limited datasets and protocol for its operation. With modern technologies of substitute materials for binders like bio-oil from food waste, reclaimed asphalt pavement (RAP), and fly ash, there is a need to understand their environmental impacts. Furthermore, in this regard is where LCA can help using three significant areas: selection of materials, normalization, and characterization. Characterization refers to the identification and quantification of the relationships between the life cycle results and the environmental impacts. This research explores the environmental impacts of substituting other materials for asphalt binders using LCA. With variations in modifying levels of substitutes, results show promising levels in emissions of harmful gasses to both the air and water. This study explores ways used in normalizing this process as well as setting up a pathway for other asphalt binder substitutes. / Civil Engineering

No description available.

Elastomeric wastes plague our time, polluting our environment and requiring urgent upcycling solutions. This research contributes to this agenda using an important source of waste, car tyre shred fibre residue (TSFR). It is demonstrated how using binders, non-foaming (SBR) and foaming (PU), we can transform these TSFR into structured porous acoustic-thermal insulation materials, suitable as underlay, cavity wall and pipe insulation. These structures were fabricated in purpose designed moulds and characterised for their porosity, tortuosity, flow resistivity and density. Their acoustic absorption performance was measured using industrial standards and the measurement underpinned with the Johnson-Champoux-Allard (JCA) model. With the under-layer materials, thermal insulation was also measured. The results were as follows: (i) 40%/60% SBR/TSFR was an optimal composition for the underlay with the addition of 15% w/w bumper crumb of size > 1mm enhancing both impact sound and thermal insulation, (ii) PU was found to produce well performing wall cavity insulation, particularly when vacuum pressure was applied, allowing micro and macro pores to be formed; (iii) PU applied with controlled amount of water to control foaming CO2 formation produced super-performing (compared with Armacell System B) stratified pipe cladding insulation, optimal at porosity stratification of 90%, 83%, and 70%; (iv) Very good agreement was observed with predictions using JCA model, allowing further research to be carried out with these now well characterised sound insulations. In addition to the developing materials, a novel technique for measuring sound absorption of pipe cladding was developed that could replace the expensive standard using a reverberation chamber.