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1
Skokan, Jan. "Vliv plastifikátoru na technologii zpracování a vlastnosti slinovaného keramického mateiálu na bázi SiC." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2015. http://www.nusl.cz/ntk/nusl-231997.
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This master’s thesis deals with an influence of physical properties and machining technology at adjustment to the basic composition granules and production of technical ceramics. Selected series of experiments have been applied to the different phases of production. Composition of the granules vary according to the used plasticizer and ranks to RTP (ready-to-press) materials. The goal of this thesis is recomendation to the production of RTP granules and next experiments.
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O'Brien, William John. "Characterisation and material removal properties of the RAP™ process." Thesis, Cranfield University, 2011. http://dspace.lib.cranfield.ac.uk/handle/1826/6560.
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The Reactive Atom Plasma® (RAP) process is a plasma chemical etching process. RAP was developed at RAPT Industries as a process for removing subsurface damage from silicon carbide optics. The process is being investigated at Cranfield University as a novel method for the fine surface correction of large optics, with the aim of shortening the manufacturing period of the next generation of large telescopes. RAP offers material removal rates that are up to 10 times higher than those of ion beam figuring, the current state-of-the-art technique and the convenience in that it can be operated at atmospheric pressure. Cont/d.
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Klekner, Martin. "Aplikace analytických metod využívajících RTG záření v oblasti analýz stavebních materiálů." Master's thesis, Vysoké učení technické v Brně. Fakulta stavební, 2012. http://www.nusl.cz/ntk/nusl-225574.
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Master’s thesis mainly deals with XRF analysis of building materials. Comprehensively analyzes the factors that limit the accuracy of the obtained data, creates a new methodology for the rapid analysis of silicate materials by XRF instrument and discusses the influences determining the reproducibility of the results of XRF analysis.
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Matemilola, Saka Adelola. "Impact damage to composite materials." Thesis, University of Cambridge, 1993. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.319939.
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Al, khasawneh Mohammad. "Evaluation of Novel Construction Technologies and Materials for Roadway Unpaved Shoulders." University of Cincinnati / OhioLINK, 2020. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1595848023340553.
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Dvořák, Vlastimil. "Návrh křidélka z kompozitních materiálů." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2008. http://www.nusl.cz/ntk/nusl-228273.
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This diploma thesis called „Aileron Design of Composite Materials” deals with the technologies of production used in aricraft industries. It shows appropriate conceptions of composite structures for the airplane aileron of Aero L-159A/B as well as a proposal of an accetable structure for RTM process.
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Veeraragavan, Ram kumar. "An Investigation of the Performance of Hot Mix Asphalt (HMA) Binder Course Materials with High Percentage of Reclaimed Asphalt Pavement (RAP) and Rejuvenators." Digital WPI, 2016. https://digitalcommons.wpi.edu/etd-theses/456.
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Use of high percentage of Reclaimed Asphalt Pavement (RAP) material in Hot Mix Asphalt is one of the several sustainable construction alternatives being considered by many Departments of Transportation (DOT). Use of RAP in HMA helps in reducing the consumption of virgin aggregates and binder and construction cost and conserving energy. Although most of the US state agencies allow the use of 30% or more RAP in the design of Hot Mix Asphalt (HMA), the current average RAP usage is only about 10 to 20%. This is because of the uncertainty about the performance of HMA mixes with a high RAP content. Several factors influence the performance of the HMA mixes with a high RAP content. Recent research has shown that the use of a high RAP content in HMA with rejuvenators is successful in reducing the stiffness of the RAP mixes, and thereby improving their performance. The present work is carried out to explore the feasibility of using a high RAP content of 50% in a binder layer HMA with the addition of rejuvenators. Ultrasonic Pulse Velocity (UPV) test was carried out to compare the stiffness of the RAP mixes with and without the addition of rejuvenators. Moisture Induced Stress Test (MIST) was conducted to study the effect of moisture damage on the HMA mixes with high RAP content. The Indirect Tensile Strength Test (ITS) was used to determine the strength of the HMA mixes with high RAP content. In addition, creep compliance and Semicircular Bend (SCB) tests were carried out to determine the cracking potential and fracture strength of the mixes respectively. The addition of rejuvenators was found to significantly reduce the stiffness of the mix with high RAP content. The predicted complex shear modulus (G*) obtained from the Hirsch model and performance grading tests on extracted binders confirmed the effectiveness of the addition of rejuvenators in reducing the stiffness of recycled asphalt binder in the recycled mixes.
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Nguyen, Viet Hung. "Effects of laboratory mixing methods and RAP materials on performance of hot recycled asphalt mixtures." Thesis, University of Nottingham, 2009. http://eprints.nottingham.ac.uk/10863/.
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The primary work reported in this thesis is concerned mainly with the effects of different mixing methods and RAP materials on homogeneity and mechanical properties of hot recycled asphalt mixtures. The recycled asphalt mixture conforms to the requirement of BS 4987-1 (2005) for dense bitumen macadam size 10 mm (DBM 10 mm). The proportion of RAP in the recycled mixture is 40%. RAP materials are artificially aged and processed in the laboratory to prevent the variability of RAP gradation, bitumen content, and the origin. Laboratory RAP is also used to assure that every single RAP particle is an agglomerate of RAP aggregate and binder. The mixing procedures include Black Rock (BR), Complete Blending (CB), the SHRP procedure, and a newly developed field simulation method (FS). The primary difference between these methods is the mixing mechanism. The BR case implies the situation in which there is completely no interaction between RAP and virgin binder. On the contrary, RAP and virgin binder are fully interacted in the CB case. The mixing procedures for BR and CB cases conform to those for conventional asphalt mixtures. However, the bitumen for BR case is pure virgin bitumen. In addition, the bitumen for CB is the blend between RAP and virgin binder. The RAP/virgin binder proportion is 4/6. In the SHRP method, RAP is preheated at 110oC for two hours before being mixed with virgin aggregate and binder for 2 minutes at 130oC. In the FS method on the contrary, the mixing procedure duplicates what occurs in the asphalt mixing plant. RAP is mixed with superheated virgin aggregate (215oC) for different durations before this combination is blended with virgin bitumen for 2 minutes at 130oC. The RAP/superheated virgin aggregate mixing duration starts from short mixing time where RAP still exists at approximately original size and gradually increases until the change in RAP lump size is insignificant. Depending on the size of RAP used, RAP/superheated virgin aggregate mixing duration varies from 1 to 8 minutes. The homogeneity of hot recycled asphalt mixture is examined by using virgin binder with a different colour from that of RAP binder. The colour of virgin binder is obtained by mixing clear binder (Shell Mexphalt C 160/220 Pen) with iron oxide pigment. The proportion of pigment is 10% by weight of the binder making this binder red. The use of virgin binder with different colour from that of RAP binder helps to clearly differentiate the locations of RAP and virgin materials. Surfaces of slices cut from compacted recycled specimens are photographed by digital camera. The analysis of these surfaces in vertical order allows the locations of RAP material to be qualitatively identified in a 3D manner. Stiffness modulus values of samples for homogeneity assessment are also determined by indirect tensile stiffness test. The stiffness test is carried out in four directions along the circumference of each specimen with 45o angular increments. The experimental results show that the stiffness measurement in four directions can indicate the heterogeneity of recycled mixture. The variation in stiffness values in different measured directions will be substantial for heterogeneous mixtures and minor in the case where recycled mixtures are homogeneous. The results indicate there are mutual relations between mixing effort, homogeneity, and stiffness values of recycled asphalt mixtures. The longer mixing time will enhance the homogeneity and reduce the variation in stiffness values of recycled mixture. In addition, as more RAP and virgin binder are incorporated, the stiffness values of recycled mixture generally increase once the mixing time is extended. As the clear binder is dyed red by 10% by weight of iron oxide, the proportion of the pigment certainly alters the flow characteristic of binder. This might affect the mixing process and rejuvenating effect between virgin and aged binder. Therefore, the effects of mixing methods and RAP sizes on mechanical performance of hot recycled asphalt mixtures are further investigated using normal straight run bitumen 160/220 Pen as virgin binder. The assessment indicators include stiffness modulus, resistance to fatigue damage, and resistance to permanent deformation. The experimental results indicate that the conventional laboratory mixing method (SHRP) tends to overestimate the mechanical properties of recycled asphalt mixture. The long RAP preheating time that never exists in the industry coincidentally enhances the reaction between RAP and virgin binder. The long RAP preheating time also slightly alters the properties of RAP binder. For the FS method, the increase in mixing duration significantly improves the homogeneity level of recycled mixtures. The homogeneity level is also substantially affected by the size of RAP material. For the same mixing effort, the mixtures comprised of small RAP are generally more homogeneous than those made from larger RAP. The more homogeneous the mixture, the more interaction between RAP and virgin binder. Therefore, recycled mixtures become stiffer and have better resistance to permanent deformation and fatigue failure. A slightly linear increase in stiffness can result in an exponential increase in fatigue life of the recycled mixture. The mechanical properties including stiffness modulus, resistance to fatigue damage, and resistance to permanent deformation of hot recycled asphalt mixtures are not similar to those of the BR or CB mixtures, even at the favourable condition where RAP is preheated for 2 hours at 110oC in the SHRP method and 8 minutes mixing duration in the FS method. This implies that RAP does not act as Black Rock. In addition, the assumption that RAP and virgin binder are fully blended also never exists in the recycled asphalt production process.
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Caricato, Edward M., and John D. Draper. "Analysis of historical Materiel Return Program (MRP) credits at the 1st Marine Logistics Group Reparable Issue Point (RIP)." Thesis, Monterey, California. Naval Postgraduate School, 2011. http://hdl.handle.net/10945/10575.
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Approved for public release; distribution is unlimitedMateriel Returns Program (MRP) credits have increased 1st Marine Logistics Group's (1st MLG) total obligation authority by an average of 27% annually since 2008. However, 1st MLG has been unable to leverage the MRP in budget execution due to an inability to forecast future credits. The purpose of this research is to determine whether analysis of historical MRP credits at 1st MLG could enable the comptroller to forecast future credits, which would enable 1st MLG to leverage MRP credits and budget more efficiently in a constrained fiscal environment. This research utilized descriptive analysis of historical credits to identify systemic patterns or trends associated with MRP. The analysis of MRP credits focused on two specific areas: (1) the accuracy of credit estimates provided by the sources of supply (SOSs), and (2) the amount of time it took for 1st MLG to receive the actual credit. The primary finding of this research was that 1st MLG should be able to forecast MRP credits. The research showed that historically over a two-year period, SOSs accurately estimated credits 88.3% of the time and SOSs issued 95% of all actual credits within 90 days of 1st MLG submitting an item into MRP.
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Opiela, Shannon Jacqueline. "Neonatal T Cell Responses are Highly Plastic: I. Neonates Generate Robust T Cell Responses against Alloantigens II. Functional Capabilities of Neonatal RTE are more Diverse than Adult RTE." Scholarly Repository, 2008. http://scholarlyrepository.miami.edu/oa_dissertations/139.
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Neonatal immune responses are typically deficient against a wide variety of antigens, including alloantigens, vaccine antigens, and infectious agents. These responses are characterized by Th2-skewed cytokine production, and deficient Th1 and cytotoxic responses. However, these deficient responses can be boosted to adult levels by the use of strong, Th1 promoting agents. This demonstrates that neonates are capable of developing mature immune responses under specific conditions. Using two different murine models, we have found that neonates develop robust Th and cytotoxic responses, which under some antigenic conditions significantly exceed those of adults. First, using a model of early life exposure to noninherited maternal antigens (NIMA), we found that murine neonates develop robust in vivo cytotoxic responses to low doses of alloantigens. Importantly, primary in vivo cytotoxic responses to alloantigen developed during the neonatal period, and persisted into adulthood. Neonates developed similar memory cytotoxic responses to donor spleen cells, bone marrow, and stem cell-enriched (Lin-) bone marrow cells, suggesting that the exposure dose is more important than the type of transplanted donor cell for the development of cytotoxicity. NIMA-exposed neonates also developed vigorous primary and memory allospecific Th1/Th2 responses which exceeded the responses of adults. These findings suggest that early exposure to low levels of NIMA may lead to long term immunological priming of all arms of T cell adaptive immunity. Second, we characterized the phenotype and function of neonatal recent thymic emigrants (RTE). RTE are the predominant cell type in murine neonates, and are present at higher frequencies within the neonatal CD4+ compartment than in adults. Our data demonstrate that RTE from murine neonates and adults are phenotypically and functionally distinct. In particular, although the magnitude of RTE cytokine responses from both age groups is dependent on the conditions of activation, neonatal RTE consistently exhibited higher levels of effector cytokine production than adult RTE. In particular, activation of neonatal RTE in the presence of IL-7 lead to greatly increased IFNgamma production, while adult responses were not altered. Overall, neonatal RTE responses were more plastic than those of adult RTE, as both Th1 and Th2 responses were altered in neonates using various activation conditions, while only Th2 responses were consistently changed in adults. Finally, in contrast to adult RTE, neonatal RTE proliferated in response to IL-7 stimulation at very early timepoints. This was associated with faster kinetics of IL-7Ralpha downregulation and higher levels of pSTAT5 in neonatal RTE. These quantitative and qualitative differences in neonatal RTE populations may largely explain the diverse responses that are elicited in neonates in response to different antigens, especially under those conditions in which Th1 responses are enhanced (i.e., exposure to NIMA alloantigens). Taken together, these data demonstrate that neonatal T cell responses are actually highly plastic, instead of intrinsically deficient. Furthermore, if given optimal stimulation conditions, neonatal responses can actually exceed those produced by adults.
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Razo, Rodríguez Roberto. "Diseño de Información e Interacción de un material didáctico de apoyo para el curso de RCP de la UDLAP." Thesis, Universidad de las Américas Puebla, 2010. http://catarina.udlap.mx/u_dl_a/tales/documentos/mdi/razo_r_r/.
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El presente proyecto se realizó por el interés en integrar
el diseño de información, las nuevas tecnologías y la
educación.
La problemática se centró en mejorar la experiencia de aprendizaje
del tema de la Resucitación Cardio-Pulmonar del taller de Primeros
Auxilios de la Universidad de las Américas Puebla (UDLAP).
Una vez establecida la problemática y el lugar, se definió
la muestra con base en la población que son los alumnos que actualmente
están tomando el taller de primeros auxilios, posteriormente se
solicitaron los permisos para realizar la técnica de observación
en la impartición del tema y se fueron registrando unidades de
información con base en los datos obtenidos para posteriormente comparar
y crear categorías con base en patrones de conducta y de
información.
Junto con esto se analizaron materiales didácticos que sirvieron de
apoyo para la impartición del curso.
De esta investigación surgieron las bases para la construcción
del prototipo pasando por los tres diseños propuestos por Shedroff
(1994) para generar una experiencia: Diseño de Información,
Diseño de Interacción y Diseño Visual.
La implementación se llevó a cabo en los salones multimediales
del de la UDLAP debido a que cuenta con recursos tecnológicos avanzados,
enfocados a la educación, lo que lo convirtió en el espacio
ideal para el estudio.
Se enfatizó en la experiencia de la simulación por medio de
una pantalla táctil que detectalos puntos de presión y responde
directamente a la intefaz y a las metáforas que son enviadas desde
la computadora a través de un proyector.
Se realizó un primer prototipo sobre el cual se realizó una
prueba de usabilidad por parte del paramédico que imparte el curso
a través de la observación y técnicas de
verbalización.
Con la información obtenida se realizaron cambios puntuales al producto
de diseño.(cont.) Una vez realizados estos cambios se solicitaron los permisos para presentar el prototipo a los usuarios en los salones multimediales. Se tuvo la oportunidad de realizar 2 pruebas de usabilidad basadas en el manejo del material simulando el contexto real de uso, con dos grupos de usuarios con características distintas. Se obtuvieron opiniones contrastadas pero resultados de usabilidad similares los cuales se muestran junto con las recomendaciones correspondientes. El registro de todo este proceso se muestra en el presente documento.
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Bertaccini, Matteo. "Valutazione dell'effetto dell'invecchiamento termico sulle proprietà meccaniche di materiali compositi." Master's thesis, Alma Mater Studiorum - Università di Bologna, 2016. http://amslaurea.unibo.it/10265/.
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L’obiettivo della presente tesi è analizzare, attraverso una campagna sperimentale, gli effetti dell’invecchiamento termico su materiali compositi avanzati. Due serie di provini, ottenuti da pannelli di fibra di carbonio/resina epossidica realizzati rispettivamente con le tecniche di produzione tramite laminazione manuale e RTM (Resin Transfer Molding), sono stati condizionati in forno o in congelatore per un determinato tempo e successivamente sottoposti a test di caratterizzazione meccanica. In questo modo sono state confrontate le prestazioni delle due tecnologie al fine di verificare l’applicabilità del processo RTM a prodotti di alta qualità.
I campioni, impiegati nel presente studio, sono stati realizzati scegliendo una configurazione cross-ply, che ben si adatta alle successive fasi della campagna.
Sui provini ottenuti sono stati eseguiti dei test di resistenza alla delaminazione tramite una pressa con supporti adattati appositamente allo scopo.
Questa campagna sperimentale è stata svolta presso i laboratori hangar della Scuola di Ingegneria e Architettura dell’Università di Bologna, sede di Forlì.
La caratterizzazione del materiale è avvenuta mediante prove a flessione D2344.
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Tanski, Mateus Camargo. "COMPORTAMENTO MECÂNICO DE MATERIAL RECICLADO A FRIO COM EMULSÃO E CIMENTO." Universidade Federal de Santa Maria, 2016. http://repositorio.ufsm.br/handle/1/7934.
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The recycled asphalt pavement (RAP) extracted from recovery distresses in highways does not receive the attention and importance it deserves in Brazil. The reuse of this material, which presents as good properties as the virgin aggregate, when applied correctly in the composition of new pavement layers or rehabilitations, is a widely used in European and United States. Besides solving the environmental liabilities of pavement, the reuse of milled material in asphalt mixtures is a sustainable alternative, which decreases consumption of asphalt and virgin aggregate, milled material transportation and allocation costs. This study seeks an alternative to the use of RAP as the base layer in the implementation of new pavements.For this paper, cold recycled mixtures were studied, wich are composed of RAP (granulometrically stabilized with fine aggregate) and RL-1C asphalt emulsion, a bituminous binder that contains added Portland Cement (CP V ARI) in the proportions of 2% to 5% for emulsion and from 0% to 1% of cement, in weight. The proposed mixtures were evaluate through mechanical resistance to single compression (RCS), indirect tensile strength (RT), resilient modulus tests (RM), Complex Modulus (E* and Ф) and Flow Number (FN). After performing these tests, it was observed that the values obtained reveal that the mixtures with proportions varying from 50% to 75% of emulsion, compared to the cement used in the mixtures, show better results. Moreover, the mixtures present resilient modulus results ranging from 1500 MPa to 3000 MPa (excellent values for base layers). The FN test shows that by adding cement to the mixture, the results improved in the form of an increment in the number of cycles, which performed at its best with samples that had 2% and 3% of emulsion. The uniaxial Complex Modulus test allowed access the viscoelastic behavior and the 2S2P1D modeling was used too. It´s possible to confirm that this technique is viable pavement maintenance.O material fresado extraído de trechos em recuperação não recebe a atenção e importância que merece no Brasil. O reaproveitamento desse material, que apresenta comportamento tão bom quanto os agregados virgens, quando empregado de maneira correta na composição de camadas de pavimentos novos ou restaurações, é uma prática largamente utilizada em países europeus e nos Estados Unidos. Além de resolver o passivo ambiental das empresas, o reemprego do fresado em misturas asfálticas, é uma alternativa sustentável que diminui o consumo de agregados virgens e custos com transporte de fresado e alocação do mesmo. Este trabalho busca uma alternativa para emprego do material fresado como camada de base na execução de pavimentos novos. Foram estudadas misturas recicladas a frio compostas de fresado estabilizado granulometricamente com pó-de-pedra e tendo como ligante betuminoso emulsão asfáltica RL-1C nas proporções de 2% a 5% e de ligante hidráulico CP V ARI de 0% a 1% de cimento. As misturas propostas foram avaliadas por meio de ensaios de resistência à compressão simples (RCS), ruptura por tração por compressão diametral (RT), módulo de resiliência (MR), módulo complexo (IE*I) e FlowNumber (FN). Após a realização dos ensaios, observou-se que os valores obtidos demonstram que as misturas com proporção variando de 50% a 75% de emulsão, em relação ao cimento empregado nas misturas, apresentam melhores resultados. Além disso, as mesmas misturas apresentam valores de módulo resiliente variando entre 1500 MPa e 3000 MPa (valores excelentes para camadas de base). O ensaio de FN mostrou que a adição de cimento na mistura melhora os resultados aumentando o número de ciclos, apresentando como melhores as amostras com 2% e 3% de emulsão. Através do ensaio de módulo dinâmico obteve-se a curva mestra das misturas utilizando a modelo 2S2P1D. Acredita-se que esta será uma alternativa técnica e economicamente viável para destinação do material fresado gerado em abundância pelas obras rodoviárias.
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Shannon, Cory Patrick. "Fractionation of recycled asphalt pavement materials: improvement of volumetric mix design driteria for High-RAP content surface mixtures." Thesis, University of Iowa, 2012. https://ir.uiowa.edu/etd/3380.
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The objective of this research is to examine the effects that different methods of RAP stockpile fractionation have on the volumetric mix design properties for high-RAP content surface mixes, with the goal of meeting all specified criteria for standard HMA mix designs. The processing of RAP materials results in the degradation of the aggregate structure of the original pavement. The increased presence of fine RAP materials in the stockpile can be attributed to the amount of crushing done on the RAP millings. Fractionation methods were designed to separate the stockpile at certain sizes to isolate the fine RAP materials which contained higher amounts of fine aggregate and negatively impacted the volumetric properties of the mix design. These isolated RAP materials were used in reduced proportions or completely eliminated, thereby decreasing the amount of fine aggregate material introduced to the mix. Mix designs were created using RAP materials included from each original stockpile and the two fractionated stockpiles created from each original stockpile at high-RAP contents of 30%, 40% and 50% by virgin binder replacement. Fractionation of RAP materials was effective in improving the volumetric properties of high-RAP content mixtures through reduction of fine aggregate material introduced by the RAP materials.
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Penny, Julie Elizabeth. "An evaluation of heated reclaimed asphalt pavement (RAP) material and wax modified asphalt for use in recycled hot mix asphalt (HMA)." Worcester, Mass. : Worcester Polytechnic Institute, 2007. http://www.wpi.edu/Pubs/ETD/Available/etd-010807-113145/.
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Urbanec, Luboš. "Problematika zvyšování podílu R - materiálu v asfaltových směsích." Master's thesis, Vysoké učení technické v Brně. Fakulta stavební, 2013. http://www.nusl.cz/ntk/nusl-226454.
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The subject of this Ing. thesis is asphalt mixture with increasing RAP (Reclaimed Asphalt Pavement). The theoretical part defines the terms of recycling and RAP and types of recycling. The practical part is devoted to the production and testing of asphalt mixtures with different volume RAP. The proposed asphalt mixture is asphalt concrete for base layer ACP22 +. Content of RAP in mixtures is 0%, 30%, 50% and 70%. As a special additive to soften the asphalt from RAP is used ingredient STORFLUX. For each mixture are established modulus stiffness of asphalt mixture and determined fatigue characteristics of asphalt mixture. The identified properties are compared for the different representation of RAP.
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Centofante, Roberta. "ESTUDO LABORATORIAL DA UTILIZAÇÃO DE MATERIAL FRESADO EM MISTURAS ASFÁLTICAS RECICLADAS A QUENTE." Universidade Federal de Santa Maria, 2016. http://repositorio.ufsm.br/handle/1/7915.
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Fundação de Amparo a Pesquisa no Estado do Rio Grande do SulThe use of recycled materials can become a constructive application with good acceptance in the road sector, and is a great contribution to the sustainability policy. In this scenario, the study of economic and sustainable techniques for execution, construction and maintenance of highways, forces a survey in which they can find alternatives to the use of materials that reduce energy consumption, taking into account also the environmental appeal. Therefore, this is an objective research on the study of a way to use, reuse, and improve the use of the recycled asphalt pavement (RAP) in hot asphalt mixtures. This is possible due to the RAP's recycling process being a viable option to replace conventional pavement materials. Then, the RAP becomes an alternative when someone wishes to improve the properties of a material, called particle size stabilization, aiming at a correct particle size and obtain a material with greater strength, efficiency and lower cost. To achieve the purpose of this study, laboratory tests were made to evaluate the mechanical properties and adhesiveness of mixtures containing 10% addition of RAP, 20% and 30%, compared to a reference mix without the RAP addition. Additionally, the initial use of the Bailey method was an important factor to the formation of the mixtures and selection of the aggregates used to Superpave methodology to design dosage strength and preparing of the samples. For mechanical evaluation were used resilient modulus tests (RM) and to review viscoelastic were used uniaxial dynamic modulus test. In addition, the indirect tensile strength tests were performed (RT) and Flow Number (FN) and damage tests induced moisture through the Modified Lottman test and wear a Cantabro abrasion, for evaluation of the properties of adhesion and cohesion of the mixtures, respectively. So after obtained these results, it was possible to make an analysis of the use of these hot mix asphalt recycling hot pavements, as well as assess how much conventional mixtures can be improved with the inclusion of recycled material, replacing virgin aggregate. Then, it was possible to infer that the mechanical evaluation showed positive results with the addition of RAP compared to a reference blend. It´s possible to reduce the new binder content between 13 and 37%. The results showed that RM stiffness and indirect tensile strength increases with RAP amount. Furthermore, the FN test results showed reductions on permanent deformation and rutting of the RAP´s mixtures. Through the master curve obtained by dynamic module, along with modeling 2S2P1D, it was found that the CAF10 mixture unexpectedly had stiffness greater than the CAF20 mixture, which has 20% more RAP than the previous.
A utilização de materiais provenientes da reciclagem pode se tornar uma aplicação construtiva com boa aceitação no setor rodoviário, além de contribuir na política de sustentabilidade. Com isso, torna-se viável o estudo de técnicas econômicas e sustentáveis para execução, construção e manutenção de rodovias, forçando uma pesquisa em que se possa encontrar alternativas para o uso de materiais que diminuam o consumo de energia, levando em conta, ainda, o apelo ambiental. Por isso, essa pesquisa se objetiva no estudo de uma maneira de utilizar, reutilizar e melhor aproveitar o material fresado em misturas asfálticas a quente. Isto se dá devido ao processo de reciclagem deste material ser uma alternativa de possível substituição aos materiais convencionais naturais de pavimentação como, por exemplo, a pedra britada. Então, o material asfáltico do pavimento deteriorado (fresado) torna-se uma das alternativas quando se deseja melhorar as propriedades de um material, denominada estabilização granulométrica, visando corrigir sua granulometria e obter um material com maior resistência, eficiência e menor custo. Para atingir o objetivo desta pesquisa, foram realizados ensaios laboratoriais que pudessem avaliar as propriedades mecânicas e de adesividade das misturas contendo 10% de adição de fresado, 20% e 30%, comparadas a uma mistura de referência sem adição de agregado reciclado. Além disso, a utilização inicial do Método Bailey foi um fator importante para a formação das misturas e seleção dos agregados, sendo utilizada a metodologia Superpave para dosagem do teor de projeto e moldagem das amostras. Para avaliação mecânica, foram usados ensaios de módulo de resiliência (MR) e, ainda, para avaliação viscoelástica, ensaio de módulo dinâmico uniaxial. Além destes, foram realizados ensaios de resistência à tração indireta (RT) e Flow Number (FN) e, também, ensaios de dano por umidade induzida, através do ensaio de Lottman Modificado, e desgaste por abrasão Cântabro, para avaliação das propriedades de adesividade e coesão das misturas, respectivamente. Assim, após obtidos estes resultados, foi possível efetuar uma análise da utilização destas misturas asfálticas na reciclagem a quente de pavimentos, bem como avaliar o quanto as misturas convencionais podem ser melhoradas com a inserção de material reciclado, em substituição ao agregado virgem. Então, foi possível concluir que a avaliação mecânica apresentou resultados positivos com a adição de fresado, quando comparados a uma mistura de referência. Os resultados de MR mostraram que a rigidez aumenta ao passo que a quantidade de fresado é maior na composição das misturas, o mesmo foi possível verificar através dos ensaios de RT, os quais apresentaram valores crescentes. Além disso, o ensaio de FN comprovou que o fresado aumenta a rigidez das misturas. Através da curva mestra obtida pelo módulo dinâmico, juntamente com a modelagem 2S2P1D, foi possível constatar que a mistura CAF10, inesperadamente, apresentou rigidez maior que a mistura CAF20, a qual tem 20% a mais de fresado que a anterior.
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Zítka, Patrik. "Problematika použití R - materiálu do asfaltových směsí." Master's thesis, Vysoké učení technické v Brně. Fakulta stavební, 2015. http://www.nusl.cz/ntk/nusl-227264.
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This thesis deals with the R-material use in asphalt mixtures. In the theoretical part, different kinds of flexible pavement recycling and ways of adding R-material into asphalt mixtures are discussed. The practical part deals with asphalt layers design and manufacture, specifically for binder course ACL 16+. R-material content in the blends is 0%, 20%, 25% and 30%. EVOTHERM MA3 rejuvenator is used as additive for softening of R-material. Various mixtures are compared based on tests - resistance to permanent deformation, resistance to the effects of water and low temperature properties.
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Bartoli, Mirco. "Caratterizzazione dei parametri di permeabilità di materiali compositi tramite prove sperimentali." Bachelor's thesis, Alma Mater Studiorum - Università di Bologna, 2017. http://amslaurea.unibo.it/14666/.
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L'obiettivo di questo lavoro di tesi è caratterizzare due tipologie di rinforzi per materiali compositi dal punto di vista della permeabilità, proprietà fondamentale per l'esecuzione di simulazioni di iniezione per tecnologie RTM.
Nello specifico, si caratterizzano nella prima parte un tessuto multistrato (biassiale, polipropilene, mat) e nella seconda invece il precedente tessuto con sopra uno strato di tessuto unidirezionale (entrambi in fibra di vetro).
Dopo un'introduzione sulle tipologie di fibre e sui vari tessuti, si analizza la teoria che è alla base delle misure di permeabilità per i rinforzi dei materiali compositi, per poi passare alla caratterizzazione vera e propria descrivendo accuratamente le prove sperimentali effettuate (rilevamento dei dati e eventuali alterazioni dovute a fattori esterni) e i relativi risultati.
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Rossi, Alessandro. "Caratterizzazione di resine epossidiche per materiali compositi realizzati in infusione ad alta pressione." Bachelor's thesis, Alma Mater Studiorum - Università di Bologna, 2016.
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I materiali compositi, grazie alla combinazione delle proprietà dei singoli componenti di cui sono costituiti, in particolare la coesistenza di elevate caratteristiche meccaniche e pesi ridotti, rivestono da tempo un ruolo fondamentale nell’industria aeronautica e nel settore delle competizioni automobilistiche e motociclistiche. La possibilità di progettare i materiali in funzione della loro applicazione, unita alla riduzione dei costi di produzione, permette una crescente diffusione del loro utilizzo e l’ampliamento delle applicazioni a moltissimi altri settori, sia per componenti di tipo strutturale, sia di tipo estetico. L’obiettivo della presente tesi è analizzare, attraverso una campagna sperimentale, il comportamento di diversi materiali realizzati con la tecnica di produzione HP-RTM, tramite prove di taglio interlaminare e flessione, al fine di verificare l’applicabilità di tale processo a prodotti strutturali, in modo da velocizzare i tempi di produzione e quindi di abbassare i costi, mantenendo al tempo stesso elevate proprietà meccaniche. Lo scopo di questa campagna quindi è fornire, attraverso lo studio di 30 serie di provini, il materiale migliore in termini di resistenza a flessione e taglio interlaminare; inoltre per ogni tipologia di materiale vengono descritte le diverse distribuzioni dei valori di rottura riscontrati, in modo da lasciare al progettista più libertà possibile nella scelta del materiale in base alle specifiche richieste per una determinata applicazione. Questo studio permette di analizzare l’influenza di ogni singolo componente (tipo di fibra, tipo di binder, presenza o assenza di IMR), all’interno della stessa resina.
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Pasche, Eduardo. "Estudo da resistência e da rigidez de uma mistura de material fresado asfáltico e pó-de-pedra com a adição de cimento." reponame:Biblioteca Digital de Teses e Dissertações da UFRGS, 2016. http://hdl.handle.net/10183/149836.
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A malha rodoviária brasileira é elemento fundamental para as cadeias produtivas, pois promove a integração de regiões, estados, portos, ferrovias, hidrovias e aeroportos. A qualidade do pavimento é um dos principais determinantes do desempenho dos usuários durante suas viagens. Uma das formas para a correção dos defeitos nos pavimentos é a restauração, sendo bastante empregada atualmente a fresagem do revestimento asfáltico, que consiste na operação de um corte do revestimento asfáltico, esta atividade produz uma grande quantidade de resíduo nas obras de restauração de rodovias, denominado de material fresado asfáltico ou somente fresado, que é constituído por agregados (graúdos e miúdos) e Cimento Asfáltico de Petróleo (CAP). Esta pesquisa objetivou avaliar, através de ensaios laboratoriais, a viabilidade da utilização de uma mistura de material fresado e pó-de-pedra estabilizados quimicamente com cimento Portland em camadas de pavimentos flexíveis, correlacionando o índice porosidade/teor volumétrico de cimento (η/Civ) com parâmetros de rigidez e resistência das misturas. O material fresado é oriundo da BR-290. Foi realizada estabilização granulométrica, sendo determinado o teor de 70% de material fresado e 30% de pó-de-pedra e a estabilização química, com os teores de 3%, 5% e 7%. Foram moldados corpos-de-prova de 10 x 20 cm para ensaios de resistência à compressão e resistência à tração. Para o módulo de resiliência, foram moldados corpos-de-prova de 6,5 x 10 cm e para o módulo complexo foram moldados corpos-de-prova de 10 x 15 cm, todos com 28 dias de cura. A análise dos resultados mostrou que ambas as resistências e módulos estudados aumentam linearmente com o aumento da quantidade de cimento e exponencialmente com a redução da porosidade. Os resultados também mostraram que o material apresenta características viscoelásticas oriundas do material fresado. A relação porosidade/teor volumétrico de cimento ajustado por um coeficiente [η/(Civ)0,41] mostrou-se adequada na previsão das resistências e módulos para todas as misturas estudadas. O desempenho satisfatório colabora com a possibilidade de abranger os estudos destes materiais.The Brazilian highways are fundamental to the productive chain once promote the integration of regions, states, ports, railways, waterways and airports. The quality of the surface is a major determinant of the performance of travelers during their travels. One way to correct the defects in the pavements is the restoration currently being used through milling of the asphalt coating and its reuse. In the operation of a drilling asphalt coating, such activity produces a lot of waste in highway restoration works, called Reclaimed Asphalt Pavement (RAP), which is composed of aggregates (coarse and fine) and asphalt binder. The use of such material is the main objective of present research, targeting the grain size and chemical stabilization, the latter adding Portland cement. This research aims to evaluate, through laboratory testing, the viability of using a mixture of RAP and powdered rock chemically stabilized with Portland cement for layers in flexible pavements, correlating the porosity/cement ratio (η/Civ) with stiffness and resistance parameters of the mixtures. The RAP used in present research comes from restoration of the BR-290. The grain size stabilization was performed; RAP content being determined as 70% and 30% of powdered rock. The chemical stabilization was carried out with early strength Portland cement contents of 3%, 5% e 7%. Specimens’10x20 cm were manufactured for the unconfined compressive and splitting tensile tests. For the resilient modulus, specimens had 6.5x10cm and for the dynamic modulus specimens had10x15 cm. All ests were cured for 28 days. The results showed that both, resistance and modules increase linearly with increasing amount of cement and exponentially with decreasing of the porosity. The results also show that the material has viscoelastic characteristics originating from the RAP. The relationship between the porosity/cement ratio adjusted by a coefficient [η/(Civ)0.41] proved adequate in predicting resistance and modules for all studied mixtures. Satisfactory performance corroborates the possibility of covering of the studies of this material.
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Slavíček, Michal. "Využití R - materiálu v asfaltových kobercích mastixových." Master's thesis, Vysoké učení technické v Brně. Fakulta stavební, 2017. http://www.nusl.cz/ntk/nusl-265415.
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This diploma thesis deals with the designs of asphalt mixtures for the wearing asphalt courses, specifically for the SMA 11S with an added 30 % and 50 % RAP (reclaimed asphalt pavement), this material was reclaimed from the wearing asphalt course type SMA. The thesis is divided into two parts. The first part is theoretical and it deals with the recycling of asphalt roads and adding RAP to the new asphalt mixures for the roads. The second part is practical. It deals with the design itself. Two types of SMA were designed, first with a 30 % RAP and second with a 50 % RAP. In those mixtures functional tests of asphalt mixtures were made.The results were compared to the asphalt mixture with 0 % of RAP and with the mixture with 30 % of RAP reclaimed from the wearing, binder and base course together. The results are summed up in the conclusion.
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Coufalíková, Iva. "Použití R-materiálu do asfaltových směsí typu asfaltový koberec mastixový." Doctoral thesis, Vysoké učení technické v Brně. Fakulta stavební, 2019. http://www.nusl.cz/ntk/nusl-408020.
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The dissertation deals with the possibilities of adding recycled asphalt pavement (RAP) to the stone mastic asphalt (SMA), which is increasingly being promoted due to its good resistance to permanent deformations and high traffic load. Thanks to the use of high-quality input materials in production, this is a valuable material source. The theoretical part describes composition of SMA mixture and problems of pavement recycling. The practical part deals with SMA 11S laboratory designs with RAP ratio of 0 to 50%. Based on these suggestions, a trial section with 17 variants was placed, which varied with the content and quality of the RAP and the used additives. All variants have been subjected to functional testing not only on mixtures but also on recovered binders. The results obtained during the dissertation were used to build a certified methodology named "Methodology of application RAP to Stone Mastic Asphalt." In conclusion, the results of the dissertation are summarized.
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Wootton, Robert James Mechanical & Manufacturing Engineering Faculty of Engineering UNSW. "Investigation into the feasibility and application of composite materials in conveyor support structures for use in underground coal mines." Awarded by:University of New South Wales. Mechanical & Manufacturing Engineering, 2009. http://handle.unsw.edu.au/1959.4/43697.
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Composite materials are well-renown for their strength to weight ratios and are widely used in many industries where high strength and low weight is required. Although steel is the traditional material of choice in the mining industry, and particularly for conveyor support structures, the strength and weight advantages offered by composite materials has prompted this investigation into the feasibility of using composite materials in underground mining conveyor support structures. The first phase of the project centred on establishing and applying selection criteria for the materials and processes which could be used in such a structure. Key concerns include fire performance, electrical conductivity, cost, availability and manufacturability. Based on these considerations, the project identified a phenolic-glass laminate manufactured using the RTM method (for moulded components) or the pultrusion process (for tube sections) as a possible basis for a composite conveyor support structure. The second phase of the project developed a set of design criteria for the use of composite materials in conveyor support structures and a series of preliminary designs based on current conveyor configurations. After analysing each preliminary design against key design criteria, in particular cost, weight, assembly time, susceptibility to damage and torsional loading, the Linestand Suspended - Beam configuration was selected as the preferred option. The third phase of the project used the findings of the preliminary design analysis and the key design criteria to develop a prototype final design. The prototype design is based on a hybrid style of frame. The majority of the structure is constructed from a custom pultruded beam connected with a composite connection piece, while the interface between the rollers and the frame utilises a steel bracket to reduce the risk of damage to the composite frame. The final design is 12kg lighter than the current smaller steel design of similar function. The project has demonstrated the feasibility of using composite materials in conveyor support structures and the weight savings that may be achieved.
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Mucha, Bohumír. "Asfaltové směsi s použitím vyššího množství R-materiálu." Master's thesis, Vysoké učení technické v Brně. Fakulta stavební, 2014. http://www.nusl.cz/ntk/nusl-226710.
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At the beginning of the Master’s thesis the asphalt mixture of the type asphalt concrete and its basic properties are described. The main point of this work is to compare the functional properties of asphalt mixtures with the addition of higher amount of RAP and various rejuvenators used in the experimental section. From individual samples of asphalt mixtures taken during the laying, the control tests were carried out and the process of permanent deformation with the wheel tracking test was monitored. After that, using functional tests the properties of asphalt mixtures with conventional modified and unmodified asphalt bitumen enriched with the addition of declaring similar properties were compared.
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Semprini, Emmanuele. "Analisi e simulazione FEM del processo di infusione sottovuoto "VARI" di una passerella nautica." Bachelor's thesis, Alma Mater Studiorum - Università di Bologna, 2012. http://amslaurea.unibo.it/3776/.
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Tesi svolta presso l'azienda “Riba composites S.r.l.” con lo scopo di riprogettare una passerella nautica utilizzata in imbarcazioni a vela da competizione, attualmente realizzata mediante formatura in autoclave di tessuti pre-impregnati, per il processo produttivo di Vacuum Assisted Resin Injection (VARI).
La formatura in autoclave di tessuti pre-impregnati è una delle tecnologie più onerose, tra i vari processi produttivi nel settore dei materiali compositi, ma assicura proprietà meccaniche e livelli estetici superlativi. L’obiettivo della Riba Composites è ridurre i costi di produzione per offrire un prodotto dalle proprietà analoghe a un prezzo più competitivo. Nella fase di riprogettazione ci siamo affidati a un software di calcolo agli elementi finiti che simula il processo del VARI, l’applicativo PAM-RTM, del gruppo ESI.
Al fine di ottenere una simulazione quanto più precisa possibile del processo, abbiamo realizzato molteplici prove sperimentali per ricavare i valori di compressibilità e permeabilità dei rinforzi da inserire nel software FEM.
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Brown, Ashley Vannoy. "Cement Stabilization of Aggregate Base Materials Blended with Reclaimed Asphalt Pavement." Diss., CLICK HERE for online access, 2006. http://contentdm.lib.byu.edu/ETD/image/etd1314.pdf.
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Stromecký, Roman. "Asfaltové směsi s vyšší životností za použití R-materiálu." Master's thesis, Vysoké učení technické v Brně. Fakulta stavební, 2019. http://www.nusl.cz/ntk/nusl-392267.
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This diploma thesis deals with a project of asphalt mixtures with high stiffness modulus using R-material. The theoretical part describes the characteristics of these mixtures in the Czech Republic and in Switzerland. Further this part deals with the use of R-material in the Czech Republic and chosen other countries of the world, it also deals with the ways of recycling roads. The theoretical part also deals with the testing methods used. In the practical part two new asphalt mixtures of the high stiffness modulus type with the addition of 25 % R-material are suggested. As a base for these two mixtures a mixture of the high stiffness modulus type, which was taken from an asphalt mixing plant, was used. Tests were run on the binders and several functional tests (stiffness modulus, fatigue resistance, low temperature qualities) wer done on the suggested asphalt mixtures and also the mixture taken from the mixing plant. Consequently, the results were compared. The conclusion of the thesis is devoted to modelling a construction of a road using the program LayEps, which verified if the suggested mixtures could reduce the thickness of roads.
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Gissi, Daniele. "Caratterizzazione dopo invecchiamento termico e igroscopico di compositi FRP realizzati con differenti resine epossidiche." Bachelor's thesis, Alma Mater Studiorum - Università di Bologna, 2016.
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L'elaborato tratta, inizialmente, delle generalità dei materiali compositi, facendo particolare riferimento agli elementi che contraddistinguono i materiali protagonisti di questa campagna sperimentale (resine epossidiche, fibre, IMR, binder). Successivamente si passa alla trattazione delle varie tecniche usate per produrre un componente in materiale composito, soffermandosi maggiormente sulla tecnica dell’HP-RTM. Inoltre, poichè nell’elaborazione dei risultati ottenuti sono utilizzati curve gaussiane e istogrammi, è inserito un capitolo con informazioni generali sulla statistica e sulle principali distribuzioni di probabilità. Sono, infine, elencati e spiegati i vari materiali utilizzati, con le varie apparecchiature e i due metodi di invecchiamento, igroscopico e termico.
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Rizzo, Andrea. "Advanced N.D.T.: analisi e studio di componenti in materiale composito." Master's thesis, Alma Mater Studiorum - Università di Bologna, 2012. http://amslaurea.unibo.it/4596/.
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Numerose evidenze dimostrano che le proprietà dei materiali compositi sono strettamente legate ai processi produttivi, alle tipologie di fibra e resina impiegate nel materiale stesso. Proprietà caratterizzate anche dai difetti contenuti nel materiale stesso. Nella tesi si presta particolare attenzione al processo produttivo con prepreg e autoclave trattando anche il tema della stesura di un ply-book. Si valutano in modo teorico e critico alcuni tra i metodi N.D.T. più avanzati tra cui: P.T.(Penetrant Test), Rx(Radiography Test), UT (Ultrasound Test in Phased Array) e IRT (InfraRed Termography - Pulsata). Molteplici sono i componenti testati che variano tra loro per: tipologia di resina e fibra impiegata, processo produttivo e geometria. Tutti questi componenti permettono di capire come i singoli parametri influenzino la visualizzazione e l'applicabilità delle tecniche N.D.T. sopra citate. Su alcuni provini è stata eseguita la prova meccanica Drop Weight Test secondo ASTM D7136 per correlare le aree di delaminazione indotte e la sensibilità di ogni singolo metodo, visualizzando così la criticità indotta dagli urti con bassa energia di impatto (BVID Barely Invisible Impact)di cui i materiali compositi soffrono durante la "service life".
A conclusione del lavoro si potrà comprendere come solo l'analisi con più metodi in parallelo permetta di ottenere una adeguata Probability Of Detection.
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McCalla, M. Katherine. "The role of maternal behavior and toddler compliance in the development of problem behaviors." View electronic thesis (PDF), 2009. http://dl.uncw.edu/etd/2009-2/rp/mccallam/mmccalla.pdf.
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Mikhailenko, Peter. "Valorization of by-products and products from agro-industry for the development of release and rejuvenating agents for bituminous materials." Thesis, Toulouse 3, 2015. http://www.theses.fr/2015TOU30094/document.
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La croissance de caution vis-à-vis l'utilisation des produits pétroliers dans la construction a nécessité le besoin de développement des alternatives. Le BTP, en particulaire pour le secteur routière, a un certain nombre des piste ou les produits pétrolières ont utilisés, par exemple le liant pour les enrobés comme les agents régénérant (pour recyclage des enrobés), mais aussi le produits qui sont utilisés sur le chantier comme les anti-adhérents (ARA) et les débituminants (BR). Alors, il y a une besoin de remplacer les produits d'origines pétrolières par les alternatives bio-sourcés. Ce présent ouvre est une partie d'un projet qui va développer une nouvelle filière dédiée à la production de nouvelles formulations pour le BTP à partir de la transformation des huiles végétales et des graisses animales. Ce thèse concerne les produits développés seront destinés au l'asphalte, et alors, deux types d'applications sont particulièrement visés : (i) des agents anti-adhérents et (ii) des agents régénérants. Un débituminant sera développé aussi. Les produits anti-adhérents ont pour fonction d'empêcher le bitume d'adhérer aux engins de travaux sans effet secondaire, théoriquement, sur la matrice liante.. L'objet du travail est de caractériser l'efficacité et l'innocuité des agents anti-adhérents développés dans le cadre du projet et de développer les méthodes expérimentales visant à les évaluer. Trois essais principaux ont été développés pour caractériser la performance et innocuité des anti-adhérents vis-à-vis des essais qui ont optimisé leur implémentation et paramètres. La performance des anti-adhérents a été caractérisé par l'essai de glissance des enrobés. L'innocuité des anti-adhérents ont été caractérisés par des essais de fendage sur les enrobés et par l'essai de la dégradation de bitume. L'essai de la dégradation de bitume a servi aussi comme une mesure de la performance de débituminant. Les essais sur les anti-adhérents commerciaux d'Etats-Unis et la France a trouvé que ils ont deux modes de fonctionnement : i) lixiviation du bitume et ii) en formation d'une interface entre le les enrobés et la surface métallique. Même comme les deux modes ont été trouvé dans des certains anti-adhérents, le mode interface ont été trouvé préférable, grâce à l'option de garder les mêmes applications du produit pour plusieurs cycles de usage. Ensuite, un produit - basé sur glycérol sourcé de l'agro-industrie - a été développé. Les débituminants commerciaux ont été essayé, aves les conclusions : i) les débituminants plus effectifs ont eu les plus grande % des esters et ii) que les esters chaines courtes (C7-10) d'hautes concentrations ont été trouvé les plus efficace. L'agent régénérant est destiné à régénérer le bitume vieilli issu des agrégats d'enrobés (RAP) en lui redonnant ses propriétés originelles et en assurant leur maintien dans le temps. Le travail sur les agents régénérants se compose de la caractérisation physico-chimique du vieillissement du bitume et du bitume vieilli avec l'agent. Plus précisément, le travail se serve des techniques de spectrométrie IRTF (avec imagerie) et thermogravimétrie. Dans ce contexte, une produit bio-sourcé a été évalué comme une régénérant. Pour la spectroscopie FTIR, une moyenne de polir le mastique a été développé pour rassuré la platitude des échantillons. La régénération du bitume a été observé avec la spectrométrie ITRF, donc quelques peaks (notamment les indices IC=O and IS=O) pendant 0-42 jours de vieillissement dans l'étuve (loin-durée). Il a été trouvé qu'une période de vieillissement de 14 jours à l'étuve était à peu près équivalente au bitume vieilli par un cycle de RTFOT + PAV en termes de rhéologie et de la pénétration. Le mastic (vieilli 14 jours) a ensuite été mélangé avec un agent de bio-source (à 7,5% en poids de mastic). Il a été constaté par imagerie FTIR que l'indicateur de l'oxydation IS=O a été réduit par l'incorporation de l'agent régénérant dans le bitumeThe growing health and environmental concerns brought on by the use of petroleum based products in the asphalt construction industry have necessitated the development of alternatives. Infrastructure, especially that involving transportation has many uses for petroleum products including, as fuel, as well as in asphalt pavement construction - where petroleum products have traditionally constituted the binder for the mix as well as the rejuvenating agents (for asphalt recycling) - along with various agents used in the construction process including bitumen removers and asphalt release agents. Thus, there is a need to replace petroleum base agents with bio-sourced and biodegradable substitutes. The present work is part of a project to develop bio-sourced (recycled from agricultural waste) products for the construction industry. This work is dedicated to developing products relating to the asphalt industry. Two types of product applications were envisioned: i) an asphalt release agent (ARA) and ii) an asphalt rejuvenating agent. Additionally, a bitumen remover (BR) developed as part of the work on the ARA. ARAs prevent asphalt from adhering to tools and equipment used in asphalt production, without producing overly negative side effects with regards to the pavement. Three principal tests methods were developed and optimized for the performance and damage to asphalt of the ARAs. The asphalt slide test was developed to quantify the performance of the ARA by sliding hot asphalt mix down a plate with the ARA applied. The testing of the damage to asphalt from ARAs consisted of testing an asphalt cylinder - in contact with an ARA for seven days - in indirect-tensile strength (ITS). The bitumen degradation test consisted of submerging a bitumen sample in an agent over a certain time and weighing the bitumen that did not dissolve in the agent. This was followed by the observation of the bitumen-ARA chemical interaction by FTIR spectrometry. This test served as an assessment of ARA damage to bitumen as well as of the performance of BRs. The testing of the commercial ARAs from both the French and USA markets found that they had two primary modes of functioning: i) by softening the bitumen and ii) by forming an interface between the asphalt and the metal surface. While some agents had elements of both, it was found that interface agents are preferable, due to the ability to use a single ARA application for multiple occasions. With this completed, a water-based bio-sourced substrate ARA - based on glycerol derived from agricultural waste - was developed. The commercially available BRs were tested as well, finding that i) the most effective BRs had the highest ester concentration and ii) that highly concentrated short chained ester (C7-10) were very effective bitumen dissolvers. The goal of rejuvenating agents is to regenerate the old bitumen from recycled asphalt pavement (RAP) by restoring the original properties and ensuring the stability of these properties over time. This part consisted of the development of methods for bitumen and aging, as well as characterization of the chemical rejuvenation of bitumen by FTIR spectrometry (including imaging) and thermogravimetric analysis. A bio-sourced rejuvenating agent was evaluated as well. For the imaging, a mastic polishing method was developed in order to attain as samples as flat as possible for the analysis. The bitumen rejuvenation was observed using FTIR spectroscopy analysis. Several peaks (notably IC=O and IS=O) were observed for bitumen oven aged up to 42 days (long term). It was found that an oven aging period of 14 days was roughly equivalent to bitumen aged by a RTFOT+PAV cycle it terms of rheology and penetration. The mastic (aged for 14 days) was then combined with a bio-sourced agent (at 7.5%w of mastic). It was found by FTIR imaging that the oxidation indicator IS=O, was reduced by the incorporation of the rejuvenating agent
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Horáček, Daniel. "Inovativní asfaltové směsi pro netuhé vozovky s použitím R-materiálu." Master's thesis, Vysoké učení technické v Brně. Fakulta stavební, 2020. http://www.nusl.cz/ntk/nusl-409809.
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The diploma thesis is focused on the design and production of two innovative asphalt mixtures of the VMT 22 type into the base asphalt course. The newly produced blends contain modified binders, such as polymer modified bitumen (PMB) and Crumb rubber modified bitumen (CRMB). The theoretical part of the thesis describes the current state of the use of Reclaimed asphalt pavement in the base asphalt course. Furthermore, there are described types of asphalt mixtures for the base asphalt course are used in the Czech Republic and other countries. The conclusion of the theoretical part is devoted to the description of Reclaimed asphalt pavement (RAP), its storage and processing in a hot mix center. In the practical part of this thesis, there is described design and test of two High modulus asphalt mixture VMT 22, into which 25% RAP is dosed cold without rejuvenators. These asphalt mixtures are then subjected to functional tests (Stiffness of asphalt mixture test, Resistance to fatigue test, Low temperature properties of asphalt mixture test). The results of the functional tests are compared with the functional requirements in the Czech regulation TP 151. In the end of this thesis it is verified by means of the LayEps software that a suitable design of the asphalt mixture can significantly extend the road life.
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Roper, Matthew B. "Evaluation of Laboratory Durability Tests for Stabilized Aggregate Base Materials." BYU ScholarsArchive, 2007. https://scholarsarchive.byu.edu/etd/902.
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The Portland Cement Association commissioned a research project at Brigham Young University to compare selected laboratory durability tests available for assessing stabilized aggregate base materials. The laboratory research associated with this project involved two granular base materials, three stabilizers at three concentration levels each, and three durability tests in a full-factorial experimental design. The granular base materials consisted of an aggregate-reclaimed asphalt pavement blend obtained from Interstate 84 (I-84) and a crushed limestone obtained from U.S. Highway 91 (US-91), while the three stabilizer types included Class C fly ash, lime-fly ash, and Type I/II Portland cement. Specimens were tested for durability using the freeze-thaw test, the vacuum saturation test, and the tube suction test. Analyses of the test results indicated that the unconfined compressive strength (UCS) and retained UCS were higher for specimens tested in freeze-thaw cycling than the corresponding values associated with vacuum saturation testing. This observation suggests that the vacuum saturation test is more severe than the freeze-thaw test for materials similar to those evaluated in this research. The analyses also indicated that the I-84 material retained more strength during freeze-thaw cycling and vacuum saturation and exhibited lower final dielectric values during tube suction testing than the US-91 material. Although the I-84 material performed better than the US-91 material, the I-84 material required higher stabilizer concentrations to reach the target 7-day UCS values specified in this research. After freeze-thaw testing, the Class C fly-treated specimens were significantly stronger than both lime-fly ash- and cement-treated specimens. In the vacuum saturation test, none of the three stabilizer types were significantly different from each other with respect to either UCS or retained UCS. Dielectric values measured during tube suction testing were lowest for cement-treated specimens, indicating that cement performed better than other stabilizers in reducing the moisture/frost susceptibility of the treated materials. The results also show that, as the stabilizer concentration level increased from low to high, specimens performed better in nearly all cases. A strong correlation was identified between UCS after the freeze-thaw test and UCS after the vacuum saturation test, while very weak correlations were observed between the final dielectric value after tube suction testing and all other response variables. Differences in variability between test results were determined to be statistically insignificant. Engineers interested in specifying a comparatively severe laboratory durability test should consider vacuum saturation testing for specimens treated with stabilizers similar to those evaluated in this research. The vacuum saturation test is superior to both the freeze-thaw and tube suction tests because of the shorter duration and lack of a need for daily specimen monitoring. Although the Class C fly ash used in this research performed well, further investigation of various sources of Class C fly ash is recommended because of the variability inherent in that material. Similar research should be performed on subgrade soils, which are also routinely stabilized in pavement construction. Research related to long-term field performance of stabilized materials should be conducted to develop appropriate thresholds for laboratory UCS values in conjunction with vacuum saturation testing.
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Šperka, Pavel. "Vliv použití R - materiálu na funkční vlastnosti asfaltových směsí." Master's thesis, Vysoké učení technické v Brně. Fakulta stavební, 2015. http://www.nusl.cz/ntk/nusl-227637.
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Diploma thesis deals with the topic of using recycled material in the production of asphalt mixtures. In the theoretical part the methods of recycling flexible pavement are described and as well as ways in which recycled material is added to asphalt mixtures produced by the stationary hot mix plant. The thesis also deals with the current state of recycled material use in the Czech Republic and the reasons for its possible greater use. The practical part of the thesis studies the effect of using the amount of 20% recycled material to asphalt mixtures of asphalt concrete for wearing course ACO11+, on selected functional properties of these mixtures. It is also investigates the influence of bitumen binder contained in the recycled material, on the final properties in manufactured asphalt mixtures. An integral part of this thesis is a description of all methods that were used during the processing of the practical part. In the end of this thesis there are some results of findings about adding recycled material into asphalt mixtures.
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Bambulová, Lucie. "Protismykové vlastnosti asfaltových vrstev s R - materiálem." Master's thesis, Vysoké učení technické v Brně. Fakulta stavební, 2018. http://www.nusl.cz/ntk/nusl-371870.
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The diploma thesis deals with the problems of pavement surface skid resistence of wearing course of asphalt mixtures with R-material. Specifically, it is a mixture of type ACO 11 (asphalt concrete for wearing layers). In the theoretical part of the thesis there are dismantled the problems of Antiskid properties of the road surface and recycling of R-material. The practical part is dedicated to the design and laboratory production of the asphalt mixture ACO 11 without admixture of R-material and with content of 38 % R-material. In addition, the results of the measurement of friction coefficient after smoothed for these bitumen mixtures are shown in the work. The aim of the thesis was to determine the influence of the increased content of R-material on the anti-skid properties of the road surface as it is planned to update the standard ČSN EN 13108-1, which will allow the use of up to 40 % R-material into the mixtures of type ACO 11.
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Sandin, Pierre. "Characterization of a refractory cement and sensor development for temperature measurements in molten steel." Thesis, Uppsala universitet, Mikrosystemteknik, 2018. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-353490.
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In steel manufacturing, temperature control is a critical parameter,as it is extremely important for the steel quality. In general,disposable sensors are regularly immersed in the melt for temperaturemeasurements. There are commercially available sensors for continuoustemperature measurements. In this study, a refractory cement is used for encapsulation andcarrier of a resistive temperature detector, for continuoustemperature measurements in molten steel. This cement is normallyused for manufacturing of steel melt crucibles. The work in thisstudy is mostly experimental and consist of characterization of thecement and development of the sensor. The characterization includesthe mechanical properties, the thermal shock resistance, the steelmelt resistance and obtainable surface roughness, for differentpowder fractions, water-to-cement ratio, firings and mixing method.Process developments were also done for the manufacturing of thesensor element and its carrier system. The end goal for continuous temperature measurement in molten steelfor more than 60 minutes was not reached. However, functional sensorswere developed where temperatures up to 1000 °C were measured duringcalibrations, and the cement was well characterized. This work has been carried out within the Strategic innovationprogram "Smartare Elektroniksystem", a joint investment of Vinnova,Formas and Energimyndigheten.
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Simancas, Coloma Jorge. "Synthesis and Characterization of Zeolitic Materials Using Phosphorous Organic Structure Directing Agents." Doctoral thesis, Universitat Politècnica de València, 2021. http://hdl.handle.net/10251/171267.
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[ES] Las zeolitas son materiales cristalinos microporosos con canales y tamaños de poro de dimensiones moleculares. La estructura y composición de las zeolitas les confiere interesantes propiedades que permiten su aplicación en una amplia gama de aplicaciones industriales como adsorción, separación o catálisis. La síntesis de zeolitas es la etapa más importante para el control de la estructura y composición de las zeolitas y, por tanto, crítica para la optimización de sus propiedades.
Esta tesis se ha centrado en la síntesis de zeolitas utilizando compuestos que contienen fósforo (cationes fosfonio y aminofosfonio) como Agentes Directores de Estructura (P-ADE). El uso de compuestos fosforados influye en la cristalización y propiedades de las zeolitas obtenidas en comparación con las zeolitas obtenidas con cationes de amonio clásicos.
Los compuestos fosforados se eligieron debido a su diferente química y estabilidad con respecto a los cationes de amonio clásicos comúnmente usados en la síntesis de zeolitas. Estos aspectos se estudiaron con un estudio comparativo de diferentes cationes de amonio y fosforados.
Los compuestos de fósforo utilizados en este trabajo han dado lugar a nuevas estructuras cristalinas (ITQ-58 e ITQ-66) y han abierto nuevas vías de síntesis de zeolitas ya conocidas (RTH, IWV y DON), ampliando su gama de composiciones químicas.
La descomposición térmica de los P-ADE confinados dentro de las zeolitas da lugar a la formación de especies de fósforo extra-red que permanecen dentro de los canales y cavidades de las zeolitas. Estas especies modulan las propiedades ácidas y de adsorción de los materiales finales dependiendo de los tratamientos post-síntesis. En este trabajo se ha estudiado una ruta para la incorporación de cantidades controladas de fósforo durante la etapa de síntesis. Esto ha permitido controlar la adsorción y las propiedades ácidas en las zeolitas de poro pequeño, lo que no se puede lograr mediante metodologías de post-síntesis.[CA] Les zeolites són materials cristal·lins microporosos amb canals i mides de porus de dimensions moleculars. L'estructura i composició de les zeolites els confereix interessants propietats que permeten la seua aplicació en una àmplia gamma d'aplicacions industrials com adsorció, separació o catàlisi. La síntesi de zeolites és l'etapa més important per al control de l'estructura i composició de les zeolites i, per tant, crítica per a l'optimització de les seues propietats. Aquesta tesi s'ha centrat en la síntesi de zeolites utilitzant compostos que contenen fòsfor (cations fosfoni i aminofosfoni) com a agents directors d'estructura (P-ADE). L'ús de compostos fosforats influeix en la cristal·lització i propietats de les zeolites obtingudes en comparació amb les zeolites obtingudes amb cations d'amoni clàssics. Els compostos fosforats es van triar a causa de la seua diferent química i estabilitat pel que fa als cations d'amoni clàssics utilitzats en la síntesi de zeolites. Aquests aspectes s¿estudiaren amb un estudi comparatiu de diferents cations d'amoni i fosforats. Els compostos de fòsfor utilitzats en aquest treball han donat lloc a noves estructures cristal·lines (ITQ-58 i ITQ-66) i han obert noves vies de síntesi de zeolites ja conegudes (RTH, IWV i DO), ampliant la seua gamma de composicions químiques. La descomposició tèrmica dels P-ADE atrapats dins de les zeolites dona lloc a la for-mació d'espècies de fòsfor extra-xarxa que romanen dins dels canals i cavitats de les zeolites. Aquestes espècies modulen les propietats àcides i d'adsorció dels materials finals depenent dels tractaments post-síntesi. En aquest treball s'ha estudiat una ruta per la incorporació de quantitats controlades de fòsfor durant l'etapa de síntesi. Això ha permés controlar l'adsorció i les propietats àcides en les zeolites de porus petit, el que no es pot aconseguir mitjançant metodologies de post-síntesi.
[EN] Zeolites are microporous crystalline materials with channels and pore openings of molecular dimensions. The structure and composition of zeolites confers them interesting properties that allow their application in a wide range of industrial applications as adsorption, separation or catalysis. The synthesis of zeolites is the most important stage to control the structure and composition of zeolites, and thus, critical to optimize their properties. This thesis has been focused on the synthesis of zeolites using phosphorous containing compounds (phosphonium and aminophosphonium cations) as Organic Structure Directing Agents (P-OSDA). The use of these phosphorous compounds influence the crystallization and properties of the obtained zeolites compared to zeolites obtained with classical ammo-nium cations. Phosphorous compounds were chosen because of their different chemistry and stabil-ity properties respect to classical ammonium cations commonly used in the synthesis of zeo-lites. These aspects were studied in a comparative study with different ammonium and phosphorous cations. The phosphorous compounds used in this work have yielded new crystalline structures (ITQ-58 and ITQ-66) and opened new routes for the synthesis of already known zeolites (RTH, IWV and DON), widening their chemical composition range. The thermal decomposition of the P-OSDAs entrapped inside the zeolites yields to the formation of extra-framework phosphorus species that remain inside the channels and voids of the zeolites. These species modulate the adsorption and acid properties of the final materials depending on the post-synthesis treatments. In this work, a route for the incorporation of controlled amounts of phosphorus during the synthesis stage has been studied. This has allowed to control the adsorption and acid properties in small pores zeolites, which cannot be achieved by post-synthesis methodologies.
I wish to firstly acknowledge the Spanish Government for the necessary funding for the FPI pre-doctoral fellowship (BES-2013-062999). Also, this thesis would not have been possible without the infrastructures provided by the UPV and the CSIC staff, fused into the ITQ. Furthermore, I want to acknowledge the Microscopy Service of the UPV for their support in sample microscopy characterization
Simancas Coloma, J. (2021). Synthesis and Characterization of Zeolitic Materials Using Phosphorous Organic Structure Directing Agents [Tesis doctoral]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/171267
TESIS
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Cooley, Dane A. "Effects of Reclaimed Asphalt Pavement on Mechanical Properties of Base Materials." Diss., CLICK HERE for online access, 2005. http://contentdm.lib.byu.edu/ETD/image/etd1094.pdf.
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Ahmed, Ananna. "Evaluation of cracking potential of superpave mixtures with high reclaimed asphalt pavement content." Thesis, Kansas State University, 2015. http://hdl.handle.net/2097/20411.
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Master of ScienceCivil Engineering
Mustaque A. Hossain
Approximately 89% of 11,000 miles of Kansas roads are surfaced with asphalt. Hundreds of thousands of tons of reclaimed asphalt pavement (RAP) are produced annually in the United States, including in Kansas. This bulk volume of RAP must be economically managed in order to achieve environmental friendliness. Recycling of RAP conserves natural resources and reduces landfill usage. However, many agencies have reported that increased RAP content produces drier hot-mix asphalt (HMA) mixtures than virgin mixtures that are susceptible to premature cracking. In this research, laboratory-produced Superpave HMA mixtures containing increased percentages (20, 30, and 40%) of RAP materials from three RAP sources (Shilling Construction Co., Konza Co., and the Kansas Department of Transportation’s project, US 73) were studied for cracking performance. Mix designs were produced using Superpave design criteria for 12.5-mm nominal maximum aggregate size mixture. The static and repetitive Semicircular Bending (SCB) test, the Texas Overlay Tester test, the dynamic modulus test, and Viscoelastic Continuum Damage (VECD) tests were performed on laboratory-prepared samples. In general, cracking performance decreased with increased RAP content. The RAP from the US 73 project performed most consistently compared to other two sources of RAPs. Test results were analyzed using two-way Analysis of Variance (ANOVA), proving that mixtures containing 4.5% to 4.9% binder performed the best against cracking. The RAP source was found to have more effect on cracking propensity than RAP content. Mixtures with RAP content up to 40% performed satisfactorily. Tukey’s pairwise comparison method was used to compare results from all tests; VECD was determined to be the most appropriate test to evaluate cracking propensity of HMA mixtures.
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ARANHA, Rudá. "Estudo do processamento de materiais compósitos com inserts impermeáveis embebidos via RTM." Universidade Federal de Campina Grande, 2017. http://dspace.sti.ufcg.edu.br:8080/jspui/handle/riufcg/1489.
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Os materiais compósitos são sinônimos de boas propriedades mecânicas associadas a baixo peso estrutural com vasta aplicação na área da engenharia. A partir dos avanços tecnológicos e da necessidade de desenvolvimento de novos materiais, torná-los multifuncionais surge como interesse imediato. O método mais simples para conferir multifuncionalidade a um compósito é através da introdução de inserts nos compósitos antes de sua fabricação, conferindo-os as mais variadas características, sendo importante entender as consequências geradas a partir do uso dos inserts no processamento das placas. O estudo experimental do escoamento de resina através da pré-forma e os efeitos recorrentes devido à adição dos inserts impermeáveis aos compósitos durante o processo de Moldagem por Transferência de Resina (RTM) são os objetivos deste trabalho. Neste trabalho, foram utilizados reforço de tecido de fi bra de vidro e matriz de resina poliéster na composição de placas de material compósito com dimensões de 250x250x14 mm3 com 1 e 9 inserts impermeáveis de polietileno com dimensões de 50x50x4 mm3, processadas pelos métodos de RTM Light e VARTM para futura aplicação estrutural e/ou balística. Como esperado, a introdução de inserts na pré-forma causou distúrbio no escoamento da resina durante os processamentos, sendo evidenciadas regiões super ciais em algumas das placas, acima dos inserts, onde as bras não foram molhadas. Ao fim dos processamentos foram observadas variações nas espessura das placas, sendo esta uma consequência da compactação das fi bras devido à presença dos inserts. Também foi identi cada a movimentação dos inserts quando os pontos de entrada e saída foram posicionados em planos diferentes no molde. Tal movimentação foi evitada a partir da fixação dos inserts em uma tela antes do processamento. Com o corte das placas, regiões ricas em resina próximas às laterais dos inserts foram observadas, sendo esta uma consequência do mecanismo de afastamento das fibras devido à presença dos inserts. Assim, 4 zonas foram identifi cadas nos compósitos com inserts impermeáveis embebidos. Por fim,nos ensaios de flexão em 3 pontos, falhas de delaminação por cisalhamento tipo II foram identi cadas nos corpos de prova.
Composite materials are synonymous with good mechanical properties associated with low structural weight and have a great variety of applications in the engineering area. Taking into account technological advances and the necessity to develop new materials, make them multifunctional appears as immediate interest. The simplest method to confer multifunctionality to a composite is through the introduction of inserts into the composites, giving them the most varied characteristics. It is important to understand how these inserts will a ect the fabrication process and the structural characterization of the material. The experimental analysis of the ow through the preform and the effects due to the addition of the impermeable inserts to the composite during the process of Resin Transfer Molding (RTM) are the objectives of this work. In this work, reinforcement of glass ber fabric and polyester resin matrix was used in the composition of 250x250x14 mm3 composite materials sheets with 1 and 9 polyethylene impermeable inserts with dimensions of 50x50x4 mm3, processed by the RTM Light and VARTM methods for future structural and/or ballistic application. As expected, introduction of inserts into the preform caused disturbances in resinow during processing, with surface regions in some of the plates above the inserts where the bers were not wetted. At the end of the processing, variations in the thickness of the plates were observed, being this a consequence of the bercompaction due to the presence of the inserts. The movement of the inserts was also identi ed when the resininlet and outlet were positioned on di erent planes in the mold. the inserts movimentation was prevented from attaching the inserts to a mesh before the processing.With the cutting of the plates, resin-rich regions close to the sides of the inserts were observed, which is a consequence of the mechanism of ber spacing due to the presence of the inserts. Thus, 4 zones were identi ed in the composites with embedded impermeable inserts. Finally, in the 3-point bending tests, delamination failures for shear mode II were identi ed in the specimens.
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Bykov, Igor. "Experimental studies of materials migration in magnetic confinement fusion devices : Novel methods for measurement of macro particle migration, transport of atomic impurities and characterization of exposed surfaces." Doctoral thesis, KTH, Fusionsplasmafysik, 2014. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-145045.
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During several decades of research and development in the field of Magnetically Confined Fusion (MCF) the preferred selection of materials for Plasma Facing Components (PFC) has changed repeatedly. Without doubt, endurance of the first wall will decide research availability and lifespan of the first International Thermonuclear Research Reactor (ITER). Materials erosion, redeposition and mixing in the reactor are the critical processes responsible for modification of materials properties under plasma impact. This thesis presents several diagnostic techniques and their applications for studies of materials transport in fusion devices. The measurements were made at the EXTRAP T2R Reversed Field Pinch operated in Alfvén laboratory at KTH (Sweden), the TEXTOR tokamak, recently shut down at Forschungszentrum Jülich (Germany) and in the JET tokamak at CCFE (UK). The main outcomes of the work are: Development and application of a method for non-destructive capture and characterization of fast dust particles moving in the edge plasma of fusion devices, as well as particles generated upon laser-assisted cleaning of plasma exposed surfaces. Advancement of conventional broad beam and micro ion beam techniques to include measurement of tritium in the surfaces exposed in future D-T experiments. Adaption of the micro ion beam method for precision mapping of non uniform elements concentrations on irregular surfaces. Implementation of an isotopic marker to study the large scale materials migration in a tokamak and development of a method for fast non destructive sampling of the marker on surfaces of PFCs.QC 20140508
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Čumíčková, Markéta. "Dávkování oživovacích přísad do asfaltové směsi s vysokým obsahem R-materiálu." Master's thesis, Vysoké učení technické v Brně. Fakulta stavební, 2019. http://www.nusl.cz/ntk/nusl-392144.
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The diploma thesis is focused on the appropriate dosage of rejuvenating agents in asphalt mixtures with high content of RAP. The empirical and functional laboratory tests are described in the theoretical part. The practical part deals with the estimation of the optimal amount of rejuvenating agents by means of laboratory tests so that the rheological properties of the degraded asphalt binder can be restored by suitable dosing into the RAP. As part of the TAČR ZÉTA project, an experimental section of asphalt mixture containing 50 % of the RAP and an appropriate amount of the rejuvenating agents was created. The aim of the thesis is to find an optimal dosage of the rejuvenating agents in the samples of the RAP and laboratory aged asphalt binder of gradation 50/70, to determine the effectiveness of selected rejuvenating agents and to monitor changes in the parameters of the experimental section during the period of time.
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Gascons, i. Tarrés Marc. "Assessment of virtual design and manufacturing techniques for fibre reinforced composite materials." Doctoral thesis, Universitat de Girona, 2011. http://hdl.handle.net/10803/52864.
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Virtual tools are commonly used nowadays to optimize product design and manufacturing process of fibre reinforced composite materials. The present work focuses on two areas of interest to forecast the part performance and the production process particularities. The first part proposes a multi-physical optimization tool to support the concept stage of a composite part. The strategy is based on the strategic handling of information and, through a single control parameter, is able to evaluate the effects of design variations throughout all these steps in parallel. The second part targets the resin infusion process and the impact of thermal effects. The numerical and experimental approach allowed the identificationof improvement opportunities regarding the implementation of algorithms in commercially available simulation software.Les eines de disseny virtual son usades de forma habitual per optimitzar el disseny i el procés productiu de peces de material compòsit reforçades amb fibra. Aquest treball es centra en dos àrees d’interès per la predicció de les prestacions de la peça i les particularitats del seu procés productiu. La primera part proposa una eina d’optimització multi-física per recolzar l’etapa de desenvolupament d’una nova peça. La estratègia es basa en la gestió intel•ligent de la informació a través d’un paràmetre de control comú, permeten l’avaluació dels canvis en totes les etapes en paral•lel. La segona part es centra en la infusió de resina, i particularment en l’impacte dels efectes tèrmics. Aquesta investigació numèrica i experimental ha permès la identificació de possibilitats de millora en la implementació d’algoritmes usats actualment en codis comercials de simulació.
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Pires, Gustavo Menegusso. "ESTUDO DA ESTABILIZAÇÃO GRANULOMÉTRICA E QUÍMICA DE MATERIAL FRESADO COM ADIÇÃO DE CIMENTO PORTLAND E CINZA DE CASCA DE ARROZ PARA APLICAÇÃO EM CAMADAS DE PAVIMENTOS." Universidade Federal de Santa Maria, 2014. http://repositorio.ufsm.br/handle/1/7865.
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Coordenação de Aperfeiçoamento de Pessoal de Nível SuperiorRoad transport is of great importance for many countries, in Brazil it can be even more extreme, due to the concentration of cargo through this modal. We also know that maintenance costs are elevated, forcing managers and researchers to find new alternatives to increase the utilization of materials, reduce energy consumption, speed up restoration interventions, among others. Besides the high costs, another important factor that stands out is the environmental issue, which is directly affected in the construction and maintenance of highways, whether using natural materials, movements of soils, in the fuel used by the equipment, etc. Thus, it becomes feasible to study reuse of old materials in the execution of highways recycling of deteriorated pavement, because all the material can be used for construction of a new layer, and with little addition of new materials for stabilization, reducing the consumption. Therefore, the material deteriorated asphalt pavement, the Reclaimed Asphalt Pavement (RAP), is the objective of this research, aiming to stabilize pavement layers in two ways, the particle size and chemical stabilization, the latter with the addition of Portland cement and rice husk ash. This research aims to evaluate, through laboratory testing, the feasibility of using pure and stabilized milled material (mechanical, chemical and particle size) in layers of flexible pavements. The milled materials are from BR-290 and ERS-509. Particle size stabilization was performed and determined the level of 70% of milled material and 30% of natural aggregate. For testing of compressive strength were molded into test specimens of 10x20 cm with different levels of Portland cement (CP IV-32), and determine the content of 4,86% (BR-290) and 5,37% (ERS-569) from the compressive strength of 2.1 MPa at 28 days. From the results obtained, specimens were molded for testing the Axial compressive strength, tensile strength by diametrical compression and resilient modulus; in these specimens, the cement was replaced by Rice Husk Ash (mesh #325 and #500) in ratios of 15, 30 and 50% by weight of cement content, and put into moist chamber for 7, 28 and 160 curing days. The results showed that the amount of 15% of CCA reached values very close to the reference mixtures. The satisfactory performance confirms the possibility to cover studies of these materials.
O transporte rodoviário é de grande importância para muitos países, no Brasil isso pode ser ainda mais extremo devido à concentração da movimentação das cargas através deste modal. Sabemos também que os custos de manutenção são elevados, forçando os gestores e pesquisadores a encontrar sempre novas alternativas para melhorar o aproveitamento dos materiais, diminuir o consumo de energia, agilizar as intervenções de restauração, entre outros. Outro fator importante que se destaca é a questão ambiental, onde é diretamente afetada nas construções e manutenções de rodovias, seja no consumo de materiais naturais, nas movimentações de terras, nos combustíveis utilizados, etc. Assim, torna-se viável o estudo de reaproveitamento dos materiais antigos das rodovias, na execução da reciclagem do pavimento deteriorado, pois todo o material poderá ser utilizado para construção de uma nova camada. Portanto, o material asfáltico do pavimento deteriorado, o fresado, é o objetivo de estudo desta pesquisa, visando a estabilização granulométrica e química, esta última com adição de cimento Portland e cinza de casca de arroz. Esta pesquisa objetivou avaliar, através de ensaios laboratoriais, a viabilidade da utilização de material fresado puro e estabilizado (mecânica, granulométrica e quimicamente) em camadas de pavimentos flexíveis. Os materiais fresados são oriundos da BR-290 e da ERS-509. Foi realizada estabilização granulométrica, sendo determinado o teor de 70% de material fresado e 30% de agregado natural. Para ensaio de resistência à compressão simples foram moldados em corpos-de-prova de 10x20 cm com diferentes teores de cimento Portland (CP-IV 32), sendo determinados os teores de 4,86% (BR-290) e 5,37% (ERS-569) a partir da resistência à compressão de 2,1 MPa aos 28 dias. A partir dos resultados obtidos foram moldados corpos de prova para ensaios de resistência à compressão, resistência à tração e módulo de resiliência; sendo nestes substituído em massa o CP-IV 32 em 15, 30 e 50% por cinza de casca de arroz moída (CCA #325 e CCA #500), colocados em câmara úmida por 7, 28 e 160 dias. A análise dos resultados mostrou que o teor de 15% de CCA alcançou valores muito próximos das misturas de referência. O desempenho satisfatório corrobora com a possibilidade de abranger os estudos destes materiais.
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Dario, Pieck. "Optimisation de l'utilisation du gadolinium comme poison consommable dans le combustible nucléaire : Vers un REP sans bore." Phd thesis, Aix-Marseille Université, 2013. http://tel.archives-ouvertes.fr/tel-00951801.
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L'excès de réactivité neutronique dans les centrales nucléaires est compensé par des sys-tèmes actifs de contrôle du réacteur : acide borique et barres de contrôle. L'apport d'antiréactivité peut se faire passivement avec des poisons consommables, c'est-à-dire des absorbants de neutrons, en particulier avec du gadolinium (Gd). Dans le cadre d'une augmentation de l'enrichissement en U²³⁵ et de réduction de l'utilisation d'acide borique, cette thèse a pour objectif d'optimiser la distribution du ga-dolinium dans des céramiques d'UO₂ afin d'obtenir un apport optimisé d'antiréactivité dans un Réacteur à Eau sous Pression. Dans ce sens, le travail est orienté à trouver des nouveaux matériaux riches en gadoli-nium. Le diagramme de phase U-O-Gd a donc été exploré dans le domaine des fortes teneurs en Gd. Deux phases cubiques ont été trouvées et caractérisées : les phases C1 et C2. En vue d'une application industrielle, la phase C1 a été retenue comme candidate pour l'ajout du Gd dans les pastilles d'UO₂. La distribution optimale de cette phase C1 dans les assemblages de combustible nucléaire a été étudiée avec le code de calcul neutronique APOLLO2.8. Des études paramétriques ont été réalisées. Ces études neutroniques ont aboutit à un concept performant de pas-tille empoisonnée. Finalement, des pastilles prototype ont été fabriquées en laboratoire suivant ce concept. L'ensemble des résultats obtenus montre qu'un concept de pastille avec un dépôt super-ficiel neutrophage de phase C1 est une manière d'apporter de l'antiréactivité de manière optimisée dans le cadre de cycles longs. Ceci pourrait potentiellement être appliquée à l'échelle industrielle. Un brevet a été déposé en ce sens.
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Gadal, Aurélie. "Traitement d'effluent gazeux par biofiltration : Impact des caractéristiques physico-chimiques et hydrodynamiques du matériau support sur les performances et la structure de la communauté bactérienne totale au sein du réacteur." Thesis, Montpellier 2, 2012. http://www.theses.fr/2012MON20006/document.
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La pollution odorante est une problématique majeure, deuxième source de plaintes après le bruit. La réduction des émissions d'odeurs est incontournable, contraignant le plus souvent les industriels à la mise en œuvre d'un procédé de traitement performant et économiquement acceptable. Parmi les techniques disponibles, les procédés biologiques en général et la biofiltration en particulier sont les plus utilisés à l'échelle industrielle. Les performances de ce procédé sont étroitement liées aux paramètres opératoires. Le matériau support apparaît comme un élément clé. Du fait des critères qu'il doit satisfaire, son choix est difficile et reste encore empirique. Ces travaux de thèse visent par conséquent à rationaliser le choix d'un matériau en s'intéressant plus particulièrement à la relation entre les caractéristiques physico-chimiques et hydrodynamiques du matériau support et les composantes macroscopique et microscopique du procédé. Trois matériaux modèles ont été sélectionnés : deux granulaires et un fibreux différant par leur propriétés physico-chimiques et hydrodynamiques. Les travaux ont été menés sur des unités pilote alimentées par un effluent gazeux contenant un mélange de trois composants volatils différant par leur solubilité et leur biodégradabilité. Si une influence des caractéristiques physico-chimiques du matériau a bien été observée, il n'a pas été possible de mettre en évidence un effet des propriétés hydrodynamiques. Concernant la composante microbiologique, le niveau de diversité global est similaire, quel que soit le matériau considéré. L'analyse de la structure de la communauté bactérienne totale met en évidence trois communautés distinctes, chacune étant associée à un matériau support. Il est fort probable que la communauté endogène participe largement à l‘établissement de ces communautés, rendant ainsi plus difficile de répondre aux questions posées. La communauté bactérienne totale ne semble donc pas être un indicateur adapté. Par le suivi de la communauté fonctionnelle, des réponses plus précises pourraient être apportées. Par conséquent, la recherche de niches écologiques spécifiques à la dégradation biologique d'un composé soufré (DMS) a fait l'objet d'une attention particulière dans le cadre de cette thèseOdour nuisance is a major issue, second cause of complaints after noise. Reduction of odor emissions is essential, binding the industry to implement a process for an economically acceptable treatment in terms of reduction of odours. Among the available techniques, biological ones and particularly biofiltration are the most used on industrial scale. The performances of this process are closely related to operating conditions. Packing material appears as a key factor, its choice is difficult and remains empirical because of the multiple criteriait must satisfy. This thesis work aimed to streamline the selection of a material with a focus on the relationship between physico-chemical and hydrodynamic caracteristics of the packing material and macroscopic and microscopic components of this process. Three materials were selected as models: two granulars and one fibrous differing in their physico-chemical and hydrodynamic caracteristics. The work was carried out on pilot units fed by an effluent gas containing a mixture of three volatile components differing in their solubility and biodegradability. The influence of physico-chemical characteristics of the packing material on the performances seems to be confirmed. However, the impact of the hydrodynamic characteristics of the material on these criteria has not been demonstrated. Regarding the microbiological component, the overall level of diversity is similar, regardless of the material considered. Analysis of the structure of the total bacterial community reveals the existence of three distinct communities, each associated with a carrier material. It is likely that the endogenous community participates largely to the establishment of these communities, making it difficult to give appropriate answers to the questions adressed. The total bacterial community does not seem to be a suitable indicator. By monitoring the functional community, more precise answers could be given. Therefore, the research for specific ecological niches in the biological degradation of a sulfur compound (DMS) has been the subject of special attention in the context of this thesis
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Tsernova, Inga. "jag försöker låta bli : en text om att bli till: om kroppar, hantverk, själ och Ande." Thesis, Konstfack, Ädellab, 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:konstfack:diva-7265.
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How can we live and work with craft as people in an age of global climate crisis? What must we change in order to work empathically and in harmony with our surrounding world? While not in need to actively ensure our survival, it is easy for us to forget to stay humble to our own needs, thus taking our lives and our surroundings for granted. We forget our bodies and we forget the bodies of others, animals and objects alike. We forget that we need each other in order to become. This text is a complementary exploration in how awareness of the soul, body and Spirit may help bring back a balance that we've lost in town based cultures of the west. I am looking for balance as I twist fibre into thread and into rope and as I suspend rock- and human bodies into temporary sculptures. I look for inspiration in phenomenologist thought, alchemy, shamanism and daoism, as well as in the active making of craft and art. My work centers around telling stories, crafting and material exploration as well as bodily awareness and performance. In the work, body and material are synonymous concepts drifting in and out of each other, enabling and shaping each other, becoming together. I am looking to meet my surroundings not always on my own terms, but by changing, adapting and compromising myself. This helps bring an awareness that unites me with the bodies around me, placing me not above but amidst constant becomings.
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Puaux, Grégory. "Simulation numérique des écoulements aux échelles microscopique et mésoscopique dans le procédé RTM." Phd thesis, École Nationale Supérieure des Mines de Paris, 2011. http://pastel.archives-ouvertes.fr/pastel-00667411.
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Le procédé " Resin Transfer Molding " consiste à injecter un polymère thermodurcissable à travers des fibres de renfort, qui polymérise ensuite pour former une pièce composite. L'objectif est de modéliser numériquement l'écoulement à différentes échelles, celle des mèches composants le tissu (mésoscopique) et celle des fibres composants les mèches (microscopique). Cette thèse se décompose en deux parties. La première concerne le calcul de perméabilité d'un volume élémentaire représentatif par prise de moyenne des champs de vitesse et de pression, dans le cadre de la méthode d'immersion de domaines. A l'échelle microscopique, le calcul de perméabilité a été validé en utilisant des lois analytiques. A l'échelle mésoscopique, un couplage entre les équations de Stokes et de Darcy, pour les écoulements entre les mèches et à l'intérieur des mèches a été effectué. La seconde partie aborde l'étape d'imprégnation du renfort à l'échelle microscopique, ce qui inclut la modélisation de l'avancée du front de matière entre les fibres avec prise en compte de la tension de surface. Nous avons implémenté des méthodes pour prendre en compte les phénomènes capillaires. Une méthode d'imposition de l'angle de contact statique de l'interface avec une surface solide, et la condition aux limites de Navier permettant d'imposer un glissement à la ligne triple, ont été implémentées et validées. Tous les développements ont été effectués dans une méthode éléments finis mixtes linéaires en vitesse pression, stabilisée par une fonction bulle (MINI-élément), et en utilisant la méthode d'immersion de domaines.
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Nagi, Greesh. "Preparation of polymer-clay nanocomposites via dispersion polymerization using tailor-made polymeric surface modifiers." Thesis, Stellenbosch : Stellenbosch University, 2011. http://hdl.handle.net/10019.1/18084.
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Thesis (PhD)--Stellenbosch University, 2011.ENGLISH ABSTRACT: Fully exfoliated polystyrene-clay nanocomposites were prepared via free radical polymerization in dispersion polymerization, in a mixture of ethanol and water. Sodium montomorillonite clay (MMT) was pre-modified using 3-(trimethoxysilyl) propyl methacrylate (MPTMS) before being used in a dispersion polymerization process. The particles obtained were not completely stable and TEM images showed that most of the clay platelets were distributed in the dispersing phase. A second objective included, the preparation of low molecular weight of polystyrene (PS) and amphiphilic block copolymers of poly(styrene-b-2-hydroxyethyl acrylate) (PS-b-PHEA)using reverse iodine transfer polymerization (RITP) living/controlled free radical polymerization.The reaction kinetic profile of the RITP process for styrene and 2-Hydroxyethyl acrylate (HEA) was also studied. The formation of the block copolymer PS-b-PHEA was confirmed by GPC and gradient HPLC. The resulting PS-I and (PS-b-PHEA)-I were chemically modified by dimethylethylamine and triethylamine respectively, ended with PS and PS-b-PHEA has quaternary ammonium end-chain functionality (PS-cationic and (PS-b-PHEA)-cationic). The obtained functional polymers (PS-cationic) and (PS-b-PHEA)-cationic) were then grafted onto MMT via a simple ion-exchange process to offer MMT with polymer chains on the surface (PS-MMT) and (PS-b-PHEA)-MMT). Furthermore, the ability of the interaction ofPS-b-PHEA with MMT by adsorption via several functional groups was also investigated. The third objectiveincluded the use of this new class of pre-modified clay PS-MMT in the preparation of PCNs as stabilizers, the clay particles were encapsulated into PS latexes with a partially exfoliated structure at 100% CEC, upon stoppage of the polymerization process, and the final dispersion found to be stable for up to 5 wt% of clay filler loading. The thermal and thermo-mechanical properties of PS-nanocomposites were found to be dependent on both nanocomposites morphology, and clay loading. (PS-b-PHEA)-MMT was also used as stabilizers in the preparation of PS via dispersion polymerization. PS colloidal particles obtained were found to be armoured by (PS-b-PHEA)-MMT layers, with particles sizes in the micro-size range, with fair stability were obtained for clay loadings up to 5%. Analysis of the structure and thermo-mechanical properties of the resulting PCNs revealed the efficiency of the clay surface pre-modification in stabilizing the system throughout the heterophasic polymerization process.The melt flow properties of final PCNs were found to be strongly dependent on the clay loading, with shift observed from liquid-like viscoelastic to solid-like viscoelastic behaviour as the clay content increased due to percolation of the clay network within the PS matrix taking place upon film formation above Tg.
AFRIKAANSE OPSOMMING: Die eerste doelwit was die voorbereiding van ten volle geëksfolieerde polistireen-klei nanosamestellings deur vrye radikaal polimerisasie in dispersie-polimerisasie, in 'n mengsel van etanol en water. Natrium montmorilloniet klei (MMT) is gemodifiseer deur gebruik te maak van 3-(trimetoksiesiliel) propiel metakrilaat (MPTMS), voordat dit gebruik is in die dispersie-polimerisasie. Die bekomde partikels was nie heeltemal stabiel nie. Transmissie elektronmikroskopie (TEM) resultate het getoon dat die meeste van die klei plaatjies in die dispersie-fase versprei is. Die tweede doelwit was die voorbereiding van polistireen (PS) met 'n lae molekulêre massa, gevolg deur die vorming van amfifiliese blok kopolimere van poli(stireen-b-2-hidroksie-etiel akrilaat) (PS-b-PHEA) met behulp van omgekeerde jodium oordrag polimerisasie (RITP) lewendige/gekontroleerde vrye radikaal polimerisasie. Die reaksie kinetiese profiel van die RITP proses was bestudeer met betrekking tot stireen en 2-hidroksie-etiel akrilaat (HEA). Die vorming van die blok kopolimeer PS-b-PHEA is bevestig deur GPC en gradiënt HPLC. Die gevolglike PS-I en (PS-b-PHEA)-I was chemies gewysig deur onderskeidelik dimetieletielamien en trietielamien, waardeur PS en PS-b-PHEA een kwaternêre ammonium ketting-endfunksionaliteit bekom het (PS-kationies en (PS-b- PHEA)-kationies). Laasgenoemde twee funksionele polimere was toe gekoppel aan MMT deur 'n eenvoudige ioon-ruilingsproses wat MMT met polimeerkettings op die oppervlak (PS-MMT) en (PS-b-PHEA)-MMT) tot gevolg het. Die interaksie van PS-b-PHEA met MMT deur middel van adsorpsie van verskeie funksionele groepe is ook ondersoek. Die derde doel was gerig op die gebruik van hierdie nuwe klas gemodifiseerde klei PS-MMT as stabiliseerders vir die voorbereiding van polimeer-klei-nanosamestellings (PCNs). Die 100% CEC gemodifiseerde klei deeltjies is ge-inkapsuleer in die PS emulsies met 'n gedeeltelik geëksfolieërde struktuur, na afloop van die polimerisasie proses. Die finale dispersie was stabiel tot en met 'n klei inhoud van 5 wt%. Daar is gevind dat die termiese en termo-meganiese eienskappevan die PS-nanosamestellings afhanklik is van beide die morfologie en die klei inhoud. (PS-b-PHEA)-MMT was ook gebruik as stabiliseerder in die voorbereiding van PS deur dispersie polimerisasie. Daar is gevind dat die PS kolloïdale partikels wat verkry is, versterk was deur (PS-b-PHEA)-MMT lae. Partikel groottes was in die mikro-grootte gebied, en voldoende stabiliteit is verkry vir 'n klei inhoud van tot 5%. Analise van die struktuur en die termo-meganiese eienskappe van die bekomde PCNs het getoon dat die vooraf modifisering van die klei oppervlak doeltreffend was in die stabilisering van die sisteem gedurende die heterofase polimerisasie proses. Daar is ook gevind dat die smelt vloei eienskappe van die finale PCNs sterk afhang van die klei inhoud; 'n verskuiwing vanaf vloeistof-agtige viskoelastiese tot vaste-agtige viskoelastiese gedrag is waargeneem soos die klei-inhoud verhoog. Hierdie verskynsel was te danke aan perkolasie van die klei netwerk binne die PS matriks wat plaasvind tydens film vorming by 'n hoër temperatuur as die glasoorgangstemperatuur (Tg).