Thesis (Ph. D.)--Polymer, Textile & Fiber Engineering, Georgia Institute of Technology, 2007. / Karl I. Jacob, Committee Chair ; Youjiang Wang, Committee Member ; Mary Lynn Realff, Committee Member ; Arun Gokhale, Committee Member ; Rami Haj-Ali, Committee Member.

An experiment was conducted to evaluate the durability, toughness, and strength of Synthetic Fiber Reinforced Concrete after being immersed in five separate environments for one year at FAU SeaTech. The specimens were molded and reinforced with two-inch Polypropylene/Polyethylene Fibers in a concrete aggregate matrix and were cut into identical sizes. Some of these environments had accelerated parameters meant to increase degradation to simulate longevity and imitate harsh environments or seawater conditions. The environments consisted of: a high humidity locker (ideal conditions), submerged in the Intracoastal Waterway (FAU barge), seawater immersion, a wet and dry seawater immersion simulating a splash/tidal zone, and another in low pH seawater. The latter three were in an elevated temperature room (87-95°F) which produced more degradative properties. The specimens were monitored and the environments were controlled. The specimens were then evaluated using the IDT test method using force to initiate first-cracking and post-cracking behaviors. / Includes bibliography. / Thesis (M.S.)--Florida Atlantic University, 2018. / FAU Electronic Theses and Dissertations Collection

Thesis (M.S.)--Michigan State University. Dept. of Civil and Environmental Engineering, 2008. / Title from PDF t.p. (viewed on Aug. 3, 2009) Includes bibliographical references (p.129-132). Also issued in print.

The retraction affects the setting process and the useful life of the concrete with the appearance of fissures; in last year's studies and methods have been generated to mitigate and control it with the use of different products and applications. The development of road infrastructure with the use of concrete as a rolling folder, requires methods to guarantee the durability and reduce the effects of the efforts incorporated by the use, climatic conditions, support base and restrictions of movement of the structure. To evaluate the effects of recycled synthetic polypropylene fibers in plastic retraction tests (ASTM C 1579), 3 mix designs were prepared with different ratios 58 gr., 116 gr., and 176 gr. of recycled and virgin synthetic fibers; the most significant and positive result to reduce fissures without affecting the resistance of concrete by bending and compression, was 0.50 mm without addition fibers, 0.10 mm and 0.15 mm with 176 gr. of virgin and recycled synthetic fibers. Finally, it can be concluded that adding a ratio of 4 kg per m3 allows good workability, in addition, the costs of the fibers are not representative compared to the high costs for future repairs.

Spider silk is known for its extraordinary material properties, being both very strong and extensible. Even though the fibers outperform many synthetic and natural materials, it is impractical to collect industrial amounts of silk from spiders due to their cannibalistic and venomous nature; they cannot be farmed like the commercial silk worm Bombyx mori. Thus, scientists have turned to molecular and engineering techniques to replicate the spider's silk and spinning apparatus. In the current literature there is no detailed protocol on the production of consistent synthetic fibers. To accomplish this, the fibroins and natural spinning apparatus were taken apart and analyzed in order to develop a protocol that biomimics the spider's system. The laboratory procedure, using the natural process as an example, was simplified to: protein production, purification, concentration, fiber spinning, and lastly post spin draw. Large quantities of truncated MaSp I spidroin (spider fibroin) was purified from E. coli and successfully spun into fibers using customized spinning, spooling, and stretching apparatuses. The final fiber products displayed mechanical properties that were comparable to other reported synthetic fibers, but more importantly also displayed low experimental variability between samples. The protocol developed in this study can be further used to characterize other spidroins and silk proteins, and can be further advanced to produce even better fibers with enhanced properties.

Há tempos a ubiquidade dos materiais plásticos no meio ambiente é assunto de discussão, com destaque para as partículas menores, ditas microplásticos (< 5 milímetros). Fibras provenientes de materiais têxteis são um subgrupo dos microplásticos e têm origem em diversas fontes, incluindo lavagens domesticas, uma vez que filtros de lavadoras e sistemas de tratamento de esgoto não são desenhados especificamente para retê-las. Quando no meio ambiente, estes materiais podem alcançar concentrações até milhares de unidades por metro cúbico, ficando disponíveis a uma gama de espécies. Neste cenário, o presente estudo teve como objetivo avaliar parâmetros de lavagem, e características têxteis que pudessem influenciar no desprendimento de fibras em efluentes de lavadoras domesticas. Foram realizados experimentos com dez sucessivas lavagens individuais, com e sem detergente, para quatro tipos de artigo: algodão (como padrão de comparação), acrílico, poliéster e poliamida. Os efluentes foram então filtrados (< 1 milímetro, 500 mícrons, 63 mícrons, 8 mícrons) e pesados. Resultados demonstram que todos os artigos têxteis liberaram fibras na lavagem. Dez sucessivas lavagens representaram queda na massa desprendida, bem como o uso de detergentes em comparação a lavagens sem detergente. Diferenças entre artigos sugeriram variação conforme características têxteis, onde algodão liberou mais fibras, seguido de acrílico, poliamida e poliéster. Em relação ao tamanho das fibras, a maioria ficou retida no filtro da lavadora (< 1 milímetro) e na peneira de 63 mícrons, mostrando o potencial de diminuição de porosidade do filtro. A visualização de fibras em papel-filtro de 8 mícrons sugere a existência de fibras micro e nano. Convertendo massa para numero de unidades, a lavagem individual de um artigo têxtil mostrou desprender entre milhares e centenas de milhares de fibras. Para uma extrapolação mundial, cerca de 40,4 mil toneladas de algodão e 21,5 mil toneladas de fibras sintéticas seriam liberadas em efluentes de esgoto. No Brasil estes valores corresponderiam, respectivamente, a 1,6 mil e 860 toneladas ano. Caso fossem tratadas em estações de tratamento de esgoto em condições ideais, seriam liberadas, em um ano, cerca de 737 toneladas de fibras sintéticas em escala mundial e 29 toneladas em escala nacional. Uma vez em cursos d\'água, estas fibras atingiriam, em ultima instância, o ambiente marinho, indicando a necessidade por soluções que combatam este tipo de poluição, sem antes deixar de explorar as lacunas do conhecimento, relacionadas, no âmbito têxtil, especialmente às diferenças metodológicas entre os estudos. / Since decades, the ubiquity of plastic materials in the environment has been a matter of discussion. Smaller pieces, named microplastic (< 5 millimeters) gained more attention recently and are now the focus of several studies. Textile fibers are a subgroup of microplastics and can be originated from several sources, including domestic washings, once filters and sewage treatment plants are not specifically designed to retain them. In the environment, these materials can reach concentrations up to millions of units per cubic meter, being available to many species. The objective of the present study was to evaluate washing parameters and also textile characteristics, which could influence in fibers emission from domestic washing machines. Experiments were done in ten successive times, with and without detergent, for four types of articles: cotton (as a pattern for comparison), acrylic, polyester and polyamide. Resulting effluents were then filtered in different porosities (< 1 millimeter, 500 microns, 63 microns, 8 microns), weighted, related to mass of textile articles and simulated regarding number of fibers. Results demonstrated that all textile articles emitted fibers during domestic washings. Ten successive washings represented a decrease in the emitted mass, as well as the use of detergent in relation to washings without the product. Differences between articles suggested variation of results according to textile characteristics, where the ranking of emission was: cotton, acrylic, polyamide and polyester. When considering the size of fibers, the majority was retained in the filter of the washing machine (porosity < 1 millimiter) and in 63 microns sieve, when compared to 500 microns sieve, showing the importance of the filter of the washing machine and the potential to decrease its porosity. Fibers retained in the filter- paper of 8 microns, couldnt be weighted because of its low mass, but their visualization suggests the existence of fibers in micro and nano scales. Converting mass to number of fibers, one individual washing was responsible for something between thousands and hundred of thousands of units. When extrapolating values to a global perspective, it reaches something around 40.4 thousand tonnes of cotton per year and 21.5 thousand tonnes of synthetic fibers per year. In a Brazilian perspective, these values correspond, respectively, to 1.6 thousand tonnes year and 860 tonnes year. If this effluents were all treated in sewage treatment plants, in ideal conditions, still they would release something like 737 tonnes of synthetic fibers per year in a global scale and 29 tonnes of synthetic fibers per year in a national scale. Once in water bodies, those fibers would reach the marine environment, indicating the necessity of solutions that could impair this kind of pollution, not before solving knowledge gaps, specially related, in the textile area, to methodology differences between studies

Concrete marine structures are typically exposed to harsh marine environments where the ingress of chloride ions can lead to corrosion of steel reinforcing bars, reducing both strength and service life; therefore, concrete must be proportioned to resist these environments. Current recommendations for concrete mixtures and plastic shrinkage cracking both reduce the resistance to chloride ingress. The main objective of this thesis was to understand the benefits of fiber addition to concrete exposed to chlorides and quantify those benefits, which would lead to a concrete mixture suitable for marine structures in freeze thaw environments. The research program tested two different fibers in a total of nine concrete mixtures. The results demonstrated that fiber addition at dosages up to 0.33 % by volume resulted in significant reduction or elimination of plastic shrinkage cracking and the chloride tests determined that the ternary FRC mixtures had the best resistance to chloride diffusion.

Plaster i marina miljöer är ett mycket uppmärksammat problem. På senare år har även mikroplaster uppmärksammats som ett stort miljöproblem. Mikroplasterna kan anrikas med diverse föroreningar i vattnet, de misstas även för föda och tar sig in i näringskedjan. Hälsoeffekterna av detta är ännu okända, men allt mer forskning pekar på att det kan ha en negativ inverkan. En stor andel av mikroplasterna i haven kommer från tvätt av syntetkläder. De följer med tvättvattnet ut ur maskinen och då de flesta reningsverk inte effektivt filtrerar bort dessa partiklar så förs de vidare ut i våra vattendrag. Utifrån de studier som gjorts på mikroplastemission vid hushållstvätt är det svårt att göra några jämförelser eftersom det inte finns någon standardiserad metod. Det anses viktigt att ta fram standardiserade testmetoder för att kunna få jämförbara resultat vid utvecklandet av textila material som släpper minimalt med fibrer i tvätt. Tygprover av polyetylentereftalat analyserades med syftet att utvärdera och validera en metod för att mäta fibersläpp i tvätt, framtagen hos Swerea IVF genom forskningsprogrammet Mistra Future Fashion. Metoden bygger på gyrowashtest i kombination med optisk mikroskopi med tillhörande mjukvara som automatiskt kvantifierar antalet partiklar. Enligt den statistiska analysen misslyckades försöket att upprepa metoden utan signifikanta skillnader. Troligtvis berodde detta på skillnader i förutsättningar, som exempelvis att en laserskärare nyttjades i detta projekt. För att underlätta förbehandlingen och öka repeterbarheten togs en fixtur fram för dammsugning. Fixturen gjorde även att spridningen på provresultaten minskade. Dock visade resultaten på interaktion mellan material och dammsugningsmetod vilket gör det opassande att dra entydiga statistiska slutsatser beträffande de enskilda huvudfaktorerna. Fixturen ger inga skillnader i antalet observerade fibersläpp för återvunnen polyester, men i resultatet för ny polyester syns en signifikant skillnad vid användandet av fixturen. På grund av interaktion och avvikelser för fler än en konstruktionsparameter i materialparen så går det inte att dra några signifikanta slutsatser om eventuella skillnader mellan ny och återvunnen polyester. Metoden är inte lämplig för att mäta den reella fiberemissionen vid hushållstvätt och endast funktionell för att kartlägga skillnader då en parameter i taget varieras. Vidare bör man undvika att göra jämförelser mellan försök utförda med olika förutsättningar innan dess inverkan ordentligt fastställts. / Plastics in the marine environment are an issue that has gotten a lot of attention. Lately microplastics have also been observed as an environmental problem. Contaminants in the water can be adsorbed onto the microplastics, they can also be mistaken for food and enter the food web. The health effects of this are still unknown, but research suggests that it can have a negative impact. A large proportion of the microplastics in the oceans are derived from synthetic clothing. They are shed from the garments during laundry and since most wastewater treatment plants do not efficiently filter out these particles, they end up in the ocean. Today there is no standardized method of measuring shedding and therefore difficult to make any comparisons between studies. It is considered important to develop standardized testing methods to obtain comparable results in the development of textile materials that shed less. Fabric samples of polyester were analyzed for the purpose of evaluating and validating a method of measuring shedding in laundry, developed by Swerea IVF through the research program Mistra Future Fashion. The method is based on gyrowash combined with optical microscopy and connected software that quantifies the number of particles. The method could not be reproduced at the University of Borås without significant differences in shedding. This is probably due to differences in conditions, such as the use of a laser cutter in this project. To facilitate pre-treatment and increase the reproducibility, a fixture was developed for vacuuming. The fixture also reduced the statistical dispersion of the test results. However, the results showed an interaction between the material and the method of vacuuming, thus making it inadvisable to draw any conclusions regarding each individual factor. For the recycled polyester there is no difference in shedding with the use of the fixture, but in the case of virgin polyester a significant difference is observed. Due to interaction and deviations of more than one construction parameter in the paired materials, it is not possible to draw any conclusions regarding differences in shedding between virgin and recycled polyester. The method is not suitable for measuring the actual shedding in household laundry and only functions to compare differences when one parameter is varied solely. Furthermore, comparisons between trials carried out under different conditions should be avoided unless their impact has been properly established.

Há tempos a ubiquidade dos materiais plásticos no meio ambiente é assunto de discussão, com destaque para as partículas menores, ditas microplásticos (< 5 milímetros). Fibras provenientes de materiais têxteis são um subgrupo dos microplásticos e têm origem em diversas fontes, incluindo lavagens domesticas, uma vez que filtros de lavadoras e sistemas de tratamento de esgoto não são desenhados especificamente para retê-las. Quando no meio ambiente, estes materiais podem alcançar concentrações até milhares de unidades por metro cúbico, ficando disponíveis a uma gama de espécies. Neste cenário, o presente estudo teve como objetivo avaliar parâmetros de lavagem, e características têxteis que pudessem influenciar no desprendimento de fibras em efluentes de lavadoras domesticas. Foram realizados experimentos com dez sucessivas lavagens individuais, com e sem detergente, para quatro tipos de artigo: algodão (como padrão de comparação), acrílico, poliéster e poliamida. Os efluentes foram então filtrados (< 1 milímetro, 500 mícrons, 63 mícrons, 8 mícrons) e pesados. Resultados demonstram que todos os artigos têxteis liberaram fibras na lavagem. Dez sucessivas lavagens representaram queda na massa desprendida, bem como o uso de detergentes em comparação a lavagens sem detergente. Diferenças entre artigos sugeriram variação conforme características têxteis, onde algodão liberou mais fibras, seguido de acrílico, poliamida e poliéster. Em relação ao tamanho das fibras, a maioria ficou retida no filtro da lavadora (< 1 milímetro) e na peneira de 63 mícrons, mostrando o potencial de diminuição de porosidade do filtro. A visualização de fibras em papel-filtro de 8 mícrons sugere a existência de fibras micro e nano. Convertendo massa para numero de unidades, a lavagem individual de um artigo têxtil mostrou desprender entre milhares e centenas de milhares de fibras. Para uma extrapolação mundial, cerca de 40,4 mil toneladas de algodão e 21,5 mil toneladas de fibras sintéticas seriam liberadas em efluentes de esgoto. No Brasil estes valores corresponderiam, respectivamente, a 1,6 mil e 860 toneladas ano. Caso fossem tratadas em estações de tratamento de esgoto em condições ideais, seriam liberadas, em um ano, cerca de 737 toneladas de fibras sintéticas em escala mundial e 29 toneladas em escala nacional. Uma vez em cursos d\'água, estas fibras atingiriam, em ultima instância, o ambiente marinho, indicando a necessidade por soluções que combatam este tipo de poluição, sem antes deixar de explorar as lacunas do conhecimento, relacionadas, no âmbito têxtil, especialmente às diferenças metodológicas entre os estudos. / Since decades, the ubiquity of plastic materials in the environment has been a matter of discussion. Smaller pieces, named microplastic (< 5 millimeters) gained more attention recently and are now the focus of several studies. Textile fibers are a subgroup of microplastics and can be originated from several sources, including domestic washings, once filters and sewage treatment plants are not specifically designed to retain them. In the environment, these materials can reach concentrations up to millions of units per cubic meter, being available to many species. The objective of the present study was to evaluate washing parameters and also textile characteristics, which could influence in fibers emission from domestic washing machines. Experiments were done in ten successive times, with and without detergent, for four types of articles: cotton (as a pattern for comparison), acrylic, polyester and polyamide. Resulting effluents were then filtered in different porosities (< 1 millimeter, 500 microns, 63 microns, 8 microns), weighted, related to mass of textile articles and simulated regarding number of fibers. Results demonstrated that all textile articles emitted fibers during domestic washings. Ten successive washings represented a decrease in the emitted mass, as well as the use of detergent in relation to washings without the product. Differences between articles suggested variation of results according to textile characteristics, where the ranking of emission was: cotton, acrylic, polyamide and polyester. When considering the size of fibers, the majority was retained in the filter of the washing machine (porosity < 1 millimiter) and in 63 microns sieve, when compared to 500 microns sieve, showing the importance of the filter of the washing machine and the potential to decrease its porosity. Fibers retained in the filter- paper of 8 microns, couldnt be weighted because of its low mass, but their visualization suggests the existence of fibers in micro and nano scales. Converting mass to number of fibers, one individual washing was responsible for something between thousands and hundred of thousands of units. When extrapolating values to a global perspective, it reaches something around 40.4 thousand tonnes of cotton per year and 21.5 thousand tonnes of synthetic fibers per year. In a Brazilian perspective, these values correspond, respectively, to 1.6 thousand tonnes year and 860 tonnes year. If this effluents were all treated in sewage treatment plants, in ideal conditions, still they would release something like 737 tonnes of synthetic fibers per year in a global scale and 29 tonnes of synthetic fibers per year in a national scale. Once in water bodies, those fibers would reach the marine environment, indicating the necessity of solutions that could impair this kind of pollution, not before solving knowledge gaps, specially related, in the textile area, to methodology differences between studies

Orientadores: Nilson Tadeu Mascia, Cilmar Basaglia / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Civil, Arquitetura e Urbanismo / Made available in DSpace on 2018-08-27T02:41:52Z (GMT). No. of bitstreams: 1 Bertoline_CarlosAugustoAbade_M.pdf: 3941772 bytes, checksum: 77c7627fa74d7ef235cd23941064704d (MD5) Previous issue date: 2015 / Resumo: A necessidade de restaurar as propriedades de rigidez e resistência iniciais ou do reforço de estruturas, bem como de projetar sistemas mais eficientes, combinada com a redução de custos, peso e de impactos ambientais torna interessante a utilização de sistemas compósitos de alto desempenho envolvendo materiais sintéticos na construção civil. Nas estruturas de madeira, imperfeições do material no estado bruto como nós, medula e pequenas fissuras causam um enfraquecimento do material. No caso de peças de madeira laminada colada, embora o próprio processo de seleção das lâminas permita reduzir este efeito, a incorporação de camadas de fibras sintéticas no elemento resulta em um aumento significativo dos valores das propriedades mecânicas desta composição. Atualmente, percebe-se um crescimento na aplicação deste tipo de reforço, sendo que as fibras mais utilizadas são as de vidro e carbono. No entanto, a busca por materiais capazes de apresentar melhor custo-benefício favorece o estudo de novas alternativas, como a fibra Vectran®. No caso desta fibra específica, a utilização no mercado internacional é direcionada principalmente às áreas aeroespacial, militar, navegação, tecidos de proteção e esportes. Porém, devido ao baixo peso específico e excelentes características de rigidez, resistência e elasticidade deste material, torna-se interessante o estudo da aplicabilidade desta fibra na construção civil. Desta forma, este trabalho consistiu em um estudo sobre vigas de madeira laminada colada reforçadas com fibra Vectran®, comparando-a com outras fibras. A partir de um modelo teórico já validado, foram programadas em código C equações que permitem verificar o ganho de resistência e rigidez de peças reforçadas, determinar o momento último resistente e inserir parâmetros de peso e custo com a finalidade de comparar alternativas. Também foi desenvolvida uma análise complementar no software Ansys para avaliar deslocamentos e tensões na estrutura. Foram comparados resultados como ganhos de rigidez e resistência entre os dois modelos. Os resultados obtidos a partir das análises propostas validaram o aumento de valores das propriedades decorrente da aplicação de fibras sintéticas e justificam a aplicação da fibra Vectran® / Abstract: The necessity to restore initial stiffness and resistance properties of structures or structural reinforcements, as well as to design more efficient systems, combined with cost, weight and environmental impact reduction makes the use of high performance composite systems involving synthetic materials interesting on civil engineering. Regarding timber structures, imperfections such as knots, pitch and small cracks cause the weakening of the material. As for glued laminated timber, even though the process of selecting the laminates reduce this effect, the use of layers of synthetic fibers on the element result in a significant increase of these properties' values. Currently, it is noted and increase in the application of this type of reinforcement and the most used fibers are glass and carbon fibers. However, the search for materials that can present a better cost-benefit ratio favor the study of new alternatives, such as Vectran® fiber. In the case of this particular fiber, the use in the international scenario is intended primarily to aerospacial, military, navigation, sports and protective fabrics area. Due to the low specific weight and excellent characteristics of stiffness, strength and elasticity of this material, it is interesting to study the applicability of this fiber in civil construction. Thus, this work consisted on a study of glued laminated timber beams reinforced with Vectran® fibers, comparing with other fibers. From a validated theoretical model, equations for verifying the gain of strength and stiffness of a reinforced element were programmed in C language, allowing to determine the ultimate resisting stress and to insert weight and cost parameters in order to compare alternatives. It was also developed an additional analysis on the software Ansys to evaluate the displacements and stresses in the structure. Results such as stiffness and strength gains were compared with the theoretical model. The results obtained from the proposed analyzes validated the gain of these properties' values with the application of synthetic fibers and justify the application of Vectran® fiber / Mestrado / Estruturas e Geotécnica / Mestre em Engenharia Civil