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Статті в журналах з теми "Fibrous Cementitious Composites"
Signorini, Cesare. "Durable and Highly Dissipative Fibrous Composites for Strengthening Coastal Military Constructions." Key Engineering Materials 893 (July 20, 2021): 75–83. http://dx.doi.org/10.4028/www.scientific.net/kem.893.75.
Повний текст джерелаMurali, G., Sallal R. Abid, Hakim S. Abdelgader, Y. H. Mugahed Amran, Mohammad Shekarchi, and Krzysztof Wilde. "Repeated Projectile Impact Tests on Multi-Layered Fibrous Cementitious Composites." International Journal of Civil Engineering 19, no. 6 (January 9, 2021): 635–51. http://dx.doi.org/10.1007/s40999-020-00595-4.
Повний текст джерелаDutkiewicz, Maciej, Hasan Erhan Yücel, and Fatih Yıldızhan. "Evaluation of the Performance of Different Types of Fibrous Concretes Produced by Using Wollastonite." Materials 15, no. 19 (October 5, 2022): 6904. http://dx.doi.org/10.3390/ma15196904.
Повний текст джерелаSreenath, Sreekumaran, Kaliyaperumal Saravana Raja Mohan, and Gunasekaran Murali. "Fracture Toughness of Reactive Powder Fibrous Concrete Composites under Pure and Mixed Modes (I/III)." Buildings 12, no. 5 (May 5, 2022): 599. http://dx.doi.org/10.3390/buildings12050599.
Повний текст джерелаLancellotti, Isabella, Federica Piccolo, Hoang Nguyen, Mohammad Mastali, Mohammad Alzeer, Mirja Illikainen, and Cristina Leonelli. "The Effect of Fibrous Reinforcement on the Polycondensation Degree of Slag-Based Alkali Activated Composites." Polymers 13, no. 16 (August 10, 2021): 2664. http://dx.doi.org/10.3390/polym13162664.
Повний текст джерелаQuerido, Victor A., José Roberto M. d’Almeida, and Flávio A. Silva. "Development and analysis of sponge gourd (Luffa cylindrica L.) fiber-reinforced cement composites." BioResources 14, no. 4 (October 31, 2019): 9981–93. http://dx.doi.org/10.15376/biores.14.4.9981-9993.
Повний текст джерелаMalchiodi, Beatrice, Erika Iveth Cedillo-González, Cristina Siligardi, and Paolo Pozzi. "A Practical Valorization Approach for Mitigating Textile Fibrous Microplastics in the Environment: Collection of Textile-Processing Waste Microfibers and Direct Reuse in Green Thermal-Insulating and Mechanical-Performing Composite Construction Materials." Microplastics 1, no. 3 (July 22, 2022): 393–405. http://dx.doi.org/10.3390/microplastics1030029.
Повний текст джерелаRizzo, Valeria, Antonio Bonati, Francesco Micelli, Marianovella Leone, and Maria Antonietta Aiello. "Influence of Alkaline Environments on the Mechanical Properties of FRCM/CRM and their Materials." Key Engineering Materials 817 (August 2019): 195–201. http://dx.doi.org/10.4028/www.scientific.net/kem.817.195.
Повний текст джерелаAdamu, Musa, Yasser E. Ibrahim, and Hani Alanazi. "Evaluating the Influence of Elevated Temperature on Compressive Strength of Date-Palm-Fiber-Reinforced Concrete Using Response Surface Methodology." Materials 15, no. 22 (November 16, 2022): 8129. http://dx.doi.org/10.3390/ma15228129.
Повний текст джерелаAbbas, Al-Ghazali Noor, Farah Nora Aznieta Abdul Aziz, Khalina Abdan, Noor Azline Mohd Nasir, and Mohd Nurazzi Norizan. "Kenaf Fibre Reinforced Cementitious Composites." Fibers 10, no. 1 (January 4, 2022): 3. http://dx.doi.org/10.3390/fib10010003.
Повний текст джерелаДисертації з теми "Fibrous Cementitious Composites"
Garcez, Estela Oliari. "Investigação do comportamento de Engineered Cementitious Composites reforçados com fibras de polipropileno como material para recapeamento de pavimentos." reponame:Biblioteca Digital de Teses e Dissertações da UFRGS, 2009. http://hdl.handle.net/10183/28642.
Повний текст джерелаMany old pavements in service today are approaching the end of their design service lives. Others are in dire need of major repair to continue serving, resulting in economical, environmental and social impacts by increasing vehicle fuel consumption and maintenance costs, traffic jam and delays. For pavements subject to moderate and heavy traffic, concrete overlays are increasingly being used as a cost effective and sustainable rehabilitation technique. However, concrete overlays have some physical limitations that contribute to durability concerns, which increase the probability of pavement overlay failure and maintenance frequency. Consequently, alternative materials are being developed to improve overlay performance. Engineered Cementitious Composites (ECC) are a special type of high performance fiber reinforced cementitious composites, designed for high ductility and damage tolerance which may overcome concrete overlay limitations. Polyvinylalcohol (PVA) fibers with special coating are typically used as reinforcement of ECC. Although some successful field application of PVAECC, the use of ECC is restrained by the high cost of the material, consequence of high PVA fibers cost. This research is focused on the investigation of using high tenacity polypropylene fibers as reinforcement of engineered cementitious composites (PPECC). Those fibers are produced and available in Brazil for fibrocement industry by less than half price of PVA fibers. PP fibers have demonstrated good performance in reinforcing ECC, assuring composite strain-hardening behavior through the development of multiple cracking processes. An important finding was the tinier crack opening of PPECC – 10 m average- comparing to PVAECC – 60 m average. This result may result in higher material durability. Furthermore, flexural and fatigue behavior or ECCs reinforced with PP fibers were investigated. Results have shown that Portland cement type V (high early strength) is not adequate for PPECCs subject to fatigue loading, resulting in fiber deterioration and premature rupture. By the other hand, promising results were found with cement ordinary type I, usually used in ECC production. A model of service life prediction was developed for PPECC, PVAECC and concrete overlays correlated to overlay thickness. Results have shown that ECCs may reduce overlay thickness in 1.5 to 2.5 times the usual thickness of overlay concrete. Reflective cracking resistance of PPECC was also testes. From the results it is possible to deduce that PPECC may modify typical rupture mode of concrete overlays through the development of multiple cracking. In the last stage of this work, life cycle analyses and life cycle cost analyses of four different overlays systems – concrete, hot mix asphalt, PVAECC and PPECC – were carried out. The results of this study have shown that an ECC overlay system have lower environmental burdens, reducing the energy consumption related to design, construction and maintenance activities, reducing green house effect as well. Life cycle costs analyses over a 40 years service life revealed that PPECC is the most economical overlay system compared to concrete, hot mix asphalt and PVAECC overlay systems. Agency costs are significantly reduced by adopting PPECC overlays. PPECC is a feasible alternative for pavement rehabilitation.
Abdallah, Sadoon Mushrif. "Bonding mechanisms and strength of hooked-end steel fibre reinforced cementitious composites." Thesis, Brunel University, 2017. http://bura.brunel.ac.uk/handle/2438/15827.
Повний текст джерелаMuñoz, Rodriguez Camilo Andrés. "Avaliação do comportamento mecânico de um ECC (Engineered Cementitious Composites) com fibras de polipropileno no recapeamento de pavimentos." reponame:Biblioteca Digital de Teses e Dissertações da UFRGS, 2018. http://hdl.handle.net/10183/179406.
Повний текст джерелаEngineered Cementitious Composite or ECC is a material with a high deformation capacity, designed at the University of Michigan. Composed of fine aggregates, cement and fibres, the composite presents high ductility associated with the ability to generate microcracks when loaded, in a behavior known as strain-hardening. The research previously developed in the Laboratory of Structural Models and Tests (LEME) of UFRGS aimed to characterize an ECC adapted to the materials of Brazil, adding polypropylene fibres in the preparation of the composite, and studying alternatives for the partial replacement of cement. In the research reported here, the previously defined reference mix proportion (ECCRef) was adopted and an alternative mix proportion was used with 30% (by volume) of unprocessed rice-husk ash grinded for 4 hours, in partial replacement of the cement (ECCCCA). The research was divided into two approaches. The first one consisted in the characterization of the mechanical properties of the ECC’s in the laboratory with the execution of tests of flexural behavior and compressive strength, evaluation of adhesion by direct shear tests and the workability, as well as fatigue tests in four point configuration. In monotonic tests ECCCCA showed a resistance to flexural strength of 8.2 MPa and average compression strength of 50 MPa; ECCRef had mean values of 6.8 MPa and 36 MPa, respectively. In the adhesion tests, shear strengths of 2050 kPa (ECCCCA) and 1900 kPa (ECCRef) were obtained The evaluation of the workability allowed for the determination of criteria to improve the process of mixing and handling of the material in fresh state, in this way, adequate workability was obtained in the flow table test, which increased from 44 to 90, permitting the use of concrete mixer machines and to obtain the required volumes of material. With the results of the dynamic tests, fatigue models were stipulated in terms of initial tensile strain (εti), normalized initial tensile strain (ti/εtP) and initial traction (σti), as well as the dissipated energy (DE), it was also possible to study the process of degradation of the composites. The second approach of the research consisted in the accomplishment of tests in true greatness, with the use of the Accelerated Loading Facility of the Laboratory of Pavements (LAPAV). Two overlays (50 and 30 mm thick) were built over flexible pavements that had the same cracking pattern. At each overlay, 100 thousand cycles of the semi-axle load of 5.5 tons were applied. The appearance and evolution of cracks and other pathologies were monitored visually, as well as surface wear through the British Pendulum and Sand Patch tests. After the end of the traffic simulator, plates of the trafficked sections were sawn to verify the propagation of the cracks and the adhesion between the composite and the pavement. It was concluded that the quality control in the mixture is fundamental to guarantee the quality of the surface. In addition, it was noticed that the appearance of cracks is associated with possible problems of adhesion ECC-asphalt pavement, and to a lesser extent reflective cracking. Overall, it has been found that it is possible to produce ECC's with Brazilian materials and the ECC can be applied in the restoration of pavements.
El ECC (Engineered Cementitious Composites) es un compósito cementicio de elevada capacidad de deformación desarrollado en la Universidad de Michigan. Conformado por agregados finos, cemento y fibras poliméricas, presenta una alta ductilidad asociada con la capacidad de generar microfisuras durante la aplicación de cargas, comportamiento conocido como strain-hardening. Las investigaciones previamente desarrolladas en el Laboratório de Ensaios e Modelos Estruturais (LEME) de la UFRGS se direccionaron para caracterizar un ECC adaptado a los materiales brasileros, utilizando fibras de polipropileno y estudiando alternativas para la sustitución parcial del cemento. En la presente investigación se adoptó el trazo de referencia definido previamente (ECCRef), también fue utilizado un trazo alternativo con 30% (en volumen) de ceniza de cáscara de arroz molida por 4 horas como substituto parcial del cemento (ECCCCA). La investigación fue dividida en dos abordajes. La primera consistió en la caracterización de las propiedades mecánicas en laboratorio con la realización de ensayos de resistencia a tracción por flexión e compresión simple, evaluación de la adherencia por corte directo y de la trabajabilidad, además de ensayos de fatiga en viga cuatro puntos. En ensayos monotónicos el ECCCCA presentó una resistencia a la tracción por flexión media (ft,f) de 8,2 MPa y resistencia a la compresión simple media (fc) de 50 MPa; ya el ECCRef tuvo valores medios de 6,8 MPa y 36 MPa, respectivamente. En los ensayos de adherencia se obtuvieron resistencias al corte de 2050 kPa (ECCCCA) y 1900 kPa (ECCRef). La evaluación de la trabajabilidad permitió establecer criterios para mejorar el proceso de mezcla y manipulación del material en estado fresco, de esa forma se obtuvo una adecuada trabajabilidad en el ensayo de flow table, que aumentó de 44 para 90, posibilitando la utilización de mezcladoras de tambor y la obtención de los volúmenes de material necesarios. Con los resultados de los ensayos dinámicos fueron establecidos modelos de fatiga en términos de la deformación específica de extensión inicial (εti), de la deformación específica de extensión inicial normalizada (ti/εtP), de la tracción inicial (σti) y de la energía disipada (DE), igualmente fue posible estudiar el proceso de degradación de los compósitos El segundo abordaje de la investigación consistió en la realización de ensayos en verdadera grandeza con la utilización del simulador de tráfico del Laboratório de Pavimentação (LAPAV). Fueron construidos dos recapeamentos (de 50 y 30 mm de altura) sobre pavimentos flexibles que presentaban idéntico patrón de fisuración. En cada recapeamento fueron aplicados 100 mil ciclos da carga de semi-eje de 5,5 toneladas. Fueron acompañados, visualmente, la aparición y evolución de fisuras y otras patologías, así como el desgaste superficial por medio de los ensayos de Péndulo Británico y Altura de Mancha de Arena. Una vez terminados los ciclos de carga, fueron extraídas placas de las secciones ensayadas para verificar la propagación de las fisuras y la adherencia entre el compósito y el pavimento. Se concluyó que el control de calidad durante el proceso de mezcla es fundamental para garantizar la calidad superficial. Además, fue percibido que la aparición de fisuras está asociada con posibles problemas de adherencia ECC-pavimento asfáltico y en menor escala reflexión de fisuras. Globalmente, se constató que es posible producir ECC’s con materiales disponibles a nivel local y que este material puede ser aplicado en la restauración de pavimentos.
Dolores, Gonzalo Mármol de los. "Low-alkalinity matrix composites based on magnesium oxide cement reinforced with cellulose fibres." Universidade de São Paulo, 2017. http://www.teses.usp.br/teses/disponiveis/74/74133/tde-17082017-113846/.
Повний текст джерелаUm cimento de baixa alcalinidade à base de blendas de MgO e SiO2 é analisado para o desenvolvimento de Compósitos Cimentícios Reforçados com Fibras (CCRF) celulósicas sem clínquer para resolver os problemas de durabilidade de este tipo de fibras quando são usadas em CCRF com cimento Portland. A evolução da hidratação, desde 7 aos 28 dias, das diferentes formulações é avaliada. Os principais produtos hidratados são o Mg(OH)2 e o gel M-S-H para todas as formulações independentemente da idade estudada. As pastas endurecidas apresentam valores de pH < 11 e bom desempenho mecânico comparado com o cimento Portland convencional. O sistema 60% MgO-40% SiO2 é escolhido como a formulação ótima para o desenvolvimento de CCRF já que é a mais resistente e menos alcalina comparada com 70% MgO-30% SiO2. CCRF com cimento à base de óxido de magnésio e sílica (MgO-SiO2) e fibras celulósicas são produzidos para a análise da durabilidade das fibras lignocelulósicas em ambientes com valores de pH mais baixos comparados com o cimento Portland (PC). O desempenho mecânico a flexão e os ensaios físicos (porosidade aparente, densidade aparente e absorção de água) são comparados aos 28 dias e após de 200 ciclos de envelhecimento acelerado. O cimento à base de MgO-SiO2 preserva a integridade das fibras após o envelhecimento. Os compósitos produzidos com este cimento exibem melhores propriedades após 200 ciclos de envelhecimento acelerado que os compósitos produzidos com cimento Portland. Ambientes com alta concentração de CO2 são avaliados como tratamento de cura para otimizar as matrizes MgO- SiO2 nos CCRF. As amostras são curadas sob 2 condições diferençadas: 1) cura com vapor de água a 55oC e 2) cura com alta concentração de CO2 (20% do volume). As amostras carbonatadas apresentam teores reduzidos de Mg(OH)2 enquanto é produzida uma nova fase cristalina: hidromagnesita [Mg5 (CO3)4⋅(OH) 2⋅4H2O]. Após a carbonatação, o conteúdo de gel M-S-H é reduzido também, indicando uma carbonatação desta fase. A carbonatação aumenta a rigidez da matriz o que influi positivamente no desempenho mecânico e as propriedades físicas dos compósitos sem efeitos prejudiciais ao longo prazo. A adição de sepiolita em CCRF é estudada como possível adição na composição da matriz aglomerante. Baixos teores (1 e 2% em massa) de cimento são substituídos por sepiolita para o estudo das pastas de cimento hidratado e, posteriormente, dos compósitos. O Módulo Elástico Dinâmico das pastas é incrementado com o tempo pela adição de sepiolita. Os ensaios a flexão demostram que a adição de sepiolita melhora a homogeneidade dos compósitos. Reportam-se os efeitos das fibras de sisal após da exposição a sistemas MgO-SiO2 e PC e submetidas a diferentes condições de envelhecimento. Este estudo comparativo da degradação das fibras expostas a diferentes matrizes cimentícias mostra a compatibilidade das fibras lignocelulósicas com os cimentos à base de Mg. As fibras de sisal, inclusive após o envelhecimento acelerado, não apresentam nem redução significativa no conteúdo de celulose nem na cristalinidade da celulose assim como do tamanho de cristalito, quando expostas a cimentos MgO-SiO2.
Sultangaliyeva, Fariza. "Formulation of fluid fire-resistant fiber-reinforced cementitious composite : Application to radioactive waste disposal." Thesis, Pau, 2020. http://www.theses.fr/2020PAUU3041.
Повний текст джерелаThe aim of the thesis is to design a self-compacting concrete with polypropylene fibers resistant to fire for a use in storage containers of medium activity long-lived waste. The challenge of the work is presented by the use of polypropylene fibers that enhance fire resistance but drastically diminish workability of concrete even when added at small volume fractions. Tests on laboratory scale are conducted with a purpose of evaluating rheological behavior and high temperature behavior of cementitious materials containing polypropylene fibers.In the first part, a study of rheological behavior of cement-based materials containing polypropylene fibers was done. The aim of this study is to investigate the influence of polypropylene fibers on the yield stress of cement pastes and mortars. A model is proposed to be able to evaluate the quantity of paste necessary to compensate the addition of polypropylene fibres according the fluidity of fresh concrete.Then an experimental and numerical investigation of behavior of cementitious materials with polypropylene fibers at high temperature was done so as to optimize the choice of polypropylene fibers for cementitious material to improve its thermal stability. Three different cementitious materials with three different granular skeleton containing various polypropylene fiber geometries and dosages were tested (residual radial permeability test and fire test) in order to select an optimal fiber geometry and dosage. Then thermomechanical computations was developped at maco and meso scale. Then, a choice of diameter, length and dosage of fibres is proposed according to the maximum size of gravels.Finally, a method of concrete formulation with polypropylene fibers optimized from perspectives of rheology and resistance to fire is presented. In this method, fresh and hardened state properties are verified to ensure an accordance with performance criteria specified by the project. At the end, designed mixes were tested in fire tests conducted on uniaxially compressed prisms and, based on outcomes, final mixes are selected for further fire tests on higher scale concrete
Costa, Fernanda Bianchi Pereira da. "Análise da durabilidade de compósitos cimentícios de elevada capacidade de deformação reforçados com fibras." reponame:Biblioteca Digital de Teses e Dissertações da UFRGS, 2015. http://hdl.handle.net/10183/130203.
Повний текст джерелаDespite the increasing technological advances in construction, the lack of concrete structures durability, both in buildings and pavement, have been found with severe attendance and proportion. The high strain cementitious composite, also known as Engineered Cementitious Composites (ECC), was widespread from the concept of high performance fiber reinforced concrete, in order to supply the fragile behavior of conventional concrete and problems related to lack of durability generated mainly due to crack propagation. In this context, the Laboratório de Ensaios e Modelos Estruturais (LEME) of the Federal University of Rio Grande do Sul (UFRGS) consolidated over the last five years, a research group focused on the ECC study allied with the use of national materials. The design has been based on the application materials that provide lower costs and promote environmental sustainability issues. Thus, they were incorporated into the material polypropylene fibers (2% by volume) and partial cement replacement of 30% (by volume) of residual rice husk ash. This study aims to examine durability issues of these composites (with and without rice husk ash), and compare them to conventional concretes, through tests related to the study of pore structure (absorptivity, absorption and void ratio, water absorption by capillarity, water absorption by the pipe method and scanning electron microscopy), penetration and diffusion of chloride ions, free and restrained shrinkage, and, finally, abrasion resistance. The results indicate that the incorporation of rice husk ash significantly improved material properties related to connection and pores solution, hindering the chloride ingress, and presents abrasion resistance similar to the reference composite. Its disadvantage is related to the larger cracks due to restrained shrinkage. However, the work demonstrates the viability and advantage of use rice husk ash in the composite production in terms of durability.
Teixeira, Ronaldo Soares. "Efeito das fibras de curauá e de polipropileno no desempenho de compósitos cimentícios produzidos por extrusão." Universidade de São Paulo, 2015. http://www.teses.usp.br/teses/disponiveis/18/18158/tde-04022016-100910/.
Повний текст джерелаThe use of composites in construction, as matrix and paste cement reinforced with fibers, has spread considerably in recent years. A wide variety of synthetic fibers such as polypropylene have been successfully used to reinforce cementitious composites. However, worldwide interest in the use of products with lower environmental impact stimulates the search for materials to replace synthetic fiber. Vegetable fiber, biodegradable, can be a great alternative because of the abundance, low cost, the lowest energy consumption for its production, appropriate mechanical properties. Curauá fiber, native plant from Amazon, with crops on a commercial scale, is used in the manufacture of ropes, baskets or as reinforcement in organic matrix. Its mechanical properties are similar to those of polypropylene. Extrusion technology is feasible in the fibercement industry, because it produces composites with high density matrix and great packaging, low permeability and good adhesion fiber matrix. However, successful extrusion process of cementitious products mainly depends on the rheological properties of fresh cement reinforced with fibers. The vegetable fibers can promote water kidnapping and strongly interfere in the flow, cohesion and fresh cement slurry flow. The incorporation of vegetable fibers influences the based cementitious materials in the fresh state and affects properties in the hardened state. In this context, the objective of the research is to evaluate the influence of curauá and polypropylene fiber in rheological and mechanical properties of fresh cement paste. Formulations without fiber, used as reference, 1 and 2% content by weight of reinforcement, fibers with a length of 6 to 10 mm were prepared. Two rheological techniques were used: Squeeze flow and extruder rheometer to analyze the flow of cement pastes. Through experimental data, as strength/displacement and numerical analysis of the pressure extruder rheometer were determined: yield stress corresponding to zero velocity (σ0), initial shear stress (τ0), effect of the velocity on yield stress (α) and effect of velocity in the shear stress (β). The mechanical properties were determined in MTS testing machine. Modulus of rupture (MOR), fracture toughness (TFT) and fracture energy (EF) were calculated. The rheological results indicate that the cement paste reinforced with curauá fiber showed higher strength, smaller displacement and increased extrusion pressure with curauá fibers compared to cementitious paste reinforced with polypropylene fibers. The length of the fibers influence the flow of the mixture more than the fiber content. Composites reinforced with polypropylene fibers presented higher values of MOR, TFT and EF compared to composites reinforced with curauá fiber. After 200 ageing cycles, the mechanical results of composites reinforced with curauá fibers decreased due to mineralization of the fibers. The nanoindentation results, as hardness and elastic modulus, increased after 200 cycles. The methodologies used to assess the rheological and mechanical behavior of fibercement during extrusion facilitate future transfer of this technology to the productive sector, with potentially higher quality products.
Monteiro, André Oliveirinha. "Development of a multifunctional carbon black/cement composite for traffic monitoring." Doctoral thesis, Universidade de Aveiro, 2018. http://hdl.handle.net/10773/23030.
Повний текст джерелаAs sociedades modernas estão fundadas em sistemas infraestruturais como redes de abastecimento de água, electricidade, comunicação e transporte. Com o aumento da procura global pela eficiência, imposto pelo século XXI, o desempenho esperado das estruturas segue inevitavelmente a mesma tendência. Esta busca de performance tem levado às infraestruturas físicas e à tecnologia digital se fundirem no conceito de “infraestruturas inteligentes”, através de vastas redes de monitorização, aliadas a subsistemas de informação. A disciplina de gestão de tráfego é talvez aquela que mais tem beneficiado destes avanços, com a implementação dos chamados Sistemas Inteligentes de Transporte (ITS). Avanços recentes na área dos materiais têm permitido o desenvolvimento de materiais de construção “inteligentes”, capazes de desempenhar tarefas autónomas. Os compósitos cimentícios piezoresistivos são um exemplo. Estes podem ser utilizados como sistemas de monitorização, graças às suas propriedades intrínsecas de sensitividade a estímulos mecânicos. A presente dissertação visa fazer a ponte entre o conceito de materiais cimentícios multifuncionais e a disciplina de monitorização de tráfego. Deste modo, um compósito piezoresistivo foi desenvolvido para aplicação em pavimentos, com base na adição de partículas de negro de fumo (CB), com o objectivo de avaliar dados de tráfego em tempo real. Numa primeira abordagem experimental foi determinada uma composição cimentícia sensitiva, concluindo que a incorporação de 7% de CB (em relação à massa de cimento) oferecia a melhor resposta resistiva a estímulos de compressão. Numa segunda campanha experimental, composição, ergonomia dos sensores cimentícios, tipologia de ensaios e sistema de aquisição foram otimizados e adequados, de acordo com a finalidade de monitorização de tráfego. Ciclos de compressão estáticos e dinâmicos demonstraram fatores de sensitividade médios (GF) de 60 e uma excelente resposta linear, não afetada por variações de temperatura, ao contrário da sensitividade piezoresistiva que registou diminuições até 30%. Em resumo, os resultados desta dissertação demonstram que a incorporação de elementos de betão sensitivo com adição de CB à superfície de pavimentos pode vir a constituir uma alternativa às soluções tradicionais de monitorização de tráfego, dado as suas vantagens como: baixo custo, simplicidade de implementação, propriedades estruturais, durabilidade e sensitividade
Today’s society is founded on infrastructure systems such as water, electricity, communication and transport networks. The global efficiency demand of the 21st century is growing rapidly and the expected performance of infrastructures follows the same trend. This pursuit for efficiency has led digital technology and physical urban infrastructures to fuse into the concept of ‘smart infrastructures’, relying on large monitoring networks coupled to information subsystems. Traffic logistics has been one of the fields which has benefited the most of such advances, with the implementation of the so-called Intelligent Transportation Systems (ITS). Over the last years, advances in materials science have enabled the development of a wide range of “smart” construction materials capable of autonomous tasks. An example of these are the piezoresistive cementitious composites, some of which may be used as monitoring systems, thanks to their self-sensing properties. The present dissertation aims to bridge the concept of multifunctional cement-based materials to the traffic monitoring discipline. Here, a stress-sensitive cementitious composite, based on the addition of carbon black (CB) particles, was developed for application in pavement surfaces with a view to perform permanent real-time evaluation of traffic data. In a first experimental approach, a sensitive CB-based cementitious composition was determined and results concluded that mixtures containing 7% of CB by mass of cement offered the most favourable piezoresistive response. In a second experimental campaign, materials, specimens design and measurement setup were reviewed, towards traffic monitoring requirements. Quasi-static and dynamic compressive load cycles showed gauge factors (GF) as high as 60 and a response linearity inaffected by temperature variations, despite registered reductions in sensitivity up to 30%. Taken together, results demonstrated that embedding conductive CB-based concrete elements in pavement surfaces may become a prospective alternative to conventional traffic monitoring solutions given their numerous advantages, including: low-cost, simplicity of implementation, structural properties, durability and good sensitivity.
Guimar?es, Elvio Antonino. "Efeito da adi??o de fibras da palma do licuri (syagrus coronata) no comportamento f?sico e mec?nico de comp?sitos de matriz ciment?cia." Universidade Federal do Rio Grande do Norte, 2013. http://repositorio.ufrn.br:8080/jspui/handle/123456789/12859.
Повний текст джерелаCoordena??o de Aperfei?oamento de Pessoal de N?vel Superior
This research was motivated by the requirement of asbestos s replacement in building systems and the need to generate jobs and income in the country side of the state of Bahia, Brazil. The project aimed at using fibers from licuri leaves (syagrus coronata), an abundant palm in the region, to produce composites appropriate for the sustainable production of cement fibre reinforced products in small plants. The composites were produced in laboratory using Portland cement CP-II-F32, sand, water, licuri palm fiber contents of 1.0, 1.5 and 2.0% by weight of binder (two different fiber length) and metakaolin. The latter was chosen as an additional binder for its efficiency to reduce the alkalinity of cementitious matrixes therefore preventing the degradation of vegetable fibers. The characterization of the composite components was carried out by sieving and laser particle size analyses, thermal analysis, fluorescence and X-ray diffraction. The composites performance was evaluated by 3- point-bending tests, compressive strength, ultrasound module of elasticity, free and restrained shrinkage, water capillarity absorption and apparent specific gravity. It has been found that the addition of fibers increased the time to onset of cracking over 200.00% and a 25% reduction in cracks opening in the restrained shrinkage test. The capillary absorption reduced about 25% when compared to fiber-free composites. It was also observed with regard to flexural strength, compressive strength and specific gravity, that the addiction of fibers did not affect the composite performance presenting similar results for compounds with and without fibers. In general it can be stated that the reinforced composite fibers of palm licuri presents physical and mechanical characteristics which enable them to be used in the intended proposals of this research
A exig?ncia da substitui??o do amianto em sistemas construtivos em conjunto com a necessidade de gera??o de renda no sert?o da Bahia fez nascer o projeto do aproveitamento da fibra da palma do licuri (syagrus coronata), palmeira abundante na regi?o, na produ??o de comp?sitos para a fabrica??o artefatos de cimento refor?ados com fibras para a constru??o civil de maneira sustent?vel, em pequenas unidades fabris. Os comp?sitos foram produzidos em laborat?rio utilizando cimento Portland CP II-F32, areia, ?gua, metacaulinita e fibra da palma do licuri. As fibras foram adicionadas em teores de 1,0, 1,5 e 2,0% da massa do aglomerante e com dois comprimentos de fibra diferentes. A metacaulinita foi selecionada como aglomerante suplementar de forma a agir na redu??o da alcalinidade da matriz ciment?cia na perspectiva de diminuir ou at? mesmo eliminar a degrada??o das fibras vegetais em meio alcalino. Foram realizados ensaios de caracteriza??o dos componentes do comp?sito, incluindo granulometria, an?lise t?rmica, fluoresc?ncia e difratometria de Raios-X. A verifica??o do desempenho dos comp?sitos foi feita com ensaios de flex?o em tr?s pontos, resist?ncia ? compress?o axial, m?dulo de elasticidade por ultrassom, retra??o livre e restringida, absor??o de ?gua por capilaridade e massa espec?fica aparente. Verificou-se que a presen?a das fibras de licuri aumentou o tempo para o surgimento da fissura??o acima de 200,00% e redu??o de 25% na abertura das fissuras no ensaio de retra??o restringida. Com rela??o ? absor??o capilar ocorreu uma redu??o de 25%, quando comparados com os materiais sem fibras. Observou-se que, com rela??o ? resist?ncia a flex?o, compress?o axial e massa espec?fica aparente, a adi??o de fibras n?o afeta o desempenho dos materiais, apresentando resultados similares para materiais com e sem fibras. De uma maneira geral pode-se afirmar que os comp?sitos refor?ados com fibras da palma do licuri apresentam caracter?sticas f?sicas e mec?nicas que viabilizam sua aplica??o dentro das condi??es estabelecidas neste trabalho
Arquez, Ana Paula. "Aplicação de laminado de polímero reforçado com fibras de carbono (PRFC) inserido em substrato de microconcreto com fibras de aço para reforço à flexão de vigas de concreto armado." Universidade de São Paulo, 2010. http://www.teses.usp.br/teses/disponiveis/18/18134/tde-29062010-114146/.
Повний текст джерелаStrengthening of reinforced concrete elements with carbon fiber reinforced polymer (CFRP) is increasingly well known, safe and accessible. The application of CFRP has been studied worldwide using various techniques. Features like high tensile strength, corrosion resistance, lightweightness and easy and speedy application are the main factors for dissemination. In particular, the technique here analyzed is known as Near Surface Mounted (NSM), which involves inserting CFRP strips into grooves made on the concrete cover of reinforced concrete elements. With double bonding area, this technique avoids the premature peeling-off that usually takes place in externally bonded CFRP reinforcement. As in others flexural strengthening techniques, the material is bonded in the concrete tension region. It is known in strengthening practice that this region usually requires prior repair. Often it shows up damaged by several reasons such as cracking caused by external actions, reinforcement corrosion and deterioration of the concrete. Whereas the good quality of this repair is essential to strengthening efficiency, an innovative technique is proposed. A high-performance cementitious composite is used as a transition layer for insertion of CFRP strips. The composite is made of Portland cement, steel fibers and microfibers of steel. It also has the potential to delay crack opening and to increase the beam stiffness. Based on fracture mechanics, it was possible to find suitable volume fractions of steel fibers and microfibers to be added to the cementitious matrix. Bonding tests were performed to analyze the shear stress transferring from the CFRP laminate to the beam anchorage zone. Once known the system behavior, real size reinforced concrete beams were tested in three different versions of the anchorage conditions, two of them with use of cementitious composites. The efficiency of the proposed innovation was proved by confirming increased stiffness and load capacity of the strengthened beam. In addition, fibers and microfibers allowed the decrease of the crack opening in later loading steps. No horizontal cracks near to the reinforcement were noticed, which means that CFRP laminate peeling-off was not likely to occur.
Книги з теми "Fibrous Cementitious Composites"
Sidney, Mindess, ed. Fibre reinforced cementitious composites. London: Elsevier Applied Science, 1990.
Знайти повний текст джерелаSidney, Mindess, ed. Fibre reinforced cementitious composites. 2nd ed. London: Taylor & Francis, 2007.
Знайти повний текст джерелаOzyildirim, H. Celik. Exploratory investigation of high-performance fiber-reinforced cementitious composites for crack control. Charlottesville, Va: Virginia Transportation Research Council, 2008.
Знайти повний текст джерелаSidney, Mindness, Skalny Jan, and Materials Research Society, eds. Fiber-reinforced cementitious materials: Symposium held November 26-28, 1990, Boston, Massachusetts, U.S.A. Pittsburgh, Pa: Materials Research Society, 1991.
Знайти повний текст джерелаMindess, Sidney, and Arnon Bentur. Fibre Reinforced Cementitious Composites. Taylor & Francis Group, 2003.
Знайти повний текст джерелаMindess, Sidney, and Arnon Bentur. Fibre Reinforced Cementitious Composites. Taylor & Francis Group, 1990.
Знайти повний текст джерелаMindess, Sidney, and Arnon Bentur. Fibre Reinforced Cementitious Composites. Taylor & Francis Group, 2006.
Знайти повний текст джерелаMindess, Sidney, and Arnon Bentur. Fibre Reinforced Cementitious Composites. Taylor & Francis Group, 2019.
Знайти повний текст джерелаMindess, Sidney, Routledge, and Arnon Bentur. Fibre Reinforced Cementitious Composites. Taylor & Francis Group, 2006.
Знайти повний текст джерелаMindess, Sidney, Routledge, and Arnon Bentur. Fibre Reinforced Cementitious Composites. Taylor & Francis Group, 2006.
Знайти повний текст джерелаЧастини книг з теми "Fibrous Cementitious Composites"
Barros, Joaquim A. O., Cristina Frazão, Antonio Caggiano, Paula Folino, Enzo Martinelli, Hernan Xargay, Zia Zamanzadeh, and Lúcio Lourenço. "Cementitious Composites Reinforced with Recycled Fibres." In Recent Advances on Green Concrete for Structural Purposes, 141–95. Cham: Springer International Publishing, 2017. http://dx.doi.org/10.1007/978-3-319-56797-6_8.
Повний текст джерелаFerrara, Liberato, Saulo Rocha Ferreira, Visar Krelani, Paulo Lima, Flavio Silva, and Romildo Dias Toledo Filho. "Cementitious Composites Reinforced with Natural Fibres." In Recent Advances on Green Concrete for Structural Purposes, 197–331. Cham: Springer International Publishing, 2017. http://dx.doi.org/10.1007/978-3-319-56797-6_9.
Повний текст джерелаLukasenoks, Arturs, Andrejs Krasnikovs, Arturs Macanovskis, Olga Kononova, and Videvuds Lapsa. "Short Composite Fibres for Concrete Disperse Reinforcement." In Short Fibre Reinforced Cementitious Composites and Ceramics, 85–95. Cham: Springer International Publishing, 2019. http://dx.doi.org/10.1007/978-3-030-00868-0_6.
Повний текст джерелаFigueiredo, Stefan Chaves, Oğuzhan Çopuroğlu, Branko Šavija, and Erik Schlangen. "Piezoresistive Properties of Cementitious Composites Reinforced by PVA Fibres." In Strain-Hardening Cement-Based Composites, 709–17. Dordrecht: Springer Netherlands, 2017. http://dx.doi.org/10.1007/978-94-024-1194-2_81.
Повний текст джерелаJolly, C. K. "The Stiffness and Strength of Small Diameter Steel Fibres in Cementitious Composites." In Composite Structures 3, 254–65. Dordrecht: Springer Netherlands, 1985. http://dx.doi.org/10.1007/978-94-009-4952-2_19.
Повний текст джерелаBaričević, Ana, Katarina Didulica, Branka Mrduljaš, and Antonija Ocelić. "Production Waste Fibres as a Sustainable Alternative for Strengthening Cementitious Composites." In International RILEM Conference on Synergising Expertise towards Sustainability and Robustness of Cement-based Materials and Concrete Structures, 593–603. Cham: Springer Nature Switzerland, 2023. http://dx.doi.org/10.1007/978-3-031-33211-1_53.
Повний текст джерелаSalvador Filho, J. A. A., D. Lavorato, A. V. Bergami, J. R. Azeredo, C. Nuti, and S. Santini. "Influence of Polyethylene and Stainless Steel Fibres on Compressive and Tensile Behaviour of High-Performance Fibre-Reinforced Cementitious Composites." In GCEC 2017, 3–16. Singapore: Springer Singapore, 2018. http://dx.doi.org/10.1007/978-981-10-8016-6_1.
Повний текст джерелаHalvaei, Mana. "Fibers and textiles reinforced cementitious composites." In Engineered Polymeric Fibrous Materials, 73–92. Elsevier, 2021. http://dx.doi.org/10.1016/b978-0-12-824381-7.00001-9.
Повний текст джерела"Steel fibres." In Fibre Reinforced Cementitious Composites, 257–97. CRC Press, 2006. http://dx.doi.org/10.1201/9781482267747-16.
Повний текст джерела"Glass fibres." In Fibre Reinforced Cementitious Composites, 298–362. CRC Press, 2006. http://dx.doi.org/10.1201/9781482267747-17.
Повний текст джерелаТези доповідей конференцій з теми "Fibrous Cementitious Composites"
"Durability of Glass / Polymer Fibrous Mesh-Reinforced Thin Cementitious Composites Durability of Glass / Polymer Fibrous Mesh-Reinforced Thin Cementitious Composites." In SP-190: High-Performance Fiber-Reinforced Concrete Thin Sheet Products. American Concrete Institute, 2000. http://dx.doi.org/10.14359/5724.
Повний текст джерелаRamli, Mahyuddin, Cheah Chee Ban, and Muhamad Fadli Samsudin. "Flexural behavior of the fibrous cementitious composites (FCC) containing hybrid fibres." In INTERNATIONAL CONFERENCE ON ENGINEERING AND TECHNOLOGY (IntCET 2017). Author(s), 2018. http://dx.doi.org/10.1063/1.5022946.
Повний текст джерелаAjouguim, Soukaina, Jonathan Page, Chafika Djelal, Mohamed Waqif, and Latifa Saadi. "Performance of Alfa Fibres in Cementitious Materials Exposed to Diverse Surface Treatments." In 4th International Conference on Bio-Based Building Materials. Switzerland: Trans Tech Publications Ltd, 2022. http://dx.doi.org/10.4028/www.scientific.net/cta.1.660.
Повний текст джерелаTao, Zhong, Richard Shuaibu, Zhu Pan, Md Kamrul Hassan, and Jian Zhou. "Compressive behaviour of steel tubes filled with strain hardening cementitious composites." In 12th international conference on ‘Advances in Steel-Concrete Composite Structures’ - ASCCS 2018. Valencia: Universitat Politècnica València, 2018. http://dx.doi.org/10.4995/asccs2018.2018.6968.
Повний текст джерелаGuilarduci, Viviane V. S., Patricia B. Martelli, Honória de F. Gorgulho, and Pablo R. Oliveira. "INCORPORATION OF REUSED SUGARCANE FIBRES APPLIED IN THE TREATMENT OF EFFLUENTS CONTAMINATED WITH ENGINE OIL AS REINFORCEMENT OF CEMENTITIOUS COMPOSITES." In Brazilian Conference on Composite Materials. Pontifícia Universidade Católica do Rio de Janeiro, 2018. http://dx.doi.org/10.21452/bccm4.2018.02.23.
Повний текст джерела"Using Steel Fibres to Increase the Projectile Impact Resistance of Cementitious Composites." In SP-347: Recent Developments in High Strain Rate Mechanics and Impact Behavior of Concrete. American Concrete Institute, 2021. http://dx.doi.org/10.14359/51732657.
Повний текст джерелаMercedes, Luis, Lluis Gil, and Ernest Bernat. "Comportamiento mecánico de compuestos de matriz cementicia y tejidos de fibras vegetales." In HAC2018 - V Congreso Iberoamericano de Hormigón Autocompactable y Hormigones Especiales. Valencia: Universitat Politècnica València, 2018. http://dx.doi.org/10.4995/hac2018.2018.5501.
Повний текст джерелаLOVICHOVÁ, ROMANA, KRISTÝNA TAKÁČOVÁ, KAREN KÜNZEL, VÁCLAV PAPEŽ, MICHAL MÁRA, JINDŘICH FORNŮSEK, PETR KONRÁD, and RADOSLAV SOVJÁK. "DIRECTED ORIENTATION OF STEEL FIBRES IN ULTRA-HIGH-PERFORMANCE CEMENTITIOUS COMPOSITE USING THE MAGNETIC FIELD." In HPSM/OPTI 2020. Southampton UK: WIT Press, 2020. http://dx.doi.org/10.2495/hpsm200051.
Повний текст джерелаCheng, Jin, Kang Hai, and Hongcun Guo. "Compressive stress-strain relationship of strain-hardening cementitious composite with hybrid fibres after high temperature exposure." In The International Conference of Applications of Structural Fire Engineering (ASFE 2017). Taylor & Francis Group, 6000 Broken Sound Parkway NW, Suite 300, Boca Raton, FL 33487-2742: CRC Press, 2017. http://dx.doi.org/10.1201/9781315107202-43.
Повний текст джерелаOcelić, Antonija, Ana Baričević, and Marina Frančić Smrkić. "POSSIBLITIES OF USING UHPC AS A REPAIR MATERIAL." In 2nd Croatian Conference on Earthquake Engineering. University of Zagreb Faculty of Civil Engineering, 2023. http://dx.doi.org/10.5592/co/2crocee.2023.111.
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