1 |
Mechanical performance and fatigue crack growth behavior of polymer-modified asphalt concrete mixturesOthman, Ayman Mahmoud January 1995 (has links)
No description available.
|
2 |
Development of novel flax bio-matrix composites for non-structural and structural vehicle applicationsZhu, Jinchun January 2015 (has links)
The use of natural fibres (e.g. flax, hemp etc.) instead of synthetic fibres (carbon and glass etc.) as composite reinforcements not only benefits the environment, but also provides economical lightweight products for transports. Although there are a few studies reported in literature on use of flax fibres, there is no comprehensive guide on use of flax fibres with bio-resins to re-engineer bio- composite systems that can be used in vehicle structures. The state-of-art of the current research towards using natural fibre reinforced composites is reviewed by the thesis. The review covers the performances of flax composites, concentrating on the effect of matrix types and existing development methods. The review also identifies the rational of selecting tannin resins and bio-epoxy resins to combine with flax fibre reinforcements. In the experimental work, mimosa tannin resin (natural phenolic resin) and pine- oil derived supersap epoxy resin are selected to manufacture the fully renewable flax composites. By tailoring the fibre configurations and chemical surface treatments, the resultant composites were investigated to provide information for engineers to understand the composite behaviours and properties. Mechanical properties (tension, flexural, shear, impact etc.) and physical properties (moisture, ageing etc.) were assessed through adequate tests and analysing methods. In addition, bio-sandwich structures based on the novel studied composites and commercial bio-foams were evaluated to study the energy absorption which could be very important in vehicle design. Based on the results, flax/supersap epoxy and flax/tannin composites are suitable for possible exterior structural and interior non-structural applications, respectively. The developed flax fibre composites with innovative bio-matrices have a potential to prevail in modern vehicle applications, due to the competitive performances, economic viability and environmental acceptability.
|
3 |
Utilização de resíduos sucro-alcooleiros na fabricação de fibrocimento pelo processo de extrusão / Use residual of sugar and alcohol in the manufacture of cement by the extrusion process.Teixeira, Ronaldo Soares 14 October 2010 (has links)
Este trabalho avalia a utilização de fibras e cinzas de bagaço de cana-de-açúcar em compósitos cimentícios extrudados. Visa o estudo da potencialidade do emprego da fibra e cinza do bagaço da cana-de-açúcar na construção civil, o aproveitamento deste produto em matrizes cimentícias representa uma alternativa para diminuição de gastos com locais para deposição do resíduo evitando a degradação do meio ambiente. A cinza de bagaço de cana-de-açúcar apresenta características pozolânicas, além de garantir uma redução do consumo de cimento. Fibras de bagaço de cana-de-açúcar (FBC) foram classificadas por peneiramento, lavadas em água fervente para reduzir o açúcar residual e foi tratado quimicamente com silicato de sódio e sulfato de alumino com finalidade de proteger as fibras contra a agressão do meio alcalino proporcionado pelo cimento, imobilizar a matéria orgânica e reduzir a absorção de água, diminuindo as variações dimensionais e proporcionar melhor qualidade no compósito, tais como durabilidade e evitar o ataque de microorganismo. As cinzas de bagaço de cana-de-açúcar (CBC) foram queimadas com temperatura e tempo controlado para ter um ótimo grau de amorficidade e conseqüentemente maior reatividade. A moagem também foi efetuada a fim de melhorar a reatividade da cinza. Foi realizada uma série de ensaios de caracterização da CBC. A atividade pozolânica foi averiguada por ensaio condutividade elétrica. O desempenho mecânico e físico e na microestrutura dos compósitos de fibrocimento foram avaliados. Os compósitos foram avaliados antes e após ciclos de envelhecimento acelerado. A extrusão foi utilizada na produção de compósitos cimentícios com geometrias diferenciadas e na produção em pequena escala. Os resultados apresentaram que a fervura da FBC reduziu o açúcar residual e o tratamento químico mineralizou as FBC. As CBC apresentaram valores de sílica elevada. Foram produzidos placas com níveis de reforço entre 0,5% e 5,0% de FBC. Compósitos extrudados com 5% de reforço de FBC com 28 dias de cura apresentaram melhores resultados em tenacidade (TE), devido à maior introdução de FBC no compósito, mas não apresentou diferença entre o tratamento químico. Compósitos extrudados com 5% de reforço de FBC tratada após 200 ciclos de envelhecimento apresentaram maior absorção de água (AA) e porosidade aparente (PA). Esse fato se deve a explicado com a maior hidratação do cimento que ocasionou mineralização drástica da FBC e descolagem da fibra na interface fibra e matriz. Compósito extrudado com 5% de FBC tratada com 28 dias e após 200 ciclos com substituição de cimento por 30% de CBC apresentaram diminuição de módulo de ruptura (MOR) e maior absorção de água (AA). A substituição da matriz (agregado) e a maior relação água/cimento da mistura influenciaram neste resultado. Os resultados indicaram que os compósitos extrudados com reforço de fibra de bagaço de cana e 30% de cinza de bagaço de cana, em substituição ao cimento Portland, podem ser utilizados para produzir elementos construtivos. / This study evaluates the use of fibre and ash from sugarcane bagasse in extruded cementitious composites. Aims at studying the potentiality of using fibre and ash from sugarcane bagasse in construction, the use of this product in cementitious matrices represents an alternative to reduce expenses with the waste disposal sites for avoiding environmental degradation. The bagasse ash cane sugar has pozzolanic characteristics and ensures a reduction in cement consumption. Fibres from sugarcane bagasse (FSB) were classified by sieving, washed in boiling water to reduce the residual sugar and has been chemically treated with sodium silicate and aluminum sulphate in order to protect the fibres against the aggression of alkaline provided by the cement, immobilize the organic material and reduce the water absorption, reducing size variations and provide better quality in the composite, such as durability and prevent the attack of microorganisms. The ashes of sugarcane bagasse (ASB) were burned with controlled temperature and time to have a great degree of amorphicity and consequently higher reactivity. The grinding was also performed to improve the reactivity of the ash. We performed a series of tests to characterize the ASB. The pozzolanic activity was determined by electrical conductivity test. The mechanical and physical performance and microstructure of cement composites were evaluated. The composites were evaluated before and after ageing accelerated cycles. Extrusion was used in the production of cementitious composites with different geometries and small scale production. The results showed that boiling FSB reduced the residual sugar and chemically treated to mineralized FSB. The ASB had high amounts of silica. Plates were produced with enhanced levels of between 0.5% and 5.0% of FSB. Composites extruded with 5% of FSB with 28 days of healing showed better results in toughness (TE) due to the increased introduction of FSB in the composite, but no difference between the chemical treatments. Composites extruded with 5% strengthening of FSB treated after 200 ageing accelerated cycles had higher water absorption (AA) and apparent porosity (AP). This fact should be explained with the higher hydration of cement which caused drastic mineralization FSB and off the fibre and fibre-matrix interface. Extruded composite with 5% FBC treated with 28 days and after 200 cycles with replacement of cement by 30% of ASB showed a decrease of modulus of rupture (MOR) and higher water absorption (AA). The substitution matrix (aggregate) and the highest water / cement ratio of the mixture affected this result. The results indicated that the extruded composites reinforced with fibre sugarcane bagasse and 30% ash sugarcane bagasse in Portland cement mortars can be used to produce building elements.
|
4 |
Desempenho mecânico do solo condicionado com lodo de esgoto calcinado / Mechanical performance of the soil conditioned with burned sewage sludgeMadalozzo, Iedo Lourenço 27 June 2008 (has links)
Made available in DSpace on 2017-07-10T19:24:29Z (GMT). No. of bitstreams: 1
Iedo Lourenco Madalozzo.pdf: 1460845 bytes, checksum: 24bad90e8966ef4c4fdc6af381c73960 (MD5)
Previous issue date: 2008-06-27 / Amongst the global problems that most rouse studies and solutions before the
environment crisis arise the ones concerning the destination of waste and the
sewage system. The sustainable development requires the creation of solutions
aiming the reduction or the elimination of the impacts on the environment. The
waste may become an Engineering solution. The aim of this work is to unite two
problems and find a unique solution that answers both to the environmental
question and to the soil engineering one. Considering the present situation of
environmental management and rational use of substance, one of the priorities
nowadays is the reduction of the industrial waste. The reduction of such waste
is possible, although its complete elimination is not and, therefore, comes the
necessity of transforming this waste into something useful. The use of solid
wastes on the soil treatment (ABNT NBR 5776) is the focus of this work, which
has the purpose of demonstrating the rational use of the wastes related to the
necessity of their reutilization, the ideal tenor of the wastes for a better
performance and low cost, accomplishing the improvement of the physical
characteristics and the mechanic performance of the soil of West Paraná. The
proposed material for this work is the dry sewage sludge (Class I of ABNT NBR
10004). Sewage sludge can be defined as every solid waste extracted during
the treatment of residual water to the elimination in water collect. In order to
determine the relation waste/ideal soil, the in natura soil was added with waste
in four parts of 0%, 8%, 17,5%, 28,5% and 43%. So as to carry out the
experiences the samples of added soil and in natura soil were prepared
according to the regulations of ABNT NBR 6457. The experiences of the soil s
characterization and performance were accomplished under ABNT rules. After
the addition process there was a considerable increase on the maximum
compactation level and an excessive decrease on the empty spaces of the soil,
generating a hardness of the compounds due to the addition of burned sewage
sludge, improving considerably the stabilization and the mechanic resistance of
the soil. / Dentre os problemas globais que mais suscitam estudos e soluções frente à
crise ambiental, despontam os referentes ao destino dos resíduos gerados e o
esgotamento sanitário. O desenvolvimento sustentável pressupõe a criação de
soluções que visem à diminuição ou eliminação dos impactos sobre o
ambiente. Os resíduos podem passar de problema à solução de engenharia.
Este estudo tem a finalidade de unir dois problemas e encontrar uma solução
única que atenda à questão ambiental e à questão de engenharia de solos. No
contexto atual, quanto à gestão ambiental e ao uso racional de materiais, uma
das prioridades é a redução dos resíduos produzidos pelas indústrias. A
redução dessa produção é possível, mas não a sua total extinção, por isso a
necessidade de tornar útil este resíduo, para o seu total reaproveitamento. O
uso de resíduos sólidos no condicionamento dos solos (ABNT NBR 5776) é o
foco deste estudo, que tem como finalidade o uso racional dos resíduos
relacionados à necessidade de reutilização, ao teor ideal de resíduos para o
melhor desempenho e ao baixo custo, conseguindo assim o melhoramento das
características físicas e do desempenho mecânico do solo da Região Oeste do
Paraná. O material proposto para estudo é o lodo de esgoto seco (Classe I da
ABNT NBR 10004). O lodo de esgoto é todo o resíduo sólido extraído durante o
tratamento de águas residuais para a eliminação nas coleções hídricas. Para a
determinação da relação resíduo/solo ideal o solo in natura foi aditivado com
resíduo em quatro proporções de tratamento em massa 0%, 8%, 17,5%, 28,5%
e 43%. Para a realização dos ensaios as amostras de solo aditivado e in natura
foram preparadas conforme a norma da ABNT NBR 6457. Os ensaios de
caracterização e de desempenho do solo foram realizados conforme as normas
da ABNT. Após o processo de adição ocorreu um acréscimo considerável no
índice máximo de compactação e uma diminuição expressiva nos vazios do
solo, gerando uma rigidez dos compostos em função do incremento do lodo de
esgoto calcinado, melhorando consideravelmente sua estabilização e
desempenho mecânico.
|
5 |
Desempenho mecânico do solo condicionado com lodo de esgoto calcinado / Mechanical performance of the soil conditioned with burned sewage sludgeMadalozzo, Iedo Lourenço 27 June 2008 (has links)
Made available in DSpace on 2017-05-12T14:47:47Z (GMT). No. of bitstreams: 1
Iedo Lourenco Madalozzo.pdf: 1460845 bytes, checksum: 24bad90e8966ef4c4fdc6af381c73960 (MD5)
Previous issue date: 2008-06-27 / Amongst the global problems that most rouse studies and solutions before the
environment crisis arise the ones concerning the destination of waste and the
sewage system. The sustainable development requires the creation of solutions
aiming the reduction or the elimination of the impacts on the environment. The
waste may become an Engineering solution. The aim of this work is to unite two
problems and find a unique solution that answers both to the environmental
question and to the soil engineering one. Considering the present situation of
environmental management and rational use of substance, one of the priorities
nowadays is the reduction of the industrial waste. The reduction of such waste
is possible, although its complete elimination is not and, therefore, comes the
necessity of transforming this waste into something useful. The use of solid
wastes on the soil treatment (ABNT NBR 5776) is the focus of this work, which
has the purpose of demonstrating the rational use of the wastes related to the
necessity of their reutilization, the ideal tenor of the wastes for a better
performance and low cost, accomplishing the improvement of the physical
characteristics and the mechanic performance of the soil of West Paraná. The
proposed material for this work is the dry sewage sludge (Class I of ABNT NBR
10004). Sewage sludge can be defined as every solid waste extracted during
the treatment of residual water to the elimination in water collect. In order to
determine the relation waste/ideal soil, the in natura soil was added with waste
in four parts of 0%, 8%, 17,5%, 28,5% and 43%. So as to carry out the
experiences the samples of added soil and in natura soil were prepared
according to the regulations of ABNT NBR 6457. The experiences of the soil s
characterization and performance were accomplished under ABNT rules. After
the addition process there was a considerable increase on the maximum
compactation level and an excessive decrease on the empty spaces of the soil,
generating a hardness of the compounds due to the addition of burned sewage
sludge, improving considerably the stabilization and the mechanic resistance of
the soil. / Dentre os problemas globais que mais suscitam estudos e soluções frente à
crise ambiental, despontam os referentes ao destino dos resíduos gerados e o
esgotamento sanitário. O desenvolvimento sustentável pressupõe a criação de
soluções que visem à diminuição ou eliminação dos impactos sobre o
ambiente. Os resíduos podem passar de problema à solução de engenharia.
Este estudo tem a finalidade de unir dois problemas e encontrar uma solução
única que atenda à questão ambiental e à questão de engenharia de solos. No
contexto atual, quanto à gestão ambiental e ao uso racional de materiais, uma
das prioridades é a redução dos resíduos produzidos pelas indústrias. A
redução dessa produção é possível, mas não a sua total extinção, por isso a
necessidade de tornar útil este resíduo, para o seu total reaproveitamento. O
uso de resíduos sólidos no condicionamento dos solos (ABNT NBR 5776) é o
foco deste estudo, que tem como finalidade o uso racional dos resíduos
relacionados à necessidade de reutilização, ao teor ideal de resíduos para o
melhor desempenho e ao baixo custo, conseguindo assim o melhoramento das
características físicas e do desempenho mecânico do solo da Região Oeste do
Paraná. O material proposto para estudo é o lodo de esgoto seco (Classe I da
ABNT NBR 10004). O lodo de esgoto é todo o resíduo sólido extraído durante o
tratamento de águas residuais para a eliminação nas coleções hídricas. Para a
determinação da relação resíduo/solo ideal o solo in natura foi aditivado com
resíduo em quatro proporções de tratamento em massa 0%, 8%, 17,5%, 28,5%
e 43%. Para a realização dos ensaios as amostras de solo aditivado e in natura
foram preparadas conforme a norma da ABNT NBR 6457. Os ensaios de
caracterização e de desempenho do solo foram realizados conforme as normas
da ABNT. Após o processo de adição ocorreu um acréscimo considerável no
índice máximo de compactação e uma diminuição expressiva nos vazios do
solo, gerando uma rigidez dos compostos em função do incremento do lodo de
esgoto calcinado, melhorando consideravelmente sua estabilização e
desempenho mecânico.
|
6 |
Investigating Mechanical Performance and Water Absorption Behavior of Organo-nanoclay Modified Biofiber Plastic CompositesChen, Jieming 02 August 2013 (has links)
Hydrophobic Surface modification of biofibers to reduce water/moisture absorption of the biofiber or biofiber-plastic composites has attracted many researchers. In order to reduce the moisture sensitivity of kraft and mechanical pulp fibers, organo-nanoclay particles were adsorbed on the biofiber surfaces. Surface hydrophobicity, in terms of moisture absorption, water uptake, water contact angle and surface energy of the modified fibers were tested. The treated fibers had nano-scale surface roughness and substantially lower surface energy. The thermal stability of the mechanical pulp fibers increased after the nanoclay modification.
The organo-nanoclay treated kraft and mechanical pulp fibers were used to make biofiber reinforced high density polyethylene (HDPE) composites. The organo-nanoclay treated kraft fibers had a more uniform dispersion in the HDPE matrix and the resulting composites had a higher Young’s modulus and thermal stability. Similar trend was observed for the mechanical pulp fiber-HDPE composites. The adhesion between the kraft fibers and matrix was greatly improved after adding maleic anhydride polyethylene (MAPE) as a compatibilizer, therefore, improvements in tensile strength, Young’s modulus, and thermal stability of both treated and untreated fiber composites were observed. However, this improvement was more significant for the composites containing the treated fibers. In addition, water absorption was decreased by incorporating the organo-nanoclay treated mechanical pulp fibers in the HDPE composites. The treated kraft fiber-HDPE-MAPE composites also showed a decrease in water absorption.
The crystallization behaviors of the organo-nanoclay treated and untreated kraft fiber-HDPE composites with and without MAPE compatibilizer were studied. It was found by differential scanning calorimetry (DSC) analysis that both organo-nanoclay treated and untreated kraft fibers could act as nucleating agents. All composites crystallized much faster than the neat HDPE, while their crystallinity levels were lower. The organo-nanoclay treatment of the kraft fibers increased the nucleation rate. However, both the crystallinity level and the nucleation rate of the treated kraft fiber composites were increased by the addition of the MAPE compatibilizer. X-ray diffraction (XRD) analysis reveled that MAPE could also increase the d-spacing of the organo-nanoclay layers in the composites. When the fiber loading was 40 wt% in the composites, exfoliation of the nanoclays in the composites was observed.
|
7 |
Investigating Mechanical Performance and Water Absorption Behavior of Organo-nanoclay Modified Biofiber Plastic CompositesChen, Jieming 02 August 2013 (has links)
Hydrophobic Surface modification of biofibers to reduce water/moisture absorption of the biofiber or biofiber-plastic composites has attracted many researchers. In order to reduce the moisture sensitivity of kraft and mechanical pulp fibers, organo-nanoclay particles were adsorbed on the biofiber surfaces. Surface hydrophobicity, in terms of moisture absorption, water uptake, water contact angle and surface energy of the modified fibers were tested. The treated fibers had nano-scale surface roughness and substantially lower surface energy. The thermal stability of the mechanical pulp fibers increased after the nanoclay modification.
The organo-nanoclay treated kraft and mechanical pulp fibers were used to make biofiber reinforced high density polyethylene (HDPE) composites. The organo-nanoclay treated kraft fibers had a more uniform dispersion in the HDPE matrix and the resulting composites had a higher Young’s modulus and thermal stability. Similar trend was observed for the mechanical pulp fiber-HDPE composites. The adhesion between the kraft fibers and matrix was greatly improved after adding maleic anhydride polyethylene (MAPE) as a compatibilizer, therefore, improvements in tensile strength, Young’s modulus, and thermal stability of both treated and untreated fiber composites were observed. However, this improvement was more significant for the composites containing the treated fibers. In addition, water absorption was decreased by incorporating the organo-nanoclay treated mechanical pulp fibers in the HDPE composites. The treated kraft fiber-HDPE-MAPE composites also showed a decrease in water absorption.
The crystallization behaviors of the organo-nanoclay treated and untreated kraft fiber-HDPE composites with and without MAPE compatibilizer were studied. It was found by differential scanning calorimetry (DSC) analysis that both organo-nanoclay treated and untreated kraft fibers could act as nucleating agents. All composites crystallized much faster than the neat HDPE, while their crystallinity levels were lower. The organo-nanoclay treatment of the kraft fibers increased the nucleation rate. However, both the crystallinity level and the nucleation rate of the treated kraft fiber composites were increased by the addition of the MAPE compatibilizer. X-ray diffraction (XRD) analysis reveled that MAPE could also increase the d-spacing of the organo-nanoclay layers in the composites. When the fiber loading was 40 wt% in the composites, exfoliation of the nanoclays in the composites was observed.
|
8 |
Effects of processing techniques on the microstructure of renewable pulp-fiber reinforced composites and their mechanical performanceJagunic, Predrag January 2018 (has links)
Commingled composites are stronger than those manufactured with the standard manufacturing method. The objective of the thesis is to answer why that is, to investigate the microstructure of the composites, to model composite strength and compare experimental values with theoretical for composites having poly lactic acid (PLA) as matrix material and composites having poly propylene (PP) as matrix material. X - Ray micro - computed tomography was used to investigate the micro structure of the composites. Input from X - Ray micro - computed tomography was used to show that commingled PLA composites are stronger than standard PLA composites because the fibers are longer and more of them are orientated closer to the loading direction. Composites having PP as matrix material have lower strength than composites with PLA as matrix material. The strength for these composites is pretty much the same regardless of manufacturing method but still a little higher for commingled PP composites. Theoretical strength is modelled with the modified rule of mixture and correlates well with experimental values, having an R2 value of 0.95 for average composite strength.
|
9 |
Cellulose Nanocrystals: Renewable Property Modifiers for Pressure Sensitive AdhesivesDastjerdi, Zahra January 2017 (has links)
Pressure sensitive adhesives (PSAs) are polymeric materials with versatile applications in industrial and consumer products such as protective films, product labels, masking tape, and sticky notes, to name a few applications. World demand for emulsion–based products is on the rise due to worldwide legislation on solvent emissions. In order to completely replace emulsion-based PSAs with their solvent-based counterpart, the property modification of emulsion-based PSAs is required. The use of nanomaterials to modify polymer properties is well established. The aim of this thesis was to use cellulose nanocrystals (CNCs) as property modifiers for emulsion-based PSAs.
CNCs are recognized as a highly efficient reinforcement nanofiller. Owing to their environmentally friendly characteristics, low density, high aspect ratio, non-toxicity, and abundant availability, the application of CNCs in composite materials is gaining increasing attention. In this thesis, the inclusion of CNCs in emulsion-based PSAs was carried out through in situ emulsion polymerization and blending technique. To the best of our knowledge, there is limited information about the synthesis of CNC/PSAs nanocomposites via in situ emulsion polymerization and the evaluation of their mechanical performance.
The addition of CNCs to the polymerization formulation caused latex instability due to the negatively charged surfaces of the CNCs. After numerous attempts to overcome the stability issues, a stable polymerization formulation and protocol were developed. CNC/PSAs were synthesized via in situ seeded-semi batch emulsion polymerization, which is a common commercial production pathway for PSAs. The mechanical performance of the resulting PSA nanocomposite films, namely, shear strength, tack, and peel strength, was evaluated at several CNC loadings. All three PSA adhesive properties were simultaneously enhanced with increasing CNC loading. The inclusion of CNCs into the films increased their hydrophilicity. Consequently, the PSA films’ improved wettability on a stainless steel substrate imparted greater tack and peel strength. The blending of the CNCs with a base latex also led to improved adhesive properties. However, the property modification through blending was not as effective as that for the CNC/PSA films synthesized via in situ emulsion polymerization. Thus, CNCs are safe nanomaterials that have been shown to provide remarkable property enhancement of emulsion-based PSA films at low loadings (1wt%).
|
10 |
Utilização de resíduos sucro-alcooleiros na fabricação de fibrocimento pelo processo de extrusão / Use residual of sugar and alcohol in the manufacture of cement by the extrusion process.Ronaldo Soares Teixeira 14 October 2010 (has links)
Este trabalho avalia a utilização de fibras e cinzas de bagaço de cana-de-açúcar em compósitos cimentícios extrudados. Visa o estudo da potencialidade do emprego da fibra e cinza do bagaço da cana-de-açúcar na construção civil, o aproveitamento deste produto em matrizes cimentícias representa uma alternativa para diminuição de gastos com locais para deposição do resíduo evitando a degradação do meio ambiente. A cinza de bagaço de cana-de-açúcar apresenta características pozolânicas, além de garantir uma redução do consumo de cimento. Fibras de bagaço de cana-de-açúcar (FBC) foram classificadas por peneiramento, lavadas em água fervente para reduzir o açúcar residual e foi tratado quimicamente com silicato de sódio e sulfato de alumino com finalidade de proteger as fibras contra a agressão do meio alcalino proporcionado pelo cimento, imobilizar a matéria orgânica e reduzir a absorção de água, diminuindo as variações dimensionais e proporcionar melhor qualidade no compósito, tais como durabilidade e evitar o ataque de microorganismo. As cinzas de bagaço de cana-de-açúcar (CBC) foram queimadas com temperatura e tempo controlado para ter um ótimo grau de amorficidade e conseqüentemente maior reatividade. A moagem também foi efetuada a fim de melhorar a reatividade da cinza. Foi realizada uma série de ensaios de caracterização da CBC. A atividade pozolânica foi averiguada por ensaio condutividade elétrica. O desempenho mecânico e físico e na microestrutura dos compósitos de fibrocimento foram avaliados. Os compósitos foram avaliados antes e após ciclos de envelhecimento acelerado. A extrusão foi utilizada na produção de compósitos cimentícios com geometrias diferenciadas e na produção em pequena escala. Os resultados apresentaram que a fervura da FBC reduziu o açúcar residual e o tratamento químico mineralizou as FBC. As CBC apresentaram valores de sílica elevada. Foram produzidos placas com níveis de reforço entre 0,5% e 5,0% de FBC. Compósitos extrudados com 5% de reforço de FBC com 28 dias de cura apresentaram melhores resultados em tenacidade (TE), devido à maior introdução de FBC no compósito, mas não apresentou diferença entre o tratamento químico. Compósitos extrudados com 5% de reforço de FBC tratada após 200 ciclos de envelhecimento apresentaram maior absorção de água (AA) e porosidade aparente (PA). Esse fato se deve a explicado com a maior hidratação do cimento que ocasionou mineralização drástica da FBC e descolagem da fibra na interface fibra e matriz. Compósito extrudado com 5% de FBC tratada com 28 dias e após 200 ciclos com substituição de cimento por 30% de CBC apresentaram diminuição de módulo de ruptura (MOR) e maior absorção de água (AA). A substituição da matriz (agregado) e a maior relação água/cimento da mistura influenciaram neste resultado. Os resultados indicaram que os compósitos extrudados com reforço de fibra de bagaço de cana e 30% de cinza de bagaço de cana, em substituição ao cimento Portland, podem ser utilizados para produzir elementos construtivos. / This study evaluates the use of fibre and ash from sugarcane bagasse in extruded cementitious composites. Aims at studying the potentiality of using fibre and ash from sugarcane bagasse in construction, the use of this product in cementitious matrices represents an alternative to reduce expenses with the waste disposal sites for avoiding environmental degradation. The bagasse ash cane sugar has pozzolanic characteristics and ensures a reduction in cement consumption. Fibres from sugarcane bagasse (FSB) were classified by sieving, washed in boiling water to reduce the residual sugar and has been chemically treated with sodium silicate and aluminum sulphate in order to protect the fibres against the aggression of alkaline provided by the cement, immobilize the organic material and reduce the water absorption, reducing size variations and provide better quality in the composite, such as durability and prevent the attack of microorganisms. The ashes of sugarcane bagasse (ASB) were burned with controlled temperature and time to have a great degree of amorphicity and consequently higher reactivity. The grinding was also performed to improve the reactivity of the ash. We performed a series of tests to characterize the ASB. The pozzolanic activity was determined by electrical conductivity test. The mechanical and physical performance and microstructure of cement composites were evaluated. The composites were evaluated before and after ageing accelerated cycles. Extrusion was used in the production of cementitious composites with different geometries and small scale production. The results showed that boiling FSB reduced the residual sugar and chemically treated to mineralized FSB. The ASB had high amounts of silica. Plates were produced with enhanced levels of between 0.5% and 5.0% of FSB. Composites extruded with 5% of FSB with 28 days of healing showed better results in toughness (TE) due to the increased introduction of FSB in the composite, but no difference between the chemical treatments. Composites extruded with 5% strengthening of FSB treated after 200 ageing accelerated cycles had higher water absorption (AA) and apparent porosity (AP). This fact should be explained with the higher hydration of cement which caused drastic mineralization FSB and off the fibre and fibre-matrix interface. Extruded composite with 5% FBC treated with 28 days and after 200 cycles with replacement of cement by 30% of ASB showed a decrease of modulus of rupture (MOR) and higher water absorption (AA). The substitution matrix (aggregate) and the highest water / cement ratio of the mixture affected this result. The results indicated that the extruded composites reinforced with fibre sugarcane bagasse and 30% ash sugarcane bagasse in Portland cement mortars can be used to produce building elements.
|
Page generated in 0.0753 seconds