Soil quality response to land-use change for sugarcane expansion in Brazil

Globally, increasing demands for biofuels have intensified the rate of land-use change (LUC) for expansion of bioenergy crops. In Brazil, the world\'s largest sugarcane-ethanol producer, sugarcane area has expanded by 35% (3.2 Mha) in the last decade. Sugarcane expansion has resulted in extensive pastures being subjected to intensive mechanization and large inputs of agrochemicals, which have direct implications on soil quality (SQ). We hypothesized that LUC to support sugarcane expansion leads to overall SQ degradation. To test this hypothesis we conducted a field-study at three sites in the central-southern region, to assess the SQ response to the primary LUC sequence (i.e., native vegetation to pasture to sugarcane) associated to sugarcane expansion in Brazil. At each land use site undisturbed and disturbed soil samples were collected from the 0-10, 10-20 and 20-30 cm depths. Soil chemical and physical attributes were measured through on-farm and laboratory analyses. A dataset of soil biological attributes was also included in this study. Initially, the LUC effects on each individual soil indicator were quantified. Afterward, the LUC effects on overall SQ were assessed using the Soil Management Assessment Framework (SMAF). Furthermore, six SQ indexes (SQI) were developed using approaches with increasing complexity. Our results showed that long-term conversion from native vegetation to extensive pasture led to soil acidification, significant depletion of soil organic carbon (SOC) and macronutrients [especially phosphorus (P)] and severe soil compaction, which creates an unbalanced ratio between water- and air-filled pore space within the soil and increases mechanical resistance to root growth. Conversion from pasture to sugarcane improved soil chemical quality by correcting for acidity and increasing macronutrient levels. Despite those improvements, most of the P added by fertilizer accumulated in less plant-available P forms, confirming the key role of organic P has in providing available P to plants in Brazilian soils. Long-term sugarcane production subsequently led to further SOC depletions. Sugarcane production had slight negative impacts on soil physical attributes compared to pasture land. Although tillage performed for sugarcane planting and replanting alleviates soil compaction, our data suggested that the effects are short-term with persistent, reoccurring soil consolidation that increases erosion risk over time. These soil physical changes, induced by LUC, were detected by quantitative soil physical properties as well as by visual evaluation of soil structure (VESS), an on-farm and user-friendly method for evaluating SQ. The SMAF efficiently detected overall SQ response to LUC and it could be reliably used under Brazilian soil conditions. Furthermore, since all of the SQI values developed in this study were able to rank SQ among land uses. We recommend that simpler and more cost-effective SQI strategies using a small number of carefully chosen soil indicators, such as: pH, P, K, VESS and SOC, and proportional weighting within of each soil sectors (chemical, physical and biological) be used as a protocol for SQ assessments in Brazilian sugarcane areas. The SMAF and SQI scores suggested that long-term conversion from native vegetation to extensive pasture depleted overall SQ, driven by decreases in chemical, physical and biological indicators. In contrast, conversion from pasture to sugarcane had no negative impacts on overall SQ, mainly because chemical improvements offset negative impacts on biological and physical indicators. Therefore, our findings can be used as scientific base by farmers, extension agents and public policy makers to adopt and develop management strategies that sustain and/or improving SQ and the sustainability of sugarcane production in Brazil.

Tratamento superficial dos agregados reciclados de RCD com hidrofugantes.

A proposta busca reduzir a absorção de água dos agregados reciclados de Resíduos de Construção e Demolição (RCD), através do tratamento de sua superfície com hidrofugante, de maneira que estes não aumentem o consumo de água tampouco reduzam a resistência mecânica. Os agregados reciclados de RCD foram caracterizados quanto à granulometria, morfologia, porosidade, ângulo de contato aparente, absorção de água, análise de imagem e rugosidade superficial. Em seguida, os mesmos foram tratados superficialmente com dois tipos de hidrofugante: solução de silano e parafina. Todos os tratamentos permitiram reduzir a absorção de água dos agregados reciclados de RCD. O tratamento por imersão foi aquele que permitiu obter os melhores resultados e a menor variabilidade entre as técnicas. Os tratamentos hidrofugam a superfície, apesar da parafina apresentar maior molhabilidade. O tratamento com parafina apresentou, em termos de absorção de água, resultados inferiores e menos variáveis que o silano. Os parâmetros de rugosidade constataram que, ambos os materiais perdem seu perfil topográfico original quando tratados com parafina. Os diferentes agregados reciclados com cada hidrofugante foram aplicados em materiais cimentícios analisados no estado fresco e no estado endurecido. Os tratamentos reduziram a absorção e o consumo de água de mistura, porém afetaram negativamente as propriedades mecânicas, devido nova interface gerada (no caso específica de parafina) e falta de molhabilidade nas superfícies.

Contribuição ao conhecimento de caracteristicas tecnologicas de materiais rochosos

Neste trabalho foi desenvolvida uma investigação experimental com o objetivo de ampliar o conhecimento sobre caracterização tecnológica de materiais de construção, com ênfase no aspecto da alternabilidade. Foram estudadas rochas de 15 localidades representando os seguintes 11 tipos litológicos: basalto compacto, basalto vesicular, basalto microvesicular, diabásio, quartzito, calcário, granito, charnockito, piroxenito, migmatitoe arenito. Os ensaios de laboratório foram conduzidos em corpos de prova cilídricos, cúbicos e britados obtidos a partir das amostras enviadas, para determinação dos seguintes índices: massa específica aparente, porosidade aparente, absorção, abrasão Los Angeles, resistência ao impacto em corpos de prova regulares, resistência ao impacto Treton, resistência ao esmagamento, resistência à compressão simples axial, índice escleromético, resistência ao desgaste a úmido e durabilidade. Foram executados quase 3000 ensaios para obtenção de índices fisicomecânicos e de durabilidade, por um período de aproximadamente 2 anos. Todos os ensaios foram efetuados em amostras inicialmente lavadas, secas em estufa a 100-110°C por aproximadamente 10 horas e posteriormente, esfriadas à temperatura ambiente durante pelo menos 2-3 horas, antes de cada ensaio. Os seguintes ensaios novos foram introduzidos: índice esclerométrico, impacto em corpos de prova moldados e desgaste úmido, com discussões a respeito de sua aplicabilidade. Os resultados de cada grupo de corpos de prova em diferentes rochas, para estes ensaios novos, foram submetidos à análise estatística para obtenção de valores médios e coeficientes de variação para determinar a precisão e o número de ensaios necessários para cada uma destas propriedades. Os resultados médios foram submetidos à correlação estatística e análises de regressão pelo método dos mínimos quadrados, para os quais foram determinados os coeficientes de correlação ) simples, erros padrão de estimativa e relações funcionais para cada par selecionado de variáveis. Estas relações foram apresentadas graficamente para comparação visual com os correspondentes resultados de ensaios. A partir dos resultados obtidos quanto à precisão e reprodutibilidade dos ensaios e verificada sua aplicabilidade, foram elaboradas propostas para métodos de ensaios. Os ensaios de durabilidade, que constituem a segunda parte deste trabalho, foram executados nas rochas acima mencionadas, cujas amostras foram submetidas a ciclos sucessivos de, saturação em solução de sulfato e secagem em estufa, saturação em etilenoglicol e secagem em estufa, saturação em água e secagem em estufa, lixiviação contínua no exterior Soxhlet e exposição natural, em 2 séries de ensaios. A primeira série consistiu na comparação de processos de alteração e a segunda série, na investigação do comportamento mecânico dos materiais rochosos face a diferentes condições fisicoquímicas de alteração artificial e natural. P parâmetro mecânico utilizado neste caso, foi a resistência ao impacto Treton. Os resultados obtidos na primeira série, foram submetidos à análise de regressão, obtendo-se gráficos de comparação de linhas teóricas de velocidades de alteração pelos diferentes processos e, gráficos mostrando a influência do fator de escala no processo de alteração. Os resultados da segunda série de ensaios, permitiram estabelecer 2 parâmetros numéricos: queda percentual de resistência mecânica e coeficiente de alterabilidade específica, que refletem a suscetibilidade das rochas a estes diferentes processos de alteração. A correlação estatística, entre estes parâmetros numéricos da alteração e a relação entre as tensões máximas de ruptura, no estado saturado e no estado seco, do ensaio de compressão simples axial, indicou ser esta relação, um índice promissor da alterabilidade de rochas. Finalmente, discutida a validade ) destes índices, tendo em vista os resultados encontrados e a ausência na literatura de procedimentos adequados, que permitam classificar as rochas quanto ao comportamento mecânico face à alteração natural ou artificial, foram elaboradas propostas de métodos de ensaios, que poderão preencher esta lacuna.

Efeitos citotóxicos e biocompatibilidade dos materiais dentários nas células da mucosa oral

Dissertação para obtenção do grau de Mestre no Instituto Superior de Ciências da Saúde Egas Moniz

Estudo experimental do punçoamento centrado em lages de betão leve

As aplicações do betão com agregados leves foi iniciada há mais de dois milénios pelos Romanos, sendo esse material produzido inicialmente com agregados leves naturais. Apesar do uso em Portugal ainda ser reduzido, quando comparado com outros países da Europa e da América, a utilização do betão estrutural de agregados leves (BEAL) pode ser bastante vantajosa, principalmente em elementos de laje e tabuleiros de pontes, associando a redução do peso próprio a resistências elevadas. Além da eficiência de desempenho estrutural e das vantagens económicas globais, o BEAL apresenta geralmente elevado desempenho de durabilidade, sendo uma solução competitiva em obras de reabilitação e reforço estrutural e de elementos pré-fabricados. Uma vez que a aplicação de BEAL em elementos de laje é particularmente vantajosa e eficiente, o estudo do comportamento e respetiva resistência ao punçoamento é fundamental para os casos de lajes fungiformes em BEAL armado. Apesar dos recentes códigos europeus estabelecerem parâmetros e expressões de dimensionamento para esse tipo de betão, estes são geralmente baseados nos dos betões de densidade normal e corrigidos por coeficientes de correção para os BEAL, os quais resultam, por vezes, em desvios significativos. Aliando a este facto, a escassez de estudos experimentais para essa aplicação, o presente estudo surge nesse contexto. O trabalho de investigação apresentado tem como principal objetivo o estudo do punçoamento centrado em lajes de BEAL, variando a sua resistência. Para o efeito foram produzidas seis lajes, onde se utilizaram três tipos de BEAL com diferentes classes de resistência à compressão. Produziram-se duas lajes de cada classe de resistência e procedeu-se aos ensaios definidos, aplicando uma carga pontual no centro da laje, com aumento gradual até originar a rotura por punçoamento. Através da análise dos resultados dos ensaios, observou-se que, o aumento da resistência do betão à compressão originou maior capacidade resistente ao punçoamento e maior capacidade de deformação das lajes ensaiadas. Estudaram-se também os seguintes parâmetros, em função da resistência do BEAL: carga de fendilhação, rigidez, o ângulo do cone de punçoamento e o perímetro de contorno crítico. Os valores obtidos foram ainda comparados com as previsões de vários códigos de betão armado e apresentam-se as principais conclusões

Avaliação da influência de cinza da casca de arroz em cimentos para poços de petróleo submetidos à injeção de vapor

Reservoirs that present highly viscous oils require methods to aid in their recovery to the surface. The elev ated oil viscosity hinders its flow through porous media and conventional recovery methods have not obtained significant efficiency. As such, the injection of steam into the reservoir through an injection well has been the most widely used method of therma l recovery, for it allows elevated volumes of recovery due to the viscosity reduction of the oil, facilitating the oil’s mobility within the rock formation and consequently into the production well where it will be exploited. On the other hand, the injecti on of vapor not only affects the fluids found in the rock pores, but the entire structure that composes the well where it is injected due to the high temperatures used in the process. This temperature increment is conducted to the cement, found in the annu lus, responsible for the isolation of the well and the well casing. Temperatures above 110 ̊C create new fazes rich in calcium in the cement matrix, resulting in the reduction of its permeability and the consequential phenomenon of mechanical resistance ret rogression. These alterations generate faults in the cement, reducing the well’s hydraulic isolation, creating insecurity in the operations in which the well will be submitted as well as the reduction of its economic life span. As a way of reducing this re trograde effect, this study has the objective of evaluating the incorporation of rice husk ash as a mineral additive substitute of silica flour , commercially utilized as a source of silica to reduce the CaO/SiO 2 ratio in the cement pastes submitted to high temperatures in thermal recovery. Cement pastes were formulated containing 20 and 30% levels of ash, apart from the basic paste (water + cement) and a reference paste (water + cement + 40% silica flour) for comparison purposes. The tests were executed th rough compression resistance tests, X - Ray diffraction (XRD) techniques, thermogravimetry (TG), scanning electron microscopy (SEM) and chemical anal ysis BY X - ray fluorescence (EDS) on the pastes submitted to cure at low temperatures (45 ̊C) for 28 days following a cure at 280 ̊C and a pressure of 2,000 PSI for 3 days, simulating vapor injection. The results obtained show that the paste containing 30% r ice shell ash is satisfactory, obtaining mechanical resistance desired and equivalent to that of the paste containing 40% silica flour, since the products obtained were hydrated with low CaO/SiO 2 ratio, like the Tobermorita and Xonotlita fases, proving its applicability in well subject to vapor injection.

Viabilidade técnica da fabricação de compósito utilizando fibra de pneu na fabricação de blocos intertravados

This work aims to demonstrate the feasibility of a ceramic composite containing fiber in the rubber manufacturing interlocking blocks. Gravel, sand, cement, rubber and fiber: the processes of manufacture and assembly of blocks produced and the various formulations studied with different proportions between the constituent elements were addressed. Mechanical properties were determined for the different formulations, compressive strength, diametral compressive strength, water absorption and apparent density, obeying the rules related to each property. It was concluded that the addition of rubber fiber gave the concrete studied resistance lower than conventional concrete which can be verified on the microstructural analysis obtained by SEM, which revealed the presence of pores and the low adhesion between the fiber and the matrix compression (tire fiber / cement paste). The composite of more viable tire BCPB1 (1/2) fiber can be used in places requests as light squares, pavements, roads and other cycle as well as in the manufacture of the curb and gutter, by having compressive strength in about 20 MPa

Redução in situ de NIO durante a sinterização de misturas NI/NIO produzidas por metalurgia do pó

The nickel alloys are widely used in the production of various materials, especially those that require mechanical strength characteristics associated with resistance to corrosion, for example, the stainless steel. Another use is the production of nickel alloy sintered from powder of metallic nickel. A promising alternative for the production of sintered components of nickel with an important reduction in costs of starting material is the use of mixtures of powders of Ni-NiO. This work aimed to study in situ reduction of NiO during sintering mixtures of Ni / NiO produced by powder metallurgy. The nickel mixtures have been processed by the technique of powder metallurgy and were pre-sintered in an oven under plasma reducing atmosphere of hydrogen. Mixtures Ni +15%NiO, Ni +25%NiO and Ni +35%NiO were studied and compared with samples consisting only of metallic Ni. Dilatometric tests were performed to study the sintering conditions of the mixtures. The consolidated material was analyzed for their microstructure and microhardness. Dilatometry graphs showed that the addition of nickel oxide in all compositions the active sintering the mixtures studied. In tests of microhardness indentations were made at different points of the sample surface. All compositions showed microhardness values close to the consolidated material from metallic nickel. However, sample containing Ni+35% NiO, showed a large dispersion of the values of microhardness tests performed at different points of the sample surface. Microstructural analysis of the material showed a higher concentration of voids and the presence of oxides in the waste composition of the mixtures Ni 35% NiO. The samples containing Ni+15%NiO showed microstructural characteristics and mechanical properties similar to metallic nickel consolidated under the same conditions of the compositions studied in this work and therefore had great potential for production of sintered nickel alloys

Avaliação de compatibilidade entre pasta de cimento e fluido de perfuração não-aquoso utilizados em poços petrolíferos

Compatibility testing between a drilling fluid and a cement slurry is one of the steps before an operation of cementing oil wells. This test allows us to evaluate the main effects that contamination of these two fluids may cause the technological properties of a cement paste. The interactions between cement paste and drilling fluid, because its different chemical compositions, may affect the cement hydration reactions, damaging the cementing operation. Thus, we carried out the study of the compatibility of non-aqueous drilling fluid and a cement slurry additives. The preparation procedures of the non-aqueous drilling fluid, the cement paste and completion of compatibility testing were performed as set out by the oil industry standards. In the compatibility test is evaluated rheological properties, thickening time, stability and compressive strength of cement pastes. We also conducted analyzes of scanning electron microscopy and X-ray diffraction of the mixture obtained by the compatibility test to determine the microstructural changes in cement pastes. The compatibility test showed no visual changes in the properties of the cement paste, as phase separation. However, after the addition of nonaqueous drilling fluid to cement slurry there was an increased amount of plastic viscosity, the yield point and gel strength. Among the major causative factors can include: chemical reaction of the components present in the non-aqueous drilling fluid as the primary emulsifier, wetting agent and paraffin oil, with the chemical constituents of the cement. There was a reduction in the compressive strength of the cement paste after mixing with this drilling fluid. Thickening test showed that the oil wetting agent and high salinity of the non-aqueous fluid have accelerating action of the handle of the cement paste time. The stability of the cement paste is impaired to the extent that there is increased contamination of the cement slurry with the nonaqueous fluid. The X-ray diffraction identified the formation of portlandite and calcium silicate in contaminated samples. The scanning electron microscopy confirmed the development of the identified structures in the X-ray diffraction and also found the presence of wells in the cured cement paste. The latter, formed by the emulsion stability of the drilling fluid in the cement paste, corroborate the reduction of mechanical strength. The oil wetting agent component of the non-aqueous drilling fluid, the modified cement hydration processes, mainly affecting the setting time.

Uso de resíduos de queima de casca de café e argila da região sul da Bahia na obtenção de isolador elétrico cerâmico

The electrical ceramic insulators industry, uses noble raw materials such as siliceous and aluminous clays of white burning, in order to provide plasticity of the mass and contribute to electrical and mechanical properties required of the product, and feldspar with the flux function In literature references the composition of the masses indicates that the clay participates in percentage between 20 and 32, and feldspar 8 to 35, these materials have significant cost. In this research was performed the total replacement of commercial clay, for white burning clay from Santa Luzia region in southern Bahia and partial replacement of feldspar by ash residue of husk conilon coffee burning, from extreme south of Bahia. The objective of replacement these raw materials is to aver its technical feasibility and call attention for the embryo pole of ceramic industry for the existing in the south and extreme south of Bahia, which has significant reserves of noble raw materials such as clay white burning, kaolin, quartz and feldspar, and generates significant volume of gray husk conilon coffee as alternate flux. Clay Santa Luzia is prima noble material whose current commercial application is the production of white roofing. The residue of coffee husk ash is discarded near of production sites and is harmful to the environment. Phase diagrams and statistic design of experiments, were used for optimization and cost savings in research. The results confirmed the expectations of obtaining electrical ceramic insulators, with white burning clay of Santa Luzia and partial replacement up to 35.4% of feldspar, by treaty residue of conilon ash coffee husk burning. The statistic design that showed best results was for formulation with percentages of: clay 26.4 to 30.4%; kaolin 14.85 to 17.1%; feldspar 12.92 to 16.96%; R2 residue 7.08 to 9.2% and Quartz 32.5 to 38.75%, relative to the total mass of the mixture. The best results indicated; 0.2 to 1.4% apparent porosity , water absorption 0.1 to 0.7%, flexural strength 35 to 45MPa , dielectric strength 35-41 kV/cm , the transverse resistivity 8x109 2.5x1010 Ω.cm and for the dielectric constant ε/ε0 7 to 10.4, specification parameters for manufacturing ceramic electrical insulators of low and medium voltage.

Tratamento de argila montmorilonítica para a produção de nanocompósitos poliméricos com retardo de propagação de chama

Compared to conventional composites, polymer matrix nanocomposites typically exhibit enhanced properties at a significantly lower filler volume fraction. Studies published in the literature indicate t hat the addition of nanosilicate s can increase the resistance to flame propagation in polymers. In this work, a treatment of montmorillonite (MMT) nano clay and the effect of its ad dition o n flame propagation characteristics of vinyl ester were studied. The resea rch was conducted in two stages. The first stage focused on the purification and activation of the MMT clay collected from a natural deposit to improve compatibility with the polymer matrix . Clay modification with sodium acetate was also studied to improve particle dispersion in the polymer. The second step was focused on the effect of the addition of the treated clay on nanocomposites ’ properties. Nanocomposites with clay con tents of 1, 2, 4 wt. % were processed. T he techniques for the characterization of the clay included X - ray fluorescence (XRF), X - r ay d iffraction (XRD), thermogravimetric a nalysis (TGA), d ifferential scanning c alorimetry (DSC) , s urface area (BET) and Fourier transform infrared spectroscopy (FTIR). For t he characterization of the nanocomposites , the techniques used were thermogravimetric a nalysis (TGA) , differential scanning c alorimetry (DSC), Fourier transform infrared spectroscopy (FTIR) , scanning electron mi croscopy (SEM), transmission electron m icroscopy (TEM), and the determination of tensile strength, modulus of elasticity and resistance to flame propagation. According to the results, the purification and activation treatment with freeze - drying used in thi s work for the montmorillonite clay was efficient to promote compatibility and dispersion in the polymer matrix as evidenced by the characterization of the nanocomposite s . It was also observed that the clay modifica tion using sodium acetate did not produce any significant effect to improve compatibilization of the clay with the polymer. The addition of the treated MMT resulted in a reduction of up to 53% in the polymer flame propagation speed and did not affect the mechanical tensile strength and modulus o f elas ticity of the polymer, indicating compatibility between the clay and polymer. The effectiveness in reducing flame propagation speed peaked for nanocomposites with 2 wt. % clay, indicating that this is the optimum clay concentration for this property. T he clay treatment used in this work enables the production of vinylester matrix nanocomposites with flame - retardancy properties .

Análise de microestrutura e de características geotécnicas de misturas de resíduo de polimento de porcelanato e solo

Brazil is a country in development, rich in natural resources. In order to grow sustainably, it is necessary to Brazil to preserve its environment, which is an expressive challenge, especially to industries, such as those producing ceramic materials. This study was developed using Porcelain Tile Polishing Residue (RPP) in blends with soil to build compacted fills. This residue is a slurry generated during the polishing process of porcelain tiles and contains powdery material from the polished tile, the abrasives used during the process and cooling water. The RPP was collected from a private company located in Conde/PB and it was mixed with a sandy-clayey soil, to build the fills. Laboratorial tests were conducted with pure soil, pure RPP and blends in proportions of 5%, 10%, 15% and 20% of RPP in addition to the dry mass of pure soil. The Chemical and Physical Characterization tests performed were: specific solid weight, grain size distribution, laser analysis of grain size distribution, Atterberg limits, X ray fluorescence, X ray diffraction, scanning electron microscopy and soil compaction,. The materials and blends were also compacted and direct shear tests and plate load tests were performed. Plate load tests were conducted using a circular plate with 30 cm diameter, on specimens of pure soil and 5% blend, compacted in a metallic box inside the Soil Mechanics Laboratory of the Federal University of Rio Grande do Norte, Brazil. Both mechanical tests performed were conducted under inundated conditions, willing to reduce the influence of soil suction. An evaluation of the results of the tests performed shows that RPP is a fine material, with grain size distribution smaller than 0,015mm, composed mainly of silica and alumina, and particles in angular shape. The soil was characterized as a clayey sand, geologically known as a lateritic soil, with high percentages of alumina and iron oxide, and particles with rounded shape. Both the Soil and the blends presented low plasticity, while the residue showed a medium plasticity. Direct shear tests showed that the addition of RPP did not cause major changes into blends’ friction angle data, however, it was possible to note that, for the proportions studied, that is a tendency of obtain lower shear stresses for higher percentages of RPP in the blends. Both pure soil and 5% mixture showed a punching disruption for the Plate load test. For this same test, the allowable stress for 5% mixture was 44% higher than the pure soil, and smaller vertical settlement results for all stresses.

Análise de microestrutura e de características geotécnicas de misturas de resíduo de polimento de porcelanato e solo

Brazil is a country in development, rich in natural resources. In order to grow sustainably, it is necessary to Brazil to preserve its environment, which is an expressive challenge, especially to industries, such as those producing ceramic materials. This study was developed using Porcelain Tile Polishing Residue (RPP) in blends with soil to build compacted fills. This residue is a slurry generated during the polishing process of porcelain tiles and contains powdery material from the polished tile, the abrasives used during the process and cooling water. The RPP was collected from a private company located in Conde/PB and it was mixed with a sandy-clayey soil, to build the fills. Laboratorial tests were conducted with pure soil, pure RPP and blends in proportions of 5%, 10%, 15% and 20% of RPP in addition to the dry mass of pure soil. The Chemical and Physical Characterization tests performed were: specific solid weight, grain size distribution, laser analysis of grain size distribution, Atterberg limits, X ray fluorescence, X ray diffraction, scanning electron microscopy and soil compaction,. The materials and blends were also compacted and direct shear tests and plate load tests were performed. Plate load tests were conducted using a circular plate with 30 cm diameter, on specimens of pure soil and 5% blend, compacted in a metallic box inside the Soil Mechanics Laboratory of the Federal University of Rio Grande do Norte, Brazil. Both mechanical tests performed were conducted under inundated conditions, willing to reduce the influence of soil suction. An evaluation of the results of the tests performed shows that RPP is a fine material, with grain size distribution smaller than 0,015mm, composed mainly of silica and alumina, and particles in angular shape. The soil was characterized as a clayey sand, geologically known as a lateritic soil, with high percentages of alumina and iron oxide, and particles with rounded shape. Both the Soil and the blends presented low plasticity, while the residue showed a medium plasticity. Direct shear tests showed that the addition of RPP did not cause major changes into blends’ friction angle data, however, it was possible to note that, for the proportions studied, that is a tendency of obtain lower shear stresses for higher percentages of RPP in the blends. Both pure soil and 5% mixture showed a punching disruption for the Plate load test. For this same test, the allowable stress for 5% mixture was 44% higher than the pure soil, and smaller vertical settlement results for all stresses.

Obtenção e caracterização de um compósito polimérico de matriz poliéster e reforço/carga de tecido plano de algodão

He was obtained and studied the feasibility of using TPA (Tissue Cotton Plan) screen type, for bagging, with a weight of 207.9 g / m2 in a composite of orthophthalic crystal polyester resin matrix. The process for obtaining the composite was tested against the maximum number of layers that could be used without compromising the processability and manufacturing of CPs in compression mold. Five configurations / formulations were selected and tested at 1, 4, 8, 10 and 12 layers of cotton tissue - TPA. TPA was not subjected to chemical treatment, only by passing a mechanical washing process. The composite in its various configurations / formulations was characterized to determine its physical properties. The properties of the composite were higher viability resistance to bending, approaching the matrix and impact resistance, superiority in relation to the polyester resin. Another property that has shown good result compared to other composite has water absorption. Analyzing all the properties set the settings / formulations with higher viability were TA8 and TA10, by combining good processability and higher mechanical strength, with lower loss compared to polyester resin matrix. The composite showed lower mechanical behavior of the resin matrix for all the formulations studied except the impact resistance. The SEM showed a good adhesion between the layers of TPA and polyester resin matrix, without the presence of micro voids in the matrix confirming the efficient manufacturing process of the samples for characterization. The composite proposed proved to be viable for the fabrication of structures with low requests from mechanical stresses, and as demonstrated for the manufacture of solar and wind prototypes, and packaging, shelving, decorative items, crafts and shelves, with good visual appearance.

Obtenção e caracterização de um compósito polimérico de matriz poliéster e reforço/carga de tecido plano de algodão

He was obtained and studied the feasibility of using TPA (Tissue Cotton Plan) screen type, for bagging, with a weight of 207.9 g / m2 in a composite of orthophthalic crystal polyester resin matrix. The process for obtaining the composite was tested against the maximum number of layers that could be used without compromising the processability and manufacturing of CPs in compression mold. Five configurations / formulations were selected and tested at 1, 4, 8, 10 and 12 layers of cotton tissue - TPA. TPA was not subjected to chemical treatment, only by passing a mechanical washing process. The composite in its various configurations / formulations was characterized to determine its physical properties. The properties of the composite were higher viability resistance to bending, approaching the matrix and impact resistance, superiority in relation to the polyester resin. Another property that has shown good result compared to other composite has water absorption. Analyzing all the properties set the settings / formulations with higher viability were TA8 and TA10, by combining good processability and higher mechanical strength, with lower loss compared to polyester resin matrix. The composite showed lower mechanical behavior of the resin matrix for all the formulations studied except the impact resistance. The SEM showed a good adhesion between the layers of TPA and polyester resin matrix, without the presence of micro voids in the matrix confirming the efficient manufacturing process of the samples for characterization. The composite proposed proved to be viable for the fabrication of structures with low requests from mechanical stresses, and as demonstrated for the manufacture of solar and wind prototypes, and packaging, shelving, decorative items, crafts and shelves, with good visual appearance.