Propriedades mecânicas e durabilidade do concreto branco com adições pozolânicas

O presente trabalho tem a finalidade de verificar o comportamento do concreto de cimento Portland Branco com adição de metacaulim e sílica ativa, avaliando o comportamento mecânico, a absorção de água e o nível de porosidade e durabilidade em concretos com este aglomerante. Para isso, foram realizados ensaios no estado plástico (consistência e massa específica) e endurecido (resistência à compressão axial, resistência à tração por compressão diametral, módulo de elasticidade, absorção de água, penetração de cloretos e carbonatação). Foram realizadas avaliações de sua resistência à compressão axial e à tração por compressão dimetral nas idades de 7 e 28 dias através do método IPT/EPUSP que utiliza os traços 1:5, 1:3,5 e 1:6,5. O módulo de elasticidade aos 28 dias. Além destes foi avaliada a permeabilidade por meio de ensaio de absorção; durabilidade através do ensaio acelerado de cloretos e da carbonatação; a porosidade foi verificada com a realização da microscopia eletrônica de varredura. De maneira geral, verificou-se que mesmo a resistência dos concretos de menor proporção agregado/aglomerante (traço pobre), está acima das resistências mais usuais na região metropolitana de Belém que é em torno de 25 a 30 MPa, visto que o cimento branco utilizado é o estrutural, por isso, justifica-se o alcance destes valores mesmo com traço pobre. Com relação à permeabilidade, os resultados demonstraram que assim como a resistência, esta é dependente do tipo de cimento empregado e das adições utilizadas. Os valores mais elevados de permeabilidade foram obtidos nos concretos referência (sem adição). Para estudar a porosidade viu-se que concreto referência apresenta-se menos compacto e com mais poros perceptíveis, principalmente os com maiores proporções agregado/aglomerante. Já nas micrografias dos concretos CMT e CSA, é possível observar uma menor quantidade de poros na região ocupada pela pasta Por fim, foi feita uma comparação das propriedades mecânicas, capacidade de absorção de água e porosidade do Cimento Portland Branco (CPB).

Obtenção da liga Ti-35Nb por metalurgia do pó para utilização em próteses ortopédicas

Pós-graduação em Engenharia Mecânica - FEG

Influência do tratamento dentinário com Clorexidina, Ácido Hialurônico ou Vitamina C na resistência adesiva e propriedades mecânicas da camada híbrida

Pós-graduação em Odontologia Restauradora - ICT

Tubos de concreto com adição de resíduos de borracha de pneu

Pós-graduação em Engenharia Civil - FEIS

Processamento, caracterização microestrutural e propriedades elásticas de metais celulares do sistema Ti-6Al-4V para fins de regeneração óssea

Pós-graduação em Ciência e Tecnologia de Materiais - FC

Efeito de elementos substitucionais e intersticiais na microestrutura, dureza e módulo de elasticidade de ligas Ti-Nb

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Estudo da viabilidade do emprego do pó de mármore para produção de concreto autoadensável e substituição parcial dos agregados por pérolas de poliestireno expandido (EPS)

Pós-graduação em Engenharia Civil - FEIS

Painéis aglomerados fabricados com mistura de partículas de madeiras tropicais

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Efeito de tratamentos térmicos nas propriedades mecânicas, eletroquímicas e citotoxidade de ligas do sistema Ti-15Mo-XNb

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Efeito do oxigênio intersticial no módulo de elasticidade de Ligas Ti-15Mo-xZr(x=5,10,15%p)

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Painel particulado composto por casca de eucalipto na camada intermediária

This work was developed to evalute the physical and mechanical properties of a panel of three particle layers from the test specification of NBR 14810-3 (2006), using wood of Eucalyptus sp. and Eucalyptus saligna and Eucalyptus urograndis bark. The mechanical properties were evaluated to obtain the bending modulus of rupture (MOR) and modulus of elasticity (MOE) and Internal bond. The physical properties were obtained thickness sweeling, water absorption, moisture content and board density. Were evaluated four different compositions of panels containing 5, 10, 15 and 20% in the inner layer of bark. The results were compared with the Brazilian standard NBR 14810-2 (2006) and also with studies in the literature. The panels produced were adequate to all the optimal values suggested by the standard only in the composition with 5% skin in the inner layer. The other treatments showed satisfactory results in all tests except for moisture content

Desenvolvimento e caracterização de compósitos de fibras naturais modificadas e híbridos: fibras da coroa do abacaxi/polipropileno e fibras da coroa do abacaxi/fibras de vidro/polipropileno

The concern with the environment preservation has done with that researchers as well as industries invest in the search for materials that come from renewable sources. Natural fibers, because they are ecologically correct and have low cost, have been studied as a possible substitute, even if partial, of synthetic fibers in the development of polymeric composites. In this context, the hybrid composites (natural/synthetic) increase considerably the range of application of natural composites. The auto industry, in its constant quest for good mechanical properties materials which are developed with sustainability, has in composites with hybrid reinforcement a very viable alternative. In the present work, the nature Crown pineapple fibers and nature Crown pineapple fibers treated with alkaline solution were studied in order to evaluate the influence of chemical treatment in its properties. For this techniques were used x-ray diffractometry, Thermogravimetry and Infrared Spectroscopy (FTIR). Composites have been developed using polypropylene, reinforced with pineapple fibers and pineapple fibers hybrids/glass fibres, both with levels of 5 and 10%. These composites were analyzed by Thermogravimetry techniques and tested by traction. The realization of this work indicated that although the chemical treatment did not affect the thermal stability of the fibers, caused an increase in crystallinity index fibers and decreased its hydrophilic. The tests performed on composite indicated that the composites process was suitable because it provided good dispersion of the polymer matrix. The addition of natural fibers from the pineapple's Crown, in a proportion of 10%, provided the greatest increase in modulus of elasticity (27%) when compared to the pure polymer

Obtenção de constantes elásticas da madeira de duas espécies de Pinus sp

There are many studies about longitudinal modulus of elasticity of wood, but you can´t say the same of transverse modulus, especially for conifers. The study aimed to characterize and compare the species Pinus elliottii var. elliottii and Pinus elliottii var. elliottii x Pinus cariabeae hondurensis (hybrid), and the longitudinal modulus of elasticity (E) and lateral (G) in bending, to analyze the modulus of elasticity in different spaces and to verify the species studied the ideal range is equal to 21 times the height of the specimen, as prescribed in the normative document NBR 7190/1997, as well as analyzing the relationship G = E/20 defined in the normative document NBR 7190/1997. The wood came from the farm located in Paranapanema, split at the mill São José and the rest of the work was conducted at the Experimental Itapeva Campus - UNESP. Were removed fourteen specimens of each species. The average values of the modulus of elasticity and cross were, respectively, 5828 MPa and 452 MPa for Pinus elliottii var. elliottii and 6407 MPa and 320 MPa for the species of Pinus elliottii var. elliottii x Pinus cariabeae hondurensis (hybrid). The trend lines for the plotted graphs showed an exponential behavior to near linear 21he will equal the constant after this value. We have found the relationship G = E/13, for Pinus elliottii var. elliottii and G = E/20 for hybrid. The results of the modulus and strength for Pinus elliottii var. elliottii and the hybrid were lower than those reported in the literature, showing that this batch inferior quality to apply to structures

Análise da estabilidade dimensional e resistência mecânica em bambu Guadua angustifolia pós-processos de tratamentos químicos e térmico

Nowadays, bamboo is being studied because of their strength properties according with their specific mass and speed of growth, which makes it an important alternative as a new resource that will help reduce pressure on forests and helpping them favoring the minimization of uncontrolled deforestation in many regions of Brazil. This study aimed, in general, to analyze physical and mechanical properties of the material with the divulgation of its potential for industrial application. To do so, in this research were determined in relation to the physical properties, moisture content, dimensional stability and the apparent densities and the mechanics and basic, just a tension parallel to grain, in order to observe the interference of various kinds of treatments (chemical, thermal and natural) on the strength and modulus of elasticity in this request. The species used was the Guadua angustifolia, a species native of Brazil. All tests were performed at Universidade Estadual Paulista - Campus Experimental Itapeva in the laboratory of Materials Properties. The methodology used for testing of moisture, density and tension parallel to grain were based on NBR 7190/1997 for the wood, and dimensional stability tests were based on much the same as in COPANT 462/1972 (South American) . The preservative treatments conducted followed the recommendation of each manufacturer. The values obtained in tests of physical properties were satisfactory especially with respect to density and dimensional stability analyzed by the coefficient of anisotropy, showed that, compared to wood, excellent quality for the shrinkage test, obtaining a coefficient of 1.2. With respect to parallel tensile tests to fibre results showed, in most cases, that test specimens with the presence of us have lower values of resistance and modulus of elasticity when compared with those without us. In the treatment of thermal-treatment there was an apparent treatment there was an apparent increase in...

Caracterização físico-mecânica de elementos estruturais roliços perfilados de Amaru

The study of physical and mechanical properties of wood is essential for its structural use and it is of great importance to the construction industry. Thus, this study aimed to determine the physical and mechanical properties of the wood Amaru - a hybrid of Eucalyptus, developed by Plantar Projects and Forest Products Ltda. In order to determine the properties of Amaru, round samples were used, which were provided to the Laboratory of Wood and Wooden Structures of the School of Engineering of São Carlos, University of São Paulo - LaMEM / EESC / USP. For the characterization of the physical properties, the apparent specific gravity and moisture content of the samples were determined. To the mechanical characterization, the following properties were evaluated: strength and stiffness in compression, strength and stiffness in bending, shear and tension. The procedures of the tests performed in this study were done according to the recommendations of the Brazilian Wood Standard ABNT NBR 7190:1997. The specimen used were confectioned in actual dimensions, according to as those used in the construction system proposed by Plantar. The results obtained from the tests performed showed that the mechanical properties approached the values proposed by the Wood Standard NBR 7190. The visual grading was important to provide a primary idea about the failure modes to be obtained from the tests performed. The bending test showed the modulus of elasticity (MOE) and Modulus of Rupture (MOR), which resulted in 15822 MPa and 101,7 MPa, respectively. The compression test resulted in values Ec0,m and fc0, 15698 MPa and 50,7 MPa. The tensile strength (ft0) of this hybrid was calculated and its value obtained was 60,8 MPa. The shear strength (fv0) was 8,2 MPa. The results obtained from the tests are the basis for engineers and architects to design structures using wood species Amaru