923 resultados para Cimento composto


Relevância:

20.00% 20.00%

Publicador:

Resumo:

The use of sewage sludge as a raw material falls within the waste recycling key in the current process model environmental sustainability .Waste recycling has been consolidated as a sustainable environmentally sound technical solution, and. Despite showing very variable composition and characteristics, sewage sludge, can be considered as a residue with a high recycling potential in the building sector. In this paper the feasibility of using sewage sludge ash was studied in addition to Portland cement mortar in 1:3 mass considered the standard dash. This gray additions were studied in proportions of 5%, 10 %, 15 %, 20 %, 25% and 30% by mass of cement. The methodology was focused on the characterization of materials by physical, chemical , mechanical , environmental and morphological followed by the production of mortar tests ,and finalized by the characterization tests of mortar in the fresh state, through the consistency index, content of entrained air, bulk density and water retention, and in the hardened state by bulk density, water absorption by capillarity capillarity coefficient, compressive strength, tensile strength in bending ,tensile bond strength and microstructural analysis for percentages of 0 to 20%. After comparing with the standard mortar mortars with addition of ash, it is concluded that the ash of sewage sludge did not impair the integrity and properties of mortars with addition, including increasing resistance to compression and tension, being 20% more indicated percentage. Thus, it becomes feasible the addition of sewage sludge ash in Portland cement mortar for the trait studied

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Objetivou-se neste trabalho, comparar a resistência à compressão de tijolos de solo-cimento fabricados com o montículo do cupim Cornitermes cumulans (Kollar, 1832), com tijolos que utilizaram como matéria prima um NEOSSOLO QUARTZARÊNICO (Empresa Brasileira de Pesquisa Agropecuária (EMBRAPA), 1999), ambos submetidos a duas idades de cura (07 ou 28 dias). O experimento foi montado em delineamento inteiramente casualizado, em esquema fatorial 2x2, sendo analisados dois cofatores: a matéria prima base e a idade de cura. Os ensaios físicos e mecânicos obedeceram às prescrições das normas da Associação Brasileira de Normas Técnicas NBR-8492 (ABNT, 1982) e NBR-8491 (ABNT, 1984). Concluiu-se que a resistência à compressão dos tijolos foi maior com o aumento das idades de cura. O tratamento T4 apresentou maior valor de resistência à compressão, não diferindo estatisticamente dos tratamentos T2 e T1. Os tijolos fabricados com o montículo do cupim C. cumulans (Kollar, 1832) apresentaram diminuição da absorção de água com o aumento das idades de cura, o que normalmente corresponde a um maior aumento da resistência à compressão, ao contrário dos que utilizaram o NEOSSOLO QUARTZARÊNICO (Empresa Brasileira de Pesquisa Agropecuária (EMBRAPA), 1999).

Relevância:

20.00% 20.00%

Publicador:

Resumo:

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

Relevância:

20.00% 20.00%

Publicador:

Resumo:

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

Relevância:

20.00% 20.00%

Publicador:

Resumo:

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

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Relevância:

20.00% 20.00%

Publicador:

Resumo:

The study was carried out with the objective to evaluate the broccoli seeds (cultivar Ramoso Santana) germination and vigor from plants cultivated with different organic compost levels and after storage in dry chamber. At seed production stage, the experiment was conducted in randomized complete blocks design, with five treatments (0; 30; 60; 90 and 120 t ha(-1) of Biomix (R) organic compost) and four replications. Soon after harvesting and after 12 and 24 months of conservation in dry chamber room (20 degrees C and 40% relative humidity) it was evaluated germination, following seed analisys rules, and vigor (first count of germination and germination speed index - IVG). There were no differences in germination and vigor in seeds as soon as they were harvested and after 12 month of storage. After 24 months of storage, the lesser the organic compost rates, the lesser seed germination and IVG, with respective values, without compost, of 69% and 12,3. For another hand, the highest values for germination and IVG, 82% and 16,1, respectively, were obtained with the highest rate of organic compost (120 t ha(-1)).

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Thermal recovery methods, especially steam injection, have been used to produce heavy oils. However, these methods imply that the metallic casing-cement sheath interface is submitted to thermal cycling. As a consequence, cracking may develop due to the thermal expansion mismatch of such materials, which allows the flow of oil and gas through the cement sheath, with environmental and economical consequences. It is therefore important to anticipate interfacial discontinuities that may arise upon Thermal recovery. The present study reports a simple alternative method to measure the shear strength of casing-sheath interfaces using pushthrough geometry, applied to polymer-containing hardened cement slurries. Polyurethane and recycled tire rubber were added to Portland-bases slurries to improve the fracture energy of intrinsically brittle cement. Samples consisting of metallic casing sections surrounded by hardened polymer-cement composites were prepared and mechanically tested. The effect of thermal cycles was investigated to simulate temperature conditions encountered in steam injection recovery. The results showed that the addition of polyurethane significantly improved the shear strength of the casing-sheath interface. The strength values obtained adding 10% BWOC of polyurethane to a Portland-base slurry more than doubled with respect to that of polyurethane-free slurries. Therefore, the use of polyurethane significantly contributes to reduce the damage caused by thermal cycling to cement sheath, improving the safety conditions of oil wells and the recovery of heavy oils

Relevância:

20.00% 20.00%

Publicador:

Resumo:

New materials made from industrial wastes have been studied as an alternative to traditional fabrication processes in building and civil engineering. These materials are produced considering some issues like: cost, efficiency and reduction of nvironmental damage. Specifically in cases of materials destined to dwellings in low latitude regions, like Brazilian Northeast, efficiency is related to mechanical and thermal resistance. Thus, when thermal insulation and energetic efficiency are aimed, it s important to increase thermal resistance without depletion of mechanical properties. This research was conducted on a construction element made of two plates of cement mortar, interspersed with a plate of recycled expanded polystyrene (EPS). This component, widely known as sandwich-panel, is commonly manufactured with commercial EPS whose substitution was proposed in this study. For this purpose it was applied a detailed methodology that defines parameters to a rational batching of the elements that constitute the nucleus. Samples of recycled EPS were made in two different values of apparent specific mass (ρ = 65 kg/m³; ρ = 130 kg/m³) and submitted to the Quick-Line 30TM that is a thermophysical properties analyzer. Based on the results of thermal conductivity, thermal capacity and thermal diffusivity obtained, it was possible to assure that recycled EPS has thermal insulation characteristics that qualify it to replace commercial EPS in building and civil engineering industry

Relevância:

20.00% 20.00%

Publicador:

Resumo:

O presente trabalho objetivou avaliar a influência da adubação orgânica durante cinco safras, nas características de crescimento e produtividade de plantas de bananeira-'Prata-anã'. O experimento foi instalado no município de Botucatu-SP, em novembro de 2002, com mudas convencionais, adotando-se o espaçamento de 2,5 x 2,5 m, sendo as plantas adubadas com composto orgânico produzido a partir de serragem de madeira e esterco bovino devidamente compostados, que constituíram os tratamentos: 0; 43; 86; 129 e 172 kg de composto por planta, sendo estas doses de composto calculadas de acordo com o teor de potássio presente no composto. No florescimento das plantas em cada ciclo (2003, 2004, 2005, 2006 e 2007), foram medidas a circunferência do pseudocaule, a altura de inserção da inflorescência e determinou-se o número de folhas úteis por planta. Na colheita, foram determinados a massa do cacho, o número de frutos por cacho, o número de pencas por cacho, a massa da 2ª penca, o número de frutos na 2ª penca, o comprimento e o diâmetro de frutos da 2ª penca. As doses de composto orgânico não causaram alterações nas características de crescimento das plantas; contudo, em função dos ciclos avaliados, foi possível observar queda no número de folhas a partir do segundo ciclo e alterações na altura de plantas e circunferência do pseudocaule. No presente trabalho, onde as doses de K2O oscilaram entre zero e 394 g por planta, os cachos com massa mais elevada foram obtidos com as duas maiores quantidades de compostos aplicadas, o que, economicamente, indica como a melhor dose a ser recomendada a de 129 kg de composto por planta, que fornece 290,5 g de K2O por planta.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Composite materials can be defined as materials formed from two or more constituents with different compositions, structures and properties, which are separated by an interface. The main objective in producing composites is to combine different materials to produce a single device with superior properties to the component unit. The present study used a composite consisting of plaster, cement, EPS, tire, PET and water to build prototype solar attempt to reduce the manufacturing cost of such equipment. It was built two box type solar cookers, a cooler to be cooled by solar energy, a solar dryer and a solar cooker concentration. For these prototypes were discussed the processes of construction and assembly, determination of thermal and mechanical properties, and raising the performance of such solar systems. Were also determined the proportions of the constituents of the composite materials according to specific performance of each prototype designed. This compound proved to be feasible for the manufacture of such equipment, low cost and easy manufacturing and assembly processes

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Improving the adherence between oilwell metallic casing and cement sheath potentially decrease the number of corrective actions present/y necessary for Northeastern wells submitted to steam injection. In addition to the direct costs involved in the corrective operations, the economic impact of the failure of the primary cementing aIso includes the loss in the production of the well. The adherence between casing and cement is current/y evaluated by a simple shear tests non standardized by the American Petroleum Institute (API). Therefore, the objective of the present is to propose and evaluate a standardized method to assess the adherence of oilwell metallic casing to cement sheath. To that end, a section of a cemented oilwell was simulated and used to test the effect of different parameters on the shear stress of the system. Surface roughness and different cement compositions submitted or not to thermal cycling were evaluated. The results revealed that the test geometry and parameters proposed yielded different values for the shear stress of the system, corresponding to different adherent conditions between metallic casing and cement sheath

Relevância:

20.00% 20.00%

Publicador:

Resumo:

This work deals with the kinetics assay of Cajá (Spondias mombin L.) bagasse drying by an experimental design using a tray dryer. In order to add-value to this product a kinetic study has been carried out. A central composite experimental design has been carried out to evaluate the influence of the operational variables: input air temperature (55; 65 e 75ºC); the drying air velocity (3.2; 4.6 e 6.0 m/s) and the fixed bed thickness (0.8; 1.2 e 1.6 cm) and as response variable the the moisture content (dry basis). The results showed that the diffusional Fick model fitted quite well the experimental data. The best condition found has been input air temperature of 75ºC, drying air velocity of 6.0 m/s as well as fixed bed thickness of 0.8 cm. The experimental design assay showed that the main effects as well as the second ones were significant at 95% confindance level. The best operational condition according to statistical planning was 75 oC input air temperature, 6.0 m.s-1 drying air velocity and 0.8 cm fixed bed thickness. In this case, the equilibrium moisture content (1.3% dry basis) occured at 220 minutes

Relevância:

20.00% 20.00%

Publicador:

Resumo:

This study was conducted in the Sao Manuel experimental Farm, in Sao Manuel-SP, which belongs to the Faculdade de Ciencias Agronomicas (FCA) of the Universidade Estadual Paulista (UNESP), Botucatu/SP Campus, in order to evaluate the influence of organic compost doses, with and without added phosphorus to the soil, on the levels of macronutrients in plants and seeds of the lettuce cultivar Veronica. The experimental design was randomized blocks with ten treatments (0, 20, 40, 60, 80 Mg ha(-1) of organic compost, with and without 400 kg ha-1 P 2 0 5 added to the soil) and four replicates. The content of macronutrients in plants and seeds was evaluated. The data were submitted to analysis of variance and regression. The decreaning order of macronutrient content in plants was potassium > calcium > nitrogen > magnesium > phosphorus > sulfur and in seeds it was nitrogen > phosphorus > potassium > calcium > magnesium > sulfur. The nitrogen content in seeds, was about three and a half times higher than in plants, the sulfur was one and half times higher, while phosphorus content was approximately five times higher.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

This study had aim to evaluate influences of organic compost and phosphorus on lettuce seeds (cv. Veronica), measuring production and quality parameters of seeds in this species. Experimental design was in randomized blocks with 10 treatments, being 5 organic compost levels (0, 20, 40, 60, 80 t ha(-1) organic compost) combined with 2 phosphorus levels (0 and 400 kg ha(-1) P(2)0(5)), presenting 4 replicates. Parameters evaluated were seed mass, seed number, germination percentage, and vigor. Results obtained reveal that phosphorus application increased seed production. In the presence of phosphorus, the level of 33, 4 t ha(-1) of organic compost, and in the absence of phosphorus, the level of 49,21 t ha(-1), resulted higher seed weight per plant. The quality of seeds was not affected by fertilization with organic compost neither by phosphorus.