Architectural proposal for the rehabilitation and improvement of the houses of the city Yagúl housing unit, Oaxaca

This article presents the results of an investigation carried out in the Yagul city housing unit in the state of Oaxaca, in order to study the deterioration problems that have caused the abandonment of the houses, and in this context, to propose strategies that solve these problems in addition to improving the quality of life of the inhabitants. For this investigation, non-destructive tests were carried out on the houses of the place, such as: Concrete compression resistance test using a digital sclerometer, temperature tests with a thermographic camera and infrared digital thermometer, detection of reinforcements using a portable Pachometer and soil mechanics. The results obtained have allowed us to know the current state of the houses and based on these data, make an architectural proposal for the rehabilitation and improvement of said houses, generating a bioclimatic environment and comfort for its inhabitants.

Uso de Resíduo Madeireiro Amazônico na Fabricação de Tijolos de Solo-Cimento no Município de Alta Floresta – MT / Timber Residue Use in the Manufacture of Soil-Cement Bricks for Civil Construction in the City of Alta Floresta- MT

Resumo: A discussão sobre edificações sustentáveis vem sendo abordada há décadas por diferentes autores, em geral com foco no consumo energético e na vida útil dos materiais, contudo para atender esses objetivos são necessárias novas tecnologias que promovam mais sustentabilidade. Para tanto, a inclusão de fibras vegetais em compostos de solo-cimento se mostram uma alternativa interessante, e pelo fato do setor industrial madeireiro movimentar a economia local no município de Alta Floresta o resíduo serragem passa a ser um possível agregado nos tijolos ecológicos, uma vez que o armazenamento inadequado deste resíduo pode causar sérios impactos ambientais, portanto, este estudo se propôs a desenvolver um tijolo ecológico fabricado a partir da mistura de solo-cimento e serragem de três espécies florestais da Amazônia, Cambará - Vochysia sp., Cedrinho - Erisma uncinatum Warm., Garapeira. - Apuleia sp, e ainda avaliar a resistência a compressão com intervalos de cura de 7, 14, 21 e 28 dias, com o intuito de verificar a viabilidade do material construtivo. Para a realização do experimento, os tijolos foram fabricados com traço de 1:8:2,5, (cimento: solo: serragem) e a serragem utilizada com dois tratamentos, in natura e tratada por imersão e padronização granulométrica. O material misturado foi compactado em uma prensa hidráulica. Como resultado, os tijolos com serragem apresentaram valores de resistência mecânica de: Cedrinho 1,26Mpa, Cambará 1,70Mpa e Garapeira 1,95Mpa e teores de absorção de umidade de 15,7%, 17,6% e 13,8%, respectivamente.Palavras-chave: Sustentabilidade. Tijolo solo-cimento. Serragem. Abstract: The discussion about sustainable edifications has been addressed in decades by different authors, generally focusing energetic consume and the materials lifespan, however to reach these goals it is necessary new technologies that promote more sustainability. For that the inclusion of vegetal fibers in soil-cements composts present as an interesting alternative, and because the timber industry moves the local economy in the city of Alta Floresta the sawdust residue become a possible aggregate of ecologic bricks since inadequate storage of this material can cause serious environment impacts, therefore this study propose to develop an ecologic brick manufactured by the mix of soil-cement and sawdust of three Amazonian species: Cambará - Vochysia sp., Cedrinho - Erisma uncinatum Warm, Garapeira. - Apuleia sp., and also evaluate the compression resistance in 7, 14, 21, 28 days intervals, aiming to verify the feasibility of the constructive material. To carry out the experiment the bricks were manufacture with the ratio of 1:8:2,5 (cement: soil: sawdust), and the sawdust used was treated twice, in natura, treated by immersion and granulometric standardization. The mixed material was compacted in a hydraulic press. As a result, the sawdust bricks showed resistance values of: Cedrinho 1.26 MPa, Cambará 1.70 MPa and Garapeira 1.95 MPa and humidity absorption percentage of 15.7%, 17.6%, and 13.8% % respectively.Keywords: Sustainably, Ecologic Brick, Sawdust

EFFECT OF MICROSTRUCTURE OF CARDBOARD ON ITS MECHANICAL PROPERTIES

The article is devoted to the prediction of mechanical properties on the study of the microstructure of the cross section of cardboard. The results of the work in the future can be used as an addition to standard methods for evaluating the mechanical properties of cardboard. On the basis of images of the microstructure of the cross sections of the two-layer test liner cardboard and their graphic processing using modern computer programs, the lengths of fiber contacts were determined. Guided by the fact that the most significant indicator of all geometric parameters of the microstructure is the length of fiber contacts, the main mechanical properties of cardboard were determined (bursting strength and compression resistance, breaking length, bending stiffness, interlayer strength)produced according to various technologies (conventional method of preparing recovered paper stock, dry defibration of recovered paper with aerodynamic formation of the top layer, dry defibration of recovered paper with subsequent supply of fibers to the stock and dry defibration of recovered paper with subsequent grinding in the stock). Each of the technologies allows to obtain cardboard with different mechanical parameters. It has been established that almost all mechanical indicators depend directly proportionally on the length of the fiber contact lines. The obtained dependencies can be used to predict the mechanical properties of cardboard in its production at industry enterprises.

Production and Physical–Mechanical Characterization of Peat Moss (Sphagnum) Insulation Panels

Peat moss (sphagnum) is a commonly used sealant, fill, and insulation material in the past. During the efforts to rewet drained moors due to ecological considerations, the technical use of peat moss (sphagnum farming) again became the focus of attention. In the framework of this investigation, insulation panels consisting of peat moss, bound with urea formaldehyde, were produced. Panels manufactured in a wet process and mats bound with textiles were also fabricated. The specimens’ thermal conductivity, water vapor diffusion resistance, modulus of rupture, modulus of elasticity, internal bond, compression resistance, water absorption, and thickness swelling were measured. Physical–mechanical properties were adequate with the resin-bound panels, but not with wet process panels. Moss mats had good characteristics for cavity insulation purposes. The thermal conductivity of the moss panels and mats was found to be lowest with a density of 50 kg/m³, accounting for 0.04 W/m·K. The results show that peat moss is a promising resource for production insulation panels, because their thermal conductivity and mechanical stability are comparable to other insulation materials.

RESISTANCE TO VIBRATION OF WOOD TEMPERATURE POLYMER COMPOSITE MATERIAL

In this work, a wood composite material is considered, which incorporates all the best properties of the known wood polymer composites: water resistance, moisture resistance, high bending strength. It was concluded that according to the criterion of resistance to temperature fluctuations, it is possible to give more complete recommendations on the optimal composition of the wood polymer composite material based on a two-factor study. To ensure comparability of optimization results for a number of other properties, a series of computer experiments was carried out according to the same plan as for the study of compression resistance, that is, the concentration of wood and at the same time the concentration of sand was changed from 10 to 50 % with a step of 10 %, respectively. The material has acquired new advantages, which do not have known analogues – the possibility of using any wood waste, higher strength due to the content of sand in the composition, cheaper production due to the fact that most of the components of the material are household and wood waste, namely waste from the woodworking and forestry industries in the form of chips, sawdust, chips, lump waste, as well as sand, which is a publicly available and inexpensive material.

Al-Based Foams as Permanent Cores in Al Castings: Effect of Surface Skin Thickness and Composition on Infiltration and Core-Shell Bonding

An emerging and still poorly explored application of aluminum foams is their potential use as permanent cores (inserts) in the casting of aluminum alloys. In this context, Al-based foams can introduce a weight reduction, the obtainment of cavities, a strength increase, the ability to absorb impact energy and vibration, acoustic insulation ability, the possibility to simplify the technological processes (no removal/recycling of traditional sand cores), and finally, they can be fully recyclable. Cymat-type Al foams with thin outer skin were used as permanent cores in Al-alloy gravity casting in the present research. Al-foams were characterized in terms of porosity, density, cell wall and skin thickness, surface chemical composition and morphology, and compression resistance. Cast objects with foam inserts were characterized by means of optical microscopy. The preservation of up to 50% of the initial porosity was observed for foam inserts with higher density. Metallurgical bonding between the foam core and the cast metal was observed in some regions.