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In Brazil, the characterization of solid wood for structural design must be carried out according to the recommendations of the ABNT NBR 7190:1997 standards. Studies about alternatives to improve reliability to test methods are always relevant. Thus, the present study aims to examine the bending modulus of elasticity of samples of three wood species: Canelão (Nectandra membranacea), Corymbia citriodora (Corymbia citriodora) and Angelim (Angelim sp). The results for Canelão and Angelim showed statistical equivalence between the methods at 5% significance level. However, for the Corymbia species, statistical differences of results for bending tests with three and four points were observed. More studies are recommended in order to investigate other wood species, different strength classes and moisture content ranges. No Brasil, a caracterização da madeira maciça para uso estrutural deve ser realizada de acordo com as recomendações da norma ABNT NBR 7190:1997. Estudos sobre alternativas para avaliar a confiabilidade dos métodos de ensaio são relevantes. Assim, este estudo objetiva determinar o módulo de elasticidade na flexão de amostras de três espécies de madeira: Canelão (Nectandra membranacea), Corymbia citriodora (Corymbia citriodora) e Angelim (Angelim sp.). Para tanto, foi planejada uma série de métodos de ensaio com base nos testes de flexão estática a três e a quatro pontos e para as duas faces de cada amostra de madeira. Os resultados foram estatisticamente equivalentes para as espécies Canelão e Angelim a 5.0% de nível de significância. Por outro lado, para a espécie de Corymbia foram identificadas diferenças de resultados nos testes de flexão a três e quatro pontos, e como sugestão foi recomendada a condução de mais estudos para investigar também este efeito em outras espécies de madeira, diferentes classes de resistência e variando a faixa de umidade. &nbsp

The concept of sustainable buildings addresses the environmentally efficiency, with respect to energy consumption, by adopting products that offer thermal insulation. Moreover, use of wastes from different materials also contributes to obtain products for this application. The volume of wastes from timber industry and those from tires are an environmental problem. This study aimed to production and characterization of particleboards using wastes from wood and tire rubber with castor-oil polyurethane resin. Panels were produced containing only wood and also with addition of tire rubber. The properties determined were density, modulus of rupture (MOR) and modulus of elasticity (MOE) in bending, according to Brazilian Code NBR 14810-3 (2006), and thermal conductivity. Statistical analysis was conducted in physical and mechanical properties. Panels containing wood were classified as low density (0.55 g/cm³), while those with wood and tire rubber resulted in medium density (0.78 g/cm³). For mechanical properties, the addition of rubber resulted in increased of MOR and reduction for MOE. Superior performance for thermal conductivity was achieved for panels produced only with wood. However, samples with a mixture of wood and tire rubber also showed consistent thermal conductivity with similar products. Considering the results obtained, panels containing wood and tire rubber addition have potential for application as thermal insulation.

Wood is a renewable source of structural material with high relative strength/weight, low energy production, which kidnaps and stores carbon in its production. The large use of wood is due to its special qualities as raw material for other products manufactured in residential construction or major works such as bridges, has been widely used in roofing for industrial and commercial buildings. Commercially there are limitations on the length of the wood, resulting from the extraction of tree trunks, thus requiring the adoption of binding elements is the use of self-tapping screws efforts required by side and which can be axial, shear, tensile or compression. Whereas in Brazil does not yet exist and the promising future of the product, this research aims to study the behavior of self-tapping screws together with Brazilian reforestation species ofPinusoocarpaandLyptus(softwood and hardwood). Rothoblaas self-tapping screws had a good penetration in both woods without requiring pre-drilling, the species of Lyptus wood showed the highest values of strength and the inclination of the screws, at 45 degrees showed the best results on either species of wood.

The segment of wood preservation is responsible for considerable waste generation, typically consisting of products not approved by quality control or post-consumer. Another type of waste to be considered is tire rubber, which accumulate due to deficiencies in logistics and fiscalization. Although it has been classified as intractable, tire rubber enables to add properties in products that promote the use of materials in particulate form. This study aimed producing and characterization of particulate composites containing CCB-treated Pinus sp. with addition of tire rubber, and castor oil-based polyurethane resin. Properties of particleboards were obtained according to Brazilian Code NBR 14810:2006. The results were compared by statistical analysis. It was observed that addition of tire rubber waste resulted in higher densities, and rubber proportion of 50% showed greater internal bond. In some cases, strength in bending of panels was in accordance with standards requirements and commercial products destined for acoustic conditioning, enabling different applications.

OSB panels were developed as a substitute for plywood. However, their properties in static bending, i.e. modulus of elasticity (MOE) and modulus of rupture (MOR) are often reduced. The aim of this study was to evaluate MOE and MOR of OSB manufactured with Pinus sp. and castor-oil based polyurethane resin, applying a wire mesh in order to improve those properties. Recommendations of normative document EN 310:1993 were obeyed. Results showed that mechanical properties considered are compatible with codes requirements and with values obtained by several authors in related literature. In static bending tests, the difference between parallel-to-grain MOE and MOR values of panels with and without wire mesh treatment was not significant. Statistical analysis reveals that the wire mesh pressing position does not affect MOE and MOR. However, these values are superior to those recommended, for OSB and plywood, by normative documents.

RESUMO – A utilizacao do preservante CCA (sais de cromo, cobre e arsenio) tem sido questionada devido ao impacto relacionado a dispersao, principalmente, do cobre e do arsenio para o ambiente, antes de sua completa fixacao na madeira. Outra questao se relaciona a disposicao indevida dos residuos provenientes da madeira tratada, viabilizando a lixiviacao devido a maior area passivel desses rejeitos sujeita a tal fenomeno. Este trabalho teve como objetivo a producao de paineis de particulas, avaliando o efeito da adicao de residuos de Pinus sp. tratado com sais de cromo, cobre e arsenio (CCA), em associacao com material da mesma especie sem preservantes, alem de alteracoes no teor de adesivo poliuretano a base de mamona empregado na producao. As propriedades dos paineis produzidos foram determinadas conforme recomendacoes da NBR 14810-3: 2006. Por meio de analise estatistica, observou-se que a adicao da madeira tratada proporcionou desempenho superior no inchamento em espessura (2 h), ao passo que esse insumo utilizado na mesma proporcao que a madeira sem preservantes foi significante, obtendo os melhores resultados na adesao interna. Os modulos de ruptura e de elasticidade na flexao nao sofreram influencia das variacoes nos insumos utilizados nos paineis. Os paineis, em grande parte, apresentaram-se em conformidade com os principais requisitos nesse âmbito, mostrando a possibilidade da utilizacao dos referidos insumos na producao, alem da obtencao de um produto com consideravel apelo ambiental. Palavras-chave: Pinus sp.; Paineis aglomerados; Tratamento CCA. PARTICLEBOARDS USING WASTES FROM CCA-TREATED Pinus sp. AND RESIN FROM BIOMASS

MDF in Brazil is an almost recent product, available in the market from the late '80s. The resin content appears as one of the factors that most influence the final properties of MDF panels. Identification of how these factors interact is very useful for improving performance and energy inputs, determining ideal resin content based on the desirable properties. This paper analyzes the most important properties of a MDF panel in the industry, in directions: perpendicular and parallel to the direction of production, thus verifying the homogeneity throughout the panel, according to EN 622-5, by determining the MOE and MOR in bending, draw perpendicular, swelling and water absorption. In the same way, it was analyzed if there is a direct relationship between the bending and tensile perpendicular to face properties. Results showed that the panels studied cannot be considered within the normative standards, despite having attended many of these requirements, for example, in presenting an MOE greater than the relevant standard. Through the analysis of variance, we observed the uniformity of properties in both directions studied. As a result of feedback from the wheel perpendicular and thickness swelling, can admit a bad distribution of the patch panel and a larger amount of paraffin, which was observed by the inconsistency between these properties. Through the low value in the analysis of R², we can say that there isn’t a correlation between the MOR in bending and tensile strength perpendicular.

Brazil cultural heritage is composed by numerous constructions that describe the various historical periods lived by country. Constructions arent in good conservation status, showing systematically some deterioration level of their structural elements, among them those of wood. Restoration process aims to preserve the identity of original cultural heritage. It is essential maintain structural characteristics related to mechanical loads response which are closely dependent on wood properties avoiding possible structural shocks. Wood deterioration can be characterized by fungi decay or termite attack. Depending on level and position of the deteriorated area in structural set, local interventions are enough to maintain structural integrity. Polymeric resins are material options that can be used when removed these deteriorated regions, requiring compatibility with wood to maintain structural elements properties. This paper aims use of a technical for restoring structural timber from historic buildings, based on removal of decayed regions and filling them with epoxy resin. To analyze restoration effectiveness, properties in static bending, according to Brazilian standard, were determined. Samples were produced containing one and three restorations along the specimens (105 cm in length and nominal square cross section of 4.5 cm side), on the same side. Samples of Pinus taeda with gaps generated in the specimens with dimensions of 1.10 cm in depth and 8 cm in length were tested, with restorations placed in central region. For grafting of these gaps bicomponent epoxy resin was employed, prepared by mixing components in 1:1.5 proportions. Resin was injected into splices and its cure occurred in a seven days period, using methodology restoration to simulate a situation in which these structural elements have been used. Samples were requested in static bending to obtaining the product of inertia, analyzing the amendment under the aspect of tractioned and as well under compressed edge. It is observed the viability of restoration using filling epoxy resin in timber samples, considering the mechanical performance and practicality of the methodology for local keeping.

USP - Universidade de Sao Paulo / EESC - Escola de Engenharia de Sao Carlos, Av. Trabalhador Saocarlense, n. 400

Questões ligadas ao desempenho térmico e acústico de edificações têm sido cada vez mais abordadas, num cenário em que ganham importância a economia de energia e o controle do ruído. O advento dos materiais compósitos propiciou o emprego de resíduos de processos que, aliados a materiais de origem renovável, contribuem para a obtenção de produtos de reduzido impacto ambiental. Neste contexto, o presente trabalho teve como objetivo a produção e caracterização de painéis de partículas e espuma poliuretana à base de óleo de mamona, para destinação em composições termoacústicas. Os painéis de partículas foram produzidos utilizando-se resíduos de madeira de Pinus sp., tratado com CCB (preservante de cromo, cobre e boro - base óxido), borracha de pneus inservíveis e adesivo poliuretano à base de óleo de mamona. Foram adotadas variações na produção dos painéis, quanto aos fatores: proporção e configuração da borracha, espessura e pressão de prensagem; verificando sua influência no desempenho dos painéis. As propriedades físicas e mecânicas dos painéis foram determinadas conforme a ABNT NBR 14810-3 (2006) e avaliadas segundo os principais requisitos de normas neste âmbito. Análises estatísticas (ANOVA) foram realizadas para verificação da influência dos fatores de produção, e de suas interações, nas propriedades físicas e mecânicas dos painéis. Também foram avaliadas a morfologia e estabilidade térmica dos painéis e espumas. O isolamento térmico foi avaliado pela determinação experimental da condutividade térmica. A absorção sonora dos painéis e espumas, em diferentes montagens, foi determinada por medições em câmara reverberante, conforme ISO 354 (1985). Os resultados das propriedades físicas e mecânicas dos painéis estiveram em grande parte condizentes com os documentos normativos. O teor de borracha e a sua interação com os demais fatores apresentaram influência estatística nas propriedades físicas e mecânicas dos painéis. A morfologia dos painéis e espumas permitiu visualizar sua adequação aos produtos propostos, por meio da porosidade. Em relação ao isolamento térmico e absorção sonora, os painéis e espumas, bem como as composições formadas, apresentaram desempenho coerente com produtos e normas utilizados como referência. Sendo assim, verificou-se a viabilidade de produção e aplicação dos painéis e espuma poliuretana à base de mamona em composições destinadas ao conforto termoacústico. Issues relating to thermal and acoustic performance of buildings have been increasingly addressed in a scenario where energy savings and noise control are essential. Advent of composite materials enabled the use of residues from production processes that, coupled with renewable source materials, contribute to obtain products with low environmental impact. So, this study aimed to the production and characterization of particleboards and castor-oil-based polyurethane foam, for thermo-acoustic compositions. Panels were produced with residues of Pinus sp., treated with CCB (chromium, copper and boron basic oxide preservative), tire rubber wastes and castor-oil-based polyurethane adhesive. Variations in the production parameters were adopted: proportion and configuration of tire rubber; panels thickness; and pressing pressure, to determine their influence on panel performance. Physical and mechanical properties of particleboards were determined based on ABNT NBR 14810-3 (2006) and evaluated according to the main requirements of standards in this area. Statistical analysis (ANOVA) was performed to check the influence of production factors, and their interactions, in those properties. Morphology and thermal stability of foams and panels were also evaluated. Thermal insulation was evaluated by experimental values of thermal conductivity. Sound absorption of the panels and foams, in different assemblies, was determined by measurement in a reverberation room, according to ISO 354 (1985). Results of evaluated panel properties were consistent with the normative requirements. The tire rubber content and its interaction with other factors influenced in almost all physical and mechanical properties of the particleboards. Morphology of the foams and panels permitted confirming their suitability to the proposed product by the porosity. With respect to thermal insulation and sound absorption, panels and foams as well as the correspondent compositions showed performance consistent to the references. Therefore, it was demonstrated the production feasibility and applying of studied compositions intended for the thermo-acoustic comfort.

O CCB (sais de cromo, cobre e boro) surgiu como alternativa ao CCA, apresentando menor toxicidade ao meio ambiente e em muitos casos conferindo excelentes propriedades mecânicas à madeira. Estima-se que, de 15 a 20% (aproximadamente 240 mil \'M POT.3\'/ano) da madeira tratada no Brasil atualmente sejam resíduos, considerando-se apenas aqueles provenientes do seu beneficiamento, desconsiderando os produtos pós-consumo. Por outro lado, o Brasil possui excelentes condições para a produção dos painéis aglomerados, com produção estimada atualmente em 2,5 milhões \'M POT.3\'/ano. Observando o crescimento do mercado de painéis à base de madeira e a constante busca por produtos sustentáveis, este trabalho teve como objetivo principal a análise da viabilidade de produção de chapas de partículas, empregando-se resíduos de Pinus sp tratado com preservante CCB e resina poliuretana à base de mamona. Foram variados parâmetros de produção para obtenção de melhores condições de processo, sendo estes: quantidade de partículas, com 1300g e 1400g; teor de adesivo, de 12% e 15% e; tempo de prensagem, de 10 e 12 minutos. Caracterizaram-se as partículas empregadas quanto as suas propriedades físicas e morfológicas, além da análise dos painéis quanto às características físico-mecânicas, segundo NBR 14810-3 (2006), submetendo-se também amostras com melhores desempenhos ao Envelhecimento Artificial Acelerado, conforme ASTM G155 (1999) e análise da morfologia, por meio de ensaios de Microscopia Eletrônica de Varredura (MEV) e Porosimetria por Intrusão de Mercúrio. Determinou-se também a retenção dos ingredientes ativos de preservante nas partículas e chapas, para avaliação de possíveis perdas na retenção devido ao processo de prensagem. Os resultados apontaram para excelentes propriedades físicas e mecânicas das chapas de partículas, em alguns casos em média 50% superiores ao estipulado pela norma brasileira em questão e superiores aos requisitos das normas internacionais. Assim, ficou evidenciada a viabilidade de produção dos painéis com os insumos estudados bem como seu potencial de emprego para as finalidades compatíveis com produtos desta natureza. CCB (chromium, copper and boron sales) has risen as an alternative to CCA, because of its toxicity level and, in several cases, conferring high properties to treated wood. In Brazil, some evaluations show that nearly 15 to 20% (something like 240.000 \'M POT.3\'/year) of this wood are residues generated by processing phases, without taking in account pos-used product. Besides, Brazilian particleboard industry produces 2.500.000 \'M POT.3\'/year. Observing wood based panels demand improvement and sustainable products search, the aim of this work is to confirm feasibility of producing particleboards with CCB treated Pinus sp residues and polyurethane resin based on castor oil. Different production parameters were employed in order to optimize process conditions, like: particles (1300g and 1400g); adhesive percentage (12 and 15%); pressure time (10 and 12 minutes). Particles were characterized by their physical and morphological properties. Panels\' performance was determined based on their physical and mechanical properties, as prescript in Brazilian Code NBR 14810-3 (2006). Special specimens were used in order to evaluate influence of accelerated aging as proposed in ASTM G155 (1999). Morphological aspects were analyzed by Scanning Electron Microscopy (SEM) and Mercury Intrusion Porosimetry. Active ingredients retention was also determined to establish casual lost after producing process. Results show excellent physical and mechanical properties, some of them 50% higher than NBR14810-3 and international codes requirements. Feasibility of producing particleboards like those studied was demonstrated as well as potential of their employing in same uses of commercial boards.

Wood toughness is a mechanical property of interest in structural design where the load impact must be considered, finding a strong application in bridges, however, not an integral part of the mechanical properties commonly investigated in the characterization of this material. This study aimed to investigate with the aid of variance analysis, the influence of growth ring orientation to obtain toughness for Angelim Saia (Parkia pendula), Eucalyptus grandis, Pinus elliottii and Corymbia citriodora wood species, considering three different positions, so that the orientation causes tensile strength in fibers near the pitch, near the bark, and in the radial direction. The results of the statistical analysis revealed that there was no significance in the orientation of the growth rings to obtain the toughness of the wood species investigated, where the highest values were for Corymbia citriodora and the least values were for Pinus elliottii.

Este trabalho objetivou avaliar a viabilidade da produção de painéis OSB feitos com espécies de madeira da caatinga do nordeste do Brasil - marmeleiro (Croton sonderianus Muell. Arg.), jurema-branca (Piptadenia stipulacea (Benth.) Ducke) e catanduva (Piptadenia moniliformis Benth.) - e resina poliuretana bicomponente derivada de mamona. As propriedades investigadas foram: densidade aparente; inchamento em espessura e absorção de água, ambos em 2 h e 24 h; módulo de elasticidade e resistência na flexão, na direção paralela e na direção perpendicular ao painel; adesão interna e arrancamento de parafuso em relação à face, conforme as normas europeias EN. Os resultados das propriedades físicas e mecânicas obtidas evidenciaram a possibilidade da produção em laboratório de painéis OSB com as três espécies analisadas, conforme valores médios e variabilidade de propriedades equivalentes às chapas fabricadas em escala industrial, além de comparados aos requisitos da norma EN 300 (EUROPEAN..., 2006) para painéis dos tipos OSB/3 e OSB/4. Pela análise de variância, os painéis OSB fabricados com strands de madeiras de catanduva apresentaram os melhores resultados para as propriedades mecânicas; para as físicas, os melhores desempenhos foram provenientes dos painéis feitos com madeira de marmeleiro e jurema-branca. This research study aimed to evaluate the feasibility of OSB (Oriented Strand Board) production using wood species from the Brazilian Northeast's Caatinga: marmeleiro (Croton sonderianusMuell. Arg.), jurema-branca (Piptadenia stipulacea (Benth.) Ducke) and catanduva (PiptadeniamoniliformisBenth.) and castor-oil polyurethane bicomponent resin. The properties investigated were: density; thickness swelling and water absorption (2 hours and 24 hours); modulus of elasticity and bending strength in the parallel and perpendicular directions; internal bond and resistance to screw withdrawal from the face, according to EN standards. The results of the analysis of the physical and mechanical properties showed the possibility of manufacturing OSB with the cited species in the laboratory, according to the mean values and the variability of properties equivalent to those panels produced on industrial scale, and compared to EN standard requirements for OSB/3 and OSB/4. Variance analysis showed that OSB panels containing catanduva wood strands yielded the best results in terms of mechanical properties, as for the physical properties, the best performances were those of panels made with the marmeleiro and jurema-branca species.

OSB (Oriented Strand Board) is the most important development in the industry of wood products in recent years. However, mainly for reasons of cost industries use as adhesive resins that emit formaldehyde. Formaldehyde is considered a hazardous substance and its concentration indoors is restricted in many countries because of its reactivity, toxicity and pungent odor. This study aimed to attest the feasibility of production of OSB from resin with part of your component derived renewable resource (castor oil-based polyurethane) and Pinus sp. The panels were produced technically evaluated by determining their mechanical properties. In comparison to the minimum requirements of the European normative document EN 300 (2006), average values were higher than the panels for structural use in special wet environment (OSB/4) by up to 41% and 58% modulus of elasticity (MOE) and of modulus of rupture (MOR) in bending parallel to the grain, respectively. Adherence internal reached values at least three times higher than OSB/4.

The aim of this research was to produce and evaluate mechanical performance in compression parallel to the grain for composites made with wastes from Pinus sp. and Portland cement. To obtain the composites were used treated and untreated wood particles, average size 1.7mm, and Portland cement-II-E-32, determining a ratio for cement/wood/water of 1: 0.21: 0.6. Treatment of particles was based on thermal bath in water for a period of 6 hours. Effect of treatment on density and mechanical properties of these composites was analyzed, according to NBR 7215:1996. Results showed that inclusion of treated wood particles in manufacture of wood-cement composite was significant in all properties investigated, by reducing density (7%); increasing modulus of elasticity (126%) and compressive strength (70%). Large gains in these properties demonstrate the feasibility of wood-cement composites manufacture.

This research aimed verifies, with the aid of the analysis of variance (ANOVA), the influence of particles size of Eucalyptus grandis wastes in density and modulus of elasticity and strength modulus in compression of wood-cement composites. For this study was performed production and characterization of specimens, using portland cement, water and particle waste of Eucalyptus wood species, classified into sieves 10, 20, 32 and 60 mesh. The results of ANOVA showed significant differences in particle size, while samples with smaller particles had higher densities and lower mechanical performances. The composites studied have fully capable of being used as paving blocks, pavers or closure without the need for structural performance panels.

As especies utilizadas na arborizacao urbana requerem periodicas podas para atender aosrequisitos peculiares das essencias e para garantir a seguranca em relacao as redes eletricase de telefonia. O grande volume de material oriundo das podas tem potencial para, naforma de particulas, ser empregado na producao de paineis para emprego na confeccaode moveis e para aplicacao como componente de edificacoes. No presente trabalho, utilizaram-se residuos de poda de arvores de Canelinha (Nectandra lanceolata), obtidos na cidadede Sao Carlos (SP). Foram produzidos paineis de madeira aglomerada, tendo comoadesivo a resina poliuretana bicomponente a base de oleo de mamona, desenvolvida noInstituo de Quimica de Sao Carlos, da USP. Os parâmetros de processo foram: particulasde dimensao maxima 2,8 mm; porcentagem de adesivo 16%; temperatura de prensagem:90oC; tempo de prensagem: dez minutos. Os ensaios para avaliacao do desempenho dospaineis produzidos foram feitos de acordo com as recomendacoes da NBR 14810:2006,da Associacao Brasileira de Normas Tecnicas. Os resultados evidenciaram a viabilidadetecnica da referida producao, pois boa parte dos requisitos normativos foi atingida. Ajustesnos parâmetros de processo, principalmente no que tange a temperatura de prensagem,serao necessarios para que os paineis atendam a todos os requisitos da NBR 14810:2006

A tenacidade da madeira é uma propriedade mecânica de interesse em situações em que o carregamento por impacto deve ser considerado, encontrando aplicação em silos, pontes e fôrmas para estruturas de concreto armado. Apesar das recomendações do Anexo B - NBR 7190:1997, não tem sido usual a determinação da tenacidade na caracterização da madeira. Este trabalho objetivou investigar a influência do teor de umidade (30; 20; 12; 6; 0%) na obtenção da tenacidade da madeira angelim-saia (Vatairea sp), Eucalyptus grandis, Pinus elliottii e Corymbia citriodora, considerando a orientação dos anéis de crescimento em relação à direção da força de impacto. Análises estatísticas dos resultados por análise de variância (ANOVA) e teste de Tukey revelaram ser significativa a influência do teor de umidade na tenacidade apenas para a madeira de angelim-saia. Para as demais espécies, a análise estatística demonstrou resultados estatisticamente equivalentes, ou seja, o teor de umidade não foi influente na propriedade de tenacidade. Neste sentido, foi observado que o teor de umidade pode ser significativo na obtenção da tenacidade conforme a espécie e que maiores teores podem fornecer valores superiores desta propriedade. Wood toughness is a mechanical property of interest in structural design where load impact must be considered, as in the construction of silos, bridges and formwork for reinforced concrete structures. However, toughness is not an integral part of the mechanical properties commonly investigated in the characterization of this material. This study aimed to investigate, with the aid of analysis of variance and Charpy pendulum test, the influence of moisture content (30; 20; 12; 6; 0%) to obtain the toughness of angelim saia (Vatairea sp), Eucalyptus grandis, Pinus elliottii and Corimbia citriodora wood species, considering the orientation of growth rings in relation to the direction of impact load. Statistical analysis carried out using ANOVA and Tukey test revealed significant influence of moisture content on toughness only with respect to angelim saia wood. Statistical analysis also showed equivalent results for the other three species, that is, moisture content did not significantly influence toughness. Thus, we conclude that moisture content may be significant in obtaining toughness according to the wood species analyzed and higher moisture content can provide higher values of toughness.

Os elementos estruturais utilizados na construção civil devem ser projetados para atender aos requisitos de desempenho mecânico, durabilidade e resistência ao fogo. Os principais atributos do concreto de alta resistência (CAR) são sua maior resistência mecânica e durabilidade, características estas fundamentais para o desempenho de uma edificação. Todavia, dada sua baixa porosidade, o CAR tem menor resistência ao fogo quando comparado com concreto de resistência normal (CRN), ou seja, é mais propenso a sofrer ruptura, normalmente explosiva, expondo a armadura da estrutura. Sendo assim, este trabalho tem o objetivo estudar a influência das altas temperaturas sobre as propriedades mecânicas residuais e a durabilidade do concreto de alta resistência com e sem adição de fibras de polipropileno, bem como analisar a possível ocorrência dedesplacamento(spalling). Para isso, foram realizados testes em corpos de provas cilíndricos em fornos de aquecimento para temperaturas crescentes, que variaram de 100 °C a 800 °C à taxa de aquecimento constante de 1 °C/min, permanecendo por 60 minutos na temperatura preestabelecida e então sendo submetidos à taxa de resfriamento constante de 1 °C/min. Posteriormente, foram realizados os ensaios destrutivos e não destrutivos e as análises laboratoriais. Quando comparados com o CAR sem o uso de fibras, os resultados mostraram que o uso de 2 kg/m3 de fibras de polipropileno no CAR melhorou a resistência à compressão até a faixa de temperatura de 400 °C e a resistência à tração até próximo de 200 °C, enquanto na temperatura ambiente houve um ligeiro aumento do módulo de elasticidade. Constatou-se também a eficiência do uso das fibras de polipropileno no CAR nos resultados de ensaios de durabilidade, como o ultrassom até aproximadamente 200 °C, bem como melhorias nos resultados do ensaio de resistividade elétrica até a faixa de temperatura de 400 °C. Em contrapartida, nos ensaios de absorção e de perda de massa, o CAR sem o uso de fibras teve melhor desempenho. Em elevadas temperaturas os resultados demonstraram que o desempenho nas propriedades mecânicas residuais e a durabilidade entre o CAR com e sem fibras de polipropileno são praticamente similares. Na observação física da superfície das amostras após o ensaio de aquecimento entre 600 °C e 800 °C, foi possível identificar como o uso de fibra de polipropileno no CAR leva a reduções nas fissuras e poros na superfície, quando comparada com o CAR sem o uso de fibras. Quanto à análise de microestrutura, verificou-se o surgimento de canais na estrutura de concreto pelo derretimento de fibras de polipropileno após o ensaio de aquecimento das amostras de CAR-FP (concreto de alta resistência com fibras de polipropileno). Além disso, não houve spalling em nenhum ensaio de aquecimento para as amostras de CAR com e sem fibras de polipropileno. Structural elements when used in civil construction must be designed to meet the requirements of mechanical performance, durability, and fire resistance. The main attributes of high-strength concrete (HSC) are its greater mechanical strength and durability, which are fundamental to the performance of a building. However, given its low porosity, the HSC has lower fire resistance when compared to normal strength concrete (NSC), i.e., it is more prone to rupture, usually explosive, exposing the structure's reinforcement. Therefore, this work aims to study the influence of high temperatures on the residual mechanical properties and the durability of HSC with and without the addition of polypropylene fibers, as well as to analyze the possible occurrence of spalling. For this, tests were performed on cylindrical specimens in heating furnaces for increasing temperatures, which varied from 100 °C to 800 °C at a constant heating rate of 1 °C/min, remaining for 60 minutes at the pre-established temperature and then being submitted to a constant cooling rate of 1 °C/min. Subsequently, destructive and non-destructive tests and laboratory analyses were performed. When compared to the HSC without the use of fibers, the results showed that the use of 2 kg/m3 of polypropylene fibers in the HSC improved the compressive strength up to the temperature range of 400 °C and the tensile strength up to around 200 °C, while at room temperature there was a slight increase in the elastic modulus. The efficiency of the use of polypropylene fibers in the HSC was also verified in the results of durability tests, such as ultrasound up to approximately 200 °C, as well as improvements in the results of the electrical resistivity test up to the temperature range of 400 °C. On the other hand, in the absorption and mass loss tests, the HSC without the use of fibers performed better. At high temperatures, the results showed that the performance in residual mechanical properties and durability between the HSC with and without polypropylene fibers are practically similar. In the physical observation of the surface of the samples after the heating test between 600 °C and 800 °C, it was possible to identify how the use of polypropylene fiber in the HSC leads to reductions in cracks and pores on the surface when compared to the HSC without the use of fibers. As for the microstructure analysis, it was verified the appearance of channels in the concrete structure by the melting of polypropylene fibers after the heating test of the HSC with fibers samples. In addition, there was no spalling in any heating test for the HSC samples with and without polypropylene fibers.

A madeira é muito empregada em diferentes campos, dentre os principais tem-se a construção civil, visto que a relação entre resistência mecânica e densidade, para a madeira, é das mais altas no caso dos materiais empregados na construção civil. Neste sentido, o Brasil se encontra em posição favorável, pois já dispõe diversas áreas certificadas para extração de madeiras, no âmbito da Floresta Amazônica. A fim de obter as melhores respostas na utilização desse material, necessita-se de sua completa caracterização. Entretanto, com a anisotropia e a heterogeneidade da madeira, muitas propriedades devem ser determinadas, o que exige equipamentos específicos, técnicos especializados e, por conseguinte, o tempo despendido é considerável. Neste contexto, é urgente a definição de procedimentos que tornem mais expedita e igualmente confiável a caracterização. No presente estudo foi avaliada, de forma inédita, a possibilidade de propriedades físico-mecânicas da madeira se relacionar com parâmetros como porosidade, densidade aparente e componentes químicos (celulose, hemicelulose, lignina, extrativos e cinzas). Foram caracterizadas dez espécies tropicais de madeira, por meio dos ensaios descritos no Anexo B da Norma ABNT NBR 7190/1997. Os componentes químicos foram determinados pelo método Klason modificado, a partir da norma TAPPI T-222 om-02, e a porosidade pela intrusão de mercúrio. A partir dos resultados, foram aplicados modelos de regressão multivariadas, dos quais se obtiveram equações para estimar cada propriedade a partir das diversas variáveis fixas (densidade aparente, porosidade e componentes químicos). Nas relações encontradas verificaram-se ótimos resultados como, por exemplo, a equação que estima a resistência à compressão paralela às fibras (fc0) levou a R² 99,69%. Deste modo, a hipótese inicial se confirmou, o que possibilita a estimativa confiável das propriedades estudadas com os parâmetros citados. Wood is a very used material in different fields, among them civil construction can be highlighted, since the relation between mechanical strength and density for wood is the highest in the case of building materials. In this sense, Brazil is in a favorable position, as it already has several areas certified for timber extraction, within the Amazon Forest. In order to obtain the best responses in the use of this material, its complete characterization is required. However, due to wood anisotropy and heterogeneity, many properties must be determined, which requires specific equipment sets, technical expertise and therefore time spent is considerable. In this context, it is urgent to devise procedures that make more expeditious and equally reliable the wood characterization. In the present study, it was considered the possibility of wood physical-mechanical properties can be estimated in an unprecedented way, based on parameters such as porosity, chemical components (cellulose, hemicellulose, lignin, extractives and ash) and density. Ten tropical wood species were characterized by tests described in Annex B of ABNT NBR 7190/1997. Chemical components were determined by the modified Klason method, from TAPPI standard T-222 om-02 and the porosity by the intrusion of mercury. To the results, multivariate regression models were applied and equations were obtained to estimate each property from the several fixed variables (apparent density, porosity and chemical components). Very great results were reached from these relationships, for example, the equation that estimates strength in compression parallel to the grain (fc0) led to R² 99.69%. Thus, the initial hypothesis was confirmed, which allows the reliable estimation of the studied properties with the mentioned parameters.