Fabiane Salles Ferro

Influence of Proportion Polyol/Pre-Polymer Castor-Oil Resin Components in Static Bending Properties of Particleboards Produced with Pinus sp.

The aim of this research is to evaluate the influence of castor-oil based polyurethane resin formulation (particularly proportion pre-polymer/polyol) in static bending properties of particleboards produced with Pinus sp. wood specie. Results related to modulus of rupture (MOR) and modulus of elasticity were determined. Four proportions polyol/pre-polymer were evaluated: 0.75:1; 1:1; 1:1.25; 1:1.5. Results showed improvement in MOR and MOE with increase of pre-polymer component. Proportion 1:1.25 (poliol: pre-polymer) was considered the most interesting once employs the least amount of the petroleum-derived component.

Comparação entre valores de ensaios experimentais e calculados da resistência ao embutimento da madeira de Pinus taeda L.

To design connections between timber parts with metal dowels (nails or bolts), two phenomena must be considered: bending of the metal dowel and the embedment strength in the wood. The Brazilian Standard ABNT NBR 7190:1997 proposes the methods used in the laboratory tests to determine the embedment strength with the metal dowell and, in the absence of testing, specifies relations to calculate the embedment strength from the compression strength. The aim of this research was to compare the embedment strength values obtained by experimental tests and calculated by the relationships established by the Brazilian Standard ABNT NBR 7190:1997. By the results of the hypothesis tests, it was possible to conclude that the estimate of the embedment strength parallel to the grain proposed by the Brazilian standard ABNT NBR 7190:1997, establishing equivalence with the strength compression results in the same direction, must be effective to the wood species Pinus taeda L., however, the same was not found in the perpendicular direction with respect to the grain, possibly explained by the αe values in the equation to calculed fe90.

Influência do teor de umidade na propriedade de tenacidade de espécies florestais

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.

Influência do Teor de Umidade na Propriedade de Tenacidade de Espécies Florestais / Influence of the Moisture Content of Some Wood Species on Toughness

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.

Modulus of Elasticity of Schizolobium amazonicum Wood Evaluated by Transversal Vibration Technique

Schizolobium amazonicum is being much used in Brazil for several purposes because, besides being a native Brazilian wood specie, has important features such as low density and small incidence of natural defects. At this point, researches with the purpose of obtaining further knowledge of their properties are being conducted to better targeting their use. The aim of this research is to evaluate the modulus of elasticity of structural size pieces of Schizolobium amazonicum wood using the technique of transverse vibration. Tests were carried out using 30 pieces (standard moisture content 12%) with sizes of 3 cm x 15 cm x 2.5 m. The average value of elastic modulus determined for lumber of Schizolobium amazonicum was interesting to its low specific gravity.

Hardness of the Schizolobium amazonicum Wood

Brazil has an infinity of native species that provide wood with good properties for use in civil engineering, industries and other segments. Schizolobium amazonicum Wood is a species that is much used in Brazil to manufacture of wood based-products. Researches regarding the properties are being performed in order to rationalize their use. The aim of this research is to determine the hardness of the Schizolobium amazonicum Wood in directions parallel and normal to the grains. The tests occurred in accordance with the Brazilian Code ABNT NBR 7190: 1997. The average values determined were interesting hardness upon the low specific gravity presented by Schizolobium amazonicum Wood.

Nondestructive Evaluation of Timber Columns of a Capela Bridge in the State of São Paulo, Brazil

After years of exposure in environmental conditions, the wood is subject to decay by chemical, mechanical, physical and biological agents. Consequently its physical and mechanical properties can be reduced, affecting their use. Timber used in bridge sustention columns is subject to intense decay process, mainly in outcrop area (area in contact to the ground), the most critical situation, because of the best combination of humidity e oxygen, factors that provide wood decay organisms. Decay process can be minimized with preventive maintenance, as wood impregnation with preservatives, before installation of the timber. After wood is installed, a periodical maintenance is necessary to conserve and prolong its life time. Thus, the aim of this study is to evaluate degradation occurred in timber columns used in Capela Bridge sustention, built with mixed system of wood and concrete, after 10-years-old of use. Located in Piracicaba - SP, Brazil, the bridge was made with Corymbia citriodora CCA-treated. The columns strength and degradation conditions were evaluated in 2 points with isntrumented driller. Point A was approximately 1,5 m of the ground and point B was in outcrop area. Instrumented driller results showed that all the columns, in both points, presented good strength and had no degradation level.

Environmental Life Cycle Assessment of industrial pine roundwood production in Brazilian forests

Pine (Pinus oocarpa) wood has great economic importance in Brazil. Pine stands represent the second largest reforested area in the country due to their industrial interest. Combining the relevance of industrial pine stands in the country and corresponding environmental concerns, this current study aims to identify and quantify the environmental impacts derived from industrial pine roundwood production in Brazil. The environmental study was developed considering the Life Cycle Assessment (LCA) methodology according to ISO14040 framework. The study convers the life cycle of pine roundwood production from cradle-to-forest gate perspective and considers the current practices in the country. The production system was divided in five main stages: Soil preparation, seedlings plantation, forest management, forest harvesting and infrastructure establishment. The environmental profile was estimated considering characterization factors from the ReCiPe method, in terms of twelve impact categories. According to the results, forest harvesting stage was identified as the environmental hotspot being the main responsible of contributions to nine impact categories under assessment with contributing ratios ranging from 21% (e.g., freshwater eutrophication) to 76% (e.g., photochemical oxidants formation). The high amount of fossil fuel required by heavy machinery used in the activities involved in this stage is behind this result. Soil preparation stage reported also an outstanding contribution in categories such as freshwater eutrophication (37%) and toxicity related categories (≈35%). The rationale behind these contributions is associated with the use of chemical fertilizers, mostly superphosphate. The identification of the environmental hotspots in forest biomass production can assist the Brazilian forest practitioners to improve the environmental profile by means of the optimization of forest practices.

Effect of Alternative Wood Species and First Thinning Wood on Oriented Strand Board Performance

This study aimed to evaluate the feasibility of using and influence of alternative wood species such as Cambara, Parica, Pinus, and wood from first thinning operations on oriented strand board (OSB) physical and mechanical properties. Besides that, an alternative resin, castor oil-based polyurethane, was used to bond the particles, due to the better environmental performance when compared to other resins commonly used worldwide in OSB production. Physical properties such as the moisture content, thickness swelling, and water absorption, both after 2 and 24 hours of water immersion, and mechanical properties such as the modulus of elasticity and resistance in static bending, in major and minor axes, and internal bonding were investigated. All tests were performed according to European code EN 300:2006. Results showed the influence of wood species on physical and mechanical properties. Panels made with higher density woods such as Cambara presented better physical performance, while those made with lower density woods such as Pinus presented better mechanical properties. Besides that, strand particle geometry was also influenced on all physical and mechanical properties investigated. Therefore, the feasibility of using alternative species and wood from first thinning and with castor oil-based polyurethane resin in OSB production was verified.

Compression Strength of Brazilian Exotics Wood Species Perpendicular to the Grain

Wood is a natural material that present variability of their properties. When used as ties in railways or as bridges decks, wood is request with compressive loads in direction perpendicular to the grain. The aim of this research is determining the compressive perpendicular to the grain strength (fc90) of two Brazilian exotic wood species. Tests were carried out using wood of Corymbia (Corymbia citriodora) and Pinus (Pinus taeda L.). Specimens and test methods were realizes according to Brazilian Standard Code ABNT NBR 7190:1997 (specimens at 12% of moisture content). Compressive perpendicular to the grain strength values to Corymbia and Pinus were equal to 17.00 MPa and 3.60 MPa, respectively. More studies about mechanical and physical properties of wood is important to rationalize their uses and provide greater knowledge about this material.