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Technology, environment and sustainability Tecnología, medioambiente y sostenibilidad Tecnologia, meio ambiente e sustentabilidade Revista de Arquitectura (Bogotá) Recibido: marzo 15 / 2018 Disponibilidad de las técnicas constructivas de habitación en madera, en Brasil Availability of timber housing construction techniques in Brazil Disonibilidade das técnicas construtivas de moradia em madeira no Brasil

Due to the high dimensional variation of bamboo, the manufacturing of materials such as plywood and laminated bamboo produces a high amount of residues. The production of particleboards could be used to overcome this problem and become a viable solution to reuse the generated waste as a raw material to high value-added products. This study aimed to present an overview of the bamboo particleboard production, as well as the mechanical and physical properties of this material, followed by a review of the advances in its research and development. In general, independently of the resin or bamboo species utilization, several bamboo particleboards meet the mechanical properties requirements of international standards for wood-based medium-density particleboards. The main focus of this study is to provide a review, in order to support research groups interested in using new bamboo-based materials for the development of manufactured durable products.

The focus of this research was to study the utilization of residues from bamboo (Dendrocalamus giganteus) lamination in the manufacturing of panels for structural purposes. Bamboo particleboards were produced under three conditions: pure boards, reinforced with bamboo laminas, and with treated particles. Castor oil-based polyurethane was the resin binder, in view of using lower toxicity materials. The mechanical tests were performed according to Brazilian Standard (NBR) 14810-3 (2006) and European Standard (EN) 310 (2000). The results were superior to those recommended by these and other standards for internal adhesion resistance, modulus of rupture, and elasticity in static bending, as well as to the results of other studies. Starch treatment was an unnecessary stage. According to the conditions of this process, the studied panels showed a good potential for construction use. Moreover, the bamboo particleboards are an economically viable, environmentally friendly, and sustainable alternative for the use of waste generated during the processing of Dendrocalamus giganteus bamboo species, allied with castor oil-based polyurethane resin. The reinforced particleboard and its production process are being licensed as an Innovation Patent in Brazil, (BR 1020130133919-1-2013).

The economic exploitation of rubber tree (Hevea brasiliensis) usage is primarily directed toward latex extraction. After the productive life of the rubber tree forest, the managed area is harvested for planting reformulation. The harvested wood is most often used for energy generation purposes. The aim of this work was to study the feasibility of using rubberwood waste and castor oil-based polyurethane resin in the production of particleboards. Homogeneous and heterogeneous panels were made with nominal dimensions of 500 x 500 mm and thicknesses of 10 mm using particles from GT1 and RRIM600 clones of the rubber tree and 12% castor oil-based polyurethane adhesive. The panels were pressed at 140 °C for 12 min with 40 kgf/cm 2 specific pressure. Density, moisture content, thickness swelling, water absorption for 2 and 24 h, static bending, and internal bonding determinations were performed according to the Brazilian Standard (NBR) 14810-3 (2006) for the physicalmechanical panel characterization. The results show that using Hevea brasiliensis in particleboard production is viable. However, multilayer boards exhibited better results.

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Brazilian timber housing producers were evaluated through a survey, which was based on face-to-face interviewing supported by a semi-structured questionnaire. Derived from expansive research, this paper aimed to identify labor size and to characterize economic size from this production sector. The sampling process evaluated 50.95% (n = 107) of all producers (n = 210) whose performance was considered close to ideal. This sector is mostly concentrated in micro and small-scale companies, though a small portion of medium-sized companies owned by sole proprietors, families, or small groups of entrepreneurs does exist. Due to compact sizing, no producer was classified as an industry or a large corporation. The main contrast was indicated by the number of direct jobs, whose estimation was about 3,700 workers for the whole studied sector, representing 1% of the overall Brazilian timber industry. Around 95% of timber housing producers are considered micro or small from a labor perspective. Unprecedented information could support discussions for the creation of assertive public policies.