This work aimed to investigate the feasibility of using and mixing Toona ciliata, Eucalyptus grandis/ urophylla and Pinus oocarpa woods in OSB production. Three one-species and four mixed-species combinations were compared. Layer structure varied by positioning different wood species in the surface and core of the panels. Phenol-formaldehyde (PF) adhesive was applied at 9% for all OSB panels. Three-layer mats with mass proportion of 25/50/25% for surface/core/surface were produced. Pressing time was 8 min, under a 4 MPa pressure and temperature of 180 ˚C. Physical and mechanical properties were evaluated and compared to EN (300) commercialization standard. Most OSB panels did not fully attain such requirements. OSB panels made with Eucalyptus grandis/urophylla and Pinus oocarpa woods have potential to be commercialized as OSB/1 and OSB/2 types, respectively. Among panels made with T. ciliata wood, those produced with this species in the surface and Eucalyptus grandis/urophylla wood in the core met the requirements established for OSB/1 commercialization. Eucalyptus wood has great potential to substitute Pinus wood in OSB production. The utilization of T. ciliata wood for OSB production decreased mechanical performance, but remarkably enhanced water resistance properties.
Com a finalidade de verificar a viabilidade do tijolo de terra crua (adobe) na execução de moradias, realizou-se pesquisa para identificar as características físicas e mecânicas do solo e definição de procedimentos e métodos de produção do mesmo, estabelecendo critérios que melhorem a qualidade do produto final. O solo escolhido foi o LATOSSOLO VERMELHO - AMARELO Distrófico, que é característico da Região Sul de Minas Gerais. Teores de umidade e correção granulométrica com areia média (0,25-0,50 mm) foram adotados segundo Hernandez et al. (1983) e Pacheco & Dias Júnior (1990). A produção seguiu dois processos, um deles com blocos de terra comprimida (BTC), utilizando prensa manual modelo MRC-1 TECMOR, no tamanho denominado AP (23 x 11 x 5,0 cm) e o outro artesanal, com formas de madeira, denominado BTA, nos tamanhos BA (23 x 11 x 5,5 cm), CA (29 x 14 x 10 cm) e DA (29 x 14 x 14 cm). Após a fabricação, os adobes foram submetidos a ensaios de resistência à flexão e compressão, com monitoramento de peso, volume, peso específico e umidade em três períodos distintos de "cura" ( secagem) que foram 7, 21 e 35 dias, sendo colocados em cômodo fechado (F), galpão coberto (G) e em local desprotegido sujeito às intempéries (T). Para análise dos dados, optou-se pelo delineamento experimental inteiramente casualizado no esquema fatorial, com quatro repetições, adotando-se o teste de Tukey com nível de significância de 5%. A produção de BTC não apresentou resultados satisfatórios quando comparada com a produção de BTA. O tamanho BA apresentou os melhores resultados para resistência à flexão e compressão. A estabilização com areia média nos solos argilosos proporcionou a produção de adobes com menor contração. O galpão coberto é ideal para a cura. A resistência à compressão atingiu valores superiores aos encontrados na bibliografia consultada. Concluiu-se que a produção de adobes seguindo os critérios definidos na pesquisa como umidade adequada, estabilização com areia média (0,25-0,50 mm), utilização de "maromba", cuidados na produção e cura, resulta em tijolos de qualidade superior tanto em resistência como no aspecto estético, comprovando sua viabilidade como alvenaria na construção.
Adobe is an efficient construction material for several reasons, such as its thermal comfort, sustainability, and lower energy cost, as well as the simplicity of its production and execution. However, challenges such as water absorption, capillarity, and compressive strength should be investigated to improve its physical and mechanical properties. "Synthetic termite saliva" (STS) is an excellent stabilizer with high cohesive and hydrophobic power. Therefore, the objective of this work was to evaluate the effects of STS incorporation into adobe, analyzing its physical, mechanical and thermal properties. Five treatments were studied: 0 (control); 0.1; 0.2; 0.4 and 0.8% STS by mass. These adobe samples were evaluated according to bulk density, linear shrinkage, capillarity, water absorption, thermal conductivity and compressive strength, according to Norma Técnica de Edificación (NTE) E0.80 testing using a new methodology. Linear shrinkage decreases from 2.7 to 1.91 cm with 0.4% STS. Capillarity decreases with the increasing amounts of STS. Water absorption decreased from 12.03 to 6.31% using 0.4% STS, and its mass was reduced from 779 to 19 grams. The thermal conductivity showed no differences between concentrations. The compressive strength was reduced but was still acceptable based on NTE E.080. The stabilization of the adobe using STS showed an improvement in its physical properties, mainly due to its hydrophobic power.
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