In this study, different proportions of gypsum composite reinforced with recycled cellulose fibers and expanded polystyrene were produced to study the properties of thermal conductivity, density, and flexural strength to be used as sealing plates to improve the thermal comfort of buildings. Different gypsum matrix composites were produced with varied proportions of cellulose fiber and expanded polystyrene, to analyze the influence of residues on the properties of the material. The thermal conductivity obtained for composites with greater amounts of expanded polystyrene was 0.18 W/mK, a 48% reduction in relation to plasterboard, improving thermal performance. The flexural strength was also analyzed, which met the minimum strength requirement for use as gypsum composites, however, it is not enough to be used in places that require mechanical resistance, thus it is indicated for sealing plates applications, improving the thermal performance of places where only plasterboard is used.

The objective of the present work was to study the use of bamboo foils as structural reinforcement for MDP wooden panels. Four wooden panels of homogeneous layer were produced using particles of GT1 and RRIM 600 clones ofHevea brasiliensis(rubber tree), and glued with urea-formaldehyde resin (UF). These panels were also overlaid with foils ofPhyllostachys edulis(mossô bamboo). The tests were realized to evaluate the physical-mechanical characterization according to European standards (EN). The production of the particleboards with reinforcement of bamboo improves the physical-mechanical characteristics of these commercial wooden panels.

Indian cedar (Acrocarpus fraxinifolius) is a wood species that occurs naturally in India, Myanmar (Burma) and Bangladesh, and has a high commercial value, with characteristics like mahogany and native cedars. The planting of Indian cedar has been undertaken in Brazil, but there is little information available regarding the characterization of the species. Therefore, considering its timber potential and its possibility of development in the country, the present work aimed to evaluate the physical, chemical, and mechanical properties of 9-year-old Indian cedar wood, planted in the southern region of Brazil. A low specific mass (502 kg/m³), low average dimensional stability (anisotropy coefficient of 2,09 %) was observed, in addition to the low content of extractives (1,94 %). From the mechanical characterization, an average value for the elastic modulus of 8963 MPa was obtained, and for the compressive strength parallel to the grain the average and characteristic values were 32,14 MPa and 21,46 MPa, respectively. This indicates that this wood belongs to resistance class C20 (dicotyledons). The results obtained classify the wood for use in light, external, or internal civil construction

This work physically, mechanically, and chemically characterized the composites produced from Portland CP II-E32 cement and fresh Indian cedar wood particles previously treated by immersion in hot and cold water. Density values for wood particulate composites were around 50% lower compared with the wood-free control treatment, from 0.88 to 1.78 g/cm³. A larger swelling was observed for the composite material. The results of compressive strength and stiffness indicated that there is no need for particle treatment for composite production. Hot and cold water immersion treatments reduced the total Indian cedar wood extractives by 33% and 42%, respectively. Optical microscopy analysis was used to identify adhesion failures between the cement/wood interface of the composite produced with fresh particles, which presented a higher percentage of extractives. This result indicated that the greater concentration of total extractives partially inhibits the matrix-matrix interaction reinforcement. Despite the reduction in total extractives caused by the treatments, this process is not necessary for the composite production because there is no statistical difference between the treatments. The values obtained for the composite indicate the possibility of application in sealing blocks in light construction systems.

The Brazilian Code ABNT NBR 7190 (1997) is currently under review process and one of the proposals is the change and add of some test procedures. Several specimen geometric configurations and test conditions have been evaluated by the study committee CE-02:126.10. The aim of this paper was the analysis of the tensile strength perpendicular to the grain through the current Brazilian Code and from an adaptation of ISO 13910 (2005). Pine and Indian Cedar were used and simplified relationships were proposed. Numerical simulations were performed to identify the stress distributions in the specimens. The results obtained by ISO 13910 (2005) did not differ statistically for the two species. Brazilian standard method cedar had a higher strength value than pine. The simplified ratios obtained ranged between 0,017 and 0,123. The numerical simulations of ISO 13910 (2005) specimens showed predominant failure by tension in the lower fiber due to stress concentration.