Percorrer por autor "Mofreita, Filipe"
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- Fire behaviour of wood and wood-based composite panels towards the development of fire-resistant multilayer systemsPublication . Alves, Matheus Henrique; Mesquita, L.M.R.; Piloto, P.A.G.; Ferreira, Débora; Barreira, Luísa; Mofreita, FilipeThe use of sustainable natural resources has been practiced by the construction sector as a means to reduce energy demand and increase the efficiency of buildings. In this sense, wood and wood-based materials are alternative and renewable material sources that can be effectively used in building elements, such as doors and partition walls, which are required to provide adequate thermal, acoustic, and fire resistance performance. Such elements play an important role in the fire compartmentation of buildings. Appropriate selection of materials with a reduced potential of ignition and enhanced fire behaviour may reduce the heat flux, and the passage of hot gases and smoke, thus minimizing fire hazards. In the case of wood products, the combustibility of wood usually limits its use in fire-resistant components. However, the fire performance of wooden assemblies can be improved by using engineered wood products and insulation materials, which can be assembled into multilayer systems. This work investigates the performance of wood and wood-based multilayer panels exposed to ISO 834 standard fire curve to improve the knowledge about their fire resistance in terms of insulation (I) and integrity (E) criteria. The study considers pinewood, OSB (oriented strand board), and moisture-resistant MDF (medium-density fibreboard) of different thicknesses.
- Fire behaviour of wood and wood-based composite panels towards the development of fire-resistant multilayer systemsPublication . Alves, Matheus Henrique; Mesquita, L.M.R.; Piloto, P.A.G.; Ferreira, Débora; Barreira, Luísa; Mofreita, FilipeThe use of sustainable natural resources has been practiced by the construction sector as a means to reduce energy demand and increase the efficiency of buildings. In this sense, wood and wood-based materials are alternative and renewable material sources that can be effectively used in building elements, such as doors and partition walls, which are required to provide adequate thermal, acoustic, and fire resistance performance. Such elements play an important role in the fire compartmentation of buildings. Appropriate selection of materials with a reduced potential of ignition and enhanced fire behaviour may reduce the heat flux, and the passage of hot gases and smoke, thus minimizing fire hazards. In the case of wood products, the combustibility of wood usually limits its use in fire-resistant components. However, the fire performance of wooden assemblies can be improved by using engineered wood products and insulation materials, which can be assembled into multilayer systems. This work investigates the performance of wood and wood-based multilayer panels exposed to ISO 834 standard fire curve to improve the knowledge about their fire resistance in terms of insulation (I) and integrity (E) criteria. The study considers pinewood, OSB (oriented strand board), and moistureresistant MDF (medium-density fibreboard) of different thicknesses. Rockwool with a thickness of 27 mm was also used as a core material. The multilayer systems have a dimension of 580×580 mm, fixed to a wood frame and mounted to a wall made of refractory bricks and mortar. The composite panels were tested in a small-scale furnace. During each test, temperatures were measured using type k thermocouples attached between layers and to the panel’s surfaces and wood frame. The specimens were considered to have failed when the insulation and integrity criteria were met according to EN 1363-1. The results showed that a 1-hour insulation fire resistance was achieved when using 16 mm-thick MDF panels on both sides and rockwool as a core material. Similar assemblies using 6 mm-thick and 10 mm-thick MDF panels reached 30 min., and 40 min., respectively. The specimen with 20 mm-thick pinewood on both sides and rockwool core had an insulation fire resistance of 41 min. but had one of the highest superficial masses and highest total thickness amongst tested specimens. Pinewood has been tested as a core material sandwiched between two 10 mm- thick MDF panels, and its insulation fire resistance was 30 min. The assembly with 15 mm-thick OSB placed between two 10 mm-thick MDF boards had the smallest insulation fire resistance of around 27 min. The fall-off of the exposed panel and warping of the edges of the panels greatly influenced the integrity behaviour of the samples. The insulation performance was mostly affected by the type of material and its thickness, as well as by the relative position of the layer in the composite assembly. The results provide important data regarding heat transmission effects and integrity issues related to the exposure of wood and wood-based composite multilayer systems under fire.
- Thermomechanical behaviour of bonded joints of wood and wood-based panels at room and elevated temperaturesPublication . Andrade, Djems; Alves, Matheus Henrique; Mesquita, L.M.R.; Barreira, Luísa; Manhique, Jocyla; Santamaria-Echart, Arantzazu; Barreiro, Filomena; Mofreita, FilipeWood is a natural material traditionally used in the construction industry. In recent decades, developments in scientific research have turned wood into a high-tech construction material. Increased interest in bonded joints in wood construction is due to the advantages of adhesive technology compared to traditional mechanical joining techniques. It is very important to understand the influence of elevated temperatures on adhesives due to their use in multilayer systems such as compartmentation walls and fire-resistant doors, which require adequate mechanical and thermal resistance in fire situations. The purpose of this study is to investigate the mechanical behaviour of different structural adhesives on bonded connections of wood and wood-based panels at room and elevated temperatures through experimental testing. The performance of the adhesives was evaluated at room temperature and at 50 °C, 100 °C, 150 °C, and 200 °C.
- Thermomechanical behaviour of bonding joints of wood and wood-based panels at room temperature and elevated temperaturesPublication . Alves, Matheus Henrique; Andrade, Djems; Mesquita, L.M.R.; Barreira, Luísa; Manhique, Jocyla; Santamaria-Echart, Arantzazu; Barreiro, M.F.; Mofreita, FilipeWood is a natural material traditionally used in the construction industry. In recent decades, developments in scientific research have turned wood into a high-tech construction resource. Increased interest in bonded joints in wood construction is due to the advantages of adhesive technology compared to traditional mechanical joining techniques. It is very important to understand the influence of elevated temperatures on adhesives due to their use in multilayer systems such as compartmentation walls and fire-resistant doors, which require adequate mechanical and thermal resistance in fire situations. The purpose of this study is to investigate the mechanical behaviour of different structural adhesives on bonded connections of wood and wood-based panels at room and elevated temperatures through experimental testing. The performance of the adhesives was evaluated at room temperature and at 50 °C, 100 °C, 150 °C, and 200 °C. The resins tested were a polyurethane prepolymer resulting from the reaction between polyols and diphenylmethane diisocyanate (MDI), Flexpur151, and urea resin glue for hot pressing. The tensile shear tests with lap joints were performed using combinations of pinewood-pinewood and MDF-MDF. The experimental tests were done according to EN 205:2016, which allows for determining the tensile shear strength of bonded joints. The failure mode of the tested specimens was classified according to ASTM D5573. The results show that the bonding strength and the displacement of the specimens decrease with the increase of the temperature. The failure mode presents a different result for different temperatures. For example, for the urea resin, the shear resistance of MDF-MDF panels decreases about 50 % when exposed to 100 ºC with the failure mode usually occurring on the panel, and 98 % when exposed to 200 ºC with the failure mode in the adhesion plane. For the MDI based resin, the shear resistance of MDF-MDF panels decreases about 35 % when exposed to 100 ºC with the failure usually occurring on the panel, and 65 % when exposed to 200 ºC with the failure mode occurring in the adhesion plane.