Thermal analysis of cement panels with lignocellulosic materials for building

P.F.P. Ferraz¹, R.F. Mendes², G.A.S. Ferraz¹, V.R. Carvalho², M.R.C. Avelino², C.R.P. Narciso³, T.M.C. Eugênio³, V.G. Cadavid⁴ and G. Bambi⁵

¹Federal University of Lavras, Department of Agricultural Engineering, Campus Universitário, PO Box 3037, Lavras, Minas Gerais, Brazil
²Federal University of Lavras, Department of Engineering, Campus Universitário, PO Box 3037, Lavras, Minas Gerais, Brazil
³Federal University of Lavras, Department of Forest Sciences, Campus Universitário, PO Box 3037, Lavras, Minas Gerais, Brazil
⁴Universidad Nacional de Colombia, Sede Medellin, Faculty of Agrarians Science, Medellín, Colombia
⁵University of Firenze, Department of Agriculture, Food, Environment and Forestry (DAGRI), Via San Bonaventura 13, IT50145 Firenze, Italy
*Correspondence: patricia.ponciano@ufla.br

Abstract:

The use of lignocellulosic material residue in cement composites can be considered as a good option because they allow good thermal behaviour. This paper aimed to compare three kinds of cement panels reinforced with different lignocellulosic materials (Coffee husk, Coconut shell, and Banana pseudostem) based on their thermal properties. To produce each panel, the methodology suggested by Souza (1994) was used. Six replicates of each lignocellulosic panel with dimensions of 7.0×7.5 were evaluated. The thermal analysis was performed in a chamber composed of MDP (medium density particleboard). The chamber contained the heat source (incandescent lamp) connected to a thermostat that maintained the temperature at 48.0 °C. The porosity and thickness of the panels and the thermal behaviour of each sample panel (thermal conductivity, resistivity, resistance, and transmittance) and the difference in temperature of both sides of the panel were evaluated. The temperature difference to stabilization was obtained after a sampling time of 200 minutes, with 1,000 readings of 12 s each. Although all the panels were submitted under the same temperature, the inner and external superficial temperatures of the coffee husk panels reached smaller values. Besides, coconut and banana pseudostem panels presented the best results of thermal transmittance and thermal resistance. Thus, coconut shell panels present the best thermal performance, which means that this panel might be an attractive alternative building material, in terms of heat insulation for indoor applications.

Key words:

Comparison between the thermal properties of cement composites using infrared thermal images

P.F.P. Ferraz¹, R.F. Mendes², G.A.S. Ferraz¹, F.A. Damasceno², I.M.A. Silva², L.E.V.S.B. Vaz², L.M. Mendes³, D. Cecchin⁴ and J.O. Castro²

¹Federal University of Lavras, Department of Agricultural Engineering, Campus Universitário, PO Box 3037, Lavras, Minas Gerais, Brazil
²Federal University of Lavras, Department of Engineering, Campus Universitário, PO Box 3037, Lavras, Minas Gerais, Brazil
³Federal University of Lavras, Department of Forest Sciences, Campus Universitário, PO Box 3037, Lavras, Minas Gerais, Brazil
⁴Federal University Fluminense, Department of Agricultural Engineering and Environment, Campus Praia Vermelha, São Domingos, Niterói, Rio de Janeiro, Brazil
*Correspondence: patricia.ponciano@ufla.br

Abstract:

The use of agribusiness residual lignocellulosic fibres can be a good alternative in the development of lignocellulosic composites. The current work aimed to investigate the thermal performance of cement-based composites with lignocellulosic materials: Eucalyptus, sugarcane bagasse, coconut fibre in comparison with commercial gypsum board to be used as internal partitions of the building using infrared thermal images. Three repetitions for each kind of lignocellulosic material were made, and three commercial gypsum boards were used. In the production of the panels, the following parameters were applied: material and cement ratio, 1:2.75; water and cement ratio, 1:2.5; hydration water rate of 0.25; additive, 4% (based on cement mass). The calculations were performed for a nominal panel density of 1,200 kg m^-³. The thermal analysis was performed in a chamber composed of MDP (Medium-Density Particleboard) and with an internal layer of rock wool and the heat source (thermal resistance). For the superficial temperature measurement, a FLIR E75 camera was used to capture the infrared images. When the internal temperature of the chamber stabilized at 50 °C, an infrared thermal image was collected from each side of the composite. Thermal properties were analysed: thermal conductivity, resistivity, resistance, and transmittance. Based on the results, sugar cane cement composites were characterized by higher values of thermal conductivity. Related to thermal resistivity, thermal resistance, and thermal transmittance, only the coconut panel presented similar behaviour to the commercial gypsum board. Thus, cement composite using coconut can be a potential alternative that might solve energy and environmental concerns simultaneously.

Key words:

alternative building material, conductivity, thermal analyses, thermal cameras, thermal transmittance