Studies of wooden cladding materials degradation by spectroscopy

Abstract

Claddings or façades are the outer part of building envelopes. In this study, wooden claddings are exposed to natural and accelerated weathering. The natural climate exposure was performed at a field test site located in Trondheim,Norway. Accelerated climate exposure was performed in the laboratory in an Atlas SC600 MHG solar simulator.Attenuated total reflectance -Fourier transform infrared (ATR-FTIR) spectroscopy was used to characterise surfaces.The objective was to assess degradation by use of FTIR and thereby see how this may be applied to evaluate the service life of wood. Four types of wooden materials were studied; three untreated and one treated with chromated copper arsenate. Surface concentrated cellulose and lignin are the primary wood components used to determine the quality and durability of wood during ageing. It was found that treatment with preservative chemicals and surface roughness has definitive impacts on cladding surfaces and change to the chemical properties of the materials during ageing. The acceleration factor deduced from the Arrhenius equation shows that an increase in temperature lowers the service life of cellulose at a higher rate than the other wood components.

Surface Changes of Selected Hardwoods Due to Weather Conditions

“…Photodegraded products are leached out of the wood surface by water [1]. The changes caused by weathering develop rapidly and cannot be fully avoided, as presented in previous work focused on weathering of untreated wood [14,15]. The rate of degradation is usually related to wood species [12], intensity of light and light wavelengths [16], period of irradiation [12,17,18] and climatic factors occurring during exposure [19].…”

“…Some species reached full wettability after 1 year of exposure [33]. Chemical changes in wood during weathering are often investigated by Fourier Transform Infrared Spectroscopy (FTIR) analysis [10,14,34,35]. According to Pandey [35], the total colour difference was related to the lignin degradation and increase of carbonyl groups.…”

Wood facade materials ageing analysis by FTIR spectroscopy

“…However, most construction companies and users are aware of the performance-related failures that occur in wooden claddings. Determination of environmental impact, moisture problems, preservative efficiency, degradation, coating failure and predicting service life of woods are challenging research areas Gupta et al, 2011b;Masters, 1985). Service life of a wood material exposed to natural climate is limited because of its degradation against solar ultraviolet (UV) radiation, especially against the UV-B component of the radiation (Lionetto et al, 2012).…”

“…Subsequently, performance analysis of wood as a construction material is getting increasing importance (Gupta et al, 2011b;Steer, 2001). …”

Wood coating failures against natural and accelerated climates

“…Wood degradation is a complex process (Brischke et al, 2008;Faix, 1988;Felix and Morlier, 1992;Frandsen et al, 2007;Greubel, 1987;Grull and Anderl, 2004;Gupta et al, 2010Gupta et al, , 2011Skaar, 1984). Wood anatomy, microstructure, surface roughness, surface chemistry and tree growth conditions affect the natural outdoor weathering phenomena (Kollmann, 1968;Lewin and Goldstein, 1991).…”