http://repositorio.lnec.pt:8080/jspui/handle/123456789/29 DM Sat, 04 Apr 2026 21:09:14 GMT 2026-04-04T21:09:14Z http://repositorio.lnec.pt:8080/jspui/handle/123456789/1019017 Thermally modified wood: assessing the impact of weathering on mechanical strength and exposure to subterranean termites Godinho, D.; Lourenço, A.; Araújo, S.; Saporiti Machado, J.; Lina Nunes; Duarte, M.; Duarte, S.; Ferreira, C.; Quilhó, T.; Diamantino, T.; Gominho, J. Klaus Richter; Jan-Willem van de Kuilen Abstract The main objective of this study was to evaluate the mechanical properties of three thermal-modified wood species when exposed to weathering in urban and maritime/industrial environments and their durability against subterranean termites. The wood species studied were Maritime pine, ash, and blackwood acacia. All wood samples were exposed to two diferent environments (urban and maritime/industrial) for 24 months. Then, its physical and mechanical properties were evaluated (modulus of elasticity (MOE), modulus of rupture (MOR), compression strength (CS), and modulus of compression (MOC). Thermally modied woods revealed a lower density, which could explain the loss of MOE and MOR. In compression, no significant changes were verified. The weathered samples showed changes in mechanical properties, mostly verified in MOE and MOR, where some decreases were reported in both locations. Tests were performed to evaluate biodegradation and the resistance of all wood samples to subterranean termites. The grade of attack (≈4) and termite survival rate were similar in all wood species (above 75% and lower than 80%), except for modified acacia (59%), which could indicate that thermal modification increased toxic substances. The cellulose degradation was reflected in FTIR-ATR and Py-GC/MS in natural and thermally modified woods. Py-GC/MS showed a decrease in levoglucosan, while lignin suffered some modifications with slight changes in monomeric composition reflected by the reduction of the S/G ratio. No changes were found between the two environments, and thermal modification did not give extra protection against termites and weathering. Wed, 15 Jan 2025 00:00:00 GMT http://repositorio.lnec.pt:8080/jspui/handle/123456789/1019017 2025-01-15T00:00:00Z http://repositorio.lnec.pt:8080/jspui/handle/123456789/1019016 Biological colonisation in bio-materials and composites with different bio-binder combinations Arias-Cardenas, B.; Lacasta, A.; Haurie, L.; Duarte, S.; Duarte, M.; Faria, P. Jose M. Adam The increasing demand for sustainable and biodegradable materials in the construction industry highlights the importance of developing circular bio-based building materials that align with the principles of circular bio-economy. This study forms part of a broader investigation aimed at developing novel construction materials with suitable thermal and acoustic performance. In this context, the present work focuses on evaluating the biological colonisation susceptibility of several natural organic materials in raw form and when used with bio-binder’s, with particular attention to their fungal resistance in humid environments. The studied materials are rice husk, rice straw, Posidonia oceanica and sunflower stalk, alone and in combination with three different binders: arabic gum, xanthan gum and sodium alginate. Fungal resistance was tested exposing samples for four weeks under controlled temperature and relative humidity conditions, allowing quantification of mould growth. Results indicate that the tested unbound organic materials are highly susceptible to fungal colonisation. However, fungal proliferation could be significantly reduced by the addition of binders. Among the binders tested, sodium alginate showed the highest effectiveness in limiting fungal growth for all the tested materials, especially when combined with Posidonia oceanica, which presented the lowest bio-colonisation susceptibility. On the other hand, rice husk and sunflower stalk showed the highest fungal susceptibility, even with the application of binders. The results of this work contribute to a better selection of bio-materials and binders in order to enhance durability and sustainability for bio-based construction composites, contributing to the implementation of circular economy strategies in the built environment. Tue, 05 Aug 2025 00:00:00 GMT http://repositorio.lnec.pt:8080/jspui/handle/123456789/1019016 2025-08-05T00:00:00Z http://repositorio.lnec.pt:8080/jspui/handle/123456789/1019015 Analysing the potential of optically enhanced dark-coloured nishing coats for ETICS performance improvement Veloso, R.; Souza, A.; Maia, J.; Parracha, J.; Duarte, S.; Salgueiro, T.; Ventura, J.; Veiga, M. R.; Ramos, N. Jose M. Adam Nowadays, the construction of new buildings and their renovation must consider thermal requirements, safe guarding the thermal comfort conditions during summer and winter. Inevitably, building envelope systems absorb a large part of the incident solar radiation. ETICS (External Thermal Insulation Composite Systems) have emerged to support building energy efficiency in the construction sector. However, the thermal stress induced by heat accumulation in conventional ETICS results in cracks and microfractures, allowing water penetration and compromising thermal performance. This effect is more pronounced with dark-coloured coatings, which have gained popularity for aesthetic reasons. Although visually appealing, these coatings typically absorb a significant portion of solar radiation, intensifying the thermal stress on the rendering system and leading to subsequent façade degradation. As such, this work aims to address these challenges by incorporating reflective nano-materials into dark-coloured coatings. The coatings were tailored to enhance the optical properties without compromising the visual aspect. The thermo-optical performance revealed an overall total reectance increase for the modified dark-coloured finishing coats (15 % and 20 %), compared to just 12 % for the non-modified version, with low colour variation. Additionally, the hygric behaviour of the enhanced solutions was not compromised. Consequently, the thermal oscillation responsible for fractures will be reduced, ultimately contributing to extending the service life of ETICS while promoting sustainable building practices. Thu, 14 Aug 2025 00:00:00 GMT http://repositorio.lnec.pt:8080/jspui/handle/123456789/1019015 2025-08-14T00:00:00Z http://repositorio.lnec.pt:8080/jspui/handle/123456789/1018981 Life cycle assessment of ready-mixed concrete: paths towards more sustainable practices Benoliel M. A.; Pacheco, J.; Silvestre, J.; Martins, I. M.; Brito, J. Concrete is the second most used material on Earth after water and its large-scale production generates heavy environmental burdens. Effective mitigation of this stress involves understanding the key factors contributing to it. In this work, a cradle-to-gate life cycle assessment was conducted on ready-mixed concrete (RMC) produced in two Portuguese plants. It was found that the extraction and processing of raw materials dominates most environmental impact categories, especially those relating to climate change, with cement production governing the overall global warming potential (GWP). Analysis of several short- to medium-term scenarios to reduce carbon dioxide emissions, as envisioned by the European Cement Association and the Portuguese cement industry, indicates a possible reduction of about 30% in GWP. Of this reduction, 20% is attributed to a decrease of up to 60% in the clinker content of the cement used to produce RMC, while most of the remaining 10% results from the natural carbonation of cement (a process already occurring naturally in the use stage of concrete). Wed, 01 Jan 2025 00:00:00 GMT http://repositorio.lnec.pt:8080/jspui/handle/123456789/1018981 2025-01-01T00:00:00Z