http://repositorio.lnec.pt:8080/jspui/handle/123456789/1010715 2026-10-26T10:13:54Z 2026-10-26T10:13:54Z Jones, D. Scharf, A. Dernegård, H. Oja, J. Duarte, S. Levanić, J. Humar, M. http://repositorio.lnec.pt:8080/jspui/handle/123456789/1019068 2026-05-04T16:03:38Z 2025-06-22T00:00:00Z

Novel treatments of solid wood - studies into the use of imidazole and succinimide Jones, D.; Scharf, A.; Dernegård, H.; Oja, J.; Duarte, S.; Levanić, J.; Humar, M. Robert Mourik Recent activities have focussed on the use of ionic liquids (ILs) in wood treatments and bioprocessing. Most ILs are based on imidazolium systems, so it was decided to investigate the potential of imidazole as a treatment, along with another heterocyclic compound, namely succinimide. Thus, modification of Scots pine sapwood (Pinus sylvestris L.) with heterocyclic compounds, imidazole and succinimide, was investigated. Pressure-impregnation with aqueous solutions containing imidazole, imidazole + citric acid, succinimide, succinimide + citric acid, and citric acid + sorbitol at 5%, 10%, and 15% solid content was followed by oven-curing at 220 °C for 1 hour. Mass changes during treatment steps, bending properties, and anti-swelling efficiency (ASE) were examined. Results indicate that solid concentrations within the range of 5% to 10% were optimal. Results seem to show there are two differing mechanisms in the modification of imidazole and succinimide, respectively. Mass loss due to the heat treatment was highest in imidazole-treated specimens, whereas it remained low and concentration-independent in succinimide-treated specimens. ASE after three cycles reached 31% for imidazole-treated specimens and improved to 38% with the addition of citric acid. For succinimide, ASE increased from 17% to 41%. Bending properties generally showed improvement, except for succinimide + citric acid and citric acid/sorbitol, which displayed a reduced modulus of rupture. Chemical analyses are warranted to fully understand the reaction mechanisms of the treatments. Imidazole treatment's positive effects are suggested to stem from a thermal reaction between the chemical and wood, indicated by substantial mass loss during leaching and specimen darkening. Succinimide and citric acid might exhibit polymerisation with each other and wood components, akin to the citric acid/sorbitol process. Studies into the effectiveness of these treatments against fungi and termites showed that whilst fungal protection was reasonable to exceptional, results for termites were less effective, unless higher levels of imidazole were present.

2025-06-22T00:00:00Z Lima, D. Duarte, S. Branco , J. Lina Nunes http://repositorio.lnec.pt:8080/jspui/handle/123456789/1019067 2026-05-04T16:03:14Z 2025-06-22T00:00:00Z

Moisture uptake in CLT during the construction phase real construction conditions versus specimens exposed to environment Lima, D.; Duarte, S.; Branco , J.; Lina Nunes Delphine Bernet-Travert The rapid growth in the use of Cross-Laminated Timber (CLT) in construction highlights the need to address durability concerns, particularly in regions with less experience in Mass Timber Construction and favourable climatic conditions for the biological degradation of wood, such as Mediterranean countries. A lack of awareness and deficient construction management can negatively impact the public perception of wood as a sustainable and durable material. Furthermore, the wood species commonly used for CLT production are softwoods, which have low natural durability and are not pre-treated against biological agents such as fungi and insects. This study investigates CLT moisture uptake during the construction phase through 8-month hygrothermal data (air temperature, air relative humidity, and wood moisture content) from a Mass Timber Building case study and 8-month hygrothermal data from CLT specimens directly exposed to weather. For this purpose, more than 80 pairs of insulated electrodes were installed in the case study, which were distributed in different layers of 26 CLT panels (12 floor panels, 12 wall panels and 2 balcony panels). Regarding the specimens exposed to the environment, 25 pairs of insulated electrodes were installed in each of the 6 specimens, totalling 150 pairs. Additionally, measurements of the wood moisture content and exposure to potential sources of contamination, including water, soil, and dust were used as parameters for a qualitative evaluation of mould growth risk. Results obtained reveal that, although climate exposure plays a significant role, visual mould growth was absent in natural exposure tests even after 11 months of exposure. Meanwhile, on-site CLT panels presented visual mould growth within two months, even in a dry season with limited rainfall. These findings demonstrate the difficulty to accurately replicating real construction exposure and underline the necessity of good construction practices, incorporating a more integrated approach that goes beyond weather protection measures, such as improved site cleanliness and organisation, and adoption of rigorous moisture management measures to mitigate biological risks and enhance the durability and sustainability of Mass Timber Construction.

2025-06-22T00:00:00Z Lima, D. Duarte, S. Branco , J. Lina Nunes http://repositorio.lnec.pt:8080/jspui/handle/123456789/1019066 2026-05-04T16:03:10Z 2025-10-23T00:00:00Z

Arduino Based Low-Cost Wood Moisture Content Data Logger – Setup, Code, and Validation Lima, D.; Duarte, S.; Branco , J.; Lina Nunes Swati Meherishi In recent years, the use of timber in construction has significantly increased, driven by global decarbonization targets and advancements in engineered wood products. As a result, concerns about the durability and long-term performance of new timber buildings are becoming increasingly prominent. Monitoring wood moisture content is a critical aspect of addressing these concerns, as it directly influences wood’s susceptibility to biological degradation and its physical and mechanical properties. Despite the availability of various wood moisture meters on the market, these devices are often costly or involve ongoing subscription fees, limiting their accessibility to researchers and practitioners. This study introduces an Arduino-based, low-cost wood moisture content data logger as a viable alternative. Leveraging the customizability of Arduino, an open-source platform, this device enables users to modify their measurement setups to suit specific research needs using a range of compatible sensors. The system utilizes the electrical resistance method to measure wood moisture content. The paper provides detailed information about the components used, including the Arduino board and sensors, the electronic setup, and the open-source code developed for the device. Additionally, an experimental campaign was conducted to validate the system’s performance by comparing its results with those of two commercially available wood moisture meters and one digital multimeter. The validation involved monitoring wood samples with varying moisture levels under controlled conditions to evaluate accuracy and reliability. Results demonstrate that the proposed system provides comparable accuracy to commercial solutions while maintaining a fraction of the cost. This approach empowers researchers to construct their own customizable, cost-effective wood moisture content data loggers, broadening access to critical tools for wood property analysis and degradation monitoring.

2025-10-23T00:00:00Z Godinho, D. Lourenço, A. Araújo, S. Saporiti Machado, J. Lina Nunes Duarte, M. Duarte, S. Ferreira, C. Quilhó, T. Diamantino, T. Gominho, J. http://repositorio.lnec.pt:8080/jspui/handle/123456789/1019017 2025-11-27T12:26:26Z 2025-01-15T00:00:00Z

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.

2025-01-15T00:00:00Z