Search

Recent years have shown a surge in interest in incorporating living systems into materials research to synthesize functional materials using biological resources. Among these, mycelium-based materials, notably biofoam, have emerged as innovative solutions for repurposing organic wastes that were previously considered unusable. The growth of mycelium, vital for the synthesis of biofoam, is influenced by a multuple of factors including substrate composition, moisture content, temperature, nutrient availability, pH levels, oxygen concentration, and measures for contamination control. Additionally, physical stimulation techniques have been explored to enhance mycelium growth, ranging from cold stress-induced adaptations to electrical shock-induced modifications and optimization of sound treatments and light exposure. This review highlights the growing interest in biofoam composite materials, a novel class of environmentally friendly and cost-effective materials that are gaining popularity, for advancing sustainable construction practices. Biofoam composites use organic fungal growth as a low-energy bio-fabrication process to transform abundant agricultural byproducts and waste into viable alternatives to energy-intensive manufactured building materials. Their versatility in composition and manufacturing methods allows them to be used in a wide range of applications, including insulation and door cores, panelling, flooring, and furniture components. Notably, biofoams outperform synthetic foams and engineered wood in terms of thermal insulation, sound absorption, and fire resistance, making them highly promising for construction industry. Besides, due to its customizable composition and production method, biofoam can be used in the replacement of foams, leather, wood, and plastics in a variety of applications such as water treatment and filtration, medical supplies and healthcare applications. However, despite their remarkable properties, biofoam typically serve as non- or semi-structural supplements to traditional construction materials due to inherent limitations. Nevertheless, the useful material properties of these materials, combined with their low cost, ease of manufacture, and environmental sustainability, imply that they will have an important part to play in the development of environmentally friendly materials in the future. [ABSTRACT FROM AUTHOR]

Considering the growing need for developing ecological materials, this study investigates the acoustic, mechanical, and thermal properties of wood composites reinforced with beech or oak wood fibres. Scanning electron microscopy (SEM) revealed a complex network of interconnected pores within the composite materials, with varying pore sizes contributing to the material's overall properties. Acoustic characterization was conducted using a two-microphone impedance tube. The results revealed that the fibre size significantly impacts the sound absorption coefficient, demonstrating that the highest sound absorption coefficient of 0.96 corresponds to the composites reinforced with oak wood fibres with a size of 2 mm in the low-frequency range of 1000–2500 Hz. Mechanical testing revealed a significant reduction in compressive strength as fibre size increased from 0.4 mm to 2 mm, correlating with the observed changes in sound absorption and thermal properties. Thermal analysis indicated thermal conductivity (λ) values ranging from 0.14 to 0.2 W/m·K, with a notable increase in conductivity as fibre size decreased. It was shown that composites reinforced with beech or oak wood fibres with a size of 2 mm are recommendable for insulation materials due to the lowest thermal conductivity of 0.14 W/(m·K). Oak wood composites with a fibre size of 0.4 mm recorded the highest heat capacity, which is 54.4% higher than the one corresponding to the composites reinforced with the largest fibres. The results regarding heat diffusion rates are also reported. The findings about the effects of fibre size and pores on thermal, acoustic and mechanical properties provide valuable insights for designing sustainable materials, offering potential applications in industries where balanced performance across multiple properties is required. [ABSTRACT FROM AUTHOR]

Chicken eggshells are a useful waste that may be used somewhere rather than being placed in landfills. They are created in poultry hatcheries, the food sector (making pasta, cakes, and egg products), or our homes. In this project, this study aimed to investigate the possibility of producing plywood using a filler in the gluing process in the form of ground eggshells. This study includes the production of plywood with 0, 1, 5, 10, and 20 parts by weight (pbw) of eggshell filler (called E0, E1, E5, E10, and E20, respectively) and one reference variant with rye flour (10 pbw; hereafter called REF10). This research also includes investigating the produced panels' selected physical and mechanical properties. The results show that chicken eggshells can be used to produce plywood if the right amount of filler is chosen to improve specific mechanical and physical properties. Promising properties were obtained in the determination of the modulus of elasticity under bending (MOE) for samples E5 (11,310 N mm−2) and E10 (11,394 N mm−2) and modulus of rupture (MOR) for sample E5 (130 N mm−2). The results for the internal bond (IB) show that the addition of 5 pbw of filler in the form of ground shells shows good properties with as much as 5.23 N mm−2, but still, the reference sample with the addition of filler in the form of rye flour has higher results of 6.22 N mm−2. In the test of water absorption of fillers, the absorption of calcium carbonate is 207% and is lower than that of rye flour (224%). For the swelling thickness results, the E10 sample showed the weakest results of 7.6% after 2 h and 8.9% swelling after 24 h. [ABSTRACT FROM AUTHOR]

Highlights High‐performance wood‐based composites were developed through combined microwave energy‐deep eutectic solvent (MWE‐DES) pretreatment, resin/silica impregnation, and high‐temperature densification to improve their mechanical, structural, and dimensional stability properties for advanced structural uses. Microscopic imaging, chemical composition, stability, and mechanical properties with basswood samples provided a comparative analysis of the test materials. The results show that the MWE‐DES treated basswood had a highly porous network structure with partial removal of lignin and hemicellulose. The bending strength of modified basswood was enhanced from 60.9 MPa of raw basswood to 83.2, 87.4, 99.9, and 105.8 MPa after treatment durations of 30, 60, 90, and 120 min., respectively. Furthermore, impregnating the delignified basswood with resin or silica significantly enhanced its bending strength, achieving 246 and 198 MPa, respectively. The high mechanical strength of treated wood composites is due to the combined effect of enhanced cell‐wall fibril bonding at the micro/nanoscale, strengthening with cured resin, and/or SiOSi bonding between wood fibrils and silica. Additionally, thermal stability, dimensional stability, and termite resistance of the treated wood composites were also improved. The recoverability of lignin, hemicellulose, and used DES were demonstrated. Microwave energy and deep eutectic solvent treatment partially delignified wood. Removing lignin and hemicellulose led to a highly porous wood cell wall structure. Resin/silica impregnation and densification modified macro/micro wood structures. Enhanced wood fibril‐fibril and fibril‐resin or silica bonding improved wood strength. Lignin, hemicellulose, and DES were recovered, promoting sustainability. [ABSTRACT FROM AUTHOR]

Wood–plastic composites (WPC) combine the properties of polymers and wood, providing an attractive alternative to traditional materials, particularly for terrace flooring. When exposed to various environmental conditions, WPCs are affected by factors, such as water and ultraviolet (UV) radiation. Although most test methods for assessing the durability of these products have focused on changes in mechanical properties and linear dimensions, out-of-plane deformations (concavity and convexity) are often overlooked. This study focusses on evaluating the usefulness of the test method that allows for precise determination of these deformations after ageing. The test procedure involves exposure to classic weathering for decking boards, including moisture, UV radiation, and water spray, followed by three-dimensional (3D) scanning to track deformation after different exposure times. Analysis of variance was used to assess whether the sensitivity of this method is sufficient to detect minor deformations. Additionally, scanning electron microstructural images of the aged samples were examined to determine whether there was a relationship between the deformation and the microstructural changes. This study demonstrated the potential to use scanning methods for assessing the aspects of ageing resistance of this type of composite product in the context of deformation. [ABSTRACT FROM AUTHOR]

With increasing global concern over carbon emissions in the construction industry, cross-laminated-thick veneer (CLTV) has emerged as an innovative green building material with significant potential to promote the achievement of "dual-carbon" goals. This study developed a groove and tenon splicing technique for thick veneers, enabling infinite splicing of the length direction and the preparation of a large-size CLTV measuring 12 m (length) × 3.25 m (width) × 105 mm (thickness). The mechanical properties of CLTV were studied in relation to splice position, assembly pattern of grain directions, and layer combinations. The results showed that increasing the number of // layers (// or ⊥ indicates grain direction of layer parallel or perpendicular to the length direction of CLTV) and using high-level layers significantly improved the compressive strength and reduced the coefficient of variation of CLTV. In terms of bending properties, reasonable splice distribution, placing // layers away from the neutral axis, and elevating layer level dramatically enhanced CLTV performance. Furthermore, the study revealed the synergistic effect among these design elements. The effects of layer level and the number of // layers on mechanical properties varied depending on splice arrangement and assembly pattern of grain directions, highlighting the importance of efficient structural design and raw material selection. This study addresses the limitations of traditional cross-laminated timber in raw material selection and production efficiency. Through structural innovation, it offers a solution for physical design and performance regulation, enabling the application of larger CLTV in wood structures and presenting new ideas for using fast-growing wood to reduce construction emissions. [ABSTRACT FROM AUTHOR]

This study aimed to evaluate the preservative potential of extracts from teak wood industrial waste against artificial weathering and decay fungi. Teak extracts were obtained in hot water, acetone, ethanol and methanol and tested against brown-rot (Rhodonia placenta, Gloeophyllum trabeum, Neolentinus lepideus) and white-rot fungi (Irpex lacteus). Aging tests included the leaching test and artificial weathering in a QUV accelerated weathering tester. The chemical analysis of the extracts was carried out by gas chromatography-mass spectrometry (GC-MS), and the compounds were compared with the cited literature. The extracts were characterized as quinone derivatives (35 %), mainly tectoquinone (28 %), followed by squalene (8–12 %) and other phenolic compounds (6 %). Lapachol, although found in proportions of 0.7–0.9 %, plays an important role in wood durability and biocidal activity in teak extracts. The results obtained by the chemical analysis indicated that the main compounds identified in this study can act synergistically on the resistance of wood impregnated. Teak extracts ensured high resistance to the decay fungi tested and results showed better performance of acetone extracts. In view of the results obtained, it is recommended to carry out other tests (soil bed and field tests) to verify the long-term effects of the extracts. [ABSTRACT FROM AUTHOR]

Developing novel materials is an essential requirement in the engineering field. This study investigates the effects of incorporating wood dust particles on the mechanical and erosive wear properties of Luffa acutangula fiber (LAF)-reinforced phenol-formaldehyde composites, fabricated using the hand layup method with a constant 20% fiber content and varying wood dust particle contents of 0%, 10%, 20%, and 30%. Using the Taguchi method, the study identifies the optimal combination for minimizing erosive wear − 20% wood dust content, 45 m/s impact velocity, 60° impingement angle, 600 μm erodent size, and 60 mm standoff distance—achieving a minimum erosion rate of 189.8 mg/kg. The addition of 20% wood dust results in significant enhancements in mechanical properties, with tensile strength increasing by 17.56%, flexural strength by 48.78%, and impact strength by 54.64%, compared to composites without wood dust. These findings underscore the potential of LAF composites with bio-fillers for lightweight structural applications in sectors prioritizing sustainability and mechanical durability, such as automotive and aerospace. [ABSTRACT FROM AUTHOR]

Mass timber (MT) is an engineered wood product that has been widely used in Europe and is rapidly gaining popularity in the United States (US). MT structural members consist of multiple wood components connected using adhesives and/or mechanical fasteners. Although wood is a common material in the US, MT is not readily available in the US. Some US structural engineers are reluctant to include MT as a potential construction material in their building designs due to limited MT material availability, cost, and unfamiliarity with MT as a construction material. This unfamiliarity stems from limited US MT education and lack of MT experience at the professional level. This paper attempts to provide a broad-brush MT review for architects and structural engineers interested in incorporating MT in their designs on relevant standards and specifications. Guidelines for designing with MT are provided in the International Code Council's 2024 International Building Code (2024 IBC) under "Type IV Construction." The Type IV construction description was initially greatly expanded in the 2021 IBC to allow for tall MT buildings and continues to be included in the 2024 IBC. This paper identifies and reviews the 2024 IBC criteria related to MT. Additionally, discussion is included on military standards pertinent to MT. The composite action of an MT element is highly dependent on the adhesive behavior used to attach the MT member laminations. Consequently, adhesives used with MT members and the testing protocol to validate satisfactory adhesive behavior are discussed. [ABSTRACT FROM AUTHOR]

In the last several decades, there has been significant growth in research and development activities in nanomaterials. Nanotech has been used to improve the quality of several materials, including wood and polymer composites, for their application in various fields. Nanofillers, including metal particles, nano oxides, pyrogenic silica, and carbon black, have been employed as polymer additives. However, the value of natural, low-cost, and plentiful clay materials such as nanoclay becomes more apparent as environmental regulations and consumer awareness become more rigorous. This literature outlines the role of nanoclay on polymer composites, especially in the case of thermosetting resins, including epoxy, polyester, urea-formaldehyde, and phenol-formaldehyde resins. The current article is intended to provide a comprehensive source of recent studies and literature on nanoclay as filler, its classification, polymer modification processes using nanoclay, and comparing the performance of different thermosetting polymers based on their fabrication methods through physical and mechanical properties. [ABSTRACT FROM AUTHOR]

This study investigates the development of biomimetic sound-absorbing components through laser sintering technology, drawing inspiration from wood's natural porous structure. Using a pine wood powder/phenolic resin composite, various specimens were fabricated with different structural configurations (solid, fully porous, and varying straight-pore ratios) and cavity thicknesses. Sound absorption performance was evaluated using the impedance tube transfer function method. The effect of different composite structures, placement orientations, and cavity thicknesses on sound absorption performance was evaluated. The results demonstrate that solid laser-sintered samples exhibit inherent sound absorption properties due to microscopic pores, with absorption coefficients exceeding 0.234. The biomimetic wood-like structure, featuring multi-scale porosity at both microscopic and mesoscopic levels, shows enhanced broadband sound absorption, particularly in mid-high frequencies, with characteristic double-peak absorption curves. The study reveals that absorption performance can be optimized by adjusting structural parameters and thickness, enabling targeted frequency-specific sound absorption. This research establishes the feasibility of creating multi-frequency sound-absorbing materials using laser-sintered biomimetic wood structures, providing a foundation for future applications and development in acoustic engineering. [ABSTRACT FROM AUTHOR]

The growing concern over environmental impact and the significant improvement in the quality of engineered wood products have led to the rapid growth of the timber building industry in the last decades. Although traditional, yet recent, mass timber structural systems, such as cross‐laminated timber walls, can provide satisfactory seismic performance during earthquakes in terms of life‐safety, the crucial need for more resilient timber buildings has prompted the development of low‐damage high‐performance self‐centring and dissipative solutions based on unbonded post‐tensioned hybrid connections, referred to as Pres‐Lam technology. The flexibility of design and construction speed, combined with the enhanced seismic performance, create a unique potential towards an earthquake‐proof sustainable building system. Despite the growing popularity of the technology, a comprehensive framework for the fragility analysis, to be used in risk and loss modelling applications, has not yet been developed for both component and building levels. This article aims to develop a framework for assessing the fragility curves of moment‐resisting Pres‐Lam frame systems, at both structural system and connection levels, by using and comparing different approaches that involve nonlinear static (pushover) and time history dynamic analyses. A Python‐based parametric workflow was developed to evaluate fragility curves for a wide range of case‐study buildings. Particularly, three distinct structures were selected, and their fragility curves were evaluated utilizing alternative methodologies at a building structural‐system level. Finally, fragility models were fitted for individual structural connections using the results of time‐history analyses. These models are intended for use in a component‐based loss assessment. [ABSTRACT FROM AUTHOR]

Wood plastic composites (WPCs) have recently gained attention as alternatives to traditional wood materials for outdoor use, thanks to their enhanced moisture resistance and durability, which extends their service life. Discolouration as well as surface erosion has been observed during weathering for both WPCs with untreated and heat-treated wood. However, aspects such as changes in surface hydrophobicity, chemistry, and erosion in terms of microplastic formation have received less attention; this research aimed to evaluate these factors during natural weathering. Four types of WPC samples, consisting of 50% wood particles (untreated and heat-treated) and 50% polypropylene, were naturally weathered in Latvia for two years. The samples measured 240 mm × 240 mm × 5 mm. Results showed rapid colour changes, microcracks, and exposed wood particles, suggesting microplastic formation. ATR-FTIR analysis showed increased absorption at 1715 cm⁻¹ (carbonyl groups) and at 3410 cm−1 and 3460 cm−1, typical of wood, indicating chemical changes on the surface. These changes influenced surface hydrophobicity, roughness, and water penetration. In a relatively short exposure time, WPCs without proper additives undergo significant changes in their aesthetic and physical properties, leading to surface erosion and potential microplastic formation. This could challenge the perception of WPCs as environmentally friendly materials. [ABSTRACT FROM AUTHOR]

This study investigates the effects of thermal modification (TM) on wood-filled polylactic acid composite filaments for 3D printing. Nine composite formulations with different wood content were analysed. The wood particles came from unmodified and thermally modified beech wood (180 °C or 200 °C). The results showed that the incorporation of thermally modified (TMd) wood changed the filament properties, resulting in lower density and reduced surface roughness. The 3D-printed parts with TMd wood particles had a higher water contact angle, higher storage modulus, lower glass transition temperature, higher modulus of elasticity and higher indentation hardness. However, the tensile strength of the 3D-printed parts decreases, even though the results of parts with TMd wood showed higher strength compared to unmodified wood at the same filler content. Surprisingly, TMd wood had no effect on water absorption under humid conditions. Scanning electron micrographs showed improved interfacial adhesion between TMd wood particles and PLA, with smaller voids in the filament compared to filaments with unmodified wood particles. The study suggests that further research into use of TMd wood particles in composite holds promise for environmentally friendly 3D printing materials with favourable thermal and mechanical properties, impacting the expanding market for sustainable solutions in 3D printing. [ABSTRACT FROM AUTHOR]

This work explores the elaboration of wood particle‐based composites incorporating bio‐based phase change materials, with epoxidized linseed oil or clay as a binder. Fire performance evaluation of the novel composites includes an assessment to determine the impact of the addition of boric acid as a fire retardant, as well as the incorporation of recycled paper fibres containing boric acid, and the application of trimethoxymethylsilane coating. The study employs thermogravimetric analysis and cone calorimetry under uniform external irradiance, with a T‐history method to analyse thermal behaviour. Results indicated that fire retardants do not compromise the energy functionality of bio‐based phase change material composites, exhibiting a latent heat of approximately 50 J/g. The density ranges from 750 to 875 kg/m3. The use of clay as a binder improves fire performance, leading to a 60% decrease in total heat release and 52% of the composite mass remaining after analysis. Although enhancing fire performance presents challenges, incorporating wood particles in clay demonstrates a promising potential approach for safe use in building applications, contributing to energy efficiency in indoor heating and cooling. The findings contribute valuable insights into these materials for creating safer and more efficient building solutions, particularly in terms of thermal regulation and fire safety. [ABSTRACT FROM AUTHOR]

Laminated veneer lumber panels (LVL) are engineered wood products suitable for application in construction contexts. However, LVL panels have some deficient elastic properties (e.g., E 22 ) concerning other elastic properties (e.g., E 11 and G 12 ), which may cause problems in structural applications. Carbon and basalt fibers (CF and BF) are reinforcement alternatives for LVL panels, as they can be included in the interior or exterior wood veneer bonding process. This work aims to analyze the effect of incorporating CF and BF fibers in the orthotropic elastic properties of radiata pine LVL panels through a nondestructive method based on transverse vibration tests and model updating techniques. Accordingly, 20 LVL panels of 15 mm thickness were fabricated and tested with different reinforcing fibers and adhesives. Then, some relevant panels' dynamic properties were identified through experimental modal analysis. Finally, three relevant panels' orthotropic elastic properties were estimated simultaneously using finite-element model updating techniques and Python-based deterministic calibration scripts. The results suggest that the reinforced LVL panels obtained significant increases in their orthotropic elastic properties, in the order of 22%, 333%, and 27% for E 11 , E 22 , and G 12 , respectively. These results show the effectiveness of the type of reinforcement applied and the potential application of the nondestructive evaluation method in other contexts. [ABSTRACT FROM AUTHOR]

Copyright of Low-Carbon Materials & Green Construction is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The construction industry is embracing sustainable practices to combat environmental degradation and climate change, and engineered wood products (EWPs) offer promise as structural materials for sustainable infrastructure. Despite the benefits of EWPs, challenges such as supply chain integration and market acceptance have limited their use. This paper explores how industrial engineering could facilitate the adoption of EWPs in the South African construction industry, and provides a framework for developing critical industrial engineering capabilities that the South African timber construction sector should possess to integrate EWPs efficiently into construction projects. We used a comprehensive literature review and a curriculum analysis to achieve the study's objectives. By drawing upon these capabilities, the study identified where industrial engineering as an expertise could drive innovation adoption. [ABSTRACT FROM AUTHOR]

Wood adhesives can serve as one of the key components to manufacture wood composites. Their selection has a profound impact on the resulting wood products. Wood composites are also required for the fundamental yield, high valueadded, and cost-effective production. At the same time, some issues are increasingly concerned on the formaldehyde emissions from wood composites, since formaldehyde was already recognized as a cancerogen to human beings back in 2004. As a result, the wood composites processing has been shifted to formaldehyde-free adhesives in recent years. Polymeric diphenylmethane diisocyanate (pMDI) can serve as the isocyanate wood adhesive in the wood industry, due to its exceptional water and solvent resistance, formaldehyde-free nature, and high strength. World demand for isocyanates is expected to increase significantly to 15.74 billion U.S. dollars by the next decade, indicating the large market potential of isocyanates and their wide application prospects. Despite the advancements in isocyanate adhesive technologies, the inherent low viscosity of pMDI and the "overpenetration" during hot-pressing have posed great challenges to the widespread applications. Alternatively, wheat straw is normally perceived as low-value agricultural waste, due to its chemical composition of cellulose, hemicellulose, and lignin, all of which contain hydroxyl groups. These hydroxyl-rich components can react with isocyanate groups to form strong carbamate bonds, thus resulting in a complex three-dimensional cross-linked network that is reinforced by hydrogen bonding. In this study, wheat straw microparticles were introduced to incorporate as a functional filler in the isocyanate wood adhesives, in order to strengthen the adhesion performance of the products. The results showed that the dry/wet bonding properties of strawmodified isocyanate adhesive were improved under conventional hot-pressing pressures (0.8-1.2 MPa) at weak pressure conditions (0.1 MPa). Moreover, the reactivity of the modified adhesive remained after adding straw with 9% moisture content; On the contrary, the dry strength, 24 h cold water soaking strength, and “boiling-drying-boiling” strength reached 4.07, 3.41 and 3.23 MPa, respectively, under weak pressing condition of 0.1 MPa. The strengths increased by 145%, 142%, and 197% after straw particles, respectively, compared with the control group without straw. Further characterizations indicated that the straw particles formed a stable crosslinked structure with isocyanate in the curing process, which significantly promoted the consistency of bonding interfaces; Therefore, the weak hot-pressing pressure was achieved in the high adhesive strength of wood adhesives. [ABSTRACT FROM AUTHOR]

Wood is a sustainable, benign, and high-performing green structural material readily available in nature that can be used to replace structural materials. However, insufficient mechanical performance (compared to metals and plastic), moisture sensitivity, and susceptibility to microorganism attack make it challenging to use wood as it is for advanced engineering applications. We here present an efficient approach to fabricating densified wood with minimal time and waste generation, demonstrating high mechanical strength, and decreased water penetration on the surface. Wood slabs were treated with deep eutectic solvents (DESs) to solubilize the lignin, followed by in-situ regeneration of dissolved lignin in the wood. Then, the slabs were densified with heat and pressure, turning the wood into a functionalized densified material. Lignin regeneration and morphological changes were observed via two-photon microscopy and Scanning Electron Microscopy (SEM), respectively. The final product is less susceptible to water absorption on the surface and has enhanced flexural strength (> 50% higher), surface hardness (100% increased), and minimal set recovery compared to natural wood. The improved mechanical performance is due to regenerated lignin which acts as a glue and fills spaces present within the interconnected cellulose network inside the wood, forming a highly dense composite during densification. Such enhancement in the properties of DES-densified wood composite makes it a favorable candidate for advanced structural and engineering applications. [ABSTRACT FROM AUTHOR]

Timber–concrete composite (TCC) systems join the positive aspects of engineered wood products (good seismftaic behaviour, low thermal conductivity, environmental sustainability, good behaviour under fire if appropriately designed) with those of concrete (high thermal inertia, durability, excellent fire resistance). TCC facades are typically composed of an internal insulated timber-frame wall and an external concrete slab, separated by a ventilated air cavity. However, there is very limited knowledge concerning the performance of TCC facades, especially concerning their thermal behaviour. The present paper deals with the development and optimization of a 2D Computational Fluid Dynamic (CFD) model for the analysis of TCC ventilated façades' thermal behaviour. The model is calibrated and validated against experimental data collected during the annual monitoring of a real TCC ventilated envelope in the north of Italy. Also, a new solver algorithm is developed to significantly speed up the simulation (i.e., 45 times faster simulation at an error below 3.5 °C compared to a typical CFD solver). The final model can be used for the time-efficient analysis (simulation time of approximately 23 min for a full day in real-time) and the optimization of the thermal performance of TCC ventilated facades, as well as other ventilated facades with external massive cladding. Our simulation strategy partially avoids the expensive and time-consuming construction of mock-ups, or the use of comparably slow (conventional) CFD solvers that are less suitable for optimization studies. [ABSTRACT FROM AUTHOR]

Wood-based particleboards (PBs) are widely used in construction and interior applications, yet their durability, particularly against biological degradation, remains a challenge. Recycling wood and incorporating degraded particles from rotted wood can potentially enhance PB sustainability and align with circular bioeconomy principles. This study investigates the biological resistance of the three-layer, laboratory-prepared PBs with varied amounts of particles, from sound spruce wood to particles, and from spruce logs attacked by brown- or white rot, respectively, to particles from recycled wooden composites of laminated particleboards (LPBs) or blockboards (BBs), i.e., 100:0, 80:20, 50:50, and 0:100. The bio-resistance of PBs was evaluated against the brown-rot fungus Coniophora puteana, as well as against a mixture of moulds' "microscopic fungi", such as Aspergillus versicolor BAM 8, Aspergillus niger BAM 122, Penicillium purpurogenum BAM 24, Stachybotrys chartarum BAM 32, and Rhodotorula mucilaginosa BAM 571. PBs containing particles from brown-rotten wood or from recycled wood composites, particularly LPBs, had a partly enhanced decay resistance, but their mass loss was nevertheless more than 30%. On the other hand, the mould resistance of all variants of PBs, evaluated in the 21st day, was very poor, with the highest mould growth activity (MGA = 4). These findings suggested that some types of rotten and recycled wood particles can improve the biological resistance of PBs; however, their effectiveness is influenced by the type of wood degradation and the source of recycled materials. Further, the results highlight the need for improved biocidal, chemical, or thermal modifications of wood particles to enhance the overall biological durability of PBs for specific uses. [ABSTRACT FROM AUTHOR]

The document explores the significance of wood and bamboo as biomass materials in human civilization, focusing on their environmental sustainability, strength, and versatility in various sectors. It delves into academic research on bamboo and wood materials, highlighting their properties, treatment processes, and applications. The articles cover topics such as fundamental properties, treatment methods, material development, biomimetic applications, and the conservation of archeological wood, providing valuable insights for sustainable resource utilization and the preservation of cultural heritage. [Extracted from the article]

This research aimed to examine the effects of a deep impregnation technique (Royal process) and surface coating using a linseed oil-based product, enhanced with small amounts of brown and grey pigments, on the natural and artificial weathering of wood. The treated and reference samples underwent natural weathering for five years and artificial weathering for 1900 h. Changes in color and surface roughness were assessed during weathering. For the artificially weathered samples, liquid water absorption was measured both before and after exposure. The impregnated and coated samples gradually lost their brown color, turning grey over time. More pronounced differences were observed during natural weathering, with the coated samples showing greater structural changes on the wood surface. In contrast, impregnated samples slowed down structural alterations compared to the reference samples. Both treatments effectively reduced water absorption before weathering, although this effect diminished after exposure. The treatments did not significantly impact the fire resistance of spruce and beechwood. [ABSTRACT FROM AUTHOR]

Passive radiative cooling, as a cooling technique with no energy input, can continuously radiate heat into the supercooled universe. However, the continuous cooling effect tends to cause the problem of nighttime overcooling. Moreover, non‐renewable radiative cooling materials and energy‐intensive processing methods lead to increased carbon emissions and resource consumption. Therefore, there is an urgent need to develop a renewable and environmentally friendly self‐adaption radiative cooling thermal management material. In this paper, a high‐performance self‐adaption thermal management wood composite aerogel material is designed and prepared by in situ growth of multi‐scale silicon dioxide on wood. The constructed passive radiative cooling material has a sub‐ambient cooling effect of up to 13.5 °C and 20.2 °C  during daytime in winter and summer, respectively. Meanwhile, it has a certain thermal insulation performance (2.0 °C above ambient) due to low thermal conductivity (0.063370 ± 0.000329 W m−1 k−1) at night in winter. In addition, the material is also suitable for fog–water harvesting (fog–water harvesting rate of 59.27 ± 0.76 mg min−1) due to its hydrophobicity. This work can significantly promote the practical application of passive radiative cooling materials. [ABSTRACT FROM AUTHOR]

Structural sawn timber, sourced from softwood plantations, is widely used in lightweight timber-framed residential housing and in engineered wood products for contemporary mass timber construction. However, a significant proportion of milled timber boards are considered ‘out-of-grade’, failing to attain a structural grade under existing classifications systems due to various stiffness, strength, and/or utility-limiting features. This study investigates the potential of controlled lamination techniques to produce structurally usable laminated timber products from out-of-grade timber, using a minimal number of requisite boards. Numerical and experimental methods were employed to compare different board assignment heuristics, in terms of reducing the stiffness variability in laminated board populations. The results indicate that controlled board locations produced remarkably consistent laminated products, achieving very low variability even with a minimum lamination of only two boards. The findings of this paper suggest that controlled lamination techniques have the potential to transform low-value out-of-grade timber into a valuable resource for value-added applications, challenging the existing market perception that out-of-grade timber lacks structural usability. [ABSTRACT FROM AUTHOR]

This study aims to develop a recyclable, economical, and flame-retardant composite material using polypropylene, beech flour, tetrabromobisphenol A bis (TBBPA), and antimony trioxide (ATO). Flame-retardant additives (TBBPA and ATO) were initially added into polypropylene at different rates, and masterbatch (MB) samples were produced by the extrusion method. Subsequently, different percentages of wood flour (10%, 15%, 20%, 25%, and 30%) along with 60% MB were added to the polypropylene to create wood–polymer composites (WPC) using the injection method. The TBBPA, ATO, and wood flour were introduced through side-feeding hoppers during injection to ensure a homogeneous distribution within the WPC. Physical, thermal, and mechanical tests were conducted on the WPC samples. Additionally, TGA, FTIR, and SEM analyses were performed. The results indicated that the optimal ratios for TBBPA and ATO additives were 20% and 10%, respectively. It was observed that increasing the wood flour content in the WPC samples led to enhanced density, water absorption, hardness, impact, and abrasion resistance. Conversely, MFI, bending strength, and tensile strength decreased with higher wood flour content. It was observed that WPC samples exhibited flame resistance up to 725 °C. The produced WPC materials can be used in flooring applications, interior furniture, decorative wall panels, and aesthetic structural elements due to their fire behavior, good mechanical properties, low water-absorption rates, and aesthetic appearance. [ABSTRACT FROM AUTHOR]

This study aims to optimise the water vapour adsorption capacity of polylactic acid (PLA) and wood composite materials for application in dehumidification systems through material extrusion additive manufacturing. By analysing key process parameters, including nozzle diameter, layer height, and temperature, the research evaluates their impact on the porosity and adsorption performance of the composite. Additionally, the influence of different infill densities on moisture absorption is investigated. The results show that increasing wood content significantly enhances water vapour adsorption, with nozzle diameter and layer height identified as the most critical factors. These findings confirm that composite materials, especially those with higher wood content and optimised printing parameters, offer promising solutions for improving dehumidification efficiency. Potential applications include heating, ventilation, and air conditioning systems or environmental control. This work introduces an innovative approach to using composite materials in desiccant-based dehumidification and provides a solid foundation for future research. Further studies could focus on optimising material formulations and scaling this approach for broader industrial applications. [ABSTRACT FROM AUTHOR]

The strengthening, rehabilitation and repair of wooden beams and beams made of wood-based materials are still important scientific and technical issues. This is reflected, among other things, in the number of scientific articles appearing and the involvement of research centres around the world. This is also related to society's growing belief in the importance of ecological and sustainable development. This article presents an overview of the latest work in this field and the results of our own research on strengthening solid wooden beams with carbon-fibre-reinforced polymer (CFRP) sheets. The tests were carried out on full-size solid beams with nominal dimensions of 70 × 170 × 3300 mm. A 0.333 mm thick CFRP sheet was used for reinforcement. The research analysed various reinforcement configurations and different reinforcement ratios. For the most effective solution, a 46% increase in load capacity, 35% stiffness and 249% ductility were achieved with a reinforcement ratio of 1.7%. Generally, the higher the reinforcement ratio and coverage of the surface of the wood, the higher the strengthening effectiveness. The brittle fracture of wood in the tensile zone for unreinforced beams and the ductile crushing of wood in the compressive zone for reinforced beams were obtained. The most important achievement of this work is the description of the static work of beams in previously unanalysed configurations of strengthening and the confirmation of their effectiveness. The described solutions should extend the life of existing wooden buildings and structures and increase the competitiveness of wooden-based structures. The results indicate that, from the point of view of optimizing the cost of reinforcement, it is crucial to develop cheaper ways of combining wood and composite than to verify different types of fibres. [ABSTRACT FROM AUTHOR]

Laminated veneer lumber (LVL), characterized by its efficient utilization of raw materials, flexible size design, extensive prefabrication, and favorable mechanical properties, is an engineering wood frequently employed in the post and beam construction with shear walls. As one of the predominant fast-growing wood species in China, Chinese larch (Larix gmelinii) emerges as a potentially ideal raw material for producing structural LVL. To explore the viability of utilizing fast-growing Chinese larch as LVL compression members, a series of compression tests was conducted on the fast-growing Chinese larch LVL (CLP-LVL) under various cross-section sizes. Apparent influence of member depth and width on the compressive properties parallel to grain of CLP-LVL was experimentally observed. Based on the cross-section size variables, the prediction methods for the compressive failure load and strength parallel to grain of CLP-LVL were proposed. The cross-section size effects on compressive strength parallel to grain of CLP-LVL were theoretically quantified, and the related size effect parameters were suggested to be comprehensively considered for further compressive property analysis of CLP-LVL compression members. CLP-LVL with a comparable compressive strength parallel to grain could provide favorable compressive properties for compression members in civil engineering. Practical Applications: The current research experimentally revealed the feasibility of utilizing fast-growing Chinese larch (Larix gmelinii) to produce structural laminated veneer lumber (LVL), providing LVL manufacturers with more raw material choices of fast-growing woods. The fast-growing Chinese larch LVL (CLP-LVL) has comparable compressive properties, making it a promising choice for applications in civil engineering as compression members. This study identified the compressive failure load and strength parallel to grain of CLP-LVL, and comprehensively investigated the related cross-section size effects. Considering these cross-section size effects, the prediction methods for compressive failure load and strength of CLP-LVL were proposed. The practitioners may use the proposed prediction methods to evaluate the compressive performance of CLP-LVL compression members. Besides, the related cross-section size effect parameters of compressive strength were quantified in this study. The practitioners may use the obtained compressive failure load and strength of CLP-LVL, as well as its related cross-section size effect parameters for further engineering design CLP-LVL compression members. This study aims to provide a critical theoretical support for the application of CLP-LVL in civil engineering. [ABSTRACT FROM AUTHOR]

To determine the appropriate stiffness coefficient k values for rubber belts used in dynamic testing of the elastic modulus and shear modulus of timber and solid wood composite materials, this study employed three different thicknesses of rubber belts. Dynamic tests were conducted on straw boards, Laminated Veneer Lumber (LVL), and Spruce-Pine-Fir (SPF) materials, and the results were validated and analyzed using static four-point bending tests. The conclusions drawn from this research indicate that the range of stiffness coefficient k values for the rubber belts obtained through dynamic testing fell between 0.05 and 0.28 N/m. The correctness of the dynamic testing method was verified through static fourpoint bending tests. The error levels for elastic modulus E and shear modulus G of the same type of board measured using the three different rubber belts were below 9.5% and 9.8%, respectively. [ABSTRACT FROM AUTHOR]

Development of scrimber composites and other engineered wood products from low-value wood and wood waste provides an effective opportunity to preserve natural resources, minimize waste, and innovate the production of higher-performance, environment-friendly construction materials. In this study, peeler cores, which are the center of poplar logs remaining after the peeling process in the veneer production, were utilized to develop scrimber composites. This study investigated the effects of different resins, including phenol-formaldehyde (PF) and urea formaldehyde (UF), as well as hydrothermal treatments at various temperatures (60 °C and 130 °C), on the physical and mechanical properties of the scrimber composites. Chemical changes in wood components and morphological changes in wood cell walls resulting from hydrothermal treatment were analyzed using Fourier transform infrared spectroscopy and scanning electron microscopy. To clarify how resin type and hydrothermal treatment affect structural performance, several physical and mechanical properties of scrimber composites, including thickness swelling, water absorption, internal bond strength, bending modulus of elasticity, and modulus of rupture, were measured. The test results revealed that hydrothermally treated wood scrims at 130 °C, when bonded with PF resin, produced scrimber composites with superior structural performance. [ABSTRACT FROM AUTHOR]

Mechanical properties of wood-inspired cell wall geometries were considered through compression testing and Finite Element Analysis (FEA) with ANSYS simulation. Six models, including earlywood, latewood, and various array configurations, were fabricated via 3D printing using acrylonitrile butadiene styrene (ABS) filament. Compression tests highlighted the annual ring model's robustness, exhibiting a maximum load of 12707 MPa, while the 4x3 matrix displayed the lowest strength at 4247 MPa. Shifting rows led to reduced strength, which was particularly evident in vertical prints. An analysis of variance revealed significant differences in mechanical properties. Discrepancies between experimental tests and FEA results ranged from -45.9% to 35.2%. Earlywood exhibited a maximum deformation of 2.6 mm, whereas latewood showed lower deformation, indicating geometry's influence on material behavior. Mesh quality remained consistent, ensuring dependable simulation outcomes. These findings underscore the pivotal role of geometry in compression resistance, laying the groundwork for future studies on wood densification mechanisms and the development of customized wood composites. [ABSTRACT FROM AUTHOR]

Bark plastic composite is a composite wood board consisting of a plastic matrix and bark in the form of powder or fibers as a filler. This research aimed to determine the influence of ratio and particle size on the characteristics of the composite made of Gmelina bark mixed with recycled polypropylene. Bark plastic composites were made with variations in powder: plastic ratio, namely 40:60% (P60), 30:70% (P70), 20:80% (P80), and 0:100% (P100), as well as variations in filler particle size, namely 40 to 60 mesh (M40), 60 to 80 mesh (M60), and 80 to 100 mesh (M80). Maleic anhydride (MAH) as a compatibilizer was added at 5% of the matrix's weight. The reference testing standards were JIS A 5908:2003 and SNI 03-2105-2006. In the physical property testing, including density, moisture content, water absorption, and thickness swelling, all boards with different treatments met the standards. In the modulus of elasticity (MOE) testing, none of the boards with different treatments met the standards, while in the internal bond testing, all boards with different treatments met the standards. As for the modulus of rupture (MOR) testing, hardness, and screw-holding power, some samples met both standards. The M40P80 treatment produced the best bark plastic composite. [ABSTRACT FROM AUTHOR]

With the production of wood waste constantly on the increase, questions relating to its recycling and reuse are becoming unavoidable. The reuse of wood and its derivatives can be achieved through the production of composite materials, using wood as a reinforcement or even as the main matrix of the material. Additive manufacturing (also known as 3D printing) is an emerging and very promising process, particularly with the use of bio-based and renewable materials such as wood or its industrial derivatives. The aim of this paper is to present an overview of additive manufacturing processes using wood as a raw material and including industrial solutions. After presenting wood and its waste products, all the additive manufacturing processes using wood or its industrial derivatives will be presented. Finally, for each 3D printing process, this review will consider the current state of research, the industrial solutions that may exist, as well as the main challenges and issues that still need to be overcome. [ABSTRACT FROM AUTHOR]

Phytic acid as an efficient, green and renewable bio-based flame retardant. However, in view of the large number of toxic fumes generated during combustion and the easy loss of flame retardants, to tackle these issues, the current study employed a straightforward two-step process to generate phytate metal salt wood composites (PAN-M, M = Mg, Cu, Fe, Ai and Ni) in cell walls. Compared with natural wood (Control), PAN-M has good leaching resistance of 15~50%, lower hygroscopicity of 15~30% and improved mechanical strength. The total heat release and smoke emission of PAN-Cu are reduced by 34.54% and 83.05% respectively, the LOI of PAN-Cu is increased by 117%, the smoke density SDR is only 8.38 and the weight gain is 16.9%. This is mainly due to the apparent surface coke protection of metal phytates and catalytic graphitisation of solid residues by metal ions. The improved carbon layer plays an effective insulating role, limiting flue gas emissions, flame retardant loss and water contact. In addition, results show that PAN-Cu can significantly enhance the dehydration effect of carbon compared to other metal ions. Therefore, PAN-M is an efficient, green and sustainable flame retardant for wood. [ABSTRACT FROM AUTHOR]

The global demand for sustainable building materials has fuelled research into composite panels from wood waste. Despite their potential, the widespread adoption of this practice is hindered by the absence of quality standards, inconsistent material properties, and uncertainties about durability and strength. This paper critically reviews existing standards, manufacturing processes, and the suitability of panels from wood waste. A systematic review is conducted to identify the influencing processes and parameters affecting panel performance, from waste collection to the finishing stages. The findings indicate that incorporating 10–30% of wood waste can enhance the mechanical and physical properties, with particularly improved hygroscopic properties and greater dimensional stability. By establishing comprehensive standards and optimizing manufacturing processes, wood waste-based panels can emerge as a viable and eco-friendly alternative. Furthermore, the potential for repeated recycling in a closed-loop process offers promising environmental benefits, though it necessitates balancing resource conservation with product quality. By addressing these challenges, wood waste-based panels can significantly contribute to environmental conservation and resource management. [ABSTRACT FROM AUTHOR]

A new type of laminated flooring decorated by resin impregnated paper (LWFWRIP) was designed, with the advantages of low formaldehyde emission, improved flame retardant, and high wear resistance. The structure of this new type of wood flooring is based on the ordinary laminated flooring, followed by a decorative layer of thin wood pieces, and then the transparent improved flame retardant, wear-resistant paper is added to the top. It is found that the hot-pressing temperature is the most significant factor affecting the adhesion of resin impregnated paper. The optimal hot-pressing parameters are selected as the hot-pressing pressure of 3.5 MPa, hot-pressing temperature of 180 °C, and hot-pressing time of 40 s. The new laminated flooring was improved with high flame retardant, high wear-resistant, combined with the conventional advantages of both solid wood composite flooring and reinforced wood flooring. The new laminated flooring decorated by resin impregnated paper has broad application prospects. [ABSTRACT FROM AUTHOR]

This paper is based on research placed within the broader framework of the growing environmental impact requirements of building materials. Given this context, wood-based composite materials have emerged as a promising and innovative solution for structural elements. The current work aims to define a system for testing the mechanical behavior of glued laminated timber elements when exposed to high temperatures, in the neighborhood of the pyrolytic decomposition of materials. These tests monitor the transient behavior of the composite material and characterize the parameters involved in the thermo-mechanical analysis of elements constructed using this type of engineered wood product. The tests are used for the calibration of the material models involved in the numerical analysis and for the analysis of potential prototypes, considering the transient thermal load and heat propagation through the materials. By taking such tests, benchmark models and laboratory procedures are defined that can be used in the future to evaluate different materials, existing or new, and material combinations used to construct such a composite. [ABSTRACT FROM AUTHOR]

Logjams create an upstream backwater of deepened, slower water, locally reducing bed shear stress. We compared hydraulic impact of logjam series across 37 geomorphically diverse reaches of mountain streams observed over 11 years in the US Southern Rockies. To enable reach‐scale comparison of logjam structure and spacing, we identified the modeled best‐fit effective resistance coefficient minimizing difference between outflow exiting a 1D channel with logjams present, and the same model channel with elevated channel resistance. Effective resistance increased with ratio of jam upstream depth to depth without a logjam, ratio of backwater length to average spacing, and decreased for randomly distributed jams due to close spacing, which reduced backwater impact. An analytic approximation and boundaries for region of relative spacing with steepest increase in effective resistance are provided. Our results can assist in targeting interventions to areas where hydraulic impact is greatest, providing value for money in nature‐based solution design. Plain Language Summary: In a river channel, logjams created by wood pieces create upstream backwater regions with slower, deepened water. By creating a backwater, logjams increase heterogeneity of habitat and sediment transport and increase connection between river channel and floodplain. We compared logjams in 37 reaches of mountain streams in the US Southern Rockies. The sites studied had high variation in logjam density, channel steepness, channel width, and floodplain width. To compare between reaches and identify the ability of logjam backwaters to slow water within a river channel, we found an effective channel resistance coefficient that produced similar model output as a reach containing a series of logjams. The effective resistance increased with ratio of jam upstream depth to flow depth without a logjam, and ratio of backwater length to average spacing. The highest rate of increase in effective resistance with more logjams in the river reach occurs for an intermediate range of inter‐jam spacing relative to backwater length. Engineered logjam and wood addition projects could target this range to provide the most benefit per intervention. Key Points: We compared the hydraulic impact of logjams, identified by effective resistance, across 37 reaches and 11 years in the Colorado RockiesEffective resistance increases with decreasing stream power, analytically linked to dependence on jam structure and spacingObserved random jam distribution reduces effective resistance compared to uniform distribution, due to backwater truncation [ABSTRACT FROM AUTHOR]

The growing demand for sustainable building materials, amid escalating costs, has spurred interest in alternative solutions such as wood cement composites. This study explores the feasibility of producing wood cement boards (WCBs) using locally sourced cedar sawdust as a reinforcing agent. Boards with a thickness of 10 mm and a target density of 1200 kg/m3 were manufactured under pressures ranging from 2 to 6 MPa for 24 h. Cedar sawdust, used as raw and untreated material, was incorporated into the mixture as a partial substitute for cement in varying proportions, ranging from 10% to 25% (by weight). The WCBs were cured for 28 days under ambient conditions. Physical properties including density, water absorption (WA), and thickness swelling (TS) were assessed, along with mechanical properties through flexural tests. The results showed that increasing cedar sawdust content decreased both density and mechanical performance while increasing WA and TS. Microstructural analysis (SEM and EDS) revealed significant porosity at higher sawdust contents, while lower contents had better matrix–reinforcement cohesion. Additionally, substantial levels of calcium and silicon were detected on the sawdust surface, indicating stabilized cement hydration products. These findings, supported by thermal (TGA and DSC) and FTIR analyses, clearly demonstrate that cement boards with 10% cedar sawdust exhibit favorable properties for non-structural applications, such as wall and partition cladding. [ABSTRACT FROM AUTHOR]

The experiment carried out halogen-free flame retardant modification treatment on polyethylene-based wood-plastic composite materials. The results showed that after adding flame retardant, the ignition time of the material increased to 76 seconds, an increase of 22 seconds. At combustion temperatures above 530°C, only a small amount of the material's residue continues to evaporate. When the temperature rises to 800°C, the difference in the residual carbon content of the samples gradually becomes larger. The residual carbon content of sample 1# is only 10.1%. At this time, the residual carbon content of samples 7#, 8# and 9# are respectively Reaching 27.12%, 27.09% and 25.60%. The above results show that the thermal stability of composite materials has been greatly improved after adding nano-flame retardants, providing new ideas and methods for the application of flame retardant and halogen-free flame retardant materials of wood-plastic composites. [ABSTRACT FROM AUTHOR]

Modeling the dynamic properties of wood and wood-based composites is a challenging task due to naturally growing structure and moisture-dependent material properties. This paper presents the finite element modeling of plywood panels' dynamic properties. Two panels differing in thickness were analyzed: (i) 18 mm and (ii) 27 mm. The developed models consisted of individual layers of wood, which were discretized using three-dimensional finite elements formulated using an orthotropic material model. The models were subjected to an updating procedure based on experimentally determined frequency response functions. As a result of a model updating relative errors for natural frequencies obtained numerically and experimentally were not exceeding 2.0%, on average 0.7% for 18 mm thick panel and not exceeding 2.6%, on average 1.5% for 27 mm thick panel. To prove the utility of the method and at the same time to validate it, a model of a cabinet was built, which was then subjected to experimental verification. In this case, average relative differences for natural frequencies of 6.6% were obtained. [ABSTRACT FROM AUTHOR]