Search Results (153)

Rejuvenating aged asphalt is critical for sustainable road construction and resource utilization. This paper systematically reviews the current research on rejuvenators, focusing on their classification and the micro-, and macro-properties of rejuvenated asphalt. Rejuvenators are categorized into mineral oil-based, bio-based, and compound types. Each type offers distinct advantages in recovering the performance of aged asphalt. Mineral oil-based rejuvenators primarily enhance low-temperature cracking resistance through physical dilution, while bio-based rejuvenators demonstrate superior environmental sustainability and stability. Compound rejuvenators, particularly those incorporating reactive compounds, show the best results in repairing degraded polymer modifiers and improving both low- and high-temperature properties of aged, modified asphalt. Atomic Force Microscopy (AFM), Fluorescence Microscopy (FM), and Scanning Electron Microscopy (SEM) have been applied to analyze the micro-properties of rejuvenated asphalt. These techniques have revealed that rejuvenators can restore the microstructure of aged asphalt by dispersing agglomerated asphaltenes and promoting molecular mobility. Functional groups and molecular weight changes, characterized by Fourier Transform Infrared Spectroscopy (FTIR) and Gel Permeation Chromatography (GPC), indicate that rejuvenators effectively reduce oxidation products and molecular weight of aged asphalt, restoring its physicochemical properties. Macro-property evaluations show that rejuvenators significantly improve penetration, ductility, and fatigue resistance. Finally, this review identifies the key characteristics and challenges associated with rejuvenator applications and provides an outlook on future research directions. Full article

The construction sector accounts for one-third of Europe’s total greenhouse gas (GHG) emissions, offering significant potential for emission reduction. Emission reduction can be achieved by substituting conventional building materials with wood- or bio-based alternatives; the difference in GHG emissions is referred to as the substitution potential (SP). In this study, a literature review was conducted to identify studies in which SPs had been determined. The calculation methods used for these SPs were then analysed in detail. The analysis considered the general conditions, outcomes, and scaling effects, revealing that differing initial conditions lead to inconsistent results. Therefore, transparent allocation of SPs and comparable product life cycle assessments (LCAs) based on functional equivalence are essential. To reliably extrapolate the benefits of wood use to the entire construction sector, scaling effects must be justified by consistent functional equivalence. For policy relevance, it is crucial that SPs are determined using the standardised rules and that the building level, as the actual place of material use, is not overlooked. This is particularly important when scaling up the effects of increased wood use to the landscape level. Only with these measures SPs at the product level can provide reliable results in a broader context. Additionally, the studies reviewed indicate that changes in forest management have not yet been considered. Full article

Growing environmental concerns and the depletion of fossil-based resources have accelerated the demand for sustainable alternatives in engineering and construction materials. Among these, bio-based composites have gained attention for their use of renewable and eco-friendly resources. Macadamia nutshells, typically treated as agricultural waste, possess high strength, brittleness, heat resistance, and fracture toughness, making them attractive candidates for structural applications. Australia alone contributes nearly 40% of global macadamia production, generating significant shell by-products that could be repurposed into high-value composites. This study investigates the development of novel composite cores and sandwich structures using macadamia nutshell particles reinforced in an epoxy polymer matrix. Two weight ratios (10% and 15%) and two particle sizes (200–600 µm and 1–1.18 mm) were employed, combined with laminating epoxy resin and hardener to fabricate composite cores. These cores were further processed into sandwich specimens with carbon fabric skins. Flexural and short beam shear (SBS) tests were conducted to evaluate the mechanical behaviour of the composites. The results demonstrate that higher filler content with fine particles achieved up to 15% higher flexural strength and 18% higher stiffness compared to coarser particle composites. Sandwich structures exhibited markedly improved interlaminar shear strength (8–15 MPa), confirming superior load transfer and durability. The results demonstrate that higher filler content and finer particles provided the most favourable mechanical performance, showing higher flexural strength, stiffness, and shear resistance compared to coarser particle formulations. Sandwich structures significantly outperformed core-only composites due to improved load transfer and resistance to bending and shear stresses, with the 15% fine-particle configuration emerging as the optimal formulation. By transforming macadamia nutshells into value-added composites, this research highlights an innovative pathway for waste utilisation, reduced environmental impact, and sustainable material development. The findings suggest that such composites hold strong potential for structural applications in construction and related engineering fields, especially in regions with abundant macadamia production. This study reinforces the role of agricultural by-products as practical solutions for advancing green composites and contributing to circular economy principles. Full article

This study examines the incorporation of biodiversity loss into the Life Cycle Assessment (LCA) of buildings, with a specific focus on the Danish construction sector. Motivated by the ecological crisis reflected in the Planetary Boundaries and the Kunming-Montreal Global Biodiversity Framework, it addresses regulatory gaps that prioritise climate indicators, such as Global Warming Potential (GWP), while largely ignoring biodiversity. The study analyses 73 Danish building cases for GWP and a custom method linking material quantities to ReCiPe 2016 endpoint data for biodiversity loss. The findings indicate key methodological issues include the quality of Environmental Product Declarations (EPDs), the regional relevance of assessment methods, and differences in European standards. While average GWP levels mostly meet upcoming Danish limits, variability, especially in Office and Other building categories, supports the need for differentiated regulations. Results show embodied impacts mainly drive GWP, while biodiversity loss is split between embodied and operational impacts. Detached and Terraced houses, which use more bio-based materials, have low embodied GWP but higher biodiversity loss, highlighting trade-offs in regenerative design. The shift in GWP impacts to end-of-life phases stresses the need to consider forest dynamics. Operational impacts rank similarly, despite differences in the data. The study concludes that progress toward regenerative design requires addressing climate and biodiversity together to avoid shifting environmental burdens. Full article

Reducing thermal losses through building envelopes remains a key strategy in the pursuit of low-carbon, energy-efficient buildings. This study presents an innovative and sustainable retrofitting approach involving thermal insulation plaster modified with finely ground hazelnut shells, an abundant agricultural by-product in Türkiye. The modified plaster is applied symmetrically on both sides of standard masonry briquettes in varying proportions (2%, 4%, and 6%), and its thermal performance is experimentally assessed via the laboratory-scale coheating test method. The results reveal a substantial reduction in U-values compared to the uninsulated briquette (5.5 W/m²K): the 2% shell-modified plaster achieves a U-value of 2.40 W/m²K (56.4% improvement), the 4% variant achieves 2.14 W/m²K (61.1%), and the 6% formulation performs best at 2.04 W/m²K (62.9%). In terms of effective thermal conductivity, the modified plasters exhibit values in the range of 0.0408–0.04856 W/mK. Additionally, the 6% composition exhibits enhanced thermal inertia, delaying internal heat loss and offering extended indoor comfort. All samples demonstrate exceptional measurement repeatability, with day-to-day U-value variation below 2%. These findings surpass thermal performance benchmarks reported in previous studies using bamboo or plaster thickness alterations, and position hazelnut shell-modified plaster as a high-potential solution for sustainable building retrofits. The outcomes offer practical implications for low-cost housing, rural construction, and building refurbishment programmes, while also informing policymakers and material standardisation bodies about scalable bio-based alternatives that align with circular economy and decarbonisation goals. Full article

The Digital Product Passport (DPP) is an emergent strategic tool poised to significantly enhance traceability, circularity, and sustainability within industrial supply chains, aligning with evolving European Union regulatory frameworks. This paper introduces a conceptual sensor-based DPP architecture specifically designed for the construction industry, exemplified by a real case study for a bio-based manufacturing company. This framework facilitates a transparent and accessible data management approach, crucial for fostering circular practices and guiding stakeholders in decision-making along the value chain. The proposed architecture addresses critical challenges in product-related traceability and information accessibility across the entire product life cycle, spanning from raw material supply to the construction and installation process (A1–A5 stages). Data collected from the low-tech sensor network and digital tools can generate relevant environmental indicators for Life Cycle Assessment (LCA) and DPP creation, thereby offering a comprehensive, detailed, and certified overview of product attributes and their environmental impacts. The study clarifies the benefits and current barriers to implementing a sensor-based DPP architecture in low-tech construction manufacturing, underscoring the potential of lightweight, interoperable sensing solutions to advance compliance, transparency, and digitalization in traditionally under-digitized sectors like construction materials manufacturing. Full article

In the pursuit of low-impact and renewable construction materials, various by-products from agriculture, forestry, and the wood processing industry are being explored as potential bio-based infill materials for wall assemblies. This study presents an experimental assessment of the fire performance of timber wall systems composed of block units filled with different lignocellulosic materials, subjected to radiative heat exposure. These assemblies are representative of external walls in contemporary timber-framed buildings. Two configurations were examined: one with sawdust infill and the other with wood pellet infill. Both samples were exposed to radiant heat from the interior side for 60 min, simulating conditions of a fully developed compartment fire. The applied heat flux was 20 kW·m⁻², delivered by a calibrated radiant panel. The results indicate that even minor design variations—particularly the choice of infill material—can significantly influence the thermal response, degradation kinetics of wood-based components, and the overall fire resistance of the wall assembly. The sawdust-filled system exhibited superior performance, achieving an estimated fire resistance rating of 60 min (60 REI). It showed reduced internal thermal degradation compared to the pellet-filled variant, which experienced greater charring depth due to internal voids between pellets, although it maintained structural integrity. Full article

This study investigates how perceptual and emotional factors—perceived naturalness, aesthetic pleasure, environmental concern, and disgust—shape consumer acceptance of a human-hair-derived bio-fabricated textile product (a unisex cardholder). In a scenario-based online survey, participants viewed an AI-generated image accompanied by a short vignette. A purposive sample of young adults in Istanbul with prior experience purchasing sustainable textile products was recruited and screened. All constructs were measured with standard Likert-type scales and translated into Turkish using a two-way back-translation procedure. Data were analyzed with PLS-SEM. Model fit was acceptable, and the model accounted for a substantial share of the variance in adoption intention. Aesthetic pleasure showed a clear positive influence on adoption intention, whereas perceived naturalness did not display a direct effect. Environmental concern modestly strengthened the link between naturalness and adoption. Disgust emerged as the dominant moderator, fully conditioning the naturalness pathway and reducing—but not eliminating—the effect of aesthetic pleasure. Together, these findings indicate that perceived naturalness, aesthetic pleasure, environmental concern, and disgust jointly shape adoption intention and that practical emphasis should be placed on reducing feelings of disgust while enhancing aesthetic appeal. Full article

Fiber-reinforced composites (FRCs) have emerged as transformative alternatives to traditional marine construction materials, owing to their superior corrosion resistance, design flexibility, and strength-to-weight ratio. This review comprehensively examines the current state of FRC technologies in marine deck and underwater applications, with a focus on manufacturing methods, durability challenges, and future innovations. Thermoset polymer composites, particularly those with epoxy and vinyl ester matrices, continue to dominate marine applications due to their mechanical robustness and processing maturity. In contrast, thermoplastic composites such as Polyether Ether Ketone (PEEK) and Polyether Ketone Ketone (PEKK) offer advantages in recyclability and hydrothermal performance but are hindered by higher processing costs. The review evaluates the performance of various fiber types, including glass, carbon, basalt, and aramid, highlighting the trade-offs between cost, mechanical properties, and environmental resistance. Manufacturing processes such as vacuum-assisted resin transfer molding (VARTM) and automated fiber placement (AFP) enable efficient production but face limitations in scalability and in-field repair. Key durability concerns include seawater-induced degradation, moisture absorption, interfacial debonding, galvanic corrosion in FRP–metal hybrids, and biofouling. The paper also explores emerging strategies such as self-healing polymers, nano-enhanced coatings, and hybrid fiber architectures that aim to improve long-term reliability. Finally, it outlines future research directions, including the development of smart composites with embedded structural health monitoring (SHM), bio-based resin systems, and standardized certification protocols to support broader industry adoption. This review aims to guide ongoing research and development efforts toward more sustainable, high-performance marine composite systems. Full article

Measuring the bioeconomy enables policymakers to monitor advancements in sustainable development goals, identify growth opportunities, comprehend the economic implications of bio-based products, assess environmental impacts, and shape policies that foster a sustainable economy reliant on renewable biological resources. For this purpose, this study measures the value of the bioeconomy in New Zealand using the latest published input–output table for the year 2020. This study estimates the size and economic significance of New Zealand’s bioeconomy by applying two complementary methodologies. Results indicate that, in 2020, the total value added by the bioeconomy ranged from NZD 48.8 billion to NZD 50.8 billion, representing 16.5% to 17.1% of the nation’s total value added. Agriculture emerged as the dominant contributor, accounting for approximately 89% of the sector’s total value added, followed by forestry and logging at around 11%. To identify potential growth areas, the analysis further disaggregated bioeconomy value added by economic subsectors. Among bio-based industries, food manufacturing was the largest contributor, generating 43.1% (NZD 21 billion) of total bioeconomy value added, followed by bio-based services at 12.9% (NZD 6.3 billion). The biotechnology sector contributed NZD 0.34 billion, equivalent to 0.7% of the total bioeconomy. Additional significant contributors included wood processing and manufacturing (3.3%; NZD 1.6 billion), construction (0.71%; NZD 0.35 billion), and textiles and clothing (0.58%; NZD 0.29 billion). These findings underscore the pivotal role of food manufacturing, services, wood processing, textiles and clothing, and construction in shaping the bioeconomy. They further highlight the importance of assessing the economic and environmental impacts of bio-based industries and formulating policy frameworks that support a sustainable, renewable resource-based economy. Full article

The growing demand for sustainable and energy-efficient construction has driven significant interest in the development of advanced insulation materials that reduce energy usage while minimizing environmental impact. Although conventional insulation materials such as polyurethane, polystyrene, and mineral wools offer excellent thermal and acoustic performance, they are derived from non-renewable sources, have high embodied carbon (EC) (up to 7.3 kg CO₂-eq/kg), and pose end-of-life disposal challenges. Thus, this review critically examines the emergence of insulation materials derived from natural and recycled sources, which align with circular economy principles by minimizing waste, promoting material reuse, and extending product life cycles. Sustainable alternatives such as sheep wool, hemp, flax, and jute not only exhibit competitive thermal conductivity (as low as 0.031–0.046 W/m·K) and very good sound absorption but also offer low EC, biodegradability, and regional availability. Despite some limitations, including variable fire resistance and thickness requirements, these bio-based insulators present a viable path toward greener building solutions. The review highlights that waste-based insulation materials are essential for sustainable construction due to their low EC, renewability, and contribution to waste reduction, making them a necessary alternative even when conventional materials demonstrate superior short-term performance. Full article

The increasing demand for sustainable building solutions has directed attention toward bio-based materials, among which mycelium bio-composites (MBCs) have emerged as promising alternatives to traditional insulation materials. Grown from fungal mycelium and lignocellulosic waste, MBCs offer low embodied energy, biodegradability, and effective hygrothermal performance. This review assesses the current state of the art in MBC fabrication and hygrothermal properties, encompassing both laboratory-scale and industrial methods. MBCs demonstrate thermal conductivity values in the range of 0.036–0.06 W·m⁻¹·K⁻¹, moisture buffering capacity comparable to plant-fiber composites, and up to 70% lower embodied carbon than conventional materials. Key challenges are identified, including process standardization, scalability, and durability under real-world conditions. These composites also offer moisture buffering, compostability, and design flexibility. Moreover, recent advancements in additive manufacturing and microstructural optimization suggest a path toward broader adoption of MBCs in construction. By highlighting critical technical and scientific developments, this review identifies targeted research priorities, including the development of standardized fabrication protocols, quantitative lifecycle assessment of MBCs across varying climates, and strategies to scale up production while maintaining mechanical and hygrothermal consistency. Full article

Mycelium-based composites (MBCs) are an emerging category of cost-effective and environmentally sustainable materials that are attracting significant research and commercial interest across various industries, including construction, manufacturing, agriculture, and biomedicine. These materials harness the natural growth of fungi as a low-energy bio-fabrication method, converting abundant agricultural by-products and waste into sustainable alternatives to energy-intensive synthetic construction materials. Their affordability and eco-friendly characteristics make them attractive for both research and commercialisation. Currently, mycelium-based foams and sandwich composites are being actively developed for applications in construction. These materials offer exceptional thermal insulation, excellent acoustic absorption, and superior fire safety compared to conventional building materials like synthetic foams and engineered wood. As a result, MBCs show great potential for applications in thermal and acoustic insulation. However, their foam-like mechanical properties, high water absorption, and limited documentation of material properties restrict their use to non- or semi-structural roles, such as insulation, panelling, and furniture. This paper presents a comprehensive review of the fabrication process and the factors affecting the production and performance properties of MBCs. It addresses key elements such as fungal species selection, substrate choice, optimal growth conditions, dehydration methods, post-processing techniques, mechanical and physical properties, termite resistance, cost comparison, and life cycle assessment. Full article

The catalytic conversion of bio-based glycerol (Gly) into high-value glycerol carbonate (GC) has received great attention from both the academic and industrial fields. The development of highly efficient catalysts and economical industrial processes remains a challenging subject. In this mini-review, we summary the recent advances in catalyst design, characterization, mechanism, and catalytic process optimization, including the various synthetic strategies of GC, such as the coupling of CO₂ and Gly or its derivatives like glycidol (GD), the transesterification of Gly with small carbonate-containing molecules, and the carbonylation of Gly with urea. The main difficulties and challenges faced by constructing high-performance catalysts and achieving scale production of GC have been put forward, and the future research directions and opportunities in catalyst innovation, reaction mechanism exploration, and continuous catalytic process improvement have also been suggested. Full article

The bio-fabrication of sustainable mycelium-based composites (MBCs) from renewable plant by-products offers a promising approach to reducing resource depletion and supporting the transition to a circular economy. In this research, MBCs were obtained by cultivating Ganoderma resinaceum GA1M on essential oils and agricultural by-products: hexane-extracted rose flowers (HERF), steam-distilled lavender straw (SDLS), wheat straw (WS), and pine sawdust (PS), used as single or mixed substrates. The basic physical and mechanical properties revealed that MBCs perform comparably to high-efficiency thermal insulating and conventional construction materials. The relatively low apparent density, ranging from 110 kg/m³ for WS-based to 250 kg/m³ for HERF-based composites, results in thermal conductivity values between 0.043 W/mK and 0.054 W/mK. Compression stress (40–180 kPa at 10% deformation) also revealed the good performance of the composites. The MBCs had high water absorption due to open porosity, necessitating further optimization to reduce hydrophilicity and meet intended use requirements. An aerobic biodegradation test using respirometry indicated ongoing microbial decomposition for all tested bio-composites. Notably, composites from mixed HERF and WS (50:50) showed the most rapid degradation, achieving over 46% of theoretical oxygen consumption for complete mineralization. The practical applications of MBCs depend on achieving a balance between biodegradability and stability. Full article