Search Results (3,086)

Autoclaved Aerated Concrete (AAC) is a lightweight construction material with strong relevance for energy-efficient and modular building systems, but its production remains constrained by steam-curing energy demand and carbon-intensive binders. This challenge is increasingly important as the AAC sector targets net-zero pathways and as cement and lime remain major contributors to life-cycle emissions in AAC products. This study develops an optimization framework for sustainable AAC production that leverages machine-learning surrogates for discrete-event simulations. We first construct a discrete-event factory model that represents mix preparation, mould pouring and rising, cutting, autoclaving, unloading, and product handling. We then couple the simulation to a ${\mathrm{CO}}_2$e and cost model and generate 116,640 production scenarios. Machine-learning surrogate models are trained to predict total ${\mathrm{CO}}_2$e emissions, cost, and production time, and a gradient-based optimization procedure is used to identify operating strategies under different carbon, cost, time, and balanced priorities. The results show that, autoclaving time, electricity carbon intensity, and cement use are the two most important environmental levers. The carbon–cost and carbon-priority strategies produced the lowest predicted emissions, approximately 1292 kg CO₂e, and selected the lowest electricity emission factor and cement mass considered in the design space, 0.05 kg CO₂e/kWh and 400 kg, respectively. The time-priority strategy produced the shortest predicted production time but the highest predicted emissions and cost, demonstrating a clear carbon–cost–time trade-off under the model assumptions. The proposed framework provides a practical decision-support tool for AAC manufacturers to compare production strategies, quantify trade-offs, and identify lower-carbon operating regimes before implementation. Full article

The integration of bio-based constituents into cementitious materials requires robust predictive models capable of describing mechanical degradation while supporting sustainability-driven material design. This study presents a macro-constitutive damage modelling framework for biomass-modified cement mortars subjected to monotonic compressive loading, combining experimental characterisation, continuum damage mechanics (CDM), and life-cycle assessment (LCA). The calibrated parameters are interpreted in terms of meso-scale mechanisms, but the study does not constitute a direct imaging-based multiscale characterisation. Mortars containing 0–10% dried microalgal biomass as a partial replacement for binder mass were investigated through their complete compressive stress–strain response. A scalar damage variable was employed to model stiffness degradation and progressive microcrack evolution, enabling the identification of elastic-modulus reduction, damage-initiation thresholds, softening behaviour, and residual load-bearing capacity. A thermodynamically consistent Mazars-type damage model was calibrated against the measured envelopes and internally verified by reproducing the same pre-peak and post-peak responses, with coefficients of determination ranging from 0.979 to 0.996. Increasing biomass content reduced the 28-day compressive strength from 47.8 to 23.7 MPa and the elastic modulus from 27.5 to 14.9 GPa, while increasing the damage level at peak load from 0.26 to 0.46 and promoting a more gradual post-peak softening response. The calibrated law provides a compact constitutive representation within the tested replacement range; independent external validation is still required before extrapolation to other biomass types, mixture proportions, or curing regimes. In parallel, a cradle-to-gate LCA quantified global warming, acidification, eutrophication, ozone depletion, and abiotic depletion potentials. An integrated carbon-efficiency index was used to relate mechanical performance to environmental impact. Biomass replacement reduced global warming potential by up to 7.7% but increased eutrophication potential, highlighting a clear performance–environment trade-off. Despite the reduction in mechanical properties, all mixtures satisfied masonry-unit strength requirements, supporting the application of biomass-modified mortars in low-carbon concrete masonry units. The proposed framework demonstrates how experimentally calibrated damage models can support the structural assessment and sustainable development of emerging bio-based cementitious materials. Full article

Earthen heritage constitutes a significant yet vulnerable component of the world’s cultural legacy, encompassing archeological sites, historic monuments, vernacular buildings, and living cultural landscapes. Over the past five decades, approaches to its conservation have evolved in response to changing heritage paradigms. Since their inception in 1972, the international Terra events have played a pivotal role in shaping this field by providing a recurring platform for international exchange, knowledge production, and methodological development. This study aims to examine the shifts in research and practice through the lens of the Terra gatherings. Using a systematic review methodology conducted in accordance with the PRISMA 2020 guidelines, 638 papers from thirteen Terra proceedings (1972–2022) were analyzed and classified by geographic focus, disciplinary background, knowledge area, heritage type, construction techniques, deterioration factors, and intervention methods. The findings reveal a clear transition from early material and monument-centered approaches toward more holistic, interdisciplinary, and people-centered frameworks, with increasing attention to vernacular heritage, cultural landscapes, heritage management, and capacity building. The analysis also identifies persistent regional imbalances, a strong link between conference location and geographic representation, and a growing focus in recent decades on sustainability, disaster risk reduction, and climate change. Overall, the study demonstrates how trends reflected within the Terra proceedings have evolved and contributed to the discourse in earthen heritage conservation. Full article

Sustainable construction has emerged as a strategic response to contemporary environmental, social, and economic challenges, particularly in sectors with high resource consumption, such as logistics infrastructure. This study adapts and applies existing sustainability assessment frameworks to the specific context of logistics buildings by integrating Leadership in Energy and Environmental Design (LEED) sustainability criteria with a Triple Bottom Line (TBL)-based materiality matrix. The research investigates how sustainability practices associated with LEED criteria can contribute to economic, environmental, and social performance within the TBL framework. To support this assessment, a materiality matrix is developed by integrating stakeholder perspectives and the potential impacts of sustainability practices across TBL dimensions, enabling the identification and prioritization of the most relevant strategies for the logistics context. Additionally, the study examines the contribution of LEED-based strategies to the Sustainable Development Goals (SDGs) within these dimensions. The main contribution of the study is the adaptation and application of established sustainability assessment frameworks to logistics projects through a structured decision-support framework that integrates LEED sustainability criteria, stakeholder-based materiality assessment, TBL perspectives, and sensitivity analysis to support sustainability-oriented decision-making. Full article

The building industry is central to climate change mitigation because it generates substantial energy use and carbon emissions across the full building life-cycle, from material production to operation. Passive and energy-efficient designs, renewable energy integration, use of low-carbon and reusable materials, digital optimization, and circular waste management can minimize operational and embodied emissions, and climate-responsive design can enhance heat, water stress, and other environmental resilience. This study explores sustainable construction practices and climate change mitigation strategies in four different economies: China, Malaysia, South Africa, and Peru. Based on questionnaire data collected from professional engineering and green building networks associated with the World Federation of Engineering Organizations (WFEO), the study applies thematic analysis to compare national priorities and strategies. The findings show that each country pursues sustainability according to its resources, development needs, environmental challenges, and technological strengths. China and Malaysia emphasize energy-efficient design and digital building systems, South Africa focuses on climate-responsive design and material recovery, while Peru prioritizes bio-based materials and local solutions. Overall, renewable energy, circularity, resource optimization, and digital technologies emerge as key trends in advancing low-carbon, climate-resilient construction. Full article

Rapid and reliable prediction of embodied carbon emissions is essential for supporting sustainable design decision-making and reducing the environmental impacts of building engineering projects. However, existing studies have mainly focused on single buildings, with limited attention to project-level prediction and variations in information availability across design stages. To address this gap, this study developed a machine learning framework for project-level embodied carbon prediction based on a dataset of 78 projects involving 426 individual buildings. Using project attributes, scale indicators, structural characteristics, material quantities, and construction-related information, nine machine learning models were developed for the schematic design stage and the construction drawing design stage. Two residual-corrected weighted ensemble models were further introduced to improve predictive performance. The results show that the Extra Trees–KNN residual-corrected weighted ensemble model achieved the best performance at the construction drawing design stage, with a test-set R² of 0.949. SHAP analysis further revealed a stage-dependent shift in dominant drivers: gross floor area and land area dominated at the schematic design stage, whereas concrete and reinforcement quantities became the leading predictors at the construction drawing design stage. The proposed framework provides interpretable and stage-specific quantitative support for low-carbon design decision-making, thereby facilitating embodied carbon reduction and the transition toward a more sustainable built environment. Full article

This study investigates the influence of wood fly ash (WFA) and wood bottom ash (WBA) as a partial replacement of Portland cement (PC) on the mechanical performance and durability of cement mortars. Mortar mixtures containing 20% WFA (FA-20) and 20% WBA (BA-20) were compared with a reference mixture (REF) using bending and compressive strength tests, ultrasonic pulse velocity (UPV), total water absorption (TWA), and durability tests such as alkali–silica reaction (ASR) and carbonation resistance. The results showed that BA-20 exhibited higher mechanical performance and a denser microstructure than FA-20, as confirmed by UPV and TWA. At 365 days, compressive strength reached 71.9 MPa for REF, 64.3 MPa for BA-20, and 43.7 MPa for FA-20. Durability results indicated that after 365 days, REF exhibited the highest ASR expansion (~0.50%), whereas the incorporation of wood ash reduced expansion to approximately 0.41% for FA-20 and 0.29% for BA-20. In terms of carbonation resistance, FA-20 showed the greatest accelerated carbonation depth (10–14 mm), while REF exhibited the lowest carbonation depth (~3 mm). The differences were attributed to PC dilution and microstructural variations affecting porosity and transport properties. WBA demonstrated better performance than WFA, highlighting the importance of wood ash particle characteristics in PC replacement applications. Full article

With the rapid development of the global aluminum industry, the production of aluminum dross, as a hazardous solid waste generated in the aluminum production process, has increased annually. Aluminum dross contains not only substantial amounts of harmful substances, such as aluminum nitride, fluoride, and chloride, but also valuable resources such as metallic aluminum and alumina. This review summarizes the sources, composition, and hazards of aluminum dross to the environment and human health, with a focus on the harmless treatment and resource utilization technologies for aluminum dross. Harmless treatment technologies include denitrification, defluorination, and dechlorination, which are primarily classified into hydrometallurgical and pyrometallurgical methods. In terms of resource utilization, primary aluminum dross (PAD) was mainly used to extract metallic aluminum through heat treatment and cold treatment, while secondary aluminum dross (SAD) can be used to prepare refractory materials, building materials, water treatment agents, and extract alumina. This review also compares the advantages and disadvantages of current aluminum dross treatment technology and outlines future research directions, aiming to provide a reference for the sustainable development and environmental protection of the aluminum industry. Full article

As rooftop photovoltaic (PV) systems are increasingly deployed on taller buildings and across a wider range of building applications, localized overheating or initial fires caused by electrical faults, combustible roof-covering materials, or maintenance-related ignition sources may affect PV modules and contribute to subsequent fire spread over the rooftop system. In this study, a full-scale fire experiment was conducted on a flat-laid rooftop PV system using a nominal 100 kW n-heptane pan fire as a controlled localized external fire source to investigate the fire development and escalation mechanism of the system. The results show that the fire hazard was first and primarily concentrated in the confined under-panel space: the average cavity peak temperature of the ignited array reached 684.0 °C, with a local maximum of 853.4 °C, both significantly higher than the maximum upper-surface center temperature of 370.7 °C. The involvement of the waterproofing membrane in combustion was the key amplifying mechanism driving the transition from localized heating to a sustained high-temperature event; the average cavity temperature exceeded 500 °C after 234 s and remained above this threshold for approximately 201 s, with an average cavity heat accumulation index of 178.1 × 10³ °C·s. Compared with the lower upper-surface center measuring points, hazardous temperatures beneath the modules were reached earlier by 149, 193 and 247 s at the thresholds of 50, 100 and 200 °C, respectively. Under the tested configuration, these findings provide engineering insights for fire-risk identification, early monitoring, and fire-safe design of flat-laid rooftop PV systems in high-rise building applications. Full article

Population ageing and the need to provide affordable, healthy, and energy-efficient housing represent important sustainability challenges in many European countries. Sustainable senior housing should not only reduce environmental impacts through low-carbon construction technologies but also ensure high indoor environmental quality and occupant well-being. This paper presents a preliminary assessment of predicted thermal comfort and local thermal discomfort in a prototype senior home constructed a prefabricated timber-based building system incorporating renewable and recycled materials and designed to support low operational energy demand. The research forms part of a broader development study of technology, in which indoor thermal conditions were monitored in a prototype building consisting of two 30 m² residential units intended for older adults. Predicted thermal comfort was evaluated using the PMV (Predicted Mean Vote) and PPD (Predicted Percentage of Dissatisfied) indices together with local thermal discomfort criteria. The analysis was based on short-term winter and summer measurement campaigns conducted in the prototype building. The results indicated category B thermal environment conditions in both winter and summer according to ISO 7730. In winter, local discomfort associated with a cool floor corresponded to category C, while summer conditions met category B requirements without significant local discomfort. The findings provide preliminary evidence that timber-based low-carbon construction technologies can support acceptable indoor thermal conditions while addressing environmental and social sustainability objectives related to an ageing population. The study also identifies the need for longer monitoring campaigns and future investigations involving older occupants to validate actual thermal sensation and further optimize sustainable senior housing solutions. Since the building was unoccupied during the measurements, the results should be interpreted as a prediction of predicted thermal comfort conditions rather than an assessment of thermal sensations experienced by older adults. Full article

Ventilated façades are increasingly used in building renovations, often containing non-renewable and CO₂-emissions-intensive cement-based materials. Renewable biomass-based materials offer a more sustainable alternative with a high amount of sequestered CO₂. However, water uptake is a critical factor in exterior applications. This study investigates the water resistance of high-density particleboards made of wheat straw (WS), grey alder (GA), and softwood (SW) for façade-related exterior applications. Two general board types were produced from each biomass using (1) steam explosion (SE) treatment and (2) the addition of birch-bark-derived suberinic acids (SAs) as the bio-based binder. In addition, the influence of conventional and mold hot pressing was investigated. The particleboards were coated with four types of innovative finishes, comprising (1) purified SA, (2) SA + chitosan (SH), (3) SA + earth pigment (SP), and (4) SHP. The water resistance of the particleboards was evaluated using an internal bonding (IB) test after 2 h of boiling and by measuring the water drop contact angle. FTIR analysis was performed to identify differences between the board varieties and to explain the obtained results. Only two board varieties (GASA and SWSA) fulfilled the Type P5 EN 312 water resistance requirement (0.15 N/mm²), achieving IB values of 0.81 ± 0.23 N/mm² and 0.22± 0.07 N/mm², respectively. In turn, the coatings used did not significantly increase the static contact angle compared to the reference board. Although the results of this study confirm the inherent moisture sensitivity of engineered particleboards, two board varieties demonstrate promising potential for façade-related exterior applications. Full article

Soft iontronic devices, which utilize ions as charge carriers and integrate flexibility and stretchability, exhibit diverse carrier species, high biocompatibility, multimodal stimulus responsiveness, and strong resistance to electromagnetic interference. These features make them highly promising for applications in ionic circuits, flexible sensing, implantable systems, and neuromorphic information processing. Among them, soft iontronic diodes have attracted sustained attention over the past two decades as fundamental building blocks of functional circuits. This review systematically summarizes the material types of soft iontronic diodes and their influence on key device performance. It further elucidates the mechanisms underlying ionic rectification and highlights recent advances in logic gate implementation, energy harvesting, flexible sensing, and neuromorphic computing. Finally, we discuss key challenges and future opportunities in this field, aiming to provide design principles and mechanistic insights for the development and application of soft iontronic diodes. Full article

The construction sector accounts for over 30% of global material extraction and up to 40% of solid waste, making Construction and Demolition Waste (CDW) a major sustainability challenge. This study applies the Digital Circularity Alignment Model (DCAM), supported by evidence from the RECONMATIC project, to compare policy and technological transition pathways toward circular construction in the European Union, the United Kingdom, and China. The analysis examines interactions between regulatory instruments and digital infrastructures, including Building Information Modelling (BIM) and Digital Product Passports. Results reveal a global shift toward mandatory lifecycle transparency, where digital tools function as compliance infrastructures. Crucially, the comparative review identifies distinct governance drivers: EU supranational regulation, UK procurement-driven frameworks, and Chinese state-led macroeconomic planning. Despite these differences in governance approaches, progress remains constrained by fragmented data ecosystems, limited interoperability, and uneven institutional capacity. The findings show that the principal barrier to scaling circularity is not technological availability but the misalignment between policy frameworks, data standards, and implementation mechanisms. Achieving a zero-waste construction sector by 2050 therefore requires interoperable data ecosystems and stronger policy–technology alignment. Full article

The increasing demand for sustainable building materials has motivated the search for alternative supplementary cementitious materials to reduce the use of Portland cement while maintaining concrete performance. The present study aims to investigate the synergistic effects of bagasse ash (BA) and rice husk ash (RHA) as partial cement replacements in ternary blended concrete. Previous studies used agricultural ashes individually or in binary form only, whereas in the present work, the synergistic effect of BA and RHA is systematically studied, and Response Surface Methodology (RSM) is used to develop predictive models and optimize the performance of concrete. The slump, compressive strength and splitting tensile strength were evaluated using a Central Composite Design (CCD) to determine the effect of the levels of replacement of BA and RHA. Quadratic regression models were built and evaluated using analysis of variance (ANOVA). All models were statistically significant (p < 0.05) and had high predictive accuracy (R² > 0.92). The results revealed that increases in BA and RHA contents reduced the workability because of their high specific surface areas and porous structures, while moderate combinations improved the compressive and splitting tensile strengths due to the synergistic filler effects, secondary pozzolanic reactions, and matrix densification. The multi-objective optimization based on the desirability function provided an optimal mixture of 5% BA and 15% RHA with an overall desirability of 92.8%, which provided the best compromise between workability and mechanical performance. Experimental validation of the optimized mixture showed good agreement of the model predictions with prediction errors of less than 5%, confirming the reliability and robustness of the developed RSM models. The results show that synergistic use of BA and RHA is a feasible and sustainable solution for producing high-performance ternary blended concrete and provides a reliable framework for the optimization of the mixture. Full article

The substantial volume of agrifood processing side streams represents a global sustainability challenge that requires transformation of agricultural residues into high-value molecular components. Grape pomace (GP) is a major winemaking co-product whose chemical diversity remains underutilized due to a lack of high-resolution structural data. This study applies advanced analytical platforms to provide a comprehensive molecular characterization of oligosaccharides (OS) and phenolics in GP from four grape varieties (Chardonnay, Sauvignon Blanc, Pinot Noir, and Merlot) from California. Results demonstrate that the molecular signature of the material is highly dependent on the variety and its corresponding processing; white wine pomaces exhibited significantly higher residual sugars and generally greater OS diversity compared to red wine pomaces. Using LC-Q-ToF-MS, 39 oligosaccharides were identified, primarily composed of hexoses and pentoses. Characterization of the OS building blocks via LC-QqQ-MS revealed the dominance of glucose and fructose, followed by arabinose and xylose. In parallel, targeted phenolics quantification by UPLC-DAD showed that (+)-catechin and (−)-epicatechin accounted for up to 50% of quantified phenolics in Chardonnay pomace and 45% in Pinot Noir pomace. This work highlights the molecular intricacies of GP, providing a compositional foundation for its targeted valorization. Full article