Search Results (113)

The building sector is a pivotal driver of global resource depletion and environmental deterioration, being responsible for 40% of raw material consumption, 16% of water usage, 25% of timber utilization, and 40% of total energy demand. It also accounts for 30% of worldwide greenhouse gas (GHG) emissions, predominantly CO₂. The operational phase of buildings is the most energy-intensive and emission-heavy stage, accounting for 85–95% of their total life-cycle energy consumption. This energy is primarily expended on heating, cooling, ventilation, and hot water systems, which are largely dependent on fossil fuels. Furthermore, embodied energy, the cumulative energy expended from the extraction of materials through construction, operation, and eventual demolition, plays a substantial role in a building’s overall environmental footprint. To address these pressing challenges, this study discusses sustainable innovations within green architecture and biomimicry. Our topic supports the 2030 vision Sustainable Development Goals (SDGs), both directly and indirectly (SDGs 7, 9, 11, 12, and 13). This study also explores cutting-edge applications, such as algae- and slime mold-inspired decentralized urban planning, which offer innovative pathways toward energy efficiency and sustainability. Considering the integration of renewable energy sources, passive design methodologies, and eco-friendly materials, this research emphasizes the transformative potential of biomimicry and green architecture in fostering a sustainable built environment, mitigating climate change, and cultivating a regenerative coexistence between human habitats and the natural world. Full article

The construction sector is responsible for over 40% of waste generated in Australia. Construction materials are responsible for around 11% of global carbon dioxide emissions, and a third of these materials can end up wasted on a construction site. Attention in research and industry has been directed towards waste management and recycling, resulting in 78% of construction and demolition waste being diverted from landfill. However, the waste hierarchy emphasises avoiding the generation of waste in the first place. In this paper, the PRISMA approach is used to conduct a systematic review with the objective of identifying waste reduction strategies employed across all stages of projects in the Australian construction industry. Scopus and Web of Science databases were used. The search returned 523 publications which were screened and reviewed; this resulted in 24 relevant publications from 1998 to 2025. Qualitative analysis identifies strategies categorised into five groupings: pre-demolition, design, culture, materials and procurement, and on-site activities. The review finds a distinct focus on strategies within the materials and procurement category. The reviewed literature includes fewer strategies for the avoidance of waste than for any of the other levels of the waste hierarchy, evidencing the need for further focus in this area. Full article

Background: Eighty-five percent of peri-implant malignancies are oral squamous cell carcinomas (OSCCs), and most of them are misdiagnosed as peri-implantitis because of their clinical and radiological presentation; few studies have focused on addressing and solving the diagnostic issues related to peri-implant OSCCs. Objectives: The study aimed to describe the clinicopathological features of peri-implant OSCCs and to report the staging issues related to the diagnosis of these lesions. Methods: This retrospective cohort study included patients who received a diagnosis of and treatment for peri-implant OSCCs at the Unit of Dentistry of the “Aldo Moro” University of Bari (Italy) from 2018 to 2024. By using descriptive statistics, the authors highlighted the diagnostic issues related to the clinical presentation, radiological features, and histology of peri-implant OSCCs. Results: A total of 13 women and 8 men with a mean age of 70.6 ± 11.7 years met the inclusion criteria; the medical history of the participants showed potentially malignant disorders (OPMDs) in 52.4% of patients, whereas 14.3% had already developed an OSCC. The patients showed 24 peri-implant OSCCs; the clinical presentation was leuko-erythroplakia-like (41.7%) or erythroplakia-like (58.3%), thus simulating peri-implantitis; in addition, 52.0% of dental implants involved had a probing pocket depth ≥ 10 mm, further mimicking peri-implantitis. Panoramic radiograms and cone beam computed tomography were of little use in studying bundle bone–implant interfaces; in particular, the tomography showed circumferential bone resorption only in peri-implantitis-like OSCCs. In total, 91.6% of histological examinations of OSCCs showed peri-implantitis-like inflammation; early-stage lesions (pTNM I-II) accounted for 33.3%, whereas late-stage lesions (pTNM III-IV) accounted for 66.7%; lymph nodal metastases occurred in 25.0% and 62.5%, respectively. The mean follow-up was 3.4 ± 1.0 years; all patients with OPMDs had poorly differentiated tumors and thus showed a worse prognosis than those without OPMDs (mean disease-free survival of 15.5 ± 7.7 months and 44.7 ± 12.1 months, respectively). Conclusions: The results of the study showed that peri-implant OSCCs occurred most frequently in patients with OPMDs or previous OSCC; in addition, peri-implant OSCCs required demolition rather than conservative excision, and the prognosis of patients strictly depended on the grade of the cancer. In the authors’ experience, the clinical–radiological presentation simulating peri-implantitis was the feature that concurred most in complicating the diagnosis of those tumors. Full article

The application of construction and demolition waste (CDW) as roadbed filler faces challenges due to the variable mechanical properties caused by fragile recycled brick aggregates. This study elucidates the breakage mechanism of CDW fillers under compaction effort through a combination of standardized laboratory compaction tests and discrete element method (DEM) simulations. Furthermore, the breakage evolution patterns of mixed fills comprising recycled concrete and brick aggregates at various mixing ratios were revealed. A DEM model was developed to characterize recycled concrete and brick aggregates, adopting polygonal clumps for particles >4.75 mm and spherical clumps for finer fractions. The results indicate that particle breakage progresses through three distinct stages: linear fragment stage (0–200 kJ/m³, 50% of total breakage), deceleration growth stage (200–1000 kJ/m³, 38% of total breakage), and residual crushing stage (1000–2684.9 kJ/m³, 12% of total breakage). Recycled concrete aggregates form a skeleton restraining deep cracks, while brick aggregates enhance stability through energy dissipation and void filling. However, exceeding 30% brick content impedes skeleton development. Critically, a 30% brick content optimizes performance, achieving peak dry density with 25% lower compression deformation than concrete-only fillers, while limiting breakage index rise. These results provide a science-based strategy to optimize CDW roadbed design, improving recycling efficiency and supporting sustainable infrastructure. Full article

With the acceleration of urban renewal, directional blasting has become a common method for building demolition. Analyzing the time–frequency characteristics of blast-induced seismic waves allows for the assessment of risks to surrounding structures. However, the signals monitored are frequently tainted with noise, which undermines the precision of time–frequency analysis. To counteract the dangers posed by blast vibrations, effective signal denoising is crucial for accurate evaluation and safety management. To tackle this challenge, a dual denoising model is proposed. This model consists of two stages. Firstly, it applies endpoint processing (EP) to the signal, followed by complete ensemble empirical mode decomposition with adaptive noise (CEEMDAN) to suppress low-frequency clutter. High-frequency noise is then handled by controlling the multi-scale permutation entropy (MPE) of the intrinsic mode functions (IMF) obtained from EP-CEEMDAN. The EP-CEEMDAN-MPE framework achieves the first stage of denoising while mitigating the influence of endpoint effects on the denoising performance. The second stage of denoising involves combining the IMF obtained from EP-CEEMDAN-MPE to generate multiple denoising models. An objective function is established considering both the smoothness of the denoising models and the standard deviation of the error between the denoised signal and the measured signal. The denoising model corresponding to the optimal solution of the objective function is identified as the dual denoising model for blasting seismic wave signals. To validate the denoising effectiveness of the denoising model, simulated blasting vibration signals with a given signal-to-noise ratio (SNR) are constructed. Finally, the model is applied to real engineering blasting seismic wave signals for denoising. The results demonstrate that the model successfully reduces noise interference in the signals, highlighting its practical significance for the prevention and control of blasting seismic wave hazards. Full article

The pyrolysis of non-recyclable construction, renovation, and demolition (CRD) wood waste is a complex thermochemical process involving devolatilization, diffusion, phase transitions, and char formation. CRD wood, a low-ash biomass containing 24–32% lignin, includes both hardwood and softwood components, making it a viable heterogeneous feedstock for bioenergy production. Thermogravimetric analysis (TGA) of CRD wood residues was conducted at heating rates of 10, 20, 30, and 40 °C/min up to 900 °C, employing model-fitting (Coats–Redfern (CR)) and model-free (Ozawa–Flynn–Wall (OFW), Kissinger–Akahira–Sunose (KAS), and Friedman (FM)) approaches to determine kinetic and thermodynamic parameters. The degradation process exhibited three stages, with peak weight loss occurring at 350–400 °C. The Coats–Redfern method identified diffusion and phase interfacial models as highly correlated (R² > 0.99), with peak activation energy (E_a) at 30 °C/min reaching 114.96 kJ/mol. Model-free methods yielded E_a values between 172 and 196 kJ/mol across conversion rates (α) of 0.2–0.8. Thermodynamic parameters showed enthalpy (ΔH) of 179–192 kJ/mol, Gibbs free energy (ΔG) of 215–275 kJ/mol, and entropy (ΔS) between −60 and −130 J/mol·K, indicating an endothermic, non-spontaneous process. These results support CRD wood’s potential for biochar production through controlled pyrolysis. Full article

This study focuses on a residential project in the Haidian District of Beijing, China, employing life cycle assessment (LCA) integrated with building information modeling (BIM) to quantitatively analyze carbon emissions throughout the building life-cycle, including material production, transportation, construction, operation, demolition, and recycling. The results show that the operation and production stages are the primary sources of carbon emissions, accounting for 72.51% and 47.17%, respectively. In contrast, transportation, construction, and demolition contribute relatively minor emissions, at 3.94%, 2.08%, and 0.69%, respectively. Furthermore, renewable energy systems, building recycling, and urban green spaces as carbon sinks contribute negative emissions of −10.96%, −10.48%, and −4.95%, respectively. It should be noted that these percentages reflect the net contributions to total carbon emissions throughout the building’s life-cycle, taking into account both emission sources and sinks. As such, the inclusion of negative emissions from renewable energy systems, recycling, and urban green spaces leads to some stages having a cumulative percentage exceeding 100%. Based on these findings, this paper recommends adopting low-carbon building materials over traditional ones and widely promoting photovoltaic (PV) systems with energy storage technologies to effectively reduce carbon emissions. This study serves as a valuable reference for Beijing and other regions with similar climatic conditions, highlighting the importance of integrated emission reduction strategies to promote a green transition in the construction sector. Full article

Land consolidation (LC) plays an important role in disturbing carbon storage (CS) change. Evaluating how LC affects CS is crucial for mitigating global climate change. However, existing research often overlooks differences in various aspects of land remediation, making it challenging to propose targeted policy adjustments to enhance CS effectiveness. This study presents a framework to assess the effectiveness of CS changes throughout the LC process, encompassing policy formulation stages (PF), construction stages (CO), and post-management stages (PM). Carbon density, a key factor in measuring CS changes, is adjusted using biomass model-integrated empirical measurements with dynamic growth coefficients calibrated through phenological monitoring. The Guangdong Demolition and Reclamation (D&R) project, a specific type of LC, serves as a case study. The findings are as follows: (1) D&R increased forest and garden land by 1420 hm² and 1674 hm², respectively, leading to a regional CS increase of 359,000 t, a five-fold rise per hectare. (2) The effectiveness of PF is 5.81%, with a discrepancy of over 36 million tons. The policy content’s adaptability is low, indicating significant room for improvement in CS outcomes at this stage. (3) The effectiveness of CO is 24.71%, with considerable variation between counties, ranging from 1.26% to 97.55%, due to the varying capabilities of executors and the diverse regional topographical features. Refining implementation content and encouraging collaborative efforts are effective strategies to enhance CS. (4) The effectiveness of PM is 65.03%, and the counties in the east are lower than the west. Scientific post-care is essential for improving CS. This framework provides theoretical support for optimizing LC to enhance regional CS and lays the groundwork for future investigations into the long-term impacts of LC on CS, as well as the potential for applying the methods used in this study to other regions and types of land consolidation projects. Full article

This study aimed to determine the characteristics and driving factors of spatial evolution in urban historical areas during urbanization and urban renewal and recommend how to protect these areas. The urban historical district of Zhangye, a famous historical and cultural city in China, was chosen as the study area. The research used a land transfer matrix, spatial design network analysis (sDNA), GIS analysis, and relevant statistical methods. It analyzed the spatial evolution characteristics of the district by considering the transformation of land use, the evolution of road networks, and the renewal of building profiles. GeoDetector was used to explore the effects of the factors. The study found that in the district, commercial and business land increased while industrial, manufacturing, logistics, and warehouse land decreased. The evolution speed at each stage had a wave-like development. The street pattern maintained the basic “cross” shape, with continuous improvements in the road system and overall accessibility. The building volume also increased gradually. The main types of architectural renewal included setback, integration, demolition, and addition. Meanwhile, economic and industrial factors had the most significant influence on the renewal of the district, whereas cultural factors had increasing influence. Finally, the dual-factor effects were more significant than the single-factor impacts. Full article

Single-family residential buildings represent the highest share of building sector in Romania. Their operation emits the most CO₂ into Earth’s atmosphere, as most of them are not energy efficient. A life cycle assessment is performed for a case study building, built in 2019 in Romania, establishing its carbon footprint. For this building CO₂ emissions are 177.55 tCO₂ for the construction stage, 76.19 tCO₂ for the operation stage, 3.55 tCO₂ for the demolition stage, and a total of 129.76 tCO₂ after reducing with the carbon sequestration from vegetation 127.53 tCO₂. The main purpose of this study is to analyse the carbon footprint for a typical single-family Romanian household, with an emphasis on the operational stage. The study compares the results and extrapolates them to all single-family residential buildings in Romania regarding CO₂ emissions, with an emphasis on the operational stage. The results illustrate a considerable reduction in CO₂ emissions from old, high energy consumption buildings to new, low energy consumption buildings. The highest operational stage emissions for old buildings in Romania are 962.94 tCO₂ for firewood heating and 573.69 tCO₂ for gas boiler heating, as those buildings are not insulated and don’t use a heat pump. Additionally, considering the use of photovoltaic panels for the entire lifespan, the CO₂ emissions for the operational stage decrease for the case study building from 76.18 tCO₂ to 19.90 tCO₂. Moreover, using a heat pump detriments firewood or gas boilers, decreasing CO₂ emissions for the operational stage by up to 34% and 26%, respectively. Due to the higher cost of electrical energy compared to natural gas in Romania, gas boilers are more cost-effective than heat pumps. Because of this, and the higher implementation costs, the tendency is towards natural gas. This will in turn result in an increase of CO₂ emission for the entire life cycle of the building by approximate 32% for new buildings and 86% for old, high-energy-consumption buildings. Full article

Examining the life cycle of structures, such as concrete dams, holds paramount importance for engineers, as it facilitates a comprehensive assessment of overall sustainability, enabling the balancing of the benefits and costs associated with dam development. The recycling of materials emerges as a crucial factor in mitigating environmental impacts. This study employs the IMPACT 2002+ methodology to perform a life cycle assessment (LCA) of a concrete dam, covering the stages from construction to decommissioning. Additionally, carbon footprint analysis (CFA) and life cycle costing (LCC) are performed to pinpoint greenhouse gas (GHG) emission sources and access economic performance. This investigation spans three key-stages: (1) initial construction; (2) decommissioning; (3) hypothetical scenarios with recycling rates for demolished concrete and steel, evaluating how different recycling percentages influence both the environmental benefits and LCC outcomes. The results emphasize the significance of reducing air pollution, with climate change identified as the primary environmental concern compared to ecosystem and resource indicators. The findings show that the carbon footprint associated with the construction of 1 m width of the dam is estimated to be around 355 ton CO₂ eq. Furthermore, the total carbon emissions resulting from the demolition of the dam were identified to amount to 735 ton CO₂ eq/m. The recycling of the dam materials after demolition led to a notable reduction in pollution associated with the decommissioning process of the dam, compared to the dams’ destruction without recycling. Full article

The construction industry accounts for approximately 28% of global CO₂ emissions, and emission management at the building demolition stage is important for achieving carbon neutrality goals. Systematic studies on the demolition stage, however, are still lacking. In this study, research on the development of optimal machine learning (ML) models was conducted to predict CO₂ emissions at the demolition stage. CO₂ emissions were predicted by applying various ML algorithms (e.g., gradient boosting machine [GBM], decision tree, and random forest), based on the information on building features and the equipment used for demolition, as well as energy consumption data. GBM was selected as a model with optimal prediction performance. It exhibited very high accuracy with R² values of 0.997, 0.983, and 0.984 for the training, test, and validation sets, respectively. The GBM model also showed excellent results in generalization performance, and it effectively learned the data patterns without overfitting in residual analysis and mean absolute error (MAE) evaluation. It was also found that features such as the floor area, equipment, wall type, and structure significantly affect CO₂ emissions at the building demolition stage and that equipment and the floor area are key factors. The model developed in this study can be used to support decision-making at the initial design stage, evaluate sustainability, and establish carbon reduction strategies. It enables efficient data collection and processing and provides scalability for various analytical approaches compared to the existing life cycle assessment (LCA) approach. In the future, it is deemed necessary to develop ML tools that enable comprehensive assessment of the building life cycle through system boundary expansion. Full article

The improper disposal of construction and demolition waste (CDW) exacerbates the consumption of raw materials and emissions of greenhouse gasses. In this study, due to the high recycling rate, focusing on the meltable materials of CDW, the recycling phase of CDW is divided into four stages, namely the on-site disposal stage, the transportation stage, the reprocessing stage, and the reproduction stage. Second, based on these four stages, a carbon emission accounting model (CEAM) is established to evaluate the carbon emission benefits of meltable materials during these stages. Third, the CEAM is applied to a typical old residential area to evaluate the carbon emission reduction benefits of the CDW recycling. The results indicate that (1) the full-process carbon emissions of recycled steel, recycled flat glass, and recycled aluminum per unit mass are 677.77 kg/t, 1041.54 kg/t, and 845.39 kg/t, respectively, which are far lower than their corresponding ordinary meltable building materials (OMBMs); (2) the carbon emissions during the reproduction stage represent the primary component of carbon emissions in the MW recycling phase, accounting for 88.52% to 97.45% of the total carbon emissions; and (3) the carbon emissions generated by the recycling of cullet per unit mass are very high, reaching 1768 kg/t, which is 4.3 times that of scrap steel (409.05 kg/t) and 3.6 times that of scrap aluminum (483.76 kg/t). The research findings could provide theoretical methods and experimental data for decision-makers to formulate treatment plans for meltable materials in CDW, thereby empowering urban carbon emission reduction and promoting sustainable development. Construction parties engaged in demolition tasks should enhance on-site sorting and collaborate with recycling companies to ensure its efficient recycling. Recycling companies need to focus on high-carbon-emission stages, such as the reproduction stage, and strengthen technological research to improve carbon reduction benefits. Full article

The construction industry is a major contributor to global greenhouse gas emissions, driven by the extensive use of conventional concrete in building activities. This study evaluates the environmental impacts of various concrete types, including innovative alternatives, using a computational life cycle assessment (LCA) model tailored to the Australian context. Key stages considered include raw material extraction, production, transportation, and end-of-life recycling. Results demonstrate that replacing 40% of cement with supplementary cementitious materials (SCMs) such as fly ash reduces global warming potential (GWP) by up to 25% compared to conventional concrete. Furthermore, carbonation curing technology shows a 15% reduction in ${\mathrm{C}\mathrm{O}}_2$ emissions during the production phase, underscoring its potential to significantly enhance sustainability in construction. High-strength concrete poses significant ecological challenges; however, incorporating SCMs such as fly ash, blast-furnace slag, and silica fume effectively mitigates these impacts. Recycling 60% of concrete demolition waste further decreases environmental impacts by over 20%, aligning with circular economy principles and supporting resource recovery. The findings provide actionable insights for engineers, architects, and policymakers, facilitating the design of sustainable concrete solutions that balance structural performance with reduced ecological footprints. Future research should explore dynamic modelling and broader socio-economic factors to refine sustainable practices. This study underscores the critical importance of adopting innovative materials and recycling practices to minimise the environmental impact of construction activities globally. Full article

In this study, the usability of construction and demolition waste (CDW) aggregates as filling when stabilized with alkaline activator solution (AAS) and blast furnace slag (BFS) was investigated. The initial stage of this study involved determining the engineering properties of CDW by laboratory experiments. In the next stage, modified Proctor tests were performed to investigate the compaction behavior of CDW, to which 5% to 30% BFS was added with water or AAS. In the following stage, California bearing ratio experiments were performed to determine the mixture specimen with the highest strength. In the final stage, a weak soil layer was created in a test tank, and fillings of different thicknesses were built on it using CDW with and without additives in the determined optimum mixing ratio. Then, plate-loading tests were conducted using a model foundation to evaluate the load–deformation behavior of the fillings. The study’s results indicated that adding BFS with water or AAS to CDW increased strength. Furthermore, the addition of 20% BFS yielded the highest strength value, and the CDW aggregates with the added BFS increased the ultimate bearing capacity by up to 4.72 times compared to those without the additive. Full article