Search Results (881)

Understanding the long-term production trends of MDFLAM panels, which are widely used in panel furniture manufacturing, is important for evaluating the sector’s competitiveness and environmental performance. In this study, MDF/HDF production data for Türkiye covering the period 1995–2024 were analyzed. The observations for 1995–2019 were used for model estimation, while the period 2020–2024 was reserved for out-of-sample validation. Production projections for 2025–2030 were generated using the ARIMA time series model. The relationships between fiberboard production and selected socio-economic variables (population, GDP per capita, forest area, and number of enterprises) were evaluated through correlation analysis. While strong correlations were observed in the level data, additional analysis using first-differenced (growth rate) series indicated that these relationships are weak and statistically insignificant in the short term, suggesting that the observed associations are largely influenced by common time trends. Assuming that approximately 60% of total fiberboard production consists of MDFLAM, future GWP values were estimated using verified EPD data. The results indicate that production is expected to continue increasing in the coming years. Although negative GWP values are observed due to biogenic carbon storage during the production stage, this reflects temporary carbon sequestration rather than a permanent reduction in atmospheric emissions. Emissions are expected to increase during end-of-life stages as the stored carbon is released. Overall, the study provides a forward-looking framework by integrating time-series forecasting with EPD-based environmental indicators, offering a useful basis for sustainability assessment and policy-oriented decision-making in the wood-based panel sector. Full article

To address natural aggregate scarcity and improve the high-value utilization of Reclaimed Asphalt Pavement (RAP), this study proposes a steel slag–RAP hot recycled asphalt mixture (SSRM) as a sustainable alternative to conventional limestone–RAP mixtures (RM). Unlike previous studies mainly focusing on performance verification, an integrated environmental–economic evaluation framework was developed based on real highway expansion project data under a “cradle-to-gate” boundary and incorporating transportation distance thresholds. SSRM containing 50% RAP and 23% steel slag as coarse aggregate replacement was evaluated through rutting, semi-circular bending (SCB), freeze–thaw splitting (TSR), and skid resistance tests. Compared with RM, SSRM exhibited 14–16% higher dynamic stability and 20–25% higher fracture energy at −10 °C, along with improved moisture stability and skid resistance, mainly attributed to the rough and alkaline characteristics of steel slag enhancing adhesion and aggregate interlocking. Life-cycle assessment (GWP100) and cost analysis indicate that SSRM reduces carbon emissions by 10–11% relative to RM and about 40% compared with conventional virgin mixtures, while initial construction costs decrease by 9–10%. Transportation sensitivity analysis identifies equal-emission and equal-cost thresholds of approximately 590 km and 380 km, respectively. Within typical material supply radii (300–400 km), SSRM demonstrates both environmental and economic advantages, providing a practical framework for low-carbon material selection in highway construction. Full article

This study investigates the applicability of alternative low-global warming potential (GWP) refrigerant blends in water-source heat pump systems. Binary and ternary refrigerant mixtures were generated using REFPROP 10 to identify suitable candidates. Among 379 novel blends, 18 mixtures with glide temperatures below 10 °C, high critical temperatures, and GWP values lower than 750 were selected for analysis. Thermodynamic analyses were conducted for the selected refrigerants at target water outlet temperatures ranging from 35 to 75 °C, with a heat source temperature of 15 °C and an evaporation temperature of 5 °C. In addition, compressor discharge temperature, volumetric heating capacity, and coefficient of performance (COP) were evaluated. Among the refrigerants, MX1 was recommended for condenser temperatures of 40–80 °C in large-scale heat pump and district heating applications. For refrigerants with GWP values below 150, MX7 exhibited the highest COP and second-law efficiency (η_II) and is therefore suitable for small-capacity systems. In the GWP range of 150–750, MX16 demonstrated the highest COP and η_II values over the entire temperature range. Overall, MX7 achieved the highest COP and η_II among all refrigerants considered, while MX4 emerged as the most favorable mixture in terms of low GWP (below 150) and thermophysical performance. Full article

Phosphorus is a non-renewable resource critical for global food security, yet its natural reserves are rapidly depleting. Meanwhile, the poultry industry generates vast amounts of nutrient-rich waste that pose serious environmental risks if not managed properly. While valorizing these wastes offers a sustainable raw material alternative, investigating the environmental impacts of recovering them as a phosphorus source is crucial. This study evaluates phosphorus recovery from poultry litter via acid leaching following Hydrothermal Carbonization (HTC) and pyrolysis processes holistically. By conducting a Life Cycle Assessment (LCA) using this specific substrate and method combination, this work aims to provide comprehensive environmental insights. The impact assessment reveals that the total Global Warming Potential (GWP) is 6.00 kg CO₂ eq for the pyrolysis scenario and 4.18 kg CO₂ eq for the HTC scenario. Methodologically, a ‘system expansion’ approach was applied to integrate the avoided burdens from poultry manure management into the system boundaries. Furthermore, the inventory analysis revealed that chemical consumption (specifically NaOH and H₂SO₄) in the production process is the dominant factor not only for Global Warming Potential (GWP) but also across other environmental impact categories evaluated. The findings clearly indicate that chemical intensity predominantly determines the environmental performance across carbon footprint, acidification and other environmental impact categories. Full article

This study evaluates the multi-physical effects of fiber type, length, and dosage on the fresh properties, mechanical performance, and environmental impact of roller-compacted concrete (RCC). Industrial steel (S), polypropylene (PP), and waste steel (WS) fibers with lengths of 30 mm and 60 mm were incorporated into RCC mixtures at volume fractions ranging from 0% to 1.25%. The experimental program included Vebe consistency tests, mechanical strength assessments, and fracture energy measurements, complemented by a simplified cradle-to-gate Global Warming Potential (GWP) analysis. Furthermore, Taguchi and ANOVA methods were employed to statistically determine the hierarchy of influential parameters. The statistical analysis revealed that fiber dosage was the most dominant factor, contributing approximately 68–78% to the variation in compressive, splitting tensile, and flexural strengths, whereas fiber type governed the consistency. Experimentally, S and WS fibers significantly enhanced the post-cracking behavior and fracture energy compared to the brittle control mix, although they imposed a greater penalty on workability than PP fibers. Notably, at comparable dosages, WS fibers exhibited mechanical interlock and toughness performance nearly identical to industrial steel fibers. The environmental analysis demonstrated that replacing industrial steel fibers with WS fibers reduces the embodied carbon by approximately 240 kgCO₂-eq/m³ at the maximum dosage, without compromising mechanical reliability. These findings suggest that waste steel fibers offer a superior performance-to-carbon ratio, making them a viable sustainable alternative for heavy-duty RCC pavements where crack control is prioritized. Full article

Citric acid (CA) necessitates the investigation of the environmental footprint from its production. This study compared three recovery technologies at different readiness levels, industrial calcium hydrogen salt precipitation–ion exchange (CHP-IE), pilot-scale solvent extraction (SE), and laboratory-scale bipolar membrane electrodialysis (BMED), to evaluate the life cycle environmental impacts of CA production when employing each recovery technology. SE and BMED were selected as emerging alternatives, as both are potential candidates to offer environmental or economic advantages over CHP-IE. By modeling the continuous improvement in the key production parameters as cumulative production experience increases, technological learning curves capture the efficiency gains that occur as technologies mature. This study pioneers an integrated ex-ante LCA framework that couples technological learning curves with energy transition scenarios to prospectively compare emerging CA recovery technologies against an industrialized process. Currently, CHP-IE shows the highest profit of 1078 CNY/t CA and the lowest global warming potential (GWP) of 1.79 t CO₂ eq/t CA, with the latter advantage projected to persist until 2030. By 2050, under deep decarbonization, BMED becomes the lowest-carbon option with 0.78 t CO₂ eq/t CA. Furthermore, with maize as the primary raw material, improved cultivation models in Northeast China reduce the environmental impacts of CA production by approximately 3% in acidification potential (AP) and eutrophication potential (EP), while diversified cropping systems in North China yield reductions of over 50% in these two categories. This paper provides an approach of comprehensive evaluation, supporting technology selection and green supply chain development in the CA industry. Full article

Despite timber’s strategic role in the circular economy, its application in Türkiye remains negligible compared to the rigid reinforced concrete (RC) housing stock, which limits flexibility and penalizes the environment. This study investigates the adaptability and environmental performance of modular timber construction via a 17-year longitudinal case study in Seferihisar, İzmir. Using architectural observation, user interviews, 3D BIM, and a comparative LCA, findings reveal the structure successfully accommodated a six-phase functional transformation—the structure’s gross floor area increased by 6.19 times more (from 21 m² to 151 m²) and bed capacity from 2 to 18—with virtually zero demolition waste through dry-assembly techniques. Crucially, normalized LCA proves timber’s ecological superiority: achieving an embodied energy intensity of 6.60 GJ/m² (1.2 times less than the RC equivalent’s 7.97 GJ/m²). Furthermore, biogenic carbon storage enabled the timber dwelling to reach a negative Global Warming Potential (GWP) of −26,118.39 kgCO₂ (a carbon sink), whereas the RC model emitted +39,081.22 kgCO₂. Given that secondary housing predominantly comprises two-story structures, lightweight timber sustainably meets this typological demand. Ultimately, user-driven modular timber presents a resilient, eco-efficient, circular economy model for second-home and post-disaster settlements. Full article

This LCA study addresses the research gap concerning the comprehensive environmental implications of using paving block aggregates (PBA), derived from crushed waste concrete paving blocks (CPB), as a sustainable replacement for natural aggregates in cementitious materials. While the concrete industry faces twin challenges—high CO₂ emissions from cement and the massive ecological toll of extracting 20 Gt/year of natural aggregates—a systematic life cycle assessment of this specific waste stream was necessary, especially one that considered potential material interaction trade-offs. The study’s conclusions offer critical insight into achieving genuine sustainability. Consistently, cement production was identified as the overwhelming environmental hotspot, contributing over 90% of the global warming potential (GWP) across all scenarios. This finding indicates that even substantial changes in aggregate sourcing can only deliver limited GWP reductions unless accompanied by strategies targeting cement-related emissions. While substituting natural aggregates with PBA generally provided environmental benefits, a crucial trade-off was identified: the significantly higher dosage of superplasticizer required to maintain the workability of the PBA mixes. For mortar, the burden from the increased plasticizer became a major secondary hotspot, occasionally offsetting the gains from aggregate replacement. In these scenarios, the contribution of admixtures to the total GWP was sufficiently high to reduce or negate the environmental benefits achieved through aggregate substitution. In contrast, aggregate replacement proved more favorable in concrete than in mortar, as the concrete scenarios showed a weaker correlation between environmental impact and plasticizer use. The authors conclude that future strategies must prioritize reducing cement content and, critically, systematically consider the necessary use of admixtures to ensure that the intended environmental improvements are genuine and not counteracted by the side effects of material substitution. The quantified LCA results demonstrate that cement reduction offers the highest mitigation potential, while admixture optimization is essential to prevent secondary environmental hotspots, particularly in mortar applications. Full article

The recent revision of the European Energy Performance of Buildings Directive (EPBD) introduces mandatory whole-life global warming potential (GWP) reporting, creating practical challenges for building life-cycle assessment due to incomplete life-cycle phase coverage in conventional Environmental Product Declarations (EPDs). This study develops and validates an integrated BIM–LCA framework for structured whole-building GWP evaluation through harmonized life-cycle module alignment and cross-tool comparison, with emphasis on the early design stages. The workflow combines rapid BIM-based screening with detailed external LCA validation, establishing a tiered assessment strategy that enables iterative material optimization within the BIM environment prior to expert review. The methodology is applied to two residential construction systems (masonry and timber), and three functional units are evaluated: total whole-building GWP, area-normalized GWP, and material-level contributions. Five comparative scenarios are analyzed, including reference, nationally representative, optimized low-carbon, and European benchmark configurations. The results show progressive GWP reductions ranging from 5% to 30% across scenarios. Although substantial absolute deviations are observed between BIM-integrated and professional LCA tools, scenario-level rankings remain fully consistent across all functional units, confirming the robustness of the screening approach for comparative decision-making. Cross-tool validation focuses on an aligned embodied-carbon scope (A1–A3 plus selected end-of-life modules) to ensure screening robustness, while full whole-life LC-GWP (including B-modules and services) is positioned as the regulatory context for subsequent expert-stage assessment. The framework provides an efficient and transferable decision-support methodology that supports early-stage carbon optimization while preserving methodological transparency for regulatory reporting. Full article

This study investigates the properties of concrete incorporating recycled aggregates (RAs) for rigid pavement applications. A 15-point three-level experimental design was used to vary three composition factors: Portland cement substitution with fly ash (FA), and dosages of a superplasticizer (SP) and polypropylene fibers (PFs). A set of experimental–statistical models (ES models) was developed to predict the concrete strength, abrasion and frost resistance (FR), water absorption (WA), and global warming potential (GWP). This study aimed to develop a material that achieves both adequate mechanical performance for pavement applications and enhanced environmental sustainability by incorporating RAs and FA. The results demonstrate that replacing up to 13% of cement with FA does not compromise the splitting tensile strength or FR. For non-fibrous concrete, this substitution increases FR by approximately 50 freeze–thaw cycles. Application of PFs (2.4–3 kg/m³) enhances splitting tensile strength by 14–16% and improves FR by about 50 cycles. Using response surface methodology (RSM), optimal concrete compositions were identified that meet all target criteria: compressive strength ≥ 40 MPa, flexural strength ≥ 5 MPa, FR ≥ F200 (cycles), and abrasion resistance (AR) ≤ 0.5 g/cm², while simultaneously minimizing GWP. An additional optimum composition was determined by imposing a constraint on splitting tensile strength of ≥4.5 MPa. This graphical optimization approach, utilizing two-factor interaction diagrams, provides an effective and visual methodology for practical concrete mixture design. The novelty of the method lies in the discretization of the factor space, which enables efficient identification of optimal concrete mixture compositions. Full article

Decarbonizing ocean-going shipping requires decision-grade environmental evidence for propulsion transitions, yet conventional LCA relies on static inventories that inadequately represent dynamic operations and route-dependent renewable generation. This study evaluates well-to-wake (WtW) Global Warming Potential (GWP) for two large container ships operated by a Korean company under four scenarios: conventional diesel main engine, diesel–electric with onboard generator, full battery-electric supplied by shore electricity from the Republic of Korea grid, and battery-electric with a route-resolved solar PV system. A Live-LCA (LLCA) framework couples LCI data with MATLAB/Simulink power and propulsion modeling driven by actual operating profiles and route environmental conditions to generate operational inventories for impact calculation. Diesel–electric operation increases annual WtW GWP by over 26% for both ships versus the baseline of a conventional diesel main engine, whereas shore-electric battery operation is able to reduce WtW GWP by around 40% versus diesel–electric. With limited PV installation, additional reductions are marginal. Depending on electricity profile, it can increase battery-electric GHG emissions by approximately 27%, highlighting sensitivity to electricity evolution. Overall, electric propulsion delivers climate benefits only when paired with low-carbon electricity, and LLCA enables operationally and route-grounded LCA for large container ships. Full article

Rice husk, which accounts for approximately 22% of global rice production, is often disposed of by open field burning, causing significant greenhouse gas (GHG) emissions and air pollution. Converting rice husk into biochar via pyrolysis offers a sustainable waste management and climate mitigation pathway; however, the environmental performance of biochar production is highly sensitive to the energy source used. Hence, this study presents a gate-to-gate life cycle assessment of biochar production from rice husk via slow pyrolysis at 500 °C under three energy supply scenarios: grid electricity, biomass combustion, and photovoltaic solar energy. Using the ReCiPe 2016 methodology, environmental impacts were evaluated across four categories such as Global Warming Potential (GWP), Human Toxicity Potential (HTP), Acidification Potential (AP), and Abiotic Depletion Potential (ADP), with all process parameters held constant except the energy source. The results demonstrate that energy supply is the dominant determinant of environmental performance and the photovoltaic solar-assisted biochar production route showed superior performance across all categories, with gross production impacts for 1 ton biochar of 24.0 kg CO₂-eq (GWP), 5.6 kg 1,4-DCB-eq (HTP), 0.09 kg SO₂-eq (AP), and 259.9 MJ (ADP), representing 48-165-fold improvements over grid electricity. When accounting for carbon sequestration (2800 kg CO₂-eq per ton biochar), all scenarios achieved net negative GWP, ranging from −2776.0 kg CO₂-eq (solar PV) to −1562.5 kg CO₂-eq (grid electricity), representing 78% variation attributable to energy source. Contribution analysis revealed pyrolysis heating accounts for 95.6% of environmental impacts, with no trade-offs among impact categories. The findings recommend photovoltaic solar energy for new biochar facilities, biomass combustion for co-located agricultural operations, and avoidance of grid electricity unless grids achieve substantial decarbonization. Full article

This research investigates the shear performance of sustainable self-compacting reinforced geopolymer concrete (GPC) beams incorporating granite waste powder (GWP) and ground granulated blast-furnace slag (GGBFS) as eco-friendly binding agents through experimental and numerical analyses. Five geopolymer reinforced concrete beam specimens (100 mm × 150 mm × 1500 mm) were tested under two-point loading conditions to evaluate the influence of longitudinal reinforcement ratio (0.85% to 2.0%) and shear span-to-effective depth ratio on the structural shear performance. The experimental investigation revealed that geopolymer reinforced concrete beams exhibit shear behavior characteristics similar to conventional Portland cement concrete beams, with the 2.0% reinforcement ratio achieving 18.3% higher shear strength compared to the 0.85% reinforcement ratio, while shear capacity increased proportionally with increasing shear span-to-depth ratio. Experimental data, including load–displacement response, shear strength measurements, strain distributions, failure modes, and crack patterns, were studied. Finite element nonlinear analysis was conducted by modifying the concrete modulus and stress–strain relationships to reflect the properties of geopolymer concrete using ABAQUS software integrated with the concrete damaged plasticity model. The results demonstrated that for the tested geopolymer reinforced concrete beams, first cracking load, steel yielding load, and ultimate load capacity increased systematically with increasing tension steel reinforcement ratio and proportionally with higher shear span-to-depth ratios. Full article

Methane is one of the most potent greenhouse gases, with a Global Warming Potential (GWP100) 27.9 times greater than that of CO₂ when measured as carbon dioxide equivalent. Therefore, the development and implementation of effective methods for reducing methane emissions are crucial for environmental protection, especially when these methods also provide additional technical or economic benefits. This article presents the results of an economic efficiency analysis conducted for a pilot-scale installation developed to reduce climate hazards in coal mines, based on a reactor for the catalytic oxidation of ventilation air methane. The economic feasibility of this installation operating under real conditions in underground coal mines was evaluated, and the analysis is based on actual operational data. The analysis was performed using a differential financial model. The capital and operating expenditures of the pilot-scale installation were compared with the costs of purchasing, installing, and operating a standard MK-500 cooling unit commonly used in Polish coal mines. The following economic efficiency indicators were obtained for the determined cash flows: Net Present Value (NPV) of 1.66 m EUR and Internal Rate of Return (IRR) of 24.6%. The results indicate that the pilot-scale technology becomes economically viable solely through the avoidance of methane emission penalties. The analysis identified the cost and macroeconomic parameters necessary for the economic viability of the technologies studied and established the methane emission penalty threshold at which operating the catalytic methane oxidation reactor system becomes justified (EUR 638/Mg CH₄). The paper presents the factors with the greatest and least impact on the economic efficiency of the analyzed pilot-scale installation. The proposed pilot-scale approach offers a realistic pathway for combining greenhouse gas mitigation with operational stability in underground mining. Full article

The municipal solid waste management sector is a nationally significant greenhouse gas source in Sri Lanka, yet decision makers lack comprehensive, city-level life-cycle assessment of full waste management chains. This study quantifies and compares greenhouse gas emissions and mitigation potential of alternative waste management scenarios for Colombo and Kandy, supporting nationally determined contributions (NDC) 3.0. Using IPCC 2021 GWP100 V1.03 as the impact assessment method, six scenarios were assessed, including business-as-usual, recycling, composting, confined cover windrow composting, anaerobic digestion, refuse-derived fuel production, incineration, pyrolysis, co-processing in cement kilns, open dumping, and sanitary landfilling. The business-as-usual scenario, dominated by open dumping, resulted in the highest greenhouse gas emissions in both Colombo and Kandy. In contrast, the integrated waste management approach (Scenario 3), combining anaerobic digestion, confined cover windrow composting, refuse-derived fuel production, and enhanced recycling, converted both cities from net emitters to net carbon sinks. Over the projection period of 2026–2035, this transition is expected to deliver substantial cumulative emission reductions, contributing significantly toward achieving NDC 3.0 waste sector targets in Sri Lanka despite the relatively small share of national baseline emissions in the sector. These findings highlight the strong mitigation potential of integrated waste management systems for advancing low-carbon urban strategies. Full article