Search Results (31)

Residential buildings in Erbil City are increasingly facing challenges due to climatic extremes, rapid urbanization, and inadequate insulation practices. This study investigates the effects of insulation material type and placement on the thermal performance of external walls in both newly constructed and refurbished houses under the hot semiarid climate (BSh). Using integrated environmental solutions virtual environment (IES-VE) simulations, various wall systems—concrete, brick, and lightweight block—were assessed with different insulation types (expanded polystyrene (EPS), extruded polystyrene (XPS), rock wool (RW), and mineral wool (MW)) applied either internally or externally. Field surveys combined with numerical simulations demonstrated that external insulation significantly enhances thermal mass without diminishing insulation effectiveness, leading to greater energy savings and improved indoor comfort. Among all configurations, externally applied XPS on concrete and lightweight block walls achieved the highest resistance values (R-values) and the greatest reductions in heating and cooling loads. The results indicate that prioritizing the placement of external insulation can support the development of more energy-efficient and climate-responsive housing policies in Erbil. This research offers evidence-based recommendations for optimizing building envelope design in similar climatic contexts. Full article

Rapid urbanization has significantly increased energy demand in buildings, which now represent nearly 30% of global energy use. In India, buildings are built across highly varied climatic conditions, from hot-dry and warm-humid to cold, high-altitude areas, making climate-responsive envelope design essential to enhance thermal performance. Among envelope components, roofs are the most exposed to solar and outdoor thermal loads, playing a key role in managing indoor heat transfer. This study offers a parametric analysis of climate-responsive roof design strategies for India’s five main climatic zones, using transient simulations and statistical evaluation. The effectiveness of insulation placement, insulation material and thickness, and external surface absorptivity was systematically assessed based on roof heat gain and heat loss. Results indicate that over-slab insulation can lower roof heat gain by approximately 15–35% compared to under-slab insulation in warm-humid, hot-dry, composite, and temperate zones. In comparison, under-slab insulation decreases heat loss by about 10% in colder areas. Among insulation materials, 50 mm polyurethane foam (U = 0.433 W/m²·K) consistently outperformed extruded polystyrene and expanded polystyrene, achieving 82–83% reductions in maximum heat gain in cooling-dominated climates and 89% reductions in heat loss in cold regions relative to uninsulated roofs. When combined with a white reflective surface finish (α = 0.26), the total heat transfer reduction increased further to 89–92%. Surface treatments alone cut heat gain by 37–51% in non-cold climates, highlighting their potential as cost-effective retrofit options. Statistical analysis confirmed that dry-bulb temperature is the primary climatic factor influencing roof heat transfer (R² = 0.86–0.98, p < 0.0001), while solar radiation had a weaker effect, especially in optimized roof systems. The findings emphasize the importance of climate-specific roof design and demonstrate that insulation U-value has a greater impact on thermal performance than surface absorptivity, although both are significant. This research offers practical, climate-adjusted guidance for architects, engineers, and policymakers to enhance the thermal performance of roofs in Indian buildings. It supports the development of more resilient, energy-efficient building envelopes. Full article

Improving the thermal performance of building envelopes is an effective approach for reducing energy consumption and carbon emissions in cold and heating-dominated regions. This study presents an experimentally calibrated thermal–economic optimization of external wall insulation systems for residential buildings in Northwest China, using Xi’an as a representative cold–dry continental climate. A guarded hot-box apparatus was employed to measure the steady-state thermal transmittance (U-value) of multilayer wall assemblies incorporating expanded polystyrene (EPS), extruded polystyrene (XPS), and rock wool at different insulation thicknesses. The measured U-values were integrated into a dynamic building energy simulation model (DeST-h), and the simulated energy demand was subsequently evaluated through life-cycle cost (LCC) analysis to identify cost-optimal insulation configurations. The results indicate a nonlinear reduction in heating energy demand with increasing insulation thickness, with diminishing marginal returns beyond approximately 50 mm. Among the investigated materials, XPS exhibits the most favorable thermal–economic performance. For the climatic and economic conditions of Xi’an, a 50 mm XPS insulation layer minimizes total life-cycle cost while reducing annual building energy consumption by approximately 23–24% compared with the uninsulated reference case. This experimentally calibrated framework provides practical and policy-relevant guidance for insulation design and retrofit strategies in cold and dry regions. Full article

The sandwich-insulated concrete block is one of the innovative building units developed to enhance thermal insulation in buildings. However, there are still some drawbacks that hinder the optimum utilization of these types of insulating blocks. Therefore, this study aims to conduct a systematic and comparative assessment of the performance of the sandwich-insulated concrete block available in the local market. To accurately assess the efficiency of the insulated concrete blocks, several samples from various sources available in the local market were collected and examined. Visual inspection, dimensional tolerance, compressive strength, physical properties, thermal performance, and environmental resistance tests have been conducted in accordance with local and international standards. The obtained experimental results revealed that the mixture proportion of the concrete shell plays a crucial role in the properties and performance of the whole insulated concrete block. Blocks with volcanic aggregates exhibited lower compressive strength, ranging between 3.19 and 5.26 MPa, but better thermal conductivity with an average of 0.25 W/m·K. In comparison, normal aggregate blocks showed higher compressive strength up to 8.12 MPa but slightly reduced thermal insulation around 0.44 W/m·K. Water absorption varied widely from 5% to 16%, and chloride contents in volcanic aggregates exceeded the permissible 1% limit. Broken edges and cracks were mainly observed in low-strength blocks, emphasizing the importance of proper curing and material selection. Durability assessments revealed that accelerated weathering experiments demonstrated the susceptibility of expanded and extruded polystyrene to UV-induced degradation. Nevertheless, all tested polystyrene samples showed high resistance to fungal attack, with varying antibacterial activity. Full article

Plastics are inexpensive and widely used but persist in the environment due to improper disposal. Insect-mediated biodegradation has gained attention, notably involving Tenebrio molitor larvae. Despite morphological similarities and larger size, Zophobas atratus larvae remain less studied. This work evaluated the impact of larval stage on the biodegradation of pristine and post-consumer extruded polystyrene (XPS) and the physiological effects of an XPS-based diet. Smaller (L1) and larger (L2) larvae were tested. L2 showed higher XPS consumption, weight gain, and survival, while XPS-fed larvae overall exhibited reduced lipid content and increased moisture, flavonoids, and phenolics compared to wheat bran-fed controls. Scanning electron microscopy revealed surface fragmentation in frass, more pronounced in L1, suggesting greater mechanical or enzymatic action. High-performance size exclusion chromatography indicated molecular weight reduction, with L1 more effective on pristine XPS and L2 on post-consumer XPS, likely due to nutritional residues. FTIR analysis showed oxidative changes in both groups, more prominent in L1. Thermogravimetric analysis revealed earlier degradation onset in L1 frass, supporting the presence of oxidized oligomers. Overall, Z. atratus larvae can biodegrade XPS, with degradation influenced by developmental stage and substrate type. These findings inform biotechnological strategies for sustainable plastic waste management. Full article

This manuscript is aimed at analyzing how operating factors may affect the durability of thermal insulation in building partitions located underground. It examines the durability of inverted insulation systems where thermal insulation is installed above the waterproofing layer and used in residential foundation slabs. The article demonstrates that, despite their popularity due to cost efficiency, the long-term success of these systems depends on thorough investigations of thermal isolation, especially considering different climate conditions. The analysis was based on an extensive literature review (2016–2024), supplemented with laboratory test results on extruded (XPS) and expanded (EPS) polystyrene boards. Additional tests examined the water penetration mechanism into insulation layers that are in direct contact with groundwater, revealing that cyclic freezing and thawing significantly increase moisture levels. The findings highlight the need for updated region-specific guidelines for the underground insulation in Central and Eastern Europe. Full article

Three-dimensional concrete printing (3DCP) is advancing rapidly, yet its sustainable adoption requires alignment with circular-economy principles. This study evaluates the substitution of natural aggregates with recycled constituents, 3DCP waste, brick debris, glass cullet, mixed rubble, fly ash, and slag, and the use of lightweight fillers (expanded perlite, lightweight expanded clay aggregate (LECA), and expanded polystyrene (EPS)) to reduce density and improve insulation. Key properties, such as particle-size distribution, printability, mechanical performance, thermal conductivity, and water absorption, were determined. Results indicate that grading strongly affected mixture behavior. Narrow distributions (fly ash, milled 3DCP waste) enhanced extrudability, while broader gradings (glass, rubble, slag) increased water demand and extrusion risks. Despite these differences, all systems remained within the printable window: flow spread decreased with most recycled additions (lowest for brick) and increased with glass. Mechanical responses were composition-dependent. Flexural strength typically decreased. Compressive strength benefited from broader gradings, with replacement levels up to ~6% enhancing strength due to improved packing. Loading anisotropy typical of 3DCP was observed, with perpendicular compressive strength reaching up to 13% higher values than parallel loading. Lightweight fillers significantly reduced thermal conductivity. LECA provided the best compromise between strength and insulation, perlite showed intermediate behavior, and EPS achieved the lowest thermal conductivity but induced significant strength penalties due to weak matrix-EPS interfaces. Water absorption decreased in recycled-aggregate mixes, whereas lightweight systems, particularly with perlite, retained higher uptake. The results demonstrate that non-reactive recycled aggregates and lightweight insulating fillers can be successfully integrated into extrusion-based 3DCP without compromising printability. Full article

The paper industry is always looking for possible solutions for new fiber-based products, such as protective and cushioning materials. These materials must be carefully designed to provide effective cushioning while also being lightweight to reduce transportation costs. Additionally, they need to offer protection from environmental and mechanical damage, besides having good processability to ensure proper buffering. The widely used protective and cushioning materials, such as plastic foams and expanded or extruded polystyrene, create significant disposal challenges. Therefore, there is increasing demand for biodegradable and sustainable materials for cushioning applications. The focus of our research was to develop fiber-based foams and investigate the influence of different compositions (hardwood and softwood) of cellulose fibers on the basic (mass, thickness, density) and mechanical properties (three-point bend test, tensile properties). Foams made entirely from short eucalyptus fibers (100S) exhibited the highest density (28.0 ± 0.34 kg/m³) and lowest thickness (38.82 ± 4.21 mm), resulting in superior tensile strength and elastic modulus but lower strain at break. In contrast, foams composed of long spruce fibers (100L) had the lowest density (19.0 ± 0.27 kg/m³) and highest thickness (58.52 ± 1.50 mm), with lower strength and stiffness but much higher ductility and porosity (confirmed by ~30% higher air permeability compared to 100S). Blended formulations demonstrated intermediate behavior, with the 50S50L foam showing a favorable balance of strength, stiffness, and flexibility. Visual analysis confirmed heterogeneous fiber distribution with localized agglomerates and compaction at the bottom layer due to casting. To further interpret the complex relationships within the dataset and uncover patterns, Principal Component Analysis (PCA) was applied to all experimental results. The findings of the research contribute to the broader understanding of how different fiber types and blends impact the performance of sustainable cellulose-based foams, with potential implications for the development of biodegradable packaging and lightweight construction materials. Full article

This paper presents the development of two solutions for sandwich panels composed of a thin-layer alkali-activated composite (AAc) layer and a thicker insulation layer, formed by extruded polystyrene foam or expanded cork agglomerate (panels named AP_XPS or AP_ICB, respectively). The AAc combined ceramic waste from clay bricks and roof tiles (75%) with ladle furnace slag (25%), activated with sodium silicate. The AAc layer was further reinforced with polyacrylonitrile (PAN) fibers (1% content). The mechanical behavior was assessed by measuring the uniaxial compressive strength of cubic AAc specimens, shear bond strength, pull-off strength between the AAc layer and the insulation material, and the flexural behavior of the sandwich panels. The thermal performance was characterized by heat flux, inner surface temperatures, the thermal transmission coefficient, thermal resistance, and thermal conductivity. Mechanical test results indicated clear differences between the two proposed solutions. Although AP_XPS panels exhibited higher tensile bond strength values, the AP_ICB panels demonstrated superior interlayer bond performance. Similar findings were observed for the shear bond strength, where the irregular surface of the ICB positively influenced the adhesion to the AAc layer. In terms of flexural behavior, after the initial peak load, the AP_XPS exhibited a deflection-hardening response, achieving greater load-bearing capacity and energy absorption capacity compared to the AP_ICB. Finally, thermal resistance values of 1.02 m² °C/W and 1.14 m² °C/W for AP_ICB and AP_XPS were estimated, respectively, showing promising results in comparison to currently available building materials. Full article

Natural fiber-reinforced composites are composite materials composed of natural fibers, such as plant fibers and synthetic biopolymers. These environmentally friendly composites are biodegradable, renewable, cheap, lightweight, and low-density, attracting attention as eco-friendly alternatives to synthetic fiber-reinforced composites. In this study, natural fiber-reinforced polymer foam core layered composites were produced for the automotive industry. Fabrics woven from goat wool were used as the natural fiber. Polymer foam with expanded polystyrene (EPS) and extruded polystyrene (XPS) structures was used as the core material. During production, fibers were bonded to the upper and lower layers of the core structures using resin. The hand lay-up method was used in production. After resin application, the samples were cured under a heated press for 2 h. After the production was completed, the material was cut according to the standards (10-20-30 Joule), and impact and bending tests were conducted at three different energy levels. The experiments revealed that at 10 J, the material exhibited rebound; at 20 J, it showed resistance to stabbing; and at 30 J, it experienced penetration. While EPS foam demonstrated higher impact resistance in the 10 J test, it was found that XPS foam exhibited better impact resistance and absorption capabilities in the 20 J and 30 J tests. Due to the open and semi-closed cell structure of EPS foams and the closed cell structure of XPS foams, it has been concluded that XPS foams exhibit higher impact resistance and better energy absorption properties Full article

This article addresses manufacturing structures made via injection molding from biodegradable materials. The mentioned structures can be successfully used as energy-absorbing liners of all kinds of sports helmets, replacing the previously used expanded polystyrene. This paper is focused on injection technological tests and tensile tests (in quasi-static and dynamic conditions) of several composites based on a PLA matrix with the addition of other biodegradable softening agents, such as PBAT and TPS (the blends were prepared via melt blending using a screw extruder with mass compositions of 50:50, 30:70, and 15:85). Tensile tests showed a positive strain rate sensitivity of the mixtures and a dependence of the increase in the ratio of the dynamic to static yield stress on the increase in the share of the plastic component in the mixture. Technological tests showed that increasing the amount of the plasticizing additive by 35% (from 50% to 85%) results in a decrease in the minimal thickness of the thin-walled element that can be successfully injection molded by about 32% in the case of PLA/PBAT blends (from 0.22 mm to 0.15 mm) and by about 26% in the case of PLA/TPS blends (from 0.23 mm to 0.17 mm). Next, the thin-walled elements (dimensions of 55 × 55 × 20 mm) were manufactured and evaluated using a spring-loaded drop hammer. The 60 J impact energy was tested in accordance with the EN 1078 standard. The dynamic crushing test included checking the influence of the materials’ temperature (−20, 0, 20, and 40 °C) and the impact velocity. It was proven that the maximum deflection increases with increasing material temperature and an increase in the share of the plastic component in the mixture. The PLA15PBAT85 blend was selected as the most effective material in terms of its use as an energy-absorbing liner for sport helmets. Johnson–Cook and Cowper–Symonds material plasticizing models were constructed. Their use during dynamic FE simulation provided results that were in good agreement with those of the conducted experiment. Full article

Thermal insulation applications on the exterior facades of buildings have been the subject of numerous studies from the past to the present. Some of these studies focus on the cost reduction effect of insulation, while others emphasize its ecological benefits. In this study, multi-objective optimization, the objectives of which are minimum cost and minimum CO₂ emission, has been carried out with the NSGA-II method. In emission calculations, in addition to fuel-related emissions, the carbon footprint of all materials comprising the wall has also been included. The multi-objective optimization study examined four design variables: wall thickness, wall material (light concrete, reinforced concrete, and brick), insulation material (expanded polystyrene, extruded polystyrene, mineral wool, and polyurethane foam), and heating source (natural gas, electricity, fuel oil). Analyses have been carried out for four cities (Osmaniye, Bursa, Isparta, and Erzurum), which are located in different climatic regions, and considering solar radiation effects. An existing building has been taken as the base case scenario, and the study has determined the improvements in the total cost and the amount of CO₂ released into the environment when the appropriate insulation material, insulation thickness, wall material, and heating source identified in the multi-objective optimization study have been used. At the cost-oriented optimum point in the study, the most suitable insulation material was found to be expanded polystyrene, the most suitable wall material was brick, and the most suitable heating source was natural gas. In the CO₂-oriented optimum, in contrast to the cost-oriented approach, optimal results have been obtained when light concrete was selected as the wall material. Full article

This article presents the authors’ comprehensive evaluation of the application of specific foam thermal insulation materials, namely expanded polystyrene (EPS) and extruded polystyrene (XPS), within railway substructures. The assessment extends to real-world conditions on the tracks of Slovak Railways (ŽSR), which share substantial similarities with other countries’ railway networks. The assessment of structural composition and material selection considers these technical aspects, while technological feasibility and the environmental implications associated with material production, delivery, and incorporation into railway construction do not. Additionally, the thermal insulation materials’ qualities are compared against conventional railway substructure materials. In these conventional setups, the thermal insulation layer often incorporates crushed aggregate of specified fractions and parameters in line with legislative standards. This article complements previous research conducted at the University of Žilina, focusing on the application of various thermal insulation materials within railway substructures. These materials were both experimentally tested (scale of 1:1) and numerically modelled, with results previously published by the authors. The published works detail the utilisation of diverse thermal insulation materials in railway substructures, primarily evaluating two crucial technical parameters: the protection of the subgrade surface against adverse effects of frost and, secondarily, their impact on the deformation resistance of the railway substructure. Full article

Hexabromocyclododecane (HBCD) is the most important flame retardant that has been used in Expanded Polystyrene foam and Extruded Polystyrene foam in the past forty years across the world. China was the major producer and user of HBCD, and the total HBCD production was about 0.3 million tons. Although HBCD was completely banned in China in 2021 because of its long-range transport, bioaccumulation and toxicity, there is still a lot of residue in the environment. Therefore, we reviewed multiple studies concerning the distribution of HBCD in diverse environmental matrices, such as in the air, dust, soil, water, sediment, and biota. Results revealed that HBCD levels in different environments in China present geographical variation and were at a high level compared with other countries. In all environmental media, relatively high HBCD concentrations have been found in industrial and urban areas. Industrialization and urbanization are two important factors that influence the concentration and distribution of HBCD in the environment. In terms of isomer, γ-HBCD was the dominant isomer in soil, water, and sediment, while in the biota α-HBCD was the predominant isomer. Full article

The current climate change context raises the demand for reducing energy and environmental impacts while keeping an economic balance and building users’ comfort. Thermal insulation solutions are potential allies in ensuring the adequacy of existing buildings for challenging sustainability requirements. In this scenario, silica-aerogel-fibre-based thermal renders are innovative solutions for which integrated approaches still lack information, and they should be compared with benchmark multilayer solutions, such as those based on expanded polystyrene (EPS), extruded polystyrene (XPS), mineral wool (MW), and insulated corkboard (ICB), to evidence their prospective economic, environmental, and energy benefits. This paper quantifies the optimum insulation thicknesses, life cycle savings, payback periods, and environmental impacts of innovative thermal renders compared to conventional thermal insulation materials when applied as a retrofit in existing facade walls. The results show that cost-optimised thermal renders with sisal fibres led to the best overall performance. Higher heating needs led to higher optimum render thicknesses and life cycle savings. With a 0.02 m thickness, aerogel-fibre-based thermal renders outperformed other materials in terms of heating-degree days (HDD) from 1000 °C·day onwards; they can save approximately EUR 60∙m⁻², 1000 MJ∙m⁻², and 100 kg CO₂ eq∙m⁻² while presenting a U-value 13% lower throughout their 30-year lifetime when compared with the second-best multilayer solution with XPS. Full article