Search Results (194)

The rapid transition toward electric mobility is widely recognized as a key strategy for improving urban environmental quality. However, while electric vehicles eliminate tailpipe emissions, they continue to contribute to environmental pressures through non-exhaust sources such as tire wear, road surface abrasion, and particle resuspension. This study develops a composite index framework for assessing road-segment-level operational environmental burdens associated with electric traffic, focusing on traffic operations, electric vehicle load characteristics, non-exhaust emission potential, and meteorological dispersion conditions. The framework does not constitute a life-cycle assessment and does not include battery production, electricity-generation mix, or other upstream environmental impacts. The framework combines four dimensions of influence: traffic operations, electric vehicle characteristics, non-exhaust emission processes, and meteorological dispersion conditions. Indicator selection was performed using the Delphi method, while indicator weights were determined through the Analytic Hierarchy Process (AHP). The methodological contribution lies not in the individual methods applied, but in their integration into a road-segment-level assessment framework specifically designed to identify and prioritize environmentally sensitive locations under traffic electrification scenarios. The resulting model incorporates sixteen indicators aggregated into a single environmental impact index that enables the ranking, classification, and prioritization of urban road segments according to their environmental burden. A case study conducted on selected urban streets demonstrates that non-exhaust emission indicators, particularly tire wear and particle resuspension, represent the most influential factors in the assessment process. Within the illustrative five-segment case study, the relative road-segment ranking remained unchanged under the electrified-traffic scenario, while the structure of the assessed burden shifted toward non-exhaust processes. The proposed framework provides a practical decision-support tool for urban planners and transport authorities by enabling the identification of environmentally sensitive locations, prioritization of infrastructure interventions, and support for sustainable mobility strategies in increasingly electrified urban transport systems. Full article

This study investigated the underwater abrasion resistance of recycled aggregate concrete according to ASTM C1138 using recycled aggregates obtained from demolished concrete as a 100% replacement of natural aggregates. The objective was to reduce the consumption of natural resources and minimize construction and demolition waste. In addition, ground granulated blast furnace slag (BFS) was used as a supplementary cementitious material at replacement ratios of 25% and 50%. Three BFS products with Blaine fineness values of 3000, 4000, and 6000 cm²/g were used to investigate their effects on the compressive strength and underwater abrasion resistance of recycled aggregate concrete. The experimental results showed that the compressive strength of recycled aggregate concrete was approximately 7% lower than that of natural aggregate concrete. However, the underwater abrasion test according to ASTM C1138 showed that the abrasion depth of recycled aggregate concrete was comparable to that of natural aggregate concrete. After 72 h of testing, the abrasion depth of recycled aggregate concrete was only slightly higher than that of natural aggregate concrete. In contrast, recycled aggregate concrete exhibited a higher weight loss, with an average value of 2.10% compared with 1.77% for natural aggregate concrete. Among the BFS mixtures, increasing the Blaine fineness of BFS resulted in lower abrasion depth and lower mass loss. Concrete containing BFS6000 exhibited the best underwater abrasion resistance within the BFS mixtures, although all BFS mixtures showed higher abrasion depth and mass loss than recycled aggregate concrete without BFS. At the 25% replacement ratio, concrete containing BFS6000 exhibited the lowest abrasion depth (3.11 mm) and weight loss (3.37%), whereas concrete containing BFS3000 showed higher values. A similar trend was observed at the 50% replacement ratio, although both abrasion depth and weight loss slightly increased compared with the corresponding 25% mixtures. The results demonstrate that recycled aggregate concrete combined with BFS has good potential for hydraulic structures and other concrete structures exposed to underwater abrasion. Although a slight reduction in compressive strength was observed, the underwater abrasion resistance can be improved by using BFS with higher Blaine fineness together with quality-controlled recycled aggregates. These findings provide useful information for the development of sustainable recycled aggregate concrete and support the efficient utilization of recycled materials in hydraulic engineering applications. Full article

Sustainable mortars for flooring require mechanical stability and surface durability against abrasion, not only compressive strength. This study evaluates potassium hydroxide (KOH)-activated hybrid fly ash mortars as candidate materials for sustainable flooring and surface wear layers. Ordinary Portland cement (OPC) was partially replaced with fly ash (FA) at OPC/FA ratios of 90/10, 80/20, and 70/30, using 4 M and 8 M KOH solutions. The experimental program included the characterization of fly ash, the alkaline solution, and fine aggregate, as well as flowability, bulk density, compressive strength, abrasion mass loss, and numerical consistency analysis. The results showed that OPC exhibited the highest strength and lowest wear; among the hybrid mortars, 90/10–8 M exhibited the highest relative performance, while 80/20–8 M provided the best balance between cement reduction, strength, and wear. The integrated mechanical–surface performance index $I_{\mathrm{MS}}$ and the analytical–numerical consistency assessment enabled the formulations to be ranked using an integrated selection criterion. Full article

The giant panda (Ailuropoda melanoleuca) relies on bamboo as its principal food source, exposing its enamel to sustained indentation, shearing, and abrasive loading. Mature enamel is highly mineralized but retains a small residual organic phase, whose contribution to wear resistance remains insufficiently defined. A gradient deproteinization model of mature giant panda enamel was established using KOH treatment. Thermogravimetric analysis (TGA), Fourier-transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), and scanning electron microscopy (SEM) were used to verify organic-phase removal and mineral-framework preservation. Nanoindentation, indentation creep, nanoscratch testing, atomic force microscopy (AFM), and SEM were then used to evaluate mechanical response, scratch resistance, and surface morphological evolution. The mass loss within 200–450 °C decreased with increasing KOH exposure and reached a plateau after 9 days. FTIR showed reduced organic-related or surface-sensitive bands, whereas phosphate bands were retained. XPS revealed decreased C and N contents; increased O, Ca, and P contents; and a higher Ca/P ratio. Deproteinization decreased the elastic modulus, shifted load–displacement curves toward greater indentation depth, and reduced the relative creep index. The critical load in nanoscratch testing decreased from 12.53 ± 0.35 mN to 6.07 ± 0.77 mN, while scratch depth, width, and residual depth increased. AFM showed a rightward shift in aggregate-size distribution and increased roughness. SEM revealed a transition from shallow plowing grooves to complex damage involving cracks, debris accumulation, and local spallation. Therefore, KOH treatment for 9 days provided an effective deproteinization endpoint for mature giant panda enamel. These findings suggest that the residual organic phase may contribute to surface interfacial continuity, local deformation accommodation, scratch-damage resistance, and reduced permanent damage accumulation. This material role may contribute to the adaptation of giant panda enamel to the mechanical demands of a bamboo-based, high-wear diet. Full article

Driven by the rising frequency of extreme climatic events and the escalating demand for sustainable infrastructure, modern pavement materials must deliver enhanced resilience, structural stability, and environmental adaptability. This study presents the design and synthesis of a novel polyurethane-polyurea (PU-PUa) pavement binder, engineered via a synergistic framework combining nanoscale microphase separation and a hierarchical hydrogen-bonding network. Utilizing a streamlined, one-step synthesis approach involving an aliphatic isocyanate, a polyaspartic ester, polytetramethylene ether glycol, and 1,4-butanediol, the PU-PUa copolymer achieves distinct nanoscale phase separation between its hard and soft segments. Fourier transform infrared (FTIR) spectroscopy verifies the successful formation of characteristic PU-PUa moieties and a multi-scale hydrogen-bonding network, while DSC and DMA reveal SSC-dependent soft-segment mobility, crystallization/melting behavior, and viscoelastic relaxation. These intra- and inter-segmental interactions, together with thermally activated soft-segment transitions, establish the structural foundation for the macro-performance enhancement of the system. Comprehensive evaluations demonstrate that the PU-PUa binder exhibits excellent mechanical and highly tunable properties. Rheological measurements indicate that increasing the soft segment content (SSC) or incorporating an appropriate diluent concentration significantly lowers the system viscosity, thereby enhancing processing workability during mixing and paving. Contact angle goniometry reveals that the surface hydrophobicity of PU-PUa can be effectively regulated by adjusting the SSC, offering a viable strategy to optimize moisture damage resistance. Moreover, curing behavior analyses show that the polymerization kinetics are strictly governed by both the SSC and environmental temperature, where a lower SSC or elevated curing temperature accelerates strength development. Mechanically, the PU-PUa binder displays desirable surface hardness (>80 Shore A) and exceptional aggregate adhesion (>2 MPa), ensuring robust bonding stability and resistance to traffic-induced abrasion. Characterized by balanced tensile performance, the elongation at break of the binder can be tailored from 90% to 161%, while its tensile strength varies between 6.4 MPa and 17.8 MPa at intermediate temperatures, manifesting excellent resilience and cracking resistance. Overall, this molecular-to-macroscopic design strategy establishes the PU-PUa copolymer as a highly promising, durable binder for next-generation resilient pavement infrastructures. Full article

Asphalt pavement wearing courses are directly exposed to hydrodynamic scouring, fuel erosion, freeze–thaw action, and traffic abrasion, leading to accelerated surface deterioration, skid-resistance loss, frequent maintenance, and increased life-cycle carbon emissions. To address these challenges, this study developed an organosilicon-based erosion- and skid-resistant asphalt wearing course (OES-AWC) through a stepwise material design strategy. An organosilicon-treated asphalt concrete matrix was first prepared to improve resistance to moisture damage, fuel erosion, and ice adhesion, and its curing behavior and optimal dosage were determined. A skid-resistant surface layer was then designed by optimizing the anti-skid aggregate type, organosilicon-to-aggregate ratio, and surface texture. Finally, waterborne epoxy resin was introduced to enhance aggregate anchorage, and the integrated OES-AWC was evaluated in terms of abrasion durability, rutting resistance, long-term skid resistance, and life-cycle impacts. The results show that organosilicon treatment forms a hydrophobic siloxane network, which improves the moisture damage, fuel erosion, and anti-icing resistance of asphalt concrete by 22.0–41.1%. Emery aggregates and the optimized surface structure enhance friction stability, while waterborne epoxy resin significantly suppresses aggregate stripping under repeated wheel loading. Compared with conventional asphalt wearing courses, the optimized OES-AWC increased wear durability by 148.1% while maintaining stable skid resistance under prolonged abrasion. Life-cycle assessment further demonstrates that OES-AWC can reduce carbon emissions by 47.2% and overall costs by 25.0%, with a probability exceeding 90% according to the uncertainty analysis. These findings indicate that OES-AWC provides a durable, low-carbon, and cost-effective maintenance strategy for asphalt pavements exposed to complex service environments. Full article

The workability of abrasive tools for precision grinding is significantly affected by the quality of active surface of grinding wheel in terms of the number, form, and sharpness of active abrasive grains. The aim of this study is to introduce a method for optimizing the abrasive tools based on active surface topography analysis, tool wear diagnostics, and numerical simulation of micro-cutting by one active grain and abrasive aggregate. Particular attention is given to the Shos parameter, which characterizes the machining potential of a grinding wheel by combining information on the height and sharpness of active abrasive grain vertices. Changes in this parameter allow observation of the blunting and wear of the active surface. Numerical simulation shows that material removal by one active grain and by an abrasive aggregate differs significantly. According to the obtained data, under the assumed micro-cutting conditions, the aggregate geometry reduced lateral material displacement and promoted chip formation. The coefficient of material removal efficiency for aggregate was equal to kr = 0.93 compared to kr = 0.37 for one grain. Therefore, abrasive aggregates have an effect on the material removal process and may support the improvement of the stability of precision grinding. Thus, it can be concluded that further improvements in abrasive tools require considering controlled active surface structures and abrasive aggregates, as well as diagnostic parameters that relate tool topography to wear and machining efficiency. Full article

The food packaging sector widely relies on polymeric materials, and as sustainability concerns grow, commodity polymers need to be replaced with innovative and more sustainable materials. Thermoplastic polyurethane (TPU) is a versatile elastomeric polymer characterized by flexibility, strength, chemical and abrasion resistance, and biocompatibility. However, it presents some limitations, notably in terms of functional properties (i.e., barrier properties). The use of nano-sized renewable fillers, such as cellulose nanocrystals (CNCs), may improve these properties, extending the applicability range of TPU. In this work, bio-based TPU nanocomposites were obtained by adding commercial silane-modified cellulose nanocrystals (Si−O−CNC) at different contents (1–5 wt.%). The nanocomposites were produced via melt mixing followed by compression molding and were characterized in terms of chemical (FTIR), morphological, thermal, mechanical, rheological, wettability, and barrier properties (i.e., water vapor permeability, WVP and oxygen transmission rate, OTR). The presence of Si−O−CNC promoted hydrogen bonding interactions with the TPU matrix, affecting the microphase separation and organization of the hard segments. These microstructural changes improved thermal stability, reduced WVP and OTR, and increased tensile properties at lower nanofiller contents (1–3 wt.%). At higher contents, partial nanofiller aggregation was observed, leading to a reduction in mechanical performance. Overall, these results suggest that TPU/Si−O−CNC nanocomposites have promising potential as sustainable food packaging materials. Full article

This study investigates the combined use of fly ash (FA) and plastic waste (PW) as partial replacements for cement and coarse aggregates in the production of paver blocks. Experimental mixes were developed with a substitution level of FA (10% to 30%) and PW (3% to 15%). The performance of the modified concrete block was evaluated in terms of compressive strength (CS), flexural strength (FS), ultrasonic pulse velocity (UPV), water absorption (WA), Cantabro abrasion resistance (CAR), and rapid chloride permeability test (RCPT). Experimental results revealed that the optimal mixture, containing 25% FA and 12% PW (M4), exhibited superior performance. Compared with the control mix, the 56-day compressive and flexural strengths increased by 14.1% and 15.3%, respectively. The UPV value increased to 5.1 km/s, indicating improved concrete quality and matrix densification. Durability performance was significantly enhanced, with water absorption reduced by 25.4%, Cantabro abrasion mass loss decreased by 23.7%, and chloride ion penetrability reduced by 50.0% at 56 days. Statistical analysis using two-way ANOVA confirmed that FA and PW contents significantly influenced paver block performance (p < 0.05). The economic assessment further demonstrated cost savings of up to 3.0% compared with conventional concrete paver blocks. The study demonstrates that FA and PW can be effectively valorized in paver block production, offering both economic and environmental benefits. This green approach supports sustainable construction practices and promotes efficient waste management. Full article

To address the rapid polishing and premature loss of skid resistance in conventional asphalt friction courses, as well as the weak bonding between waste ceramic aggregates and asphalt that compromises raveling resistance, this study developed a ceramic aggregate asphalt mixture incorporating TPS–SBS composite high-viscosity modified asphalt, denoted as T&S. The wear-retained skid resistance and raveling resistance of the mixture were systematically evaluated. Interfacial adhesion between the modified asphalt and ceramic aggregates was characterized using water-immersion adhesion and contact-angle tests. Mixtures with different ceramic aggregate contents were further investigated through laboratory-accelerated abrasion, immersion Cantabro particle loss, and torsional raveling tests. In addition, an empirical skid-resistance degradation model and a frictional impulse-based characterization model were established. The results showed that TPS increased the asphalt–ceramic aggregate adhesion grade from Grade 3 to Grade 5, indicating a marked improvement in interfacial adhesion. Mixture skid resistance increased with ceramic aggregate content. After 16 h of abrasion, the residual British pendulum number of the mixture containing 80% ceramic aggregates was 38.7% higher than that of the control mixture. However, a ceramic aggregate content of 40% was identified as a practical balance point between skid-resistance improvement and overall mixture performance under the present laboratory conditions. T&S-modified asphalt reduced both Cantabro particle loss and torsional mass loss by more than 40%, partly compensating for the interfacial and skeleton-interlocking limitations of ceramic aggregates. The proposed models achieved coefficients of determination (R²) greater than 0.997, indicating high fitting accuracy for the present laboratory data. The preferred mixture design was determined as 8% TPS and 40% ceramic aggregate, providing a promising technical pathway for the resource utilization of construction-derived waste ceramics in asphalt pavements. Full article

Background/Objectives: Nasopharyngeal inflammation is commonly evaluated through visual inspection of endoscopic findings, which remains subjective and prone to interobserver variability. This study aimed to develop and validate a deep learning-based system for objective quantification of key nasopharyngeal endoscopic findings. Methods: A total of 200 endoscopic videos were retrospectively analyzed as an independent evaluation dataset, while a separate annotated dataset of 279 cases was used for model training. Four findings—mucosal color tone, swelling, mucus or crust adhesion, and bleeding after abrasion—were scored by expert otolaryngologists using a three-point scale, and their sum was used as a composite reference severity score (Y8, range 0–8). A convolutional neural network generated continuous probability outputs for each finding, which were aggregated into a composite score (S8). Results: For the primary threshold (Y8 ≥ 3), the AI-derived score demonstrated strong agreement with expert consensus (AUC 0.874). A predefined rule-based diagnostic criterion also showed comparable discriminative performance (AUC 0.851). Conclusions: Deep learning-based quantification provides an objective and reproducible method for evaluating nasopharyngeal endoscopic findings. This approach may enable standardized assessment of inflammation and support more consistent clinical decision-making, particularly for identifying clinically relevant inflammation, while its ability to stratify higher severity levels is more limited. Full article

Aggregates comprise up to 95% of flexible pavement composition, critically influencing performance based on geological source and processing methods. In Pakistan, where approximately 264,175 km of roads carry 96% of inland freight, premium Margalla aggregates face increasing demand and depleting reserves, necessitating sustainable alternatives. This study comprehensively evaluates aggregates from five key quarries (Margalla, Malakand, Kohat, Swabi, and Besai) for highway suitability. Rigorous laboratory testing encompassed macro-level physical and mechanical properties and micro-characterization using Scanning Electron Microscopy (SEM), Energy Dispersive Spectroscopy (EDS), and Fourier Transform Infrared Spectroscopy (FTIR), alongside performance tests including Indirect Tensile Strength (ITS), rutting resistance, and fatigue analysis. Overall, Margalla aggregates exhibited the best performance, showing the lowest abrasion value (21%), highest Tensile Strength ratio (TSR) (82%), highest conditioned ITS (433.7 kPa), highest dynamic modulus (2120 MPa at 25 Hz), and the lowest rut depth (7.8 mm at 10,000 cycles). These superior properties are attributed to their favorable physical characteristics and high calcium content. Malakand and Kohat aggregates also demonstrated satisfactory performance, with TSR values of 79% and 76%, conditioned ITS values of 408.7 and 377.7 kPa, and rut depths of approximately 8.8 and 10.5 mm, respectively, indicating their suitability for medium-traffic pavements. In contrast, Swabi and Besai aggregates exhibited lower moisture resistance (TSR = 77% and 75%), lower conditioned ITS (355.7 and 337.7 kPa), and higher rut depths (~13.0 and 14.2 mm), making them less suitable for high-stress pavement layers. These findings support Malakand and Kohat aggregates as viable regional alternatives to Margalla. Full article

Adobe construction, as part of earthen architecture, is a traditional building technique that is widely used but particularly vulnerable to the effects of water and other climatic factors. This article analyses the physical and mechanical behaviour of three different grain sizes of adobe specimens, classified according to the predominant presence of coarse aggregates (CA), fine aggregates (FA), and fine aggregates with plant fibres (AF). In order to assess their response to climatic scenarios, these specimens are subjected to wetting–drying cycles (3, 5, and 7 cycles) and accelerated weathering tests (E) under controlled laboratory conditions. The main objective is to determine the influence of particle size distribution and the incorporation of plant fibres on the strength, stiffness, durability, and hydraulic behaviour of the material. For this purpose, an experimental programme was developed based on compression, modulus of elasticity, ultrasonic, abrasion, hydraulic erosion, and capillary absorption tests, and carried out at different stages of deterioration. Thus, six specimens were analysed for each of the five time points studied (0, 3, 5, 7, E) and for each proposed particle size distributions, giving a total of 450 samples analysed. The results show that the coarse mix exhibits greater overall mechanical stability, whereas the fine mix is more sensitive to the action of water. Although the addition of fibres improves ductility and resistance to surface erosion, it alters the porous structure of the material. Overall, the results confirm that particle size distribution and fibre reinforcement decisively influence the durability of adobe. Full article

This research explores the use of industrial waste as an alternative to natural raw materials, promoting a circular economy in the construction sector. It specifically investigates the manufacturing of paving blocks using blast furnace slag and recycled aggregates. Paving blocks were produced without altering typical industry conditions, entirely replacing cement with alkaline-activated blast furnace slag. The study replaced natural aggregate in three proportions (20%, 50%, and 100%) with three types of recycled aggregates: concrete recycled aggregate (CA), masonry recycled aggregate (MA), and recycled mixed aggregate (RMA), in both coarse and fine fractions. The experimental procedure analysed the impact of recycled aggregates in an alkaline-activated slag matrix through three phases: characterising physical properties (mechanical properties, water absorption, density, abrasion resistance, and slip resistance), evaluating leaching behaviour, and conducting a life cycle analysis. The results of physical characterisation were statistically analysed using principal component analysis (PCA). The results obtained show the feasibility of manufacturing paving blocks with blast furnace slag by completely replacing the natural aggregate with the coarse fraction of the three recycled aggregates used and replacing up to 20% in the case of using the fine fraction. The properties of the paving blocks manufactured with slag depend mainly on the degree of substitution of natural aggregate with the recycled aggregate. All paving blocks can be considered environmentally safe from leaching according to the Dutch Soil Quality Decree. Paving blocks made from alkali-activated ground granulated blast furnace slag and recycled aggregates generate a lower carbon footprint compared to concrete paving blocks. Full article

The asphalt industry, essential for the global transport infrastructure, requires substantial investments to increase the durability of production facilities. The quality of asphalt depends, essentially, on the degree of drying of mineral aggregates. Therefore, the rotary dryer is of major importance for ensuring the quality of asphalt. The rotary dryer flights are subjected to an erosive-abrasive wear process during operation, generated by the impact of abrasive aggregates. These phenomena lead to severe degradation of the flights. Experimental research, carried out by the authors, on-site, aimed at identifying solutions to improve the wear behavior of the flights, by hardfacing with four wear-resistant materials (FLUXOFIL 51, FLUXOFIL 56, SAFER R 400, SAFER R 600), using the GMAW and SMAW processes. The results revealed a decrease in the wear rate and a flattening effect of the wear curve along the profile of the flight. The research targeted the upper rear surface of the flights, which is predominantly affected by erosive-abrasive wear phenomena. The resistance to abrasive wear of the flights was improved by hardfacing with FLUXOFIL 51 wear-resistant tubular wire, resulting in the lowest wear rate, especially between the areas marked 14–26, which are the areas most affected during operation. Full article