Search Results (1,086)

To address the low resource-recovery efficiency of waste polyethylene terephthalate (PET) and the shortage of high-performance eco-friendly asphalt modifiers, PET-derived functional additives were fabricated in this work via zinc-acetate-catalyzed alcoholysis of waste PET followed by repolymerization of the obtained degradation fragments. Owing to the diverse origins of waste PET feedstock, noticeable fluctuations in molecular-weight parameters are commonly encountered. Nevertheless, waste PET can be effectively depolymerized into relatively low-molecular-weight derivatives under the proposed catalytic alcoholysis conditions. This study systematically investigated the effects of different PET degradation pathways on the molecular architecture, molecular-weight distribution, and thermal stability of as-prepared PET-derived asphalt additives. It further uncovers the intrinsic structure–performance relationships between molecular characteristics and critical asphalt properties, including rheological behavior, interfacial adhesion, high-temperature rutting resistance, and low-temperature elastic recovery. Homogeneous alcoholysis conducted at 220 °C enables efficient depolymerization of waste PET to yield derivatives with tailorable molecular weights. The resultant amphiphilic alcoholysis products can reduce asphalt viscosity and ameliorate water stability, rendering them promising warm-mix anti-stripping additives. By contrast, repolymerized PET derivatives are capable of constructing cross-linked networks within asphalt matrix, which substantially boost the high-temperature modulus and fatigue resistance of modified asphalt. Distinct from conventional physical blending approaches that are plagued by inferior interfacial compatibility and marginal performance improvement, this chemical modification strategy affords PET-based additives with tunable functions for different engineering scenarios. These findings provide technical support for high-value recycling of waste PET and the development of sustainable low-carbon asphalt materials. Full article

Porous asphalt permeable pavements suffer severe coupled mechanical–hydraulic degradation under warm-rainy climates, raising rehabilitation costs and threatening the long-term sustainability of road infrastructure. This study aims to clarify how fiber type and dosage jointly govern the climate resilience of PAC-13 porous asphalt and provide material-selection guidance for constructing durable, sustainable permeable pavements. Four typical engineering fibers (polyester, polyacrylonitrile, lignin, and basalt) were incorporated into porous asphalt mixtures at mass dosages from 0% to 0.5%. A comprehensive laboratory testing program was conducted to characterize high-/low-temperature performance, moisture-damage resistance, aggregate anti-raveling capacity, drainage permeability, and void water-storage behavior, while novel multi-dimensional evaluation indicators coupling mechanical and hydraulic responses were established to quantify trade-offs induced by fiber modification. The experimental results demonstrate that appropriately dispersed fibers form an interwoven three-dimensional reinforcement network to enhance the structural durability of mixtures; however, excessive fiber dosage occupies interconnected drainage voids and aggravates internal stagnant-water retention. A dosage range of 0.3–0.4% was identified to balance mechanical reinforcement and hydraulic functionality. Polyacrylonitrile fiber delivers excellent low-temperature cracking resistance yet shows high-performance susceptibility to dosage deviations. Polyester and basalt fibers achieve favorable trade-offs among rutting resistance, moisture stability, and permeability, whereas lignin fiber is prone to severe agglomeration that exacerbates void clogging and chronic water-related deterioration. Accordingly, polyester and basalt fibers dosed at 0.3–0.4% are prioritized for high-standard sustainable climate-resilient drainage pavements. Polyacrylonitrile fiber can be adopted for sections primarily threatened by low-temperature cracking under strict construction control, while lignin fiber demands cautious field deployment. This research can provide design support for the use of permeable pavement in warm and rainy areas, and is helpful in enhancing the long-term sustainability of transportation infrastructure in the context of climate change. Full article

The study analyzes the rut formation process, changes in the physical and mechanical characteristics of the soil, and the energy demand associated with movement of the driven pneumatic wheel during repeated passes on the same track in a laboratory soil channel stand. The tests were performed on a prepared silty loam at an average moisture of 30.64%. Three vertical wheel loads were investigated: 4.84 kN, 6.94 kN, and 8.75 kN without a brush mat, as well as a vertical load of 8.75 kN with a brush mat. After each pass, the average rut depth, its increment, and the average dynamic penetration resistance were determined. For tests without a brush mat, soil shear resistance, power, work performed per pass, and work per 1 m of path were additionally determined. It was established that the rut depth increased non-linearly. The greatest increment was formed during the initial passes, after which the deepening rate decreased. In the tests without a brush mat, the final rut depth showed a trend of increasing with load: 8.1 cm for 4.84 kN, 9.2 cm for 6.94 kN, and 9.9 cm for 8.75 kN. The brush mat was associated with lower accumulation intensity of the rut depth and lower average dynamic penetration resistance in the soil. The change in rut depth is described with sufficient accuracy by a regression model with R² = 0.9512–0.9761 and RMSE = 0.194–0.344 cm. Energy indicators showed that the first pass was the most energetically intense, and the calculated work characterizes the total work of the wheel movement, not just the work of rut formation. The results confirm nonlinear rut accumulation with the highest increment during initial passes, and the highest energy demand during the first pass. The fitted model provides an engineering tool for estimating permissible pass numbers, while the integrated geometric–mechanical–energy approach offers a more comprehensive basis for planning forestry traffic than conventional bare-soil compaction tests. Full article

Background: Helicobacter pylori colonizes the human gastric mucosa through outer membrane proteins (OMPs), particularly the adhesins BabA and BabB, which recognize host blood group antigens and mediate bacterial attachment and persistent colonization; importantly, structural and genetic studies have confirmed substantial polymorphisms in these adhesins that may affect their functional properties and contribute to differences in the clinical outcomes of infection. Therefore, the present study aimed to investigate the prevalence and genetic diversity of babA/babB variants in H. pylori isolates obtained from Jordanian patients and to evaluate their association with different gastric pathological conditions. Methods: A total of 106 gastric mucosal biopsies were collected from patients with gastric symptoms at two major hospitals in Jordan. Specimens underwent endoscopic evaluation, rapid urease testing (RUT), and histopathological examination according to the Sydney classification system. H. pylori detection was performed using real-time PCR targeting 16S rRNA and universal bab genes using novel primers designed to amplify both babA and babB variants. Conventional PCR was used for specific BabA and BabB gene amplification, followed by sequencing analysis of BabB variants. Results: A total of 106 patients were enrolled, with a mean age of 40.2 ± 15.9 years. H. pylori was detected in 76 (71.7%), 83 (78.3%), and 79 (74.5%) cases by the Rapid Urease Test (RUT), histopathology, and 16S rRNA qPCR, respectively. Using histopathology as the reference method, 16S rRNA qPCR demonstrated a sensitivity of 95.2%, compared with 91.6% for RUT. Among the 83 histopathology-positive cases, the universal bab gene was detected in 72 (86.7%), of which 53/72 (73.6%) were positive according to babB-specific PCR. Among patients with chronic gastritis, universal bab positivity increased progressively from 82.5% in mild to 88.5% in moderate and 93.3% in severe gastritis, whereas babB positivity increased from 50.0% to 76.9% and 80.0%, respectively. Sequencing of 40 babB-positive samples identified 27 distinct babB sequence profiles, with CHI-023 and LIM-008 being the most frequently identified reference sequence matches (10.0% each), highlighting substantial genetic diversity within the analyzed babB region. Conclusions: The findings demonstrate high diagnostic performance of 16S rRNA qPCR and RUT relative to histopathology, together with substantial genetic diversity within the analyzed babB region. Full article

Asphalt binders are complex viscoelastic polymeric materials whose rheological behavior is governed by interactions among their chemical constituents and, in polymer-modified systems, the morphology and stability of the dispersed polymer network. This study developed a performance-based framework for selecting the type and dosage of bio-based soybean recycling agents (RAs) for styrene-butadiene-styrene (SBS)-modified asphalt mixtures containing 30% reclaimed asphalt pavement (RAP). Ten dense-graded asphalt mixtures with a nominal maximum aggregate size of 12.5 mm were evaluated, including a control mixture produced with PG 76-22 (PG 67-22 asphalt binder modified with 3.5% SBS) and no RAP, and nine mixtures containing 30% RAP and three soybean-based recycling agents (RA1, RA2, and RA3) at dosages of 0.5%, 2.0%, and 4.0% by weight of binder. Binder characterization included Superpave performance grading, while mixture performance was evaluated using the Hamburg Wheel Tracking (HWT) test, freeze–thaw-conditioned HWT, Semi-Circular Bend (SCB), IDEAL-CT, IDEAL-RT, and Cantabro abrasion loss tests. Increasing recycling-agent dosage improved cracking resistance but progressively reduced rutting resistance, consistent with the measured decrease in binder viscosity. The magnitude of the softening effect followed the order RA3 > RA2 > RA1, consistent with measured viscosity reductions and HWT rut-depth response. Integrating SCB fracture resistance with the HWT rutting criterion identified acceptable dosage ranges of 1.4–4.0%, 0.5–2.8%, and 0.5–0.7% for RA1, RA2, and RA3, respectively. These results demonstrate that the effectiveness of the evaluated recycling agents, as reflected by binder rheology and asphalt mixture performance, influences the balance between fracture resistance and permanent deformation, providing a performance-based framework for optimizing bio-based recycling-agent selection in high-RAP polymer-modified asphalt mixtures. Full article

The mechanical compaction required for conventional warm mix asphalt (WMA) can be difficult to achieve in confined areas and during local bituminous pavement repairs. In this study, a self-compacting warm mix asphalt (SC-WMA) was developed without external compaction using EM1 (Evotherm M1), SBS (styrene–butadiene–styrene), CF (cellulose fiber), and HL (hydrated lime). Four test mixtures were fabricated with varying modifier contents and compared using Marshall, rotational viscosity, and an adapted spread test to identify the best-performing SC-WMA mixture. The SC-WMA3 mix turned out to be the most suitable mixture based on the selected design criteria. It achieved a Marshall stability of 20.2 kN, bulk density of 2.381 g/cm³, optimum binder content of 5.9%, rotational viscosity of 0.600 Pa·s, and an average spread diameter of 265 mm. These results indicated that the mixture had sufficient workability to provide good stability in shape without grade segregation or binder drainage. The Hamburg Wheel Tracking Test (HWTT) was used to evaluate the performance of the adopted SC-WMA mixture in comparison with the conventional WMA mixture. The measured rut depth was 7.48 mm after 20,000 wheel passes, compared with 7.12 mm for conventional WMA. Preliminary application observations were conducted on pothole repairs, pavement crack repairs, and raveled surface repairs to verify the practical applicability of the developed SC-WMA3. In addition, the repaired areas remained stable after 30 days of traffic exposure, providing short-term field observations without mechanical compaction and supporting the suitability of this mixture for localized pavement maintenance. Full article

Asphalt pavements in high-altitude cold regions are subjected to the coupled effects of intense ultraviolet (UV) radiation and large temperature differences, which accelerate the oxidative aging and cracking of styrene-butadiene rubber-modified asphalt (SBR-MA), severely compromising their service durability. To improve aging resistance, polyphosphoric acid (PPA) was incorporated into SBR-MA to produce a PPA/SBR-modified binder (PPA/SBR-MA). This study systematically investigated the multiscale evolution of rheological properties, chemical structure, molecular weight distribution, nanoscale morphology, and nanomechanical properties of both SBR-MA and PPA/SBR-MA under coupled aging conditions of intense UV radiation and large temperature differences. The results indicated that macroscopic surface cracking in PPA/SBR-MA was significantly less severe than that in SBR-MA after aging. In terms of high-temperature rutting resistance and fatigue life, the PPA/SBR-MA exhibited a three-stage evolution pattern of “initial enhancement—subsequent deterioration—subsequent recovery,” while the SBR-MA showed only a two-stage pattern of “initial enhancement—subsequent deterioration.” Notably, PPA/SBR-MA consistently outperformed SBR-MA both before and throughout aging. Mechanistically, PPA reacts with polar asphaltene components to form phosphate ester linkages, thereby enhancing crosslinking between SBR and asphalt, suppressing polymer chain scission and stabilizing the colloidal structure. This retards internal asphaltene decomposition and small-molecule migration while suppressing asphaltene aggregation near the surface layer, thereby alleviating surface embrittlement. Compared with SBR-MA, the PPA/SBR-MA exhibits a 68% reduction in the surface-to-bulk modulus ratio, indicating a significantly mitigated gradient aging effect along the depth direction, which in turn suppresses macroscopic surface cracking. These findings reveal a phosphorylation-driven stabilization mechanism, offering a rational materials design paradigm for pavement applications in extreme environments. Full article

Asphalt mixtures are heterogeneous composite materials primarily composed of mineral aggregates and asphalt binder; depending on the mixture design, they may also incorporate reclaimed asphalt pavement (RAP) and polymer-modified binders. Their long-term performance is governed by the rheological evolution of the asphalt binder and its interactions with surrounding composite constituents during aging. Existing laboratory long-term aging (LTA) protocols have been developed primarily to evaluate mixture cracking resistance; however, their ability to reproduce the high-temperature rheological evolution of recovered asphalt binders remains insufficiently understood. This study evaluated the fidelity of accelerated LTA protocols by comparing the high-temperature rheological response of binders recovered from plant-produced asphalt mixtures with the conventional benchmark of 85 °C for 5 days. Five mixtures, including one containing an unmodified PG 67-22 binder with RAP and four containing SBS-modified PG 76-22 binders with varying RAP contents, were characterized using continuous high-temperature performance grade (PG-HT), dynamic shear rheometer rutting parameter (|G*|/sinδ), zero-shear viscosity, multiple stress creep recovery, and interrupted shear flow. Among the investigated protocols, loose-mixture aging at 135 °C for 6 h showed the closest agreement with the benchmark rheological response, whereas 135 °C for 8 h and 120 °C for 20 h produced greater rheological stiffening relative to the benchmark. The unmodified PG 67-22 binder exhibited the greatest aging sensitivity, while SBS-modified binders showed closer agreement overall. Full article

High-modulus asphalt binders (HMABs) are critical for heavy-duty pavements but are often constrained by low-temperature brittleness and poor dispersion of conventional granular modifiers. This study develops a novel micro-pulverized composite modifier (ZY) integrating hard asphalt, an ethylene–propylene copolymer, and a plasticizer system via high-shear melt blending and centrifugal atomization. The modification effects and underlying mechanisms were systematically investigated through rheological characterization (DSR, BBR, LAS), thermodynamic analysis (DSC), chemical functional group evaluation (FTIR), and microscopic morphological observation (FM), with two commercial high-modulus agents (PR and JK) as benchmarks. The results demonstrate that ZY significantly enhances high-temperature deformation resistance, elevating the Performance Grade from PG 64-22 to PG 82-10, with the complex modulus (G*) consistently exceeding those of PR and JK across the entire temperature sweep range (46–82 °C). At low temperatures, the synergistic toughening effect of the elastomeric copolymer and plasticizer enables a creep stiffness S of 240 MPa and an m-value of 0.298 at −12 °C, satisfying Superpave requirements and ensuring superior stress relaxation capability. The LAS test reveals a fatigue life of 245,000 cycles at 2.5% strain level, representing an approximately 60% improvement over the JK-modified binder. Microscopic characterization (DSC, FTIR, and FM) confirms that the modification mechanism is dominated by physical blending, forming a highly uniform micro-scale multiphase dispersion system: the hard asphalt component integrates into the matrix to achieve viscosity enhancement and stiffening, while the elastomeric copolymer forms finely dispersed spherical microspheres that effectively impede crack propagation and dissipate strain energy. This synergistic design achieves a favorable balance between high-temperature modulus and low-temperature flexibility, offering a promising solution for durable and rut-resistant pavement applications. Full article

Reducing asphalt mixture production temperatures and partially replacing virgin aggregates with industrially derived materials are potential pathways toward more sustainable pavement technologies. This study evaluated the effects of steel slag (SS) aggregate and air-cooled blast furnace slag (ACBFS) aggregate on the properties of asphalt concrete for pavement binder courses produced as warm-mix asphalt (WMA) using water-foamed bitumen. The reference hot-mix asphalt (HMA) and WMA mixtures were compared with WMA variants in which 20% or 40% of the virgin aggregate was replaced by SS or ACBFS. The slag aggregates were characterized by physical and mechanical properties, surface morphology, and local elemental composition. Mixture performance was evaluated based on air voids content, indirect tensile strength, water and freeze–thaw resistance, dynamic modulus, and rutting resistance, followed by statistical analysis. Slag type and replacement level affected the properties differently. Increasing slag content increased air voids content, whereas slag-containing mixtures showed a lower relative loss of tensile strength after conditioning than the reference mixtures. Compared with SS, ACBFS resulted in lower dynamic modulus and poorer rutting resistance. The mixture containing 20% SS satisfied all adopted technical requirements. The results support the use of SS at this replacement level, whereas ACBFS mixtures require further optimization. Full article

As the environmental sustainability of forest management has become an increasingly important consideration, incorporating environmental performance into timber harvesting operations has grown to be correspondingly critical. This shift is reflected in a growing move away from large-scale clear-cutting toward smaller-scale harvesting operations. To conduct such small-scale harvesting efficiently, mechanized systems have increasingly been introduced into practice, yet how these systems affect the soil environment relative to conventional harvesting methods remains insufficiently understood. In the Republic of Korea, where steep, mountainous terrain predominates, this knowledge gap is particularly consequential, as the conventional (chainsaw felling and excavator-based woodgrab extraction) system often produces spatially diffuse and severe surface soil damage. This study compared surface soil disturbances between conventional and small-scale mechanized (SSM) harvesting systems across three slope gradient classes (moderate, <20°; steep, 20–25°; very steep, >25°) at five harvesting units in the Republic of Korea. Disturbance was assessed at total of 2046 systematically distributed grid points using a four-class visual disturbance protocol, with continuous disturbance surfaces derived by inverse distance weighting (IDW) interpolation. The results indicate that SSM systems shift the pattern of disturbance rather than uniformly reducing it. On moderate slopes, SSM (grapple saw felling and clambunk skidding) reduced the proportion of severe, area-wide disturbance but concentrated deep rutting along fixed skid trails, producing significantly deeper ruts than the conventional system. On the steep slope, the SSM system pairing mechanized felling with swing yarder extraction substantially reduced both the extent and the severity of disturbance relative to the conventional system by eliminating in-stand machine travel during extraction. On the very steep slope, no paired conventional unit was available for comparison, but the SSM system using a small tower yarder resulted in a notably low level of surface disturbance. These findings suggest that the soil-protective benefit of SSM systems may depend on how machine traffic is distributed during felling and extraction, offering evidence to guide slope-specific system selection for environmentally sound timber harvesting. Full article

Data-driven prediction of crumb–rubber modified asphalt (CRMA) binder properties is usually reported on datasets in which a small number of mix-designs is swept across several test temperatures, so that the row count greatly exceeds the number of independent experiments. This study asks what such a dataset can actually support. Using 221 laboratory measurements drawn from 20 independent CRMA mix designs, we evaluate a task-adaptive mixture-of-experts multi-task network (TA-MoE-MTL), a locked Huber-anchored hybrid extension, and fourteen deep and classical reference models for the joint prediction of penetration, softening point, ductility and rutting factor. Three methodological elements are introduced. First, model selection is made strictly nested and group-aware: the stopping epoch is chosen on an inner split of the training designs and the held-out designs are used once. Second, we bound what the recorded inputs can explain before any model is fitted: because the consistency targets are constant within a mix design and because eight designs share identical input vectors while their rutting factors differ, the attainable coefficient of determination for the rutting factor is 0.790 rather than unity. Third, performance is reported with each mix design weighted equally, so that high replication designs cannot dominate. The locked hybrid assigns 90% weight to a Huber-anchored robust expert branch and 10% to a freshly trained TA-MoE-MTL branch. It attains pooled out-of-fold coefficients of determination of 0.613/0.594/0.878/0.685 and ranks first of 16 models at a mean pooled R² 0.693, exceeding MLP–sklearn (0.656) by 0.037. Across three seeds, seeds 42/43/44 give mean pooled R² values of 0.693/0.689/0.693 (mean 0.691 ± 0.002), and all three runs remain above the frozen MLP sklearn reference. A learning curve over the number of training designs is still rising at the largest size the data allow. The contribution of this work is an evaluation protocol for replicated mix design datasets, a way of bounding their information content, and a robust hybrid that exposes rather than hides the value of a simple small-sample anchor. Full article

To enhance the high-temperature rutting resistance, fatigue performance and low-temperature cracking resistance of base asphalt, and promote the resource utilization of industrial solid waste, this study took 70# asphalt as the base asphalt and selected nano-montmorillonite (MMT) and fly ash (FA) as composite modified fillers. A series of composite modified asphalt samples was prepared with MMT:FA mass ratios of 1:2, 1:3 and 1:4 and total filler contents of 3%, 5% and 7%, respectively. Conventional physical tests, dynamic shear rheometry (DSR), multiple stress creep recovery (MSCR), linear amplitude sweep (LAS) and bending beam rheometry (BBR) were adopted to systematically evaluate the pavement rheological properties. The microscopic modification mechanism was revealed by thin-layer chromatography with flame ionization detection (TLC-FID) and gel permeation chromatography (GPC). The results show that MMT-FA composite filler can significantly reduce the penetration, increase the softening point, and greatly enhance the high-temperature rutting factor, creep-recovery rate and fatigue life of asphalt, while its influence on low-temperature performance is controllable. For the optimal group, S5, the rutting factor rises by 42.6% at 64 °C, and the fatigue life increases by 58.3% under 5.0% strain compared with the base asphalt. With the increase in filler content, the high-temperature and fatigue performance of asphalt increases first and then slows down, while the low-temperature stiffness rises gradually. Microscopic analysis indicates that the intercalation and strong adsorption of MMT restrict the light components of asphalt and increase the proportion of macromolecules, and FA plays the roles of particle filling and skeleton support. The two fillers synergistically optimize the colloid structure and molecular distribution of asphalt. Based on rheological properties and microscopic mechanism, the optimal ratio is 1:3 for MMT:FA with a total content of 5%, under which the composite modified asphalt achieves the best comprehensive pavement performance and can meet the requirements of heavy-load traffic and areas with large temperature differences. The research results can provide experimental and theoretical support for the material design, performance optimization and engineering application of MMT-FA composite modified asphalt. Full article

In this paper an experimental study and comparative analysis of temperature and moisture in pavements and their soil bases on experimental road sections located in two southern metropolises of Kazakhstan—in the cities of Almaty and Shymkent—were conducted. The temperature and moisture values were measured by systems for long-term continuous monitoring of temperature and moisture in structural elements of roads. Sensors were installed at ten locations within the pavements and soil bases at depths ranging from 2.5 cm to 270–275 cm below the pavement surfaces. The temperature and moisture monitoring period extends from 21 October 2024 to 31 December 2025. Temperature and moisture readings were recorded hourly. It has been established that the temperature conditions of pavements and their soil bases in the two cities are qualitatively the same, and the quantitative differences are small: air temperatures and soil temperatures at depths of 2.5 cm and 10 cm in Shymkent are higher than in Almaty by an average of 4.75 °C, 5.69 °C and 2.12 °C, respectively. These facts make it possible to use a single methodological approach to account for temperature changes in the design of new roads and in the operation of existing roads. It is recommended to pay attention to ensuring the resistance to rutting and fatigue cracking of asphalt concrete layers of pavement. The moisture regime at the experimental section in Almaty up to 130–140 cm depth is unstable due to seepage of precipitation and surface water through the stone mastic and the two coarse-grained porous asphalt concrete layers of the pavement; in Shymkent the pavement and the soil base have a stable moisture regime throughout the year; these features should be taken into account when calculating accumulations of plastic strains (increasing of rut depth) and fatigue damage in asphalt concrete layers of pavements while also accounting for temperature changes in them and transport facility loads in different time periods. Full article

Biochar is no longer considered merely a substitute for conventional fillers in asphalt materials; rather, it represents a multifunctional modifier that aligns with the goals of sustainable road design and urban mobility in smart cities. Its application now extends to the rheological modification of asphalt binders, mitigation of asphalt fume emissions, improvement in aging resistance and interfacial adhesion, and assessment of carbon sequestration potential. Biochar can improve the high-temperature stability, rutting and aging resistance, and asphalt–aggregate adhesion of asphalt materials in a suitable dosage, and at the same time reduce emissions of volatile organic compounds (VOCs), polycyclic aromatic hydrocarbons (PAHs), hydrogen sulfide (H₂S), and other fumes. However, the above effects are highly dependent on the biochar feedstock, production process, physicochemical properties, particle size, dosage and degree of dispersion. An excess amount or uneven distribution will reduce the crack resistance and fatigue life at low temperatures; phase separation may also occur and VOC emissions will increase. Therefore, the main problem in this area has shifted from whether biochar is effective to when it can be applied for particular pavement performance goals, what pollutant control targets are aimed for, and over what life-cycle periods. This review integrates evidence obtained at the binder, mastic, and mixture scales and critically evaluates the influence of biochar on pavement performance, fume emissions, aging, interfacial adhesion, and environmental safety. It also argues that empirical dosage selection should be replaced by coordinated optimization of biochar structure, material performance, emission mitigation, and life-cycle impacts. Verification of the low-carbon benefits and environmental safety of biochar-modified asphalt will ultimately require standardized assessment frameworks and consistently defined system boundaries. Ultimately, this work provides a foundation for integrating biochar-modified asphalt into eco-friendly and resilient road infrastructures, aligning with the goals of smart urban mobility and sustainable transportation. Full article