Search Results (115)

Winter road safety is threatened by black ice, while traditional de-icing methods, such as chemical spreading and electrically heated pavement systems, raise concerns about environmental impact and economic costs. This study proposed a hydronic heated pavement system utilizing geothermal energy (HHPS-G)-integrated concrete pavement that ensures environmental sustainability and structural stability. The design utilizes hollow steel pipes as both reinforcement and heat exchange conduits, thereby eliminating the need for separate high-density polyethylene (HDPE) pipes. To enhance upward heat transfer, bottom-ash concrete was introduced as an alternative to conventional insulation, providing thermal insulation and structural strength. A validated numerical model was developed to compare the de-icing and snow-melting performance of different pipe types. The results show that hollow steel pipes reduced the time to reach 0 °C on the concrete pavement surface by 30.86% and improved heat flux by 10.19% compared to HDPE. The depth of pipe installation significantly influenced performance: positioning the pipes near the surface achieved the fastest heating (up to 70.11% faster), while mid-depth placement, recommended for structural integrity, still provided substantial thermal benefits. Variations in insulation thermal conductivity below 1 W/m·K had little effect, whereas replacing the base layer with bottom-ash concrete provided both insulation and strength without the need for separate insulation layers. Full article

Conventional asphalt pavement snow and ice removal methods suffer from issues such as time-consuming operations, high costs, and pollution from chemical de-icing agents. Commonly used thermally conductive asphalt concrete (TCAC) faces problems including limited filler diversity, high filler content, and elevated costs. To address these challenges, this study developed a thermally conductive asphalt concrete incorporating carbon fiber–silicon carbide composite fillers to provide a low-cost, energy-saving winter pavement snow melting solution and enhance eco-friendly de-icing performance. Finite element simulation software was employed to model its snow and ice melting performance, investigating the factors influencing this capability. Thermal conductivity was measured using the transient plane source (TPS) technique. The results show that with 0.3% carbon fiber, thermal conductivity reaches 1.43 W/(m·°C), 72.3% higher than ordinary asphalt concrete. Finite element simulations in finite element simulation software were used to model snow and ice melting, and strong agreement with field test data (correlation coefficients > 0.9) confirmed model reliability. Then, the finite element simulation software was used to study the effects of wind speed, temperature, laying power, and spacing on the snow and ice melting of TCAC. The simulation results show that the heating rate increases with TCAC thermal conductivity. Raising the power of the embedded carbon fiber heating cord reduces de-icing time but shows a threshold effect. In this study, asphalt pavement with high thermal conductivity was prepared using a low content of thermal conductive filler, providing a theoretical basis for sustainable pavement design, reducing energy use and environmental damage. TCAC technology promotes greener winter road maintenance, offering a low-impact alternative to chemical de-icing, and supports long-term infrastructure sustainability. Full article

Snow and ice accumulation on transportation infrastructure presents significant safety and maintenance challenges in cold regions, while conventional removal methods are both energy-intensive and environmentally detrimental. This study proposes a passive Heat Pipe–Coupled Geothermal Snow Melting System (HP-GSMS) that harnesses shallow geothermal energy to maintain snow-free surfaces without external energy input. Using Fluent-based CFD simulations, the system’s thermal performance was evaluated under various working fluids (ammonia, carbon dioxide, water) and pipe materials (stainless steel, aluminum). A one-dimensional thermal resistance model validated the CFD results under ammonia–stainless steel conditions, predicting a heat flux of 358.6 W/m² compared to 361.0 W/m² from the simulation, with a deviation of only 0.66%, confirming model accuracy. Ammonia demonstrated superior phase-change efficiency, with the aluminum–ammonia configuration yielding the highest heat flux (up to 677 W/m²), surpassing typical snow-melting thresholds. Aluminum pipes enhanced radial heat conduction without compromising phase stability, while water exhibited poor phase-change performance and CO₂ showed moderate but stable behavior. Additionally, a dynamic three-node RC thermal network was employed to assess transient performance under realistic diurnal temperature variations, revealing surface heat fluxes ranging from 230 to 460 W/m², with a daily average of approximately 340 W/m². These findings demonstrate the HP-GSMS’s practical viability in cold climates and underscore the importance of selecting low-boiling-point fluids and high-conductivity materials for scalable, energy-efficient, and low-carbon snow-melting applications in urban infrastructure. Full article

With the rapid development of wireless communication, Wireless Local Area Networks (WLANs) are widely deployed in high-density environments. Ensuring fast handovers and optimal AP selection during device roaming is critical for maintaining network throughput and user experience. However, frequent mobility, high access density, and dynamic channel fluctuations complicate throughput prediction. To address this, we propose a method combining the Snow-Melting Optimizer (SMO) with decision tree regression models to optimize feature selection and model transmission opportunities (TXOP) and AP throughput. Experimental results show that the Extreme Gradient Boosting (XGBoost) model performs best, achieving high prediction accuracy for TXOP (MSE = 1.3746, R² = 0.9842) and AP throughput (MAE = 2.5071, R² = 0.9896). This approach effectively captures the nonlinear relationships between throughput and network factors in dense WLAN scenarios, demonstrating its potential for real-world applications. Full article

Aiming at the problems of serious pavement temperature diseases, low efficiency and high loss of ice-breaking methods, high occupancy rate of waste tires and the low utilization rate and insufficient durability of rubber particles, this paper aims to improve the service level of roads and ensure the safety of winter pavements. A pavement material with high efficiency, low carbon and environmental friendliness for active snow melting and ice breaking is developed. Firstly, NaOH, NaClO and KH550 were used to optimize the treatment of rubber particles. The hydrophilic properties, surface morphology and phase composition of rubber particles before and after optimization were studied, and the optimal treatment method of rubber particles was determined. Then, the optimized rubber particles were used to replace the natural aggregate in the polyurethane gel mixture by the volume substitution method, and the optimum polyurethane gel dosages and molding and curing processes were determined. Finally, the influence law of the road performance of RPGM was compared and analyzed by means of an indoor test, and the ice-breaking effect of RPGM was explored. The results showed that the contact angles of rubber particles treated with three solutions were reduced by 22.5%, 30.2% and 36.7%, respectively. The surface energy was improved, the element types on the surface of rubber particles were reduced and the surface impurities were effectively removed. Among them, the improvement effect of the KH550 solution was the most significant. With the increase in rubber particle content from 0% to 15%, the dynamic stability of the mixture gradually increases, with a maximum increase of 23.5%. The maximum bending strain increases with the increase in its content. The residual stability increases first and then decreases with the increase in rubber particle content, and the increase ranges are 1.4%, 3.3% and 0.5%, respectively. The anti-scattering performance increases with the increase in rubber content, and an excessive amount will lead to an increase in the scattering loss rate, but it can still be maintained below 5%. The fatigue life of polyurethane gel mixtures with 0%, 5%, 10% and 15% rubber particles is 2.9 times, 3.8 times, 4.3 times and 4.0 times higher than that of the AC-13 asphalt mixture, respectively, showing excellent anti-fatigue performance. The friction coefficient of the mixture increases with an increase in the rubber particle content, which can be increased by 22.3% compared with the ordinary asphalt mixture. RPGM shows better de-icing performance than traditional asphalt mixtures, and with an increase in rubber particle content, the ice-breaking ability is effectively improved. When the thickness of the ice layer exceeds 9 mm, the ice-breaking ability of the mixture is significantly weakened. Mainly through the synergistic effect of stress coupling, thermal effect and interface failure, the bonding performance of the ice–pavement interface is weakened under the action of driving load cycle, and the ice layer is loosened, broken and peeled off, achieving efficient de-icing. Full article

Winter pavement maintenance faces challenges in balancing large-scale upkeep and driving safety, particularly regarding the application of active slow-release materials. This study proposes a gel-modified salt-storing ceramsite asphalt mixture to enhance ice-melting capabilities through controlled salt release. By replacing a conventional coarse aggregate with salt-storing ceramsite in SMA-10 graded mixtures (0–80% content), we systematically evaluate its mechanical performance and de-icing functionality. The experimental results demonstrate that 40% salt-storing ceramsite content optimizes high-temperature stability while maintaining acceptable low-temperature performance and water resistance. Microstructural analysis reveals that silicone–acrylic emulsion forms a hydrophobic film on ceramsite surfaces, enabling uniform salt distribution and sustained release. The optimal 10% gel modification achieves effective salt retention and controlled release through pore-structure regulation. These findings establish a 40–60% salt-storing ceramsite content range as the practical range for winter pavement applications, offering insights into the design of durable snow-melting asphalt surfaces. Full article

Asphalt pavements are subjected to both repeated vehicle loads and erosive deterioration from complicated environments in service. Salt erosion exerts a serious negative impact on the service performance of asphalt pavements in salt-rich areas such as seasonal frozen areas with snow melting and deicing, coastal areas, and saline soils areas. In recent years, the performance evolution of asphalt materials under salt erosion environments has been widely investigated. However, there is a lack of a systematic summary of salt erosion damage for asphalt materials from a multi-scale perspective. The objective in this paper is to review the performance evolution and the damage mechanism of asphalt mixtures and binders under salt erosion environments from a multi-scale perspective. The salt erosion damage and damage mechanism of asphalt mixtures is discussed. The influence of salt categories and erosion modes on the asphalt binder is classified. The salt erosion resistance of different asphalt binders is determined. In addition, the application of microscopic test methods to investigate the salt damage mechanism of asphalt binders is generalized. This review finds that the pavement performance of asphalt mixtures decreased significantly after salt erosion. A good explanation for the salt erosion mechanism of asphalt mixtures can be provided from the perspective of pores, interface adhesion, and asphalt mortar. Salt categories and erosion modes exerted great influences on the rheological performance of asphalt binders. The performance of different asphalt binders showed a remarkable diversity under salt erosion environments. In addition, the evolution of the chemical composition and microscopic morphology of asphalt binders under salt erosion environments can be well characterized by Fourier Infrared Spectroscopy (FTIR), Gel Permeation Chromatography (GPC), and microscopic tests. Finally, the major focus of future research and the challenges that may be encountered are discussed. From this literature review, pore expansion mechanisms differ fundamentally between conventional and salt storage asphalt mixtures. Sulfate ions exhibit stronger erosive effects than chlorides due to their chemical reactivity with asphalt components. Molecular-scale analyses confirm that salt solutions accelerate asphalt aging through light-component depletion and heavy-component accumulation. These collective findings from prior studies establish critical theoretical foundations for designing durable pavements in saline environments. Full article

To further investigate the heat transfer characteristics of electric heating snow-melting pavement, this study developed two finite element models of such systems and conducted small-scale field experiments. An analysis was performed on the snow-melting pavement systems’ temperature field, temperature change rate, and gradient distribution during summer and winter, with entransy dissipation introduced to further analyze the heat transfer characteristics of asphalt snow-melting pavement. The results indicate that during system shutdown in summer and winter, the pavement structure exhibits reduced heat transfer capacity, leading to progressive decreases in the temperature variation rate and gradient with depth. The primary heat transfer loss occurs in the asphalt layer, with entransy dissipation predominantly concentrated during summer daylight and winter nighttime. During winter operation, the cable heat source modifies the temperature field distribution and gradient, which alters entransy dissipation. Installing an insulation layer improves snow-melting efficiency, and operating the system from 00:00 to 05:00 effectively prevents pavement icing. Full article

To prevent traffic accidents caused by icy roads in winter and damage to roads resulting from repeated freeze–thaw cycles, this paper proposes an optimized design plan for slow-release anti-icing fog seal. The effects of the dosages of slow-release anti-icing agent, water-based epoxy resin modifier, and penetrant on the ice- and snow-melting properties, mechanical properties, and penetration properties of the fog seal were investigated. Based on single-factor experiments, a Box–Behnken model was established, and the response surface method was employed to optimize the design of the fog seal. Subsequently, wear resistance was assessed using an accelerated loading test, while anti-skid performance was evaluated through the British pendulum test and the sand patch test. The results indicate that the optimal ratio for the slow-release anti-icing fog seal is 13% slow-release anti-icing agent, 20% water-based epoxy resin modifier, and 12% penetrant. This material demonstrated excellent ice- and snow-melting performance as well as good wear and skid resistance in testing, providing valuable insights for the application of the slow-release anti-icing agent in new pavement maintenance techniques. Full article

Winter mixed-phase precipitation (P) impacts transportation, electric power grids, and homes. Forecasting winter precipitation such as freezing precipitation (ZP), freezing rain (ZR), freezing drizzle (ZL), ice pellets (IPs), and the snow (S) and rain (R) boundary remains challenging due to the complex cloud microphysical and dynamical processes involved, which are difficult to predict with the current numerical weather prediction (NWP) models. Understanding these processes based on observations is crucial for improving NWP models. To aid this effort, Environment and Climate Change Canada deployed specialized instruments such as the Vaisala FD71P and OTT PARSIVEL disdrometers, which measure P type (PT), particle size distributions, and fall velocity (V). The liquid water content (LWC) and mean mass-weighted diameter (${\mathrm{D}}_{\mathrm{m}}$) were derived based on the PARSIVEL data during ZP events. Additionally, a Micro Rain Radar (MRR) and an OTT Pluvio2 P gauge were used as part of the Winter Precipitation Type Research Multi-Scale Experiment (WINTRE-MIX) field campaign at Sorel, Quebec. The dataset included manual measurements of the snow water equivalent (SWE), PT, and radiosonde profiles. The analysis revealed that the FD71P and PARSIVEL instruments generally agreed in detecting P and snow events. However, FD71P tended to overestimate ZR and underestimate IPs, while PARSIVEL showed superior detection of R, ZR, and S. Conversely, the FD71P performed better in identifying ZL. These discrepancies may stem from uncertainties in the velocity–diameter (V-D) relationship used to diagnose ZR and IPs. Observations from the MRR, radiosondes, and surface data linked ZR and IP events to melting layers (MLs). IP events were associated with colder surface temperatures (Ts) compared to ZP events. Most ZR and ZL occurrences were characterized by light P with low LWC and specific intensity and ${\mathrm{D}}_{\mathrm{m}}$ thresholds. Additionally, snow events were more common at warmer T compared to liquid P under low surface relative humidity conditions. The Pluvio2 gauge significantly underestimated snowfall compared to the optical probes and manual measurements. However, snowfall estimates derived from PARSIVEL data, adjusted for snow density to account for riming effects, closely matched measurements from the FD71P and manual observations. Full article

The impact of ice and snow in seasonally frozen regions has led to a significant decline in the flatness and skid resistance of highway pavements, creating severe traffic safety hazards. With economic development driving the transition from road construction to maintenance, this study proposes enhancing Ultra-Thin Wearing Course (UTWC) maintenance materials with anti-icing performance and snow-melting properties. The study first employed the Marshall mix design method to develop gradations for two common types of UTWC asphalt mixtures: the dense-graded GT-8 and the open-graded NovaChip^® Type-B. Using the volume substitution method, aggregates were replaced with equivalent volumes of ceramic grains. The optimal asphalt–aggregate ratios for the mixtures with varying ceramic grain contents were determined, and the influence of ceramic grains content on the asphalt–aggregate ratio was analyzed. The results indicate that the optimal asphalt–aggregate ratio increases with higher ceramic grains content. Subsequently, the high-temperature performance, low-temperature performance, and water stability of UTWC with varying ceramic grain contents were evaluated. Overall, NovaChip^® gradation mixtures demonstrated superior road performance compared to GT-8 gradation mixtures. Moreover, an increase in ceramic grains content enhanced the high-temperature performance of UTWC but moderately reduced its low-temperature performance and water stability. Finally, the effects of different ceramic grain contents and snowmelt agent types on the anti-icing and snowmelt properties of UTWC were examined. The results revealed that higher ceramic grains content improved snowmelt effectiveness. Considering the road performance of the specimens, a ceramic grains content of 40% was recommended. Furthermore, calcium chloride (CaCl₂) exhibited superior anti-icing performance compared to other snowmelt agents. Full article

Surface albedo measurements of snow and ice on Lake Ulansu in the Central Asian arid climate zone were conducted during the winter of 2016–2017. Observations were categorized into three stages based on the ice growth and surface condition: bare ice, snow cover, and melting. During the bare ice stage, the mean surface albedo was 0.35 with a decreasing trend due to the accumulation of wind-blown sediment on the ice surface (range: 0.99–1.87 g m⁻²). Two snowfall events occurred during the snow cover stage, significantly increasing the surface albedo to 0.91. During the melting stage, the albedo decreased at a decay rate of 0.20–0.30/day. Four existing albedo schemes were evaluated but found unsuitable for Lake Ulansu. A new surface albedo scheme was proposed by incorporating the existing albedo schemes with the measured data. This scheme incorporated the effect of sediment content on bare ice albedo for the first time. It demonstrated a modelling efficiency of 0.933 over the entire 3-month period, which was used to evaluate the fit between the predicted and observed values. When validated with albedo observations from other winters, it achieved a modelling efficiency of 0.940. The closer the value is to 1, the better the model’s predictive accuracy, indicating a higher level of reliability in the model’s performance. This scheme has potential applicability to other lakes in the Central Asian arid climate zone, which is characterized by low precipitation, frequent sandstorms, and intense solar radiation. Full article

Performance plays a critical role in the practical use of global streamflow reanalysis. This paper presents the combined use of random forest and the Shapley additive explanation to examine the mechanism by which catchment attributes influence the accuracy of streamflow estimates in reanalysis products. In particular, the reanalysis generated by the Global Flood Awareness System streamflow is validated by streamflow observations provided by the Catchment Attributes and MEteorology for Large-sample Studies dataset. Results highlight that with regard to the Kling–Gupta efficiency, the reanalysis surpasses mean flow benchmarks in 93% of catchments across the continental United States. In addition, twelve catchment attributes are identified as major controlling factors with spatial patterns categorized into five clusters. Topographic characteristics and climatic indices are also observed to exhibit pronounced influences. Streamflow reanalysis performs better in catchments with low precipitation seasonality and steep slopes or in wet catchments with a low frequency of precipitation events. The partial dependence plot slopes of most key attributes are consistent across the four seasons but the slopes’ magnitudes vary. Seasonal snow exhibits positive effects during snow melting from March to August and negative effects associated with snowpack accumulation from September to February. Catchments with very low precipitation seasonality (values less than −1) show strong seasonal variation in streamflow estimations, with negative effects from June to November and positive effects from December to May. Overall, this paper provides useful information for applications of global streamflow reanalysis and lays the groundwork for further research into understanding the seasonal effects of catchment attributes. Full article

The snow melting and runoff process in the black soil area of Northeast China has led to soil quality degradation in farmland, posing a threat to sustainable agricultural development. To investigate the regulatory effect of tillage layer construction on the infiltration characteristics of snowmelt water, a typical black soil in Northeast China was selected as the research object. Based on field experiments, four protective tillage treatments (CK: control treatment; SB: sub-soiling treatment; BC: biochar regulation treatment; SB + BC: sub-soiling tillage and biochar composite treatment) were set up, and the evolution of soil physical structure, soil thawing rate, snow melting infiltration characteristics, and the feedback effect of frozen layer evolution on snowmelt infiltration were analyzed. The research results indicate that sub-soiling and the application of biochar effectively regulate soil aggregate particle size and increase soil total porosity. Among them, at the 0–10 cm soil layer, the soil mean weight diameter (MWD) values under SB, BC, and SB + BC treatment conditions increased by 6.25%, 16.67%, and 19.35%, respectively, compared to the CK treatment. Sub-soiling increases the frequency of energy exchange between the soil and the environment, while biochar enhances soil heat storage performance and accelerates the melting rate of frozen soil layers. Therefore, under the SB + BC treatment conditions, the maximum soil freezing rate increased by 21.92%, 5.67%, and 25.12% compared to the CK, SB, and BC treatments, respectively. In addition, sub-soiling and biochar treatment effectively improved the penetration performance of snowmelt water into frozen soil layers, significantly enhancing the soil’s ability to store snowmelt water. Overall, it can be concluded that biochar regulation has a good improvement effect on the infiltration capacity of surface soil snowmelt water. Sub-soiling can enhance the overall snowmelt water holding capacity, and the synergistic effect of biochar and deep tillage is the best. These research results have important guiding significance for the rational construction of a protective tillage system model and the improvement of the utilization efficiency of snowmelt water resources in black soil areas. Full article

Waste slag and rubber particles are commonly used to modify concrete, offering benefits such as reduced cement consumption and lower greenhouse gas emissions during cement production. In this study, these two environmentally friendly, sustainable waste materials were proposed for the preparation of mortar intended for snow-melting pavements. A series of experiments were conducted to evaluate the performance of the material and to determine whether its compressive and flexural strengths meet the requirements of pavement specifications. The mortar’s suitability for snow-melting pavements was assessed based on its thermal conductivity, impermeability, and freeze–thaw resistance. The results indicate that slag, when used in different volume fractions, can enhance the compressive and flexural strength of the mortar. Slag also provides excellent thermal conductivity, impermeability, and resistance to freeze–thaw cycles, contributing to the overall performance of snow-melting pavements. When the slag content was 20%, the performance was optimal, with the compressive strength and flexural strength reaching 58.5 MPa and 8.1 MPa, respectively. The strength loss rate under freeze–thaw cycles was 8.03%, the thermal conductivity reached 2.2895 W/(m * K), and the impermeability pressure value reached 0.5 MPa. Conversely, the addition of rubber particles was found to decrease the material’s mechanical and thermal properties. However, when used in small amounts, rubber particles improved the mortar’s impermeability and resistance to freeze–thaw cycles. When the rubber content was 5% by volume, the impermeability pressure value reached 0.5 MPa, which was 166.7% lower than that of ordinary cement mortar. Under freeze–thaw cycles, the strength loss rate of the test block with a rubber content of 25% volume fraction was 9.83% lower than that of ordinary cement mortar. Full article