Search Results (1,648)

Currently, existing studies primarily perform damage simulations based on random aggregate mesoscale models of concrete. In contrast, research on freeze–thaw numerical simulations based on realistic concrete mesostructural models remains relatively scarce. In this study, based on X-ray computed tomography (CT) scanning technology, the influence of freeze–thaw action on the pore structure evolution law of aeolian sand self-compacting concrete (ASSCC) was analyzed. Mesoscale characteristics of the mortar, aggregates, and pores were extracted using image processing software, and a realistic mesostructural model of ASSCC was subsequently established. Furthermore, numerical simulations of the freeze–thaw cycle process were conducted using the finite element software ABAQUS. The results indicated that during the initial freeze–thaw stage, the formation of small new pores predominated within the concrete. As the freezing and thawing cycles progressed, these pores gradually interconnected and coalesced into larger irregular pores, which eventually led to the development of penetrating cracks that resulted in structural failure of the ASSCC. The mesostructural model derived from CT data effectively simulated the failure patterns and mechanical performance of ASSCC under both uniaxial compression and freeze–thaw conditions. This provides an effective means for predicting the mechanical properties of concrete under freeze–thaw cycling conditions. Full article

The cumulative displacement of landslides in alpine regions is jointly affected by rainfall, temperature variation, freeze–thaw cycles, and other factors, and usually exhibits nonlinear, non-stationary, and multi-scale fluctuation characteristics. To improve the accuracy of landslide displacement prediction under complex environmental conditions, this study takes the Taker Tubek Village landslide in Gongliu County, Xinjiang, China, as the study object. Cumulative displacement data from GNSS02 and GNSS03, together with daily rainfall and daily mean temperature, were used to construct a SOO-VMD-CNN-TimeXer hybrid prediction model. First, SOO was employed to adaptively optimize the VMD parameters, and the cumulative displacement series were decomposed into multiple IMF components. Then, CNN was used to extract local fluctuation features, while TimeXer was applied to model long-term temporal dependencies and the effects of exogenous variables. Finally, the predicted results of all components were reconstructed to obtain the cumulative displacement prediction. The results show that the proposed model achieved high prediction accuracy at both GNSS02 and GNSS03. The MSE, MAE, MAPE, and R² values were 0.0158, 0.0960, 0.0112, and 0.9464 for GNSS02, and 0.0483, 0.1590, 0.0203, and 0.9946 for GNSS03, respectively, outperforming LSTM, Informer, iTransformer, Crossformer, and other models. The results indicate that the SOO-VMD-CNN-TimeXer model can effectively characterize the cumulative displacement evolution of landslides in alpine regions and provide technical support for landslide deformation trend forecasting and disaster early warning. Full article

With rapid urbanization, the generation of municipal solid waste is growing, placing ever-increasing pressure on cities to close, remediate and repurpose landfill sites in environmentally sustainable and climate-adaptive ways. Traditional landfill final covers such as compacted clay and geosynthetic systems are intended to limit infiltration; yet their conceptual designs often fail in performance longevity due to effects such as desiccation, settlement, root intrusion, freeze–thaw cycling and extreme rainfall. Phytocapping, or evapotranspiration/store-and-release cover technology is the use of vegetated soil profiles to provide storage for percolating rainfall, return water to the atmosphere through evapotranspiration and support biologically mediated oxidation of methane. Phytocapping is a green-inclusive nature-based climate adaptation strategy for urban landfill closure. This study explores hydrological performance, methane mitigation, ecological co-benefits, economic feasibility, climate sensitivity, monitoring requirements and regulatory barriers linked to phytocapping systems. Field evidence is strongest in Australia and the United States, especially through ACAP- and A-ACAP-style programs, while evidence from humid tropical, monsoon, freeze–thaw and low-resource urban contexts is comparatively lacking. As reported in published studies, well-designed phytocaps can result in reduced percolation compared to traditional clay caps. Reported publications also mention considerable construction-cost savings, depending on site conditions and design assumptions. Methane-related outcomes vary by measurement method and site context, with studies reporting surface flux reductions, methane oxidation and landfill gas attenuation as distinct performance indicators. These advantages are counter-balanced by design uncertainties that vary from site to site, limited long-term monitoring data, climate transferability concerns, and regulatory systems still firmly anchored in prescriptive low-permeability barriers. This review proposes a policy-oriented analytical framework that bridges the gap between technical performance evidence, urban co-benefits, staged monitoring and performance-based landfill closure regulation. As such, phytocapping should be considered not as a general-purpose substitute for engineered covers, but as a climate-responsive nature-based solution that can complement urban waste servicing infrastructure, ecological restoration and adaptive governance of landfills when properly designed, monitored and regulated. Full article

The durability degradation of airport cement concrete pavements remains a critical concern in cold and severely cold regions. Even concrete that satisfies current durability standards often exhibits rapid performance deterioration after only a few years of service under harsh environmental conditions. This study investigates the effectiveness of a silane protective material in improving the freeze–thaw resistance of airport pavement concrete. Key durability indicators, including mass loss rate and relative dynamic modulus of elasticity, were evaluated. The experimental analysis focused on the performance enhancement provided by silane impregnation treatment under both multi-cycle freeze–thaw conditions and ultra-low-temperature (−30 °C) exposure, with particular emphasis on resistance to water freeze–thaw damage and deicing-fluid freeze–thaw corrosion. The results demonstrate that silane-impregnated specimens exhibited significantly reduced mass loss after 500 freeze–thaw cycles, along with an approximately 50% increase in flexural strength. Under ultra-low temperatures, the treatment effectively mitigated freeze–thaw deterioration, reducing deicing salt scaling by over 90%. Furthermore, the abrasion loss per unit area was reduced by approximately 68%. These findings indicate that silane impregnation enhances concrete durability from multiple perspectives—including frost resistance, salt–frost resistance, and wear resistance—by improving the pore structure and interfacial properties. Consequently, it represents a reliable technical solution for improving the long-term durability of airport concrete pavements. Full article

Dredged soil treatment and reuse remain major economic and environmental challenges in geotechnical and highway engineering. Cement-based stabilization can effectively improve the engineering properties of dredged soil, but its large-scale use is associated with high material costs, energy consumption, and carbon emissions. In this study, a solid-waste-based binder composed of calcium carbide slag (CS), ground granulated blast-furnace slag (GGBS), and fly ash (FA) was developed as a potential cement alternative for stabilizing organic-rich dredged soil in road applications. Based on mortar-performance screening, a CS:GGBS:FA mass ratio of 0.25:0.50:0.25 was selected, and the road performance and durability of the resulting CS-GGBS-FA (CGF)-stabilized soil were systematically evaluated. Laboratory tests, including California bearing ratio (CBR), dynamic resilient modulus (M_R), wet–dry (W–D) cycling, and freeze–thaw (F−T) cycling, were conducted, with cement-stabilized soil used as a reference. The results showed that the CBR and M_R of the CGF-stabilized soil increased significantly with binder content and curing time, meeting the requirements for subgrade and subbase applications under different highway classes. Compared with cement-stabilized soil, the CGF-stabilized soil showed slightly lower CBR and M_R values at the same binder content but exhibited favorable strength retention and mass stability during W–D and F–T cycling. Overall, a CGF content of at least 8% provided sufficient strength, stiffness, and durability for road use. Full article

This study investigates citrus peel powder (CP) as an environmentally friendly admixture to regulate plant-derived urease (with soybean powder (SP) as the urease source) and to promote bio-mediated CaCO₃ mineralization, thereby improving the mechanical and freeze–thaw (FT) resistance properties of cement-based materials. When CP is combined with urea and soybean urease, it exhibits a regulatory effect on urease activity. For the CPUD (CP-encapsulated urea combined with soy powder)-modified material with SP dosage in cement content of 0.2 wt%, the CP–urea modification treatment can effectively improve their mechanical properties and FT durability. The flexural and compressive strengths at 28 days are increased by 10.53% and 11.19%, respectively, compared to the blank group. After freeze–thaw cycles, the strengths are still 27.08% and 26.67% higher than those of the blank group, and their respective strength loss rates are 7.58% and −5.77% (negative indicating a net strength increase), compared with 21.31% and 9.48% for the blank group. X-ray diffraction, Fourier-transform infrared spectroscopy, and scanning electron microscopy analyses reveal that CP–urea promotes the formation and effective packing of calcium carbonate. Mechanistically, CP establishes a stable hydrogen-bonding network with both urea and urease, exerting a dual regulatory effect: it enhances the electrophilicity of urea while also creating a physical mass transfer barrier to precisely control biomineralization. Notably, CP can be directly used without pretreatment, offering a sustainable strategy for citrus peel waste valorization. Full article

Background/Objectives: This study aimed to perform analytical validation and evaluation of the clinical performance of the Access Glial Fibrillary Acidic Protein (GFAP) research-use-only (RUO) immunoassay (Beckman Coulter) in plasma. Methods: A fully automated GFAP immunoassay was developed and evaluated for analytical validity and clinical performance. Analytical validation assessed precision, sensitivity, linearity, analytical specificity, and the stability of calibrators and samples. Evaluation of predefined clinical performance criteria included method comparison against the Quanterix Simoa GFAP Advantage Plus (RUO) assay and assessment of GFAP levels between participants with Alzheimer’s disease (AD) and healthy controls. Results: The Access GFAP (RUO) immunoassay met all analytical criteria. Precision yielded coefficients of variation (CVs) < 10% across all concentration ranges. Sensitivity parameters included a lower limit of quantification (LLoQ) of 0.083 pg/mL and an analytical measurement range of 0.083–640 pg/mL. Linearity demonstrated <9% deviation across the measurement range. Interference testing showed <7% deviation for cross-reactants, common medications and AD-specific therapeutics. Plasma samples remained stable over 48 h at room temperature (<4% deviation) and five freeze–thaw cycles (<9% deviation). Method comparison demonstrated strong correlation with Simoa GFAP (R = 0.945) but systematic proportional bias, yielding 3% (slope = 0.030) of Simoa values. Samples from participants with AD exhibited significantly elevated GFAP levels (median 9.0 pg/mL, IQR: 5.3–19.1) versus controls (median 3.4 pg/mL, IQR: 1.5–6.5; p < 0.001). Conclusions: The high-throughput Access GFAP (RUO) immunoassay achieved all analytical performance criteria and demonstrated differences in GFAP levels between AD and healthy control sample cohorts. These findings support its use in research settings and as a foundation for future clinical implementation and may inform future studies evaluating cross-platform harmonization and potential clinical applications. Full article

Wood- and lignocellulosic-residue-derived constituents have attracted increasing attention in cementitious materials because they may support clinker reduction, waste valorization, moisture regulation, crack control, and longer service life. This review synthesizes evidence on wood ash, wood-derived biochar, and wood or lignocellulosic fibers in low-clinker and low-carbon-oriented cementitious systems, with emphasis on severe cold service involving freeze–thaw cycling, salt freezing, and chloride ingress. This review clarifies the evidence boundaries among direct wood-derived materials and related biomass or lignocellulosic analogues, because wood ash, non-wood biomass ashes, such as bamboo ash and bagasse ash, wood fiber, and non-wood plant fibers cannot be treated as equivalent materials. Wood ash is best regarded as a controlled partial binder replacement or filler whose performance depends on combustion temperature, oxide composition, alkali content, residual carbon, fineness, and water demand. Biochar is more appropriately treated as a low-dosage functional additive, commonly in the range of approximately 1–3 wt.% of binder, where it may assist internal curing, nucleation, moisture redistribution, and pore regulation; excessive dosage can increase porosity and reduce mechanical or transport performance. Wood and lignocellulosic fibers mainly contribute to crack control, toughness, and post-cracking behavior, but their effectiveness is limited by water absorption, swelling, lignin- and extractive-related hydration interference, and long-term interfacial degradation in alkaline matrices. Across these material classes, engineering performance is governed by the interfacial transition zone, pore-size distribution, moisture state, air–void compatibility, and exposure-specific durability response. The main contribution of this review is to propose a boundary-conscious framework for material classification, quantitative comparison, mixture-design screening, and severe-cold durability qualification. Future application requires source-specific characterization, water-demand control, treated fibers, low-dosage biochar optimization, and service-informed testing that couples freeze–thaw cycling, chloride transport, saturation state, and microstructural verification. Full article

Three-year atmospheric field-exposure tests were conducted on 304 austenitic stainless steel at the Great Wall and Zhongshan Stations in Antarctica to evaluate its corrosion behavior under severe polar conditions. The exposed specimens were dominated by localized corrosion with pronounced pitting characteristics at both sites. Corrosion was more severe at Zhongshan Station, and the mean corrosion rates at Great Wall and Zhongshan Stations were 1.428 and 1.643 μm y⁻¹, respectively. The mean/maximum pit depths were 4.16/5.51 μm at Great Wall Station and 5.85/8.24 μm at Zhongshan Station. Raman spectroscopy, X-ray photoelectron spectroscopy (XPS), grazing-incidence X-ray diffraction (GIXRD), and focused ion beam-transmission electron microscopy (FIB-TEM) showed that the corrosion products consisted mainly of β-FeOOH, α-FeOOH, and γ-Fe₂O₃, and the Antarctic exposure substantially altered the thickness, structure, and electrochemical response of the passive film. Compared with the unexposed specimen, the exposed specimens exhibited markedly lower charge-transfer resistance and higher donor density, indicating degradation of the protective passive film. Combined with the site-specific environmental features, the lower temperature, more intense freeze–thaw cycling, freezing-induced concentration of electrolytes, and stronger irradiation at Zhongshan Station are inferred to promote Cl⁻ enrichment in localized surface liquid films and destabilization of the passive film, thereby accelerating pit initiation and growth. These findings provide a mechanistic basis for material selection and corrosion-protection design for 304 stainless steel in polar engineering environments. Full article

Seasonal freeze–thaw transitions reorganize lake microbiomes, yet the coupling of environmental filters, biotic interactions, and assembly mechanisms across habitats remains unclear. We profiled bacteria and fungi in the water and sediment of Lianhuan Lake during winter (frozen) and spring (thawed) using amplicon sequencing, co-occurrence networks, and assembly models. Despite sharp physicochemical differences, α-diversity remained stable, while β-diversity was mainly driven by habitat (water vs. sediment), with seasonal turnover detectable, particularly for bacteria. Network analysis revealed a clear winter-to-spring shift: the frozen-water (FW) network was complex with high connectivity and 15% cross-domain edges, while frozen sediment (FS) was less connected but more modular. After thaw, both habitats showed reduced connectivity, with thawed sediment (TS) displaying the strongest modularity and an increase in cross-domain links (~16%). Keystone taxa shifted seasonally and by habitat: FW was dominated by peripheral taxa like Polaromonas, Pseudomonas, and Candidatus Limnoluna; FS had connectors such as the families Comamonadaceae and Ilumatobacteraceae. In spring, Luteolibacter and Rhodoferax dominated water, while Flavobacterium and Sutcliffiella took over sediment. Environmental drivers varied by season and habitat: in winter water, pH was the dominant organising factor, with permanganate index (COD_Mn) and ammonia nitrogen (NH₃-N) as secondary hubs, while NH₃-N became central after thaw. In sediments, sediment total nitrogen (STN) and sediment organic matter (SOM) promoted bacterial links in winter, but SOM had a negative effect after thaw. Assembly analyses suggested selection-driven processes, with dispersal-assisted selection for water bacteria (neutral community model (NCM) R² ≈ 0.76), stronger determinism for sediment bacteria (R² ≈ 0.30), and for fungi, assembly governed jointly by heterogeneous selection and dispersal limitation rather than by a single dominant process. These results highlight how freeze–thaw cycles reshape cross-kingdom networks and microbial assembly, providing insights for monitoring seasonally frozen lakes. Full article

This study aims to systematically evaluate the balancing mechanism between road performance, carbon emissions, and economic cost when selecting asphalt materials for severe cold regions, filling the gap in multi-criteria decision-making for composite chemical modifications. To address alternating temperatures, heavy traffic, and modified asphalt transport difficulties, this study presents a novel evaluation framework focusing on the performance–environmental–cost nexus of a desulfurized rubber powder composite SBS-modified asphalt mixture, which provides a clear technological breakthrough for high-ratio scrap tire recycling in seasonal frost zones. Two reference mixtures serve as comparisons: a conventional rubber powder composite SBS (styrene–butadiene–styrene triblock)-modified asphalt mixture (CR-SBS) and an SBS-modified asphalt mixture (SBS). A comparative experiment was conducted between the two materials and the SBS-modified asphalt mixture (ACR-SBS) compounded with desulfurized rubber powder. High-temperature stability was tested by the rutting test, low-temperature crack resistance by the beam bending test, and water stability by the immersion Marshall and freeze–thaw splitting tests. Life cycle carbon emissions and economic costs were quantified from raw material acquisition to construction. The results show that desulfurized rubber powder composite with ACR-SBS delivers the most superior overall road performance. However, it also generates the highest life cycle carbon footprint. Its total carbon emission reaches 162,800 kgCO₂eq, which is 13.7% (19,600 kgCO₂eq) higher than SBS (143,200 kgCO₂eq) and 7.7% (11,600 kgCO₂eq) higher than CR-SBS (151,200 kgCO₂eq). The total cost of ACR-SBS is 391,000 CNY, which is 1.5% (6000 CNY) higher than SBS (385,000 CNY) and 1.3% (5000 CNY) lower than CR-SBS (396,000 CNY). These findings provide a basis for the selection of high-performance, low-carbon, and economical composite-modified asphalt in severe cold regions. Full article

To address early-age cracking in concrete walls of hydraulic structures such as ship locks, basalt fibers (BFs) were incorporated as a reinforcement strategy. The effects of varying BF dosages and lengths on the workability, mechanical strength, and crack resistance of concrete were systematically evaluated. Furthermore, the internal microstructure was examined using scanning electron microscopy (SEM), and the durability performance, including impermeability, freeze–thaw resistance, and abrasion resistance, was assessed. The results indicate that workability decreased with increasing fiber content and length. The highest mechanical performance among tested mixes was achieved with 0.1% BF of 9 mm length, increasing 7-day and 28-day compressive strength by 17.47% and 22.59%, respectively, compared to plain concrete. The greatest crack resistance was observed with 0.2% BF of 18 mm length, delaying cracking by 150% and reducing crack width by 85%. Durability tests showed that a 0.2%-18 mm BF mix reduced water permeability depth by 47.37% and a 0.3% BF content optimized abrasion resistance. Freeze–thaw cycles indicated that a 0.3% fiber content effectively maintained the relative dynamic elastic modulus. SEM analysis revealed that BFs act as micro-bridges within the matrix, optimizing pore structure, inhibiting micro-crack propagation, and enhancing concrete density. This study evaluates BF-reinforced concrete and provides a practical reference for improving crack resistance and long-term durability in ship lock structures. Full article

Alpine permafrost and seasonally frozen ground threaten the long-term safe operation of highway infrastructures. Aiming at the structural performance optimization of prefabricated corrugated steel plate retaining walls in alpine permafrost regions, this study adopted finite element numerical simulation combined with field test validation to systematically explore the influences of wall height, plate thickness, corrugation geometry, and tie reinforcement layout on structural deformation and internal force, and carried out targeted parameter optimization. The core innovations include the following: (1) Structural lateral displacement and internal force rise nonlinearly with the increase in wall height, and high retaining walls exhibit an accelerated growth trend of deformation and stress. (2) Increasing plate thickness can effectively reduce structural displacement and stress, while the improvement effect gradually weakens after exceeding a critical thickness. Specifically, when the thickness increases from 4 mm to 5 mm, the displacement decreases by 33.13%. (3) Appropriately increasing corrugation pitch and height improves structural equivalent stiffness and optimizes stress distribution. Increasing the corrugation pitch from 75 mm to 400 mm and corrugation height from 25 mm to 150 mm reduces the maximum horizontal displacement by 52.6%. This demonstrates that larger corrugation profiles significantly improve structural stiffness. For walls higher than 6 m, the spacing should be reduced to 0.8 m × 1.0 m to provide additional lateral restraint. (4) Furthermore, seasonal freeze–thaw cycles and a non-uniform temperature field significantly amplify structural displacement and stress. After 12 months of freeze–thaw cycles, the maximum horizontal displacement increases by 49.7% and the maximum equivalent stress increases by 56.9% compared to the initial state. This study clarifies the parameter control mechanism and temperature coupling effect and provides a reliable theoretical basis and design reference for the engineering application of prefabricated corrugated steel plate retaining walls in alpine permafrost areas. Full article

To explore the shear behavior and evolutionary pattern of desert sand concrete beams (DSCBs) subjected to freeze–thaw cycles, 16 DSCBs were subjected to rapid freeze–thaw cycling and shear tests, with desert sand replacement ratios (0%, 20%, 40%, and 60%) and numbers of freeze–thaw cycles (0, 25, 50, and 75) considered as the main variables. The failure mode, diagonal crack development, diagonal cracking load, shear capacity, and load–stirrup strain curves of DSCBs were tested and analyzed. The results indicate that all specimens exhibited typical shear-compression failure. The diagonal crack development pattern of DSCBs was similar to that of ordinary concrete beams, whereas freeze–thaw cycles accelerated the initiation and propagation of cracks. Freeze–thaw cycling significantly reduced both the diagonal cracking load and shear capacity. After being exposed to 75 cycles of freezing and thawing, the ultimate shear capacity of test pieces with desert sand replacement proportions of 0%, 20%, 40%, and 60% decreased by 15.6%, 12.9%, 13.9%, and 13.8%, respectively, while the corresponding stirrup strains increased by 47.2%, 34.1%, 37.1%, and 53.7%, respectively. An appropriate desert sand replacement ratio can improve the shear performance of concrete beams. Among all specimens, the beam with a 20% replacement ratio exhibited the best overall mechanical performance, achieving a maximum increase of 6.0% in shear capacity and a maximum reduction of 26.8% in stirrup strain compared with conventional concrete beams. Finally, by introducing modification coefficients related to the desert sand replacement ratio as well as the freeze–thaw cycling times, predictive equations for the diagonal cracking load and shear capacity of DSCBs under freeze–thaw conditions were established. The numerical predictions achieve a high consistency with measured data. Full article

This study critically addresses the challenge of selecting optimal insulation materials for contemporary, energy-efficient building envelopes, a decision with profound environmental, structural, and occupational health consequences. The paper responds to the growing demand for sustainable, resilient solutions by comparing wool, a bio-based, regenerative material, and expanded polystyrene (EPS), a synthetic polymer widely implemented in the construction industry, and advanced laboratory testing (thermal conductivity, moisture buffering, freeze–thaw resistance) is discussed in a comprehensive synthesis of the recent literature. Also, field evaluations from European retrofits and pilot projects (UK, Denmark, Finland, Iceland, Norway, Sweden, Germany and France) further contextualize performance outcomes, and life cycle impacts are considered. Recent results reveal that wool insulation achieves a moisture buffering value (MBV) between 1.8 and 2.7 (g/m²) % RH, minimal vapor resistance (mvr = 1–2), and preserves functional and structural integrity through more than 100 freeze–thaw cycles, leading to significant stabilization of the interior microclimate and enhanced durability. In contrast, EPS delivers lower thermal conductivity (0.032–0.037 (W/mK), critical for reducing heating/cooling demand, but exhibits limited vapor permeability (lvp = 60–150 MN·s/(g·m)), increased risk of condensation and mold, and reduced compressive strength (<22% after 30 cycles), especially when ventilation details are inadequate. Hybrid envelope systems leveraging both EPS and wool are demonstrated to optimize energy efficiency (up to 23% seasonal savings) and reduce interior humidity fluctuations, while lifecycle and recycling assessments show wool panels to be markedly superior in carbon footprint reduction and circularity. The stratification of insulation layers incorporating wool for vapor and moisture control, and EPS for pure thermal resistance is emerging as best practice in sustainable retrofit and new-build projects. Recommendations highlight the necessity for rigorous laboratory validation, international standards alignment, and integrated material design for robust hygrothermal comfort and environmental performance. The review also covers wool- and EPS-based hybrid composites, showing how natural fibers can improve key mechanical properties without compromising thermal insulation performance or environmental benefits. Full article