To mitigate soil contamination risks while addressing the need for efficient performance evaluation, this study investigates the remediation of cadmium (Cd)-contaminated soil using a low-carbon binder composed of rice husk ash (RHA) and cement. While RHA is known for its pozzolanic properties, the specific quantitative relationship between its curing effectiveness and non-destructive monitoring parameters remains unclear. The investigation focused on key performance metrics, including unconfined compressive strength (UCS), electrical resistivity, and leaching behavior. Uniquely, this study integrates macroscopic tests with microstructural analyses to elucidate the solidification mechanisms. The results demonstrated that RHA not only promotes the formation of acicular ettringite (AFt) and flocculent C-A-S–H gel, which interweave to creates a dense, net-like microstructure that physically encapsulates Cd precipitates. Importantly, comprehensive optimal inclusion levels were identified—specifically 5
Flexible pavements in coastal regions are continuously exposed to saline environments, where aggressive ions accelerate moisture and chemical ageing, weakening binder–aggregate adhesion and reducing service life. Surface courses are particularly vulnerable because they are directly exposed to seawater, while binder properties, aggregate gradation and air-void structure influence the extent of moisture-induced damage. Although the effects of de-icing salts on bituminous mixtures are well documented, the combined influence of seawater exposure, binder type, filler mineralogy, and anti-stripping additives on moisture susceptibility remains insufficiently studied. This study systematically investigates bituminous concrete mixtures prepared with Viscosity Grade (VG) 30, VG 40 and Natural Rubber Modified Bitumen (NRMB 70), incorporating Quarry Dust (QD), Portland Pozzolana Cement (PPC) and Hydrated Lime (HL) as fillers. Seawater conditioning was applied using the Moisture Induced Stress Tester (MIST) and performance was evaluated through Indirect Tensile Strength (ITS), Tensile Strength Ratio (TSR) and boiling water coating tests supported by digital image analysis. Seawater conditioning caused substantially greater deterioration than normal water conditioning, reducing coating ratio, ITS and TSR across all binder–filler combinations. The results show that seawater exposure alters the relative performance of binder–filler systems and underscores the critical role of filler types in improving moisture resistance. Hydrated Lime, particularly when combined with the silane-based additive Zycotherm, demonstrated the most effective resistance to saline-induced damage. The study provides practical guidance for selecting durable bituminous mixtures for coastal regions and establishes Hydrated Lime with Zycotherm as a reliable strategy for enhancing long-term pavement performance under seawater exposure.
The increasing traffic volume and axle loads demand durable bituminous pavements with improved resistance to moisture-induced deterioration and permanent deformation. The influence of Nitrile Butadiene Rubber (NBR) and thermosetting modifiers on the mechanical, rheological and microstructural characteristics of bituminous mixtures was studied. Two modified hybrid binders called Blend 1 and Blend 2 were prepared using various ratios of NBR, Bakelite (B), Furan Resin (FR) and Epoxy Resin (ER) and tested against a conventional VG-40 control binder. The experimental programme involved Marshall Stability, Indirect Tensile Strength (ITS), Tensile Strength Ratio (TSR), Dynamic Shear Rheometer (DSR) and Scanning Electron Microscopy and Energy Dispersive X-ray Spectroscopy (SEM–EDS). The optimal hybrid formulation was determined by a performance-based optimisation framework that involved mechanical, rheological, statistical and microstructural evaluations. Blend 2 was found to have the best overall performance and presented high TSR (85.06
A temperature–strain monitoring array extending from 0 to 250 cm was embedded in the composite-flexible-base asphalt pavement of the Quannan Expressway, Fujian Province, and operated from November 2023 to September 2024 to quantify rainfall-intensity effects on the thermo-mechanical response of the road structure. The main findings are: (1) The temperature regime exhibits a three-zone profile of “drastic shallow–buffered middle–stable deep”, with daily temperature amplitude decreasing from 8 °C at 4.5 cm to less than 1 °C at below 150 cm. (2) Strains in all structural layers range from 0.002 to 0.01, and their synchronous vibration time series confirm sensor reliability. (3) Light, moderate and heavy rain events reduce pavement temperature by 2.6 °C, 5.1 °C and 6.8 °C, respectively, affecting depths of 80 cm, 80 cm and 44 cm; cooling persists for 10–20 h, 60–70 h and 90–100 h, indicating a rainfall-sensitive shallow layer and an inertia-protected deep layer. (4) A non-linear relationship among rainfall intensity, cooling amplitude and influence depth is established, and an 80–100 cm threshold is proposed for rainfall-induced thermal impacts. The results provide field-based guidance for the coupled thermal-rainfall design, maintenance and long-life technologies of asphalt pavements in subtropical monsoon regions.
The design of airfield pavements is commonly performed using mechanistic–empirical methods implemented in software tools. Although consolidated, these tools incorporate simplified modeling assumptions that may influence the estimated structural responses. In this context, this study evaluates whether different modeling assumptions affect the structural performance of flexible airfield pavements. Five existing flexible airfield pavement structures, characterized through field deflection testing and backcalculation, were reanalyzed using two software tools based on the Layered Elastic Theory for a 20-year design period. The structures were analyzed by allowing the isolated effect of five modeling variables: subgrade Poisson’s ratio, airfield reference temperature applied to the correction of the asphalt surface layer resilient modulus, bonding conditions between the asphalt surface layer and the granular base, aircraft lateral wander, and probabilistic variability of material properties. Structural performance was evaluated based on the Cumulative Damage Factor (CDF) and the estimated pavement service life. For a common reference structure with a baseline service life of 14.6 years, the variation of modeling parameters produced estimates ranging from 3.2 to 27.8 years, with temperature correction and interlayer bonding condition yielding the greatest reductions. The results highlight the sensitivity of mechanistic–empirical analyses to the adopted assumptions and the importance of a rational evaluation of input parameters in airfield pavement design.
Driven by the dual imperatives of plastic waste valorization and the development of high-performance pavement materials, polyethylene terephthalate (PET)-modified asphalt has emerged as a research hotspot in road engineering. This study adopted a multi-scale approach integrating macroscopic performance testing, microstructural characterization, and molecular dynamics (MD) simulations to systematically evaluate the large-scale engineering potential of PET-modified asphalt and delve into the compatibility mechanisms between PET and asphalt. Macroscopic tests including penetration, softening point, ductility, viscosity, and segregation were conducted on three base asphalts (SK 90#, Shell 90#, and Jingbo 90#) to quantitatively analyze the modification effects of PET particles on asphalt properties. Fluorescence microscopy (FM) and Fourier-transform infrared spectroscopy (FTIR) were employed to reveal the dispersion characteristics and interaction mechanisms of PET within the asphalt matrix, while MD simulations were performed to elucidate compatibility at the molecular level. The results demonstrated that PET incorporation slightly reduced compatibility but significantly enhanced the high-temperature performance of asphalt. Among the tested materials, Jingbo 90# asphalt modified with PET achieved the optimal balance between basic performance and compatibility. PET-modified Jingbo 90# asphalt exhibited the smallest solubility parameter, confirming its superior compatibility, a finding consistent with the results of segregation tests. This study provides a theoretical basis for the high-value utilization of plastic waste.
Problematic soils present significant challenges in civil engineering projects such as roads and pavements. Understanding their behavior and improving their properties through various additives is an effective strategy to address these issues, leading to improvements in key mechanical properties, including the California Bearing Ratio (CBR), tensile capacity, shear resistance, and unconfined compressive strength (UCS). Beyond strength improvement, ensuring adequate durability against environmental stressors—particularly repeated freeze–thaw and wet–dry cycles—is critical, especially in cold, humid and rainy regions. These cycles can induce cracking, weight loss, and deterioration of mechanical properties, including changes in moisture content and Atterberg limits, even in stabilized soils. This review synthesizes laboratory methodologies for evaluating freeze–thaw and wet–dry cycles, examines previous studies on their effects on the durability of stabilized soils with various additives, and demonstrates the role of additive properties in improving mechanical strength while ensuring sustained durability against cyclic environmental conditions. The present study provides a mechanistic and comparative analysis, highlighting key trends, contradictions, and future research directions on soil durability under freeze–thaw and wet–dry cycles in its discussion section.
Pavement failures in flexible pavements arise from environmental, structural, and traffic-related factors, with pothole formation being a common issue. Conventional repair methods, such as Hot-Mix Asphalt (HMA), are energy-intensive and environmentally demanding. This review critically examines Cold-Mix Asphalt (CMA) modified with industrial waste materials as a potential sustainable alternative for pothole repair and maintenance. CMA offers advantages, including reduced energy demand, cost-effectiveness, and suitability for remote regions. The incorporation of waste materials—such as rubber, fly ash, plastic, and glass—helps enhance durability, strength, and weather resistance, while reducing greenhouse gas emissions and conserving natural resources, thereby supporting a circular economy. Case studies demonstrate improvements in mechanical performance and environmental outcomes; however, challenges persist in ensuring material compatibility and maintaining long-term performance under diverse climatic and loading conditions. Research priorities include optimizing material proportions and exploring under-utilized wastes such as red mud and agricultural residues. This review uniquely integrates laboratory and field evidence with standardized repair procedures and life-cycle cost analysis, providing practical insights for durable and sustainable pothole management. The review also highlights the emerging solutions—such as self-healing asphalt, nanotechnology, and AI-driven maintenance systems—to further enhance sustainability, efficiency, and resilience.
To meet the demand for high-precision prediction of asphalt pavement service performance, this study proposes an interpretable prediction model integrating Long Short-Term Memory (LSTM) networks, an attention mechanism, and the SHapley Additive exPlanations (SHAP) method to predict the rutting depth of dual Wheel Paths and reveal its evolution mechanism. Based on accelerated loading test data from 19 pavement structures at the Beijing full-scale circular track, Bayesian Optimization, Crested Porcupine Optimization (CPO), and Particle Swarm Optimization (PSO) algorithms were employed to optimize the model’s hyperparameters, with the Monte Carlo method utilized to evaluate prediction reliability. The results indicate that the PSO-LSTM-Attention model achieved the highest accuracy, yielding coefficients of determination (R2) for Wheel Path 1 and Wheel Path 2 of 0.96 and 0.95, alongside root mean square errors (RMSE) of 0.564 mm and 0.444 mm, respectively. With both paths exceeding 0.89, the prediction interval coverage probabilities (PICP) confirmed the high reliability of the proposed model. SHAP analysis revealed the spatial asymmetry of rutting evolution in the dual Wheel Paths, demonstrating that different Wheel Paths exhibit varying sensitivities to base layer material types. To facilitate engineering applications, an interactive bidirectional graphical user interface (GUI) system was developed, enabling both forward prediction of rutting depth and reverse design optimization of pavement structures based on performance constraints. This study thus provides a highly accurate, interpretable, and practical tool for the performance evaluation and quantitative design of asphalt pavements.
Concrete overlays are increasingly used to restore the structural and functional capacity of deteriorated pavements subjected to growing traffic demand. This study evaluates a 4.0 km urban corridor in Trujillo, Peru, through an integrated rehabilitation assessment framework combining traffic characterisation, Falling Weight Deflectometer (FWD) testing, Pavement Condition Index (PCI) surveys, geotechnical assessment and comparative concrete overlay design. FWD deflection basins were used to assess structural variability and estimate representative support parameters, while PCI surveys quantified surface deterioration. Traffic analysis defined a critical 20-year design demand of 42.821 million equivalent axle repetitions. These inputs supported overlay design using AASHTO 93 and the Thin Concrete Pavement (TCP) methodology, allowing comparison between an empirical serviceability-based approach and a mechanistic-oriented short-slab approach using a common cumulative EE/ESAL traffic basis. Results showed severe functional deterioration, with PCI values ranging from 2 to 6, and marked structural variability, with maximum deflections (D_0) ranging from 126 to 381 μm. AASHTO 93 produced a required overlay thickness of 327 mm, rounded to 33 cm, whereas TCP implemented in OptiPave 2.0 yielded 166.9 mm, rounded to 17 cm, under the assumed support and slab-geometry conditions. The findings indicate that concrete overlay rehabilitation is feasible for the studied corridor. AASHTO 93 provides an empirical serviceability-based reference thickness, while TCP offers a project-specific lower-thickness alternative, provided that support uniformity, base stabilisation, separation-layer placement, joint layout and concrete quality are adequately controlled during construction.
To eliminate macroscopic cracks in cement stabilized base and ensure sufficient mechanical performance while enhancing its anti-cracking performance, this study focused on cement stabilized steel-slag macadam (CTSM) with an aggregate framework of limestone (particle size 15 30 mm) and steel-slag (particle size 0 15 mm). By exploiting the micro-expansion property of steel-slag and incorporating nano anti-crack reinforcing agent (NARA) together with fly ash as composite anti-cracking measure, an anti-cracking CTSM (ACTSM) was developed. In the study, the performance of CTSM was investigated via mechanical and shrinkage tests. Furthermore, the anti-cracking mechanism of ACTSM was researched through microscopy analysis. Finally, ACTSM exhibited excellent mechanical and anti-cracking performance, and the following conclusions were reached: (1) replacing part of the coarse aggregate and all fine aggregate with steel-slag while utilizing its micro-expansion property can enhance the anti-cracking performance of CTSM; (2) NARA dosage at 0 0.3
Pervious concrete plays a critical role in sponge city construction; however, Portland-cement based systems suffer from low strength and environmental concerns. This study develops a geopolymer pervious concrete using red mud (RM) and blast furnace slag (AS) as alkali-activated cementitious materials and proposes an AHP-TOPSIS-based framework for multi-criteria mix design. The effects of RM content on the mechanical properties, workability, setting behavior, electrical resistivity, and microstructure of the geopolymer were investigated. The influences of design porosity, water-to-binder ratio, and aggregate size on the mechanical and hydraulic properties of pervious concrete were subsequently evaluated. The results showed that an appropriate RM content improved the pore structure and workability of the geopolymer system, whereas excessive RM addition reduced its mechanical performance. An RM-to-AS ratio of 3:7 provided the most favorable overall binder performance. Because compressive strength, permeability, and actual porosity are mutually dependent and partly conflicting, AHP was used to determine the relative importance of these criteria, and TOPSIS was employed to rank the candidate mixtures according to their overall proximity to the ideal solution. The optimal mixture consisted of a design porosity of 15
Asphalt pavements in cold regions are highly susceptible to thermal cracking, necessitating a comprehensive understanding of viscoelastic properties to ensure long-term structural integrity. This study investigated the viscoelastic behavior of diverse asphalt materials, including SK-90 base bitumen, styrene-butadiene-styrene (SBS) modified asphalt, and stress-relaxing agent (SRA) modified mixtures across multiple aggregate gradations (AC and SMA). Dynamic modulus testing was conducted over a wide range of temperatures and loading frequencies to characterize complex stiffness and phase responses. A critical aspect of the methodology involved the mathematical interconversion between the measured dynamic modulus and the time-dependent relaxation modulus. By utilizing normalized storage modulus master curves, Prony series parameters were extracted for a generalized Maxwell model. These parameters were subsequently implemented within a finite element (FE) simulation framework to evaluate pavement structural responses under thermal loading. A unique freeze-fracture validation phase was incorporated to verify numerical predictions against physical observations. The findings indicate that the proposed modeling approach achieves an excellent goodness-of-fit with experimental data, effectively capturing stress relaxation mechanisms under varying thermal conditions. Results demonstrate that specific modifiers significantly enhance the material’s ability to dissipate thermal stresses, thereby reducing cracking potential. This research establishes a robust quantitative framework for evaluating low-temperature performance, bridging the gap between laboratory characterization and field structural prediction. The outputs offer practical guidance for selecting appropriate materials and designing resilient infrastructure capable of withstanding extreme climatic conditions.
The growing global emphasis on sustainable development has encouraged the construction industry to adopt approaches that balance environmental responsibility with economic feasibility. Among these, the use of industrial by-products has emerged as a promising strategy to reduce waste disposal while partially or fully replacing conventional cement-based materials. In this context, the present study investigates the development of alkali-activated concrete (AAC) for application in dry lean concrete (DLC), which serves as a base layer in rigid pavement systems. Ground granulated blast furnace slag (GGBFS), a by-product of the iron and steel industry, was utilized as the primary binder in the AAC system. An experimental program was conducted to evaluate the mechanical performance of AAC for DLC applications subjected for 7 days ambient curing by varying key mix design parameters, including binder content (158, 170, and 185 kg/m³), sodium oxide (Na₂O) concentration (3
Compaction quality at longitudinal joints (LJ) is critical for hot-mix asphalt (HMA) pavement durability. Traditional quality assurance (QA) methods, relying on pavement cores, are labor-intensive, time-consuming, costly, and limited in coverage. The Dielectric Profiling System (DPS) offers a non-destructive alternative, providing continuous, real-time compaction assessments via dielectric measurements correlated to HMA density. To maximize broader adoption by resource-limiting agencies, the Longitudinal Joint Quality Index (LJQI) was developed as a dielectric-based metric. Based on limited and unsegmented data, an initial LJQI threshold of 60
Pavement surface detection is highly essential for identifying the potholes that affect transportation, as well as posing severe safety concerns. Accurate detection is required for providing on-time precautions, and several methods have been developed for pothole detection in recent years. However, the model stems from high false positive rates, missing relevant information, improper extraction of pothole features, and lower accuracy. Thus, the research proposes a Crocuta Cooperative hunting optimized region-based deep convolutional neural network (C2HopRDCN) method that aims to address the complexities of pothole detection. The method works on the region-based analysis that interprets the pixel features from various orientations. In addition, the inclusion of the Crocuta Cooperative hunting optimization (C2Hopt) algorithm improves the detection of potholes with the adaptive behaviors that provide higher convergence with lower error probabilities. Moreover, the extraction of textural and shape features is complex due to the various orientations of pothole structures, which is achieved using Local Pixel and Shape pattern (LPixSP) features that are invariant to rotations. The proposed method demonstrates superior efficiency, achieving an accuracy of 99.280
To clarify the environmental and economic impact differences between asphalt and composite pavements, this study proposes a quantitative assessment framework of "environmental-economic" two-dimensional dimensions, incorporating the uncertainty of assessment results into this framework. First, a life cycle assessment model was constructed based on SimaPro; second, environmental governance costs were integrated into the life cycle cost to establish a cost assessment model considering external environmental costs; finally, the pedigree matrix combined with Monte Carlo simulation was used to quantify the randomness of input parameters on assessment results. The research results show that compared with asphalt pavements, composite pavements exhibit higher environmental impacts in terms of global warming, ozone formation, terrestrial acidification, freshwater eutrophication, and freshwater ecotoxicity. From an economic perspective, the combined effect of material costs and environmental costs leads to a higher total construction phase cost for composite pavements. The Monte Carlo simulation results indicate that the uncertainty analysis results are consistent with those of deterministic analysis, and the fluctuation ranges of the five environmental indicators for composite pavements are slightly higher than those for asphalt pavements. The findings provide references for low-carbon material selection in highway construction, optimization of construction processes, and formulation of targeted emission reduction strategies.
Permeable paving provides excellent water permeability and helps alleviate urban flooding. However, conventional systems suffer from low mechanical strength and are prone to clogging, which limits their service life. In this study, a honeycomb-structured permeable pavement was developed using self-compacting concrete. An orthogonal experimental design was adopted to evaluate the effects of water–cement ratio, fly ash content, superplasticizer dosage, and polyvinyl alcohol fibers on the mechanical properties of self-compacting concrete. ANSYS Workbench was employed to simulate the mechanical behavior of the specimens. The simulation results showed deviations of less than 3
Asphalt pavement is used extensively on highways today. However, these coatings are affected by environmental conditions and vehicle loads and thus complete their service life. Incorporating Recycled Asphalt Pavement (RAP) as a fine aggregate (0–4 mm) in concrete, replacing crushed sand, reduces natural aggregate demand and energy consumption, promoting sustainability. This study investigates reinforcement corrosion behavior in concrete containing RAP and glass fiber (GF). RAP replaced natural aggregate at 0
Strengthening existing reinforced concrete (RC) continuous beams is critical for extending the service life of aging infrastructure and meeting increased load demands. In particular, the complex moment redistribution and critical negative bending regions in continuous systems make their strengthening more challenging than simply supported members. This study investigates the flexural behaviour of two-span continuous RC beams externally strengthened with carbon fibre-reinforced polymer (CFRP) sheets under symmetrical static loading. Three CFRP strengthening strategies were evaluated: strengthening in the hogging region alone, the sagging region alone, and both hogging and sagging regions simultaneously. Four continuous RC beams, each measuring 150 × 200 × 3500 mm, were cast and tested to failure under a five-point bending configuration with a three-support setup. The CFRP sheets were bonded externally to the beam surfaces using epoxy resin. Two-point loading per span was applied gradually, and moment redistribution was observed and compared among all four beams. The results show that wrapping CFRP sheets around both the tension and compression regions significantly increase the bending strength of RC beams. The epoxy-bonded CFRP layers also delayed crack initiation, with cracks appearing at higher load levels. The results demonstrated that CFRP strengthening in the hogging region increased the ultimate load by 27.27
