Search Results (4,534)

Rollpave technology offers an efficient and low-disruption solution for pavement rehabilitation but has not yet been widely implemented in practice. This review aims to provide a comprehensive overview of rollpave technology by examining performance evaluation methods, material design strategies, and construction workflows, and identifying its advantages and limitations to support practical application. Recent advances in rollpave pavement technology are reviewed, including flexural performance testing methods and evaluation criteria for rollable pavement materials, as well as the design of flexible asphalt mixtures and interlayer bonding materials. Construction techniques across different stages of rollpave implementation are summarized, and existing engineering case studies are reviewed. The advantages and limitations of rollpave technology are evaluated in comparison with other pavement construction and rehabilitation approaches, and current research focuses are discussed. The review indicates that pavement performance requirements can be achieved through the development of specialized modified asphalt binders and optimized mixture designs. On-site installation relies on coordinated operation of multiple devices to ensure adequate interfacial bonding between new and existing layers; however, current practices are largely experience-based and lack standardized guidelines. It is believed that rollpave technology demonstrates unique advantages for rapid pavement repair and emergency rehabilitation, but there are still challenges related to material and structural design, on-site installation, and cost-effectiveness that remain, limiting large-scale adoption. Future research could focus on establishing technical standards, developing specialized equipment, and enhancing multifunctional integration. Full article

High reclaimed asphalt pavement (RAP) half-warm mix asphalt (HWMA) mixtures provide a low-energy alternative for pavement repair but often suffer from insufficient binder activation and reduced mechanical performance at low production temperatures. This study develops a high-RAP (73.8%) half-warm repair mixture using a dual-additive system comprising a rejuvenator and a low-temperature composite additive. The mixture was designed to enable effective mixing and compaction at temperatures as low as 60 °C. The optimized formulation achieved a 5.84 kN Marshall stability, 7.0% voids in total mixture, 80% retained Marshall stability after moisture conditioning, and approximately 1100 passes/mm dynamic stability. Temperature sensitivity analysis showed that stability increased from 4.50 kN at 50 °C to 9.20 kN at 90 °C with corresponding VTM reduction from 15.2% to 4.8%. The results demonstrate that a high-RAP HWMA repair mixture can satisfy mechanical and durability requirements while being produced at substantially reduced temperatures, supporting practical and sustainable pavement maintenance applications. The study further provides mixture-scale evidence that a dual-additive strategy can stabilize high-RAP mixtures under very low half-warm production temperatures (≈60–70 °C), which are representative of rapid repair conditions and remain insufficiently investigated in existing WMA–RAP research. Full article

The precision of data gathered from Ultra-Weak Fiber Bragg Grating (UWFBG) sensing technology is limited when measuring strain within asphalt pavements. To better understand its measurement mechanism and correct possible errors, this study examines the synergy deformation behavior between UWFBG and asphalt mixtures under loads. Initially, the mesoscopic model of asphalt mixture containing UWFBG was constructed using a discrete element model, followed by the validation of the model. Then, the propagation of microcracks at the interface between the asphalt mixture and UWFBG was analyzed, revealing damage characteristics of this material under various loading stages. Additionally, a quantitative relationship between the crack width and the monitoring strain was identified. The significant effect of introducing the sensor on crack propagation and interface debonding in strain response was also highlighted. The results indicate that when displacement exceeds 1.4 mm during a bending test, the number of both damage and microcracks increases markedly, with cracks progressively developing. Especially at the UWFBG interface subjected to a tensile load, microcrack growth rises sharply, leading to the failure of the interface. The mor-UWFBG interface is not the main damage location, but it is the most vulnerable location to damage and may be the one affecting the monitoring of UWFBG. Without sensors, a consistent linear relationship between monitoring strain and crack width is observed within the asphalt mixture. After introducing the UWFBG sensor, the strain-crack response of the asphalt mixture is divided into three stages: crack initiation, crack propagation, and interface debonding. When the crack width surpasses 0.03 mm, interface debonding significantly influences the strain growth rate, indicating the necessity of correcting the synergy deformation. Full article

The effective management of municipal road infrastructure requires up-to-date, standardized and reliable condition information to support sustainable maintenance. While visual road-condition assessment methods based on established standards are widely applied to municipal roads, they remain largely manual, time-consuming, costly and subjective. This study presents an end-to-end workflow for the automated visual inspection and condition assessment of municipal road infrastructure using high-resolution, 3D street-level imagery acquired by professional mobile mapping systems. The proposed approach integrates an efficient preprocessing pipeline for precise road-surface extraction with deep learning models trained for the specific task and an advanced postprocessing method for robust results aggregation. For this purpose, a large dataset covering approximately 352 km of municipal roads across eight municipalities was created by combining street-level imagery with expert-annotated road-condition index (RCI) values. Two neural network variants were implemented: a regression model predicting standardized RCI values and a binary classifier distinguishing between roads requiring maintenance and those in good condition. To ensure decision-oriented outputs at the infrastructure-asset level, frame-based predictions are aggregated into homogeneous road segments using outlier detection and change-point analysis along the road axis. The regression model achieved a mean absolute error of 0.48 RCI values at frame level and 0.40 RCI values at road-segment level, outperforming conventional inter-expert variability, while the binary classification model reached an F1-score of 0.85. These findings demonstrate that AI-based visual road-condition assessment using professional mobile mapping data can provide accurate, standardized and scalable condition information for municipal road infrastructure. The proposed workflow supports maintenance prioritization and infrastructure management decisions without requiring explicit detection of individual pavement defects, offering a practical pathway toward automated, cost-effective road-condition monitoring. Full article

The application of computational simulation in industrial engineering plays a critical role in designing sustainable infrastructure solutions. We applied a hexagonal green pavement system developed through digital simulation to address challenges in urban stormwater management. The system comprises an upper base layer that bears structural loads and a lower support layer designed for water infiltration and drainage. Structural performance was evaluated using SolidWorks simulations under static loads of up to 1100 N. The results indicate that stress values remain within the material’s yield strength, ensuring structural reliability. Hydraulic performance was also assessed using various valve opening scenarios to simulate different rainfall intensities. The system demonstrated effective infiltration capability, with flow retardation coefficients ranging from 0.66 to 0.80. These findings validate the system’s potential to reduce surface runoff and mitigate urban flooding. The study results highlight how digital simulation, as part of a digital twin framework, can support the development of resilient, modular infrastructure for sustainable urban drainage. This approach represents a practical application of industrial engineering computation to advance smart and eco-friendly urban systems. Full article

This study investigates the properties of concrete incorporating recycled aggregates (RAs) for rigid pavement applications. A 15-point three-level experimental design was used to vary three composition factors: Portland cement substitution with fly ash (FA), and dosages of a superplasticizer (SP) and polypropylene fibers (PFs). A set of experimental–statistical models (ES models) was developed to predict the concrete strength, abrasion and frost resistance (FR), water absorption (WA), and global warming potential (GWP). This study aimed to develop a material that achieves both adequate mechanical performance for pavement applications and enhanced environmental sustainability by incorporating RAs and FA. The results demonstrate that replacing up to 13% of cement with FA does not compromise the splitting tensile strength or FR. For non-fibrous concrete, this substitution increases FR by approximately 50 freeze–thaw cycles. Application of PFs (2.4–3 kg/m³) enhances splitting tensile strength by 14–16% and improves FR by about 50 cycles. Using response surface methodology (RSM), optimal concrete compositions were identified that meet all target criteria: compressive strength ≥ 40 MPa, flexural strength ≥ 5 MPa, FR ≥ F200 (cycles), and abrasion resistance (AR) ≤ 0.5 g/cm², while simultaneously minimizing GWP. An additional optimum composition was determined by imposing a constraint on splitting tensile strength of ≥4.5 MPa. This graphical optimization approach, utilizing two-factor interaction diagrams, provides an effective and visual methodology for practical concrete mixture design. The novelty of the method lies in the discretization of the factor space, which enables efficient identification of optimal concrete mixture compositions. Full article

The U.S. transportation section contributed a third of the national Greenhouse Gas (GHG) emissions in 2022. As such, the Louisiana Department of Transportation and Development (DOTD) initiated federally funded efforts to create Life Cycle Assessment (LCA) models for pavement systems. The objective of this study was to quantify the holistic, cradle-to-grave environmental impacts of asphalt pavements containing Reclaimed Asphalt Pavement (RAP) and Warm Mix Asphalt (WMA) technologies using a closed-loop recycling assumption based on 100% RAP recovery at the end-of-life stage, consistent with current practice in Louisiana. Five field sections in service for up to 16 years were collected from DOTD’s LaPave database. The LCA framework followed ISO 14040 and included definition of cradle-to-grave system boundaries, a functional unit based on in-service pavement sections, inventory data derived from public databases and field performance records, and use-phase modeling based on pavement–vehicle interaction. Public datasets were used to quantify GHG emissions across all life cycle phases. Results indicated WMA additives reduced production and construction GHG emissions by 5%. An RAP increase by 1% decreased material/construction GHG emissions by approximately 0.9%; however, it potentially increased use-phase emissions due to roughness. Mixtures combining WMA and RAP emitted the lowest GHG among the studied mixtures, which promotes integrating sustainable pavement strategies. Full article

This study explored a range of cooling interventions suitable for city laneways where space for greening opportunities is constrained. Five individual cooling interventions namely, PVC shading, cool pavement, small canopy trees, green wall and water mist, as well as multiple combinations of these individual cooling interventions were tested in a narrow laneway in the temperate setting of Melbourne, Australia. The impact of various cooling interventions was assessed by evaluating microclimatic parameters—air temperature (T_a), relative humidity (RH), mean radiant temperature (T_MRT)—alongside two thermal comfort indices, Physiological Equivalent Temperature (PET) and Universal Thermal Climate Index (UTCI). When each intervention was analysed individually, water mist was the best performing with T_a, PET and UTCI reduction. This was followed by PVC shading, small canopy trees and green walls. Cool pavement had the lowest T_a reduction and minimal thermal comfort impact. While green provided marginal reductions in thermal comfort indices, the effects were insufficient for standalone cooling. They were most effective when integrated with other cooling interventions. For example, when green walls were combined with water mist, a T_a reduction of 1.49 K and a T_MRT reduction 2.57 K were obtained. The water mist system as an individual cooling intervention or as part of a combined intervention had an impact on T_a with a reduction of maximum 1.3 K and 1.76 K, respectively. The water mist had a UTCI reduction of 1.25 K, and the water mist combined with green wall had a PET reduction of 1.84 K. The novel contribution of this study to climate-sensitive urban design is the suite of practical, site-specific interventions for extreme summer conditions. These findings provide a framework for planners and designers to evaluate and implement optimal cooling strategies tailored to the unique microclimate demands of narrow urban laneways. Full article

The present study aims to investigate the feasibility of utilizing olive stone powder (OSP), an agricultural by-product, as a modifier for bituminous binders. OSP was incorporated into a neat bitumen at dosages of 2%, 4%, 6%, and 8% by weight, and the modified binders were subjected to comprehensive laboratory tests along with the unmodified reference binder. The evaluation framework included physical, rheological, and chemical characterization tests. The results of physical tests indicate that, although the addition of OSP led to a slight increase in binder stiffness, it effectively reduced temperature susceptibility while maintaining workability within acceptable limits. Rheological results showed that OSP modification improved rutting resistance at high temperatures, while low-temperature performance was preserved at 2% and 4% OSP contents; however, increased stiffness at higher dosages (6% and 8%) may increase thermal cracking susceptibility. Chemical analyses confirmed that OSP was homogeneously dispersed within the bitumen matrix and improved binder behavior primarily through physical interactions, while also enhancing thermal stability. Overall, the results indicate that OSP behaves as a biopolymer-based, filler-like modifier and provides performance improvements primarily through physical structuring. With these characteristics, OSP offers an environmentally friendly and economical solution for bituminous binders and represents a promising option for sustainable pavement materials. Full article

This study aims to systematically synthesize and critically evaluate the characteristics of electric arc furnace slag (EAFS) and ladle furnace slag (LFS) when applied as an alternative paving material. A systematic literature review was conducted following the PRISMA methodology, with research published between 2000 and 2024. Three major databases were searched, considering only Q1–Q2 and English articles. After independent, blinded screening by two reviewers, a total of 177 papers met the selection criteria. The results were qualitatively synthesized through bibliometric analysis, slag characteristics, and application type. Results show that asphalt concrete (AC) is the most common application of EAFS, representing 61% of studies, with many studies exploring 100% substitution of natural aggregates. Overall, EAFS and LFS demonstrate favorable mechanical properties, including high toughness, hardness, and adequate soundness, largely attributed to their iron-rich composition, supporting their use in base layers, AC, and Portland cement concrete (PCC). However, significant chemical and mineralogical variability influences swelling potential and reactivity, highlighting the need for case-specific characterization. While swelling concerns limit its use as an unbound base material, these issues are reduced when EAFS and LFS are used as a soil binder or encapsulated within AC or PCC matrices. Environmental assessments show that most EAFS and LFS samples meet the regulatory thresholds for their respective local leaching limits, though behavior varies with steel type (low-alloy vs. stainless), particle size and pH. Significant gaps remain in long-term performance and testing standards. This review proposes guidelines for selecting appropriate tests according to the intended pavement application, aiming to facilitate the safe and effective use of EAFS and LFS in road infrastructure. Full article

Utilizing waste tire crumb rubber to modify asphalt enhances the damping and noise reduction performance of pavements. This study systematically evaluated the damping performance of crumb rubber–modified asphalt over a wide temperature range. A high-temperature damping index based on the loss factor and a low-temperature energy dissipation ratio derived from the Burgers model were proposed for quantitative characterization. The results show that damping performance is primarily controlled by temperature and crumb rubber content, while particle size plays a secondary role. Increasing crumb rubber content markedly improves damping performance. When the crumb rubber content exceeds 20%, the damping temperature stability, peak loss factor, and its retention tend to level off, whereas the low-temperature enhancement diminishes when the content exceeds 25%. Accordingly, the robust combinations are 80-mesh (≈180 μm) with 20% content for high-temperature conditions and 80-mesh with 25% content for low-temperature conditions. Multivariate nonlinear regression models achieved high predictive accuracy (R² = 0.927 and 0.985). Microscopic analyses indicate that crumb rubber increases constrained interfacial phases and system viscosity, and partial particle exposure at 20–25% further enhances interfacial friction and energy dissipation, consistent with the observed macroscopic damping behavior. These findings provide a theoretical basis for robust, noise-reducing pavements. Full article

Stone Mastic Asphalt (SMA) mixtures are widely used in high-capacity road pavements due to their durability and resistance to permanent deformation. However, although electric arc furnace (EAF) steel slag and recycled crumb rubber have been individually investigated as alternative materials in asphalt mixtures, evidence regarding their simultaneous incorporation in SMA mixtures under full-scale construction and real traffic conditions remains limited. Moreover, quantitative environmental assessments are often restricted to simplified or qualitative approaches, with limited reporting of carbon footprint results. This study investigates the combined use of electric arc furnace (EAF) steel slag aggregates and recycled crumb rubber in SMA mixtures, integrating laboratory evaluation with full-scale field application on a high-traffic motorway. Two SMA 11 mixtures were designed and assessed: one incorporating steel slag aggregates as a replacement for natural coarse aggregates, and another combining steel slag aggregates with recycled crumb rubber added through the dry process (0.8% by mixture mass). Laboratory testing included volumetric characterization, moisture sensitivity and rutting resistance, while field validation covered surface macrotexture, skid resistance, executed thickness and interlayer bonding. Both mixtures fully complied with the applicable technical specifications, achieving indirect tensile strength ratios (ITSR) above 90% and wheel-tracking slopes below 0.07 mm/10³ cycles. A simplified comparative life-cycle assessment (LCA), limited to modules A1–A3, showed a reduction in CO₂-equivalent emissions of approximately 2% for the mixture containing steel slag and up to 27% for the mixture combining steel slag and recycled crumb rubber, mainly due to the valorization of industrial by-products and end-of-life tyres. Overall, the results demonstrate the technical feasibility and potential environmental benefits of these SMA mixtures within the defined scope of laboratory verification, short-term field performance and screening LCA. The contribution of this study lies in providing applied evidence from a full-scale motorway intervention, complementing predominantly laboratory-based studies and offering a quantified environmental comparison under consistent methodological assumptions. Full article

Addressing the challenge that traditional flowability criteria cannot accurately characterize the grouting filling efficacy of foam concrete (FC) for cracks and voids in the base layer of asphalt pavement, this paper established a flowability evaluation method tailored for road grouting. Firstly, FC with varying flow performances were prepared by controlling the water–cement (W/C) ratio and water-reducing agent (WRA) dosage. Secondly, the flow cone method and micro-slump meter on a smooth flow degree pan method (MSM) characterized their flow performances. The porous Marshall specimens were constructed to simulate the crack–void structure of the base layer, and grouting plumpness was calculated using sectional image processing methods. Building upon this, gray relational analysis and regression analysis were employed to establish quantitative relationships between multiple factors and grouting plumpness. The results show that increasing W/C ratio and WRA dosage could improve the flow performance of FC, but reduce the compressive strength. Specifically, when the W/C ratio increased from 0.40 to 0.45, flow time decreased by 72.2% and flow diameter increased by 25%. Increasing WRA dosage from 0.3% to 0.5% could reduce flow time by 16% and increase flow diameter by 10%. Gray relational analysis revealed the strong correlations between flow indexes and grouting plumpness. The gray relational degree was 0.87 between grouting plumpness and flow diameter. In addition, the gray correlation between grouting plumpness and flow time was 0.65. Therefore, flow diameter should be first selected to measure the flow performance of FC. Furthermore, it was found that flow diameter should be higher than 230 mm to ensure that the average grouting plumpness of FC was above 80%. The results of this study provide a reliable basis for evaluating the flow performance of FC for filling cracks in the base layer of asphalt pavement. Full article

Expansive or soft soils cause significant geotechnical issues for foundations and subgrades because they show swell–shrink behaviour under wet and dry conditions. These volume changes can result in cracking, heaving, uneven settlement, and structural or pavement damage, ultimately increasing maintenance and repair costs. While traditional Portland cement and lime stabilisers effectively enhance soil strength and reduce swell–shrink behaviour, the cement production process is responsible for only approximately 7%–8% of global CO₂ emissions, prompting a transition toward sustainable alternatives. This comprehensive review consolidates recent advancements in soil stabilisation using industrial by-products, such as fly ash, ground granulated blast furnace slag (GGBS), steel slag, cement kiln dust, silica fume, bottom ash, red mud, waste foundry sand, brick dust, calcium carbide residue, water treatment sludge, etc. These materials leverage pozzolanic and latent hydraulic properties to form C-A-H, C-S-H, and N-A-S-H gels, thereby densifying the soil microstructure, improving CBR (%), UCS, and reducing plasticity and swelling potential. Optimisation studies indicate that industrial waste stabilisers often match or exceed conventional binder performance, GGBS-steel slag combinations yielding 105% higher UCS than ordinary Portland cement, and silica fume enhances cement-stabilised soils by 22% at reduced dosages. However, inherent compositional variability, long-term durability concerns including sulfate attack and freeze–thaw degradation, and the absence of standardised design guidelines restrict large-scale implementation. This review integrates mechanistic, microstructural, and sustainability insights, highlighting the need for durability research, standardised methods, and large-scale field validation to advance industrial waste-based stabilisation within circular construction practices in geotechnical engineering. Full article

Autonomous trucks can be used in different loading combinations, including different axle configurations, tire types, and lateral wander mode scenarios. In this research, four different truck types have been selected with varying gross weights and axle configurations. The four different truck types include a 5-axle long-haul semi-truck, a 6-axle electric autonomous truck, a 6-axle autonomous truck platoon leader, and a 5-axle autonomous truck platoon follower. Furthermore, three different tire footprint scenarios, consisting of a conventional dual wheel assembly, a wide base tire, and a new generation wide base tire, have been used. In order to utilize the possibility of lateral wander programmed into the autonomous trucks, three different lateral wander models, including zero lateral wander, a human-driven probabilistic lateral wander, and an optimum uniform wander mode, have been used. Finite element analysis has been employed to incorporate the effects of various scenarios on a conventional pavement section. Results showed improved pavement life with the use of uniform wander mode, where trucks T1 and T2 improved the pavement life by 47% and 56%, respectively, when compared to truck T3. Furthermore, the use of uniform wander mode decreases rutting and fatigue damage by 36% and 28%, respectively, on average for all scenarios. The use of new generation wide-base tires is recommended, since it reduces damaging strains by 38% when compared to the dual tire configuration. Full article