Search Results (888)

This study addresses the severe durability challenges for asphalt pavements in extreme, arid continental climates like Turpan, Xinjiang, where summer surface temperatures exceed 80 °C and winter lows drop below −20 °C. It evaluates Qingchuan rock asphalt (QRA) as a modifier to enhance the durability of plant-mixed hot recycled asphalt mixtures containing reclaimed asphalt pavement (RAP). Laboratory tests at binder and mixture levels evaluated the performance of QRA-modified binder and recycled mixtures. The program included binder specifications, performance grading, dynamic modulus, dynamic stability, and residual stability. Results indicate that increasing QRA dosage raises the softening point, G*/sin δ, and high-temperature PG, enhancing stiffness and rutting resistance. Although blending with RAP binder further improves high-temperature performance, it reduces workability and low-temperature resistance. In mixtures, dynamic stability, residual Marshall stability, and TSR increased by 115%, 6.59%, and 14.38%, respectively, while failure strain decreased by 30.8%. Dynamic modulus master curves confirm improved modulus retention at high temperatures. Considering the local PG 76–22 requirement and relevant specifications, a mixture containing 10% QRA and 50% RAP is recommended for durable plant-mixed hot recycled asphalt pavements in Turpan and similar arid climate regions. Full article

To address natural aggregate scarcity and improve the high-value utilization of Reclaimed Asphalt Pavement (RAP), this study proposes a steel slag–RAP hot recycled asphalt mixture (SSRM) as a sustainable alternative to conventional limestone–RAP mixtures (RM). Unlike previous studies mainly focusing on performance verification, an integrated environmental–economic evaluation framework was developed based on real highway expansion project data under a “cradle-to-gate” boundary and incorporating transportation distance thresholds. SSRM containing 50% RAP and 23% steel slag as coarse aggregate replacement was evaluated through rutting, semi-circular bending (SCB), freeze–thaw splitting (TSR), and skid resistance tests. Compared with RM, SSRM exhibited 14–16% higher dynamic stability and 20–25% higher fracture energy at −10 °C, along with improved moisture stability and skid resistance, mainly attributed to the rough and alkaline characteristics of steel slag enhancing adhesion and aggregate interlocking. Life-cycle assessment (GWP100) and cost analysis indicate that SSRM reduces carbon emissions by 10–11% relative to RM and about 40% compared with conventional virgin mixtures, while initial construction costs decrease by 9–10%. Transportation sensitivity analysis identifies equal-emission and equal-cost thresholds of approximately 590 km and 380 km, respectively. Within typical material supply radii (300–400 km), SSRM demonstrates both environmental and economic advantages, providing a practical framework for low-carbon material selection in highway construction. Full article

The performance of recycled hot-mix asphalt mixtures (RHAM) is strongly governed by the extent and uniformity of interactions between the aged binder in reclaimed asphalt pavement (RAP) and the virgin binder. However, in current engineering practice, it remains difficult to accurately evaluate the blending degree of aged and virgin asphalt during RHAM production, where the blending degree refers to the extent and uniformity of binder interaction during hot mixing. Moreover, influenced by various construction-related factors, the uniformity of interfacial diffusion between the two asphalt layers is also hard to control, which compromises the durability of RHAM. To address these issues, fluorescence microscopy was used to quantitatively characterize the blending behavior of aged and virgin asphalt, and Fourier transform infrared spectroscopy (FTIR) was employed to investigate the interfacial diffusion process and its evolution under time-temperature coupling conditions from plant production to field paving. The results indicate that, owing to the fluorescent characteristics of the Styrene-butadiene-styrene block copolymer (SBS) modifier in polymer-modified asphalt, the blending behavior during hot mixing can be quantitatively characterized by the fluorescent area and its areal proportion, providing a rapid solution for quantitative evaluation during RHAM production. Increasing the preheating temperature of RAP, extending mixing time, raising mixing temperature, and adopting Mixing Sequence I reduced the proportion of fluorescent area, suggesting improved blending between aged and virgin asphalt. After blending, the interfacial diffusion between aged and virgin asphalt occurs within the RHAM; the uniformity of this diffusion becomes more pronounced as the elapsed duration from production to paving increases. Nevertheless, excessively long duration may induce secondary aging of the blended binder. Accordingly, the duration is recommended to be controlled at approximately 90 min and should not exceed 180 min. By elucidating the blending and diffusion behaviors of aged and virgin asphalt, this study provides practical guidance for contractors in controlling production-process parameters for RHAM. Full article

Nowadays, the most widespread solutions to increase the sustainability of bituminous mixes deal with the recycling of reclaimed asphalt pavement (RAP) and the use of warm mix asphalt (WMA). However, the possibility of combining RAP recycling and WMA technologies needs to be further investigated and validated. This comprehensive laboratory study aimed at assessing the feasibility of recycling RAP in WMA mixes without compromising performance. For this purpose, WMA containing 40% RAP was produced by using softer virgin bitumen (160/220), to compensate for the high stiffness and viscosity of the RAP binder, and a WMA chemical additive. The mix was designed and characterized in terms of indirect tensile strength, water sensitivity, complex modulus, resistance to low-temperature cracking, resistance to rutting at high temperatures, and fatigue resistance. Its mechanical properties were compared with those of ordinary HMA made with virgin bitumen (50/70) and aggregates. The experimental results showed that the WMA+RAP mix had comparable volumetric properties with respect to the reference HMA despite its reduced production temperatures. Moreover, WMA+RAP exhibited similar or improved mechanical performance, with enhanced resistance to water damage, rutting, and fatigue cracking, without penalizing low-temperature behavior. Full article

The use of resource-saving technology in road construction material production is a current problem, the solution of which will allow us to increase the environmental and economic efficiency of the road construction industry. Nowadays, secondary raw materials are widely used in highway construction, obtained both from the waste of old road construction materials and collected from other industries. During asphalt production, up to 90% of raw materials can be replaced by reclaimed asphalt pavement (RAP). This technology requires residual binder modification to reduce the negative impact on the technological and operational asphalt concrete properties. On the other hand, the use of rubber crumbs or granules obtained from the disposal of old car tires in asphalt–concrete mixtures is widespread. However, some types of car tires cannot be used as raw materials to produce an effective modifier. Truck tires and tires from special vehicles are suitable for use as a modifier for asphalt–concrete mixtures. Tires designed for passenger cars do not contain enough polymer. As an experiment on asphalt–concrete mixture production using secondary resources only, a testing facility was developed. The testing facility uses hot gas obtained by burning automobile tires in a special oven as a heat source. Rubber residues from the recycling of automobile tires are used as fuel, which cannot be used to produce rubber powder or granules. RAP obtained by cold milling of the pavements of city and public roads was used as the object of the research. When studying the characteristics of the asphalt–concrete-mixture-based binder, it was found that the sulfur compounds present in the composition of hot gases change the properties of the binder, leading to a serious deterioration in the technological characteristics of asphalt–concrete mixtures. The asphalt–concrete mixture obtained during RAP processing is characterized by a narrow temperature range in which it can be laid and compacted to the required density values. After laying the pavement, quality control revealed a significant variation (the number of air voids ranged from 0.8 to 5.5%) in the average density of samples taken from the compacted layer. In addition, there were significant violations of the longitudinal evenness of the finished coating. Experiments were carried out to extract the binder from asphalt–concrete mixtures before and after regeneration. The physico-mechanical and rheological characteristics were studied and qualitative analysis of the binder was realized by IR spectroscopy. The data obtained allow us to establish the mechanism of how sulfur-containing gases influence the bitumen binder’s properties in asphalt mixtures. Additionally, the features of thermo-oxidative degradation occurring during the hot recycling of asphalt–concrete mixtures were established. A justification is also given for the need to use anti-aging modifiers to restore the properties of the residual binder. Full article

The incorporation of reclaimed asphalt pavement (RAP) in asphalt mixtures improves sustainability but significantly reduces the intrinsic self-healing capacity due to binder aging. This study aimed to quantify whether epoxy-coated rejuvenator microcapsules could restore and enhance the self-healing performance of RAP-containing recycled asphalt mixtures. Four mixture types (AC-10C, AC-13C, AC-16C, and SMA-13C) containing 20% RAP were evaluated using a fracture–healing–refracture bending test (Repair index, R_C) and a splitting healing strength ratio (S_HSR) test to determine the effects of healing time, temperature, and microcapsule dosage. R_C increased rapidly during the first 8 h of healing and then approached stabilization, with the growth rate falling below 2%, indicating 8 h as the practical optimum healing duration. R_C increased from 0 °C to 45 °C due to enhanced binder mobility and diffusion, and slightly decreased at 60 °C because temperature-induced softening reduced peak bending strength. The highest self-healing capacity was obtained at a microcapsule dosage of 4% (by RAP mass). Under the optimum healing condition (8 h and 45 °C), R_C increased by 10.38%–13.50% and S_HSR increased by 14.35%–25.27% compared with mixtures without microcapsules. Among the mixtures, SMA-13C exhibited the highest self-healing capacity, followed by AC-13C, AC-10C, and AC-16C. The contribution of this study lies in quantifying the healing enhancement in RAP-containing mixtures, identifying practical optimum healing conditions based on a growth-rate criterion, and demonstrating consistent trends between two healing indices across different mixture structures. Full article

Cold recycled asphalt mixtures incorporate a high amount of reclaimed asphalt pavement (RAP), which offers more economic and environmental advantages than hot recycling techniques. Nevertheless, the presence of aged RAP binder frequently leads to reduced low-temperature performance and uncertainty in mechanical response. The influence of slack wax on full-depth reclamation (FDR) mixtures with bitumen emulsion is assessed in this study using a dual-scale approach. The approach integrates both chemical and rheological binder-scale characterization with mixture-scale mechanical performance with variability assessment. At the binder scale, the binder beam rheometer (BBR), dynamic shear rheometer (DSR), and Fourier transform spectroscopy (FTIR) indicated that the addition of 10% recycling agent improved the low-temperature properties. The improvement at lower temperatures shifted the BBR temperature from −23 °C to −30 °C, which ultimately resulted in a less negative ΔT_c, from −0.7 °C to −0.3 °C, and moderately improved high-temperature stiffness. Moreover, the FTIR analysis indicated a reduction in oxidation-related chemical markers, as evidenced by the reduced carbonyl and sulfoxide indices. At the mixture scale, complex modulus shows a systematic decrease in stiffness, particularly at lower temperatures of −25 °C and −15 °C, and a reduced phase angle, suggesting higher elastic dominance. The reduction is observed at all temperatures and frequencies. Rutting resistance of both formulations remains below 3% after 30,000 cycles. The complex modulus coefficient of variability was found to be 8–12%, comparable to that of hot mix asphalt. In conclusion, the findings suggest that the recycling agent provides a controlled restoration of viscoelastic properties in cold recycled mixtures without compromising structural integrity. This underscores the significance of multi-scale evaluation and variability assessment when characterizing high RAP recycling agents under the studied materials and dosage. Full article

Road safety assessment is essential for reducing traffic fatalities, with road infrastructure contributing to a substantial proportion of crashes worldwide. International frameworks such as the International Road Assessment Program (iRAP) define standardized attributes for infrastructure auditing; however, many of these attributes remain challenging to automate using imagery alone. This study evaluates V-RoAst (visual question answering for road assessment), a public dataset of road images that are annotated with iRAP-style attributes, using state-of-the-art multimodal large language models (MLLMs), specifically Gemini 2.0 and Gemini 2.5. The analysis focuses on how prompt design influences the accuracy and stability of single image iRAP inference. A token-efficient reduced prompt is developed that preserves the iRAP schema while removing single-class constants, hard-coded administrative fields, and derived or non-visual codes, retaining only visually interpretable attributes. Performance is compared with the original full multi-attribute prompt and single attribute prompts using a fixed evaluation protocol incorporating majority voting, bootstrap 95% confidence intervals, and per-code sample-size checks. Results indicate only minor performance differences between Gemini 2.0 and Gemini 2.5, while prompt optimization produces the most consistent gains, improving macro-F1 scores and tightening confidence intervals for visually grounded attributes such as roadside severity, intersection channelization, and service-road presence. Token analysis shows an approximate 30% reduction in prompt length, reducing computational cost and truncation risk. Overall, the findings demonstrate that prompt scope has a greater impact than model version in image-only iRAP coding, offering practical guidance for scalable infrastructure assessment. Full article

Chemotherapy has significantly improved survival in breast cancer and, in the neoadjuvant setting, contributes to tumor downstaging and increased rates of breast-conserving surgery while enabling in vivo assessment of tumor biology and chemosensitivity. Pathological complete response (pCR) is a key endpoint associated with favorable outcomes; however, tumor heterogeneity highlights the need for reliable predictive biomarkers. This study evaluated the mRNA expression of 13 candidate genes in relation to molecular subtypes and pathological response to neoadjuvant chemotherapy (NAC) to identify potential predictive and prognostic markers. Pretreatment core biopsies from 92 patients receiving NAC were analyzed by quantitative RT-PCR. Molecular subtypes were determined by immunohistochemistry (ER, PR, HER2, Ki67), and pathological response was classified using the Miller–Payne scale as good (MP 4/5) or poor (MP 1–3). Multivariate logistic regression assessed associations between gene expression, subtype, and pCR. Hormone receptor-positive tumors showed significantly higher expression of AXL, FGFR1, RAP80, GAS6, BTRCP, and ZNF217. Significant associations with pCR were observed for AXL, FGFR1, YAP, and BRCA1. Low AXL and BRCA1 expression levels were independently associated with pCR. In addition, their combined low expression was associated most strongly with breast pCR in this cohort. These findings should be interpreted as exploratory and require validation in independent cohorts. 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 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

The reuse of milled pavement material, known as RAP (Reclaimed Asphalt Pavement), represents one of the major current challenges in highway engineering worldwide. There is no doubt that the most valuable application of this residue is its use in the production of new hot asphalt mixtures, incorporating the highest possible RAP content, a process that requires adaptations in residue processing at asphalt plants. In Brazil, the RAP content added to these mixtures is limited to a maximum of 25%. Consequently, alternative applications have gained prominence in the country to increase RAP utilization in pavement engineering, such as its use in cold premixed asphalt mixtures. This study aimed to evaluate the performance of cold asphalt mixtures containing different RAP contents through mechanistic-empirical analyses of a reference pavement structure, using the modelling framework adopted in the Brazilian Asphalt Pavement Design Method (MeDiNa). After Marshall mix design and volumetric and mechanical characterization of mixtures containing 0%, 10%, 20%, 30%, and 40% RAP, stiffness and fatigue parameters were used to estimate the evolution of cracked area in the reference pavement, with each mixture applied as the surface layer under different traffic levels. The results demonstrated that pavement performance improved for all RAP contents evaluated compared to the mixture without RAP, with the mixture containing 30% RAP showing the best overall performance. Full article

Stone Matrix Asphalt (SMA) has emerged as a premier high-performance paving solution for critical infrastructure applications. Its distinctive skeleton structure, composed of coarse aggregates bound by a fiber-stabilized bituminous mastic, delivers exceptional mechanical performance, including superior resistance to rutting (≤3 mm after 10⁶ load cycles) and fatigue cracking (>500,000 cycles to failure). While proven in demanding service environments, research has increasingly focused on enhancing the sustainability of SMA through key innovations: (1) the incorporation of recycled materials, such as 30–40% Reclaimed Asphalt Pavement (RAP) and 0.3–0.5% waste tire textile fibers (WTTF); (2) the development of bio-based binders derived from renewable sources; and (3) the adoption of Warm-Mix Asphalt (WMA) technologies that reduce production temperatures by 20–30 °C. These advancements yield significant environmental benefits, including approximately 25% lower CO₂ emissions and 15–20% reduced energy consumption compared to conventional SMA production. It is important to distinguish between these quantitatively demonstrated benefits, primarily from Life Cycle Assessment (LCA) studies of technologies like WMA and RAP, and the more qualitative sustainability claims associated with emerging materials like nanomaterials or novel bio-additives, which often lack comprehensive lifecycle inventories. Nevertheless, challenges persist, notably moisture susceptibility (manifesting as a 10–15% strength reduction after saturation) and uncertainties regarding the long-term performance of modified mixes. This review consequently identifies critical research priorities: optimizing mix designs with locally available materials to minimize transport emissions, employing nano-scale modifiers to enhance moisture resistance, and developing standardized lifecycle assessment protocols. Addressing these challenges is paramount to establishing SMA as a model sustainable pavement technology that robustly meets both structural performance benchmarks and ecological sustainability goals. Full article

Post-translational modification (PTM) encompasses diverse modifications, including phosphorylation, methylation, ubiquitin-like modifications (UBLs), and so on, which profoundly influence cellular functions. UFMylation is a recently identified ubiquitin-like modification, which is mediated by the Ubiquitin-like Ubiquitin Fold Modifier 1 (UFM1) conjugation system. The UFM1 conjugation system comprises UFM1, Ubiquitin-like protein activating enzyme 5 (UBA5), UFM1-conjugating enzyme 1 (UFC1), UFM1-specific ligase 1 (UFL1), UFM1-specific protease 1 (UFSP1), UFM1-specific protease 2 (UFSP2), UFM1-binding protein 1 (UFBP1), and CDK5 regulatory subunit-associated protein 3 (CDK5RAP3). Accumulating research has demonstrated that the UFM1 conjugation system regulates various cellular stress responses, including endoplasmic reticulum (ER) stress, protein trafficking, DNA damage repair, and autophagy. Additionally, abnormal stress adaptations of the UFM1 conjugation system contribute to the pathophysiological complications of inflammatory diseases and cancer, underscoring its significance as a key regulatory node in human health and disease. Therefore, this review provides a comprehensive exploration of the structural characteristics of UFM1 conjugation system members and the mechanistic roles of UFMylation by UFM1 conjugation system-mediated diseases related to cellular stress responses, which will not only facilitate the identification of novel diagnostic and prognostic indicators but also enable the identification of specific therapeutic targets for UFM1 conjugation system-related diseases. Full article

The main goal of this study is to evaluate the feasibility of designing high-performance MASAI mixtures produced at ambient temperature. For this purpose, the impacts of certain variables, such as the type and amount of asphalt emulsion and the use or non-use of RAP, on its performance are evaluated. Subsequently, its stiffness modulus, tensile strength, permanent deformation, and resistance to thermal cracking were evaluated and compared against a conventional dense-graded asphalt concrete (AC 16) and an open-graded (BBTM11B) hot-mix asphalt used for wearing courses. The results showed that these materials could represent more sustainable and good solutions for the rehabilitation of some types of pavements. Full article