This study investigates kraft lignin, hydrolysis lignin, and tall-oil bio-additives as bio-based extenders for a 70/100 penetration-grade bitumen. The objectives were to evaluate whether kraft lignin behaves predominantly as a reinforcing filler rather than as a more interactive binder modifier, and to assess how tall-oil bio-additives influence rheological and thermal performance. Bio-extended binders were produced using kraft lignin (KLEB−15%) as the core system and benchmarked against hydrolysis lignin (HLEB−15%) and a conventional limestone mastic (LSM−15%) representing an inert filler reference. Composite binders were prepared by adding 5 wt% and 10 wt% of crude tall oil (CTO) or tall oil pitch PN (TOP PN) to KLEB−15%. The chemical composition and thermal stability of unaged binders were determined using Fourier-transform infrared spectroscopy and thermogravimetric analysis, while frequency sweep and multiple stress creep recovery tests characterised the linear and non-linear rheological response. The results indicate that kraft lignin was incorporated predominantly through physical blending and behaved mainly as a reinforcing filler, closely resembling the response of the limestone mastic. In contrast, hydrolysis lignin showed a more modifier-like character with higher elastic recovery and lower non-recoverable compliance. The tall-oil bio-additives acted as effective softening agents: a 5 wt% dosage reduced stiffness while preserving much of the high-temperature performance, whereas 10 wt% CTO caused pronounced softening and compromised rutting resistance. Overall, the findings suggest that kraft lignin’s filler-like behaviour can be modulated by tall-oil additives, while hydrolysis lignin provides a more modifier-type bio-extension. This functional classification offers a viable framework for designing performance-balanced, lignin-extended binders.

This study presents a rheological evaluation of composite binders in which kraft lignin is blended with tall oil bio-additives, crude tall oil (CTO) and tall oil pitch (TOP PN), to mitigate the brittleness induced by lignin. The linear and non-linear viscoelastic properties of these bio-composites were characterised using a Dynamic Shear Rheometer and Multiple Stress Creep and Recovery tests. Results show that lignin substantially increased stiffness and elastic response, enhancing rutting resistance. Both tall oils acted as effective plasticisers, though TOP PN provided a more selective softening that largely preserved this high-temperature performance. This complementary (‘synergistic’) interaction yielded an optimal balance with a formulation of 15% lignin and 5% TOP PN. These findings, based on binder rheology, demonstrate the potential of lignin–tall oil systems for developing sustainable asphalt binders, though further investigation into fundamental interactions and long-term durability is needed to determine practical applicability.

With increasing interest in 'greener' road construction materials, lignin has drawn attention as a promising partial replacement for bituminous binders. This systematic literature review synthesises research from 1983 to 2024, providing an overview of lignin's potential in sustainable pavements, integrating material performance, environmental and economic perspectives to evaluate current knowledge and identify key challenges and research gaps hindering its adoption in practice. Findings demonstrate that lignin can enhance asphalt's high-temperature performance, ageing resistance, and moisture resilience, while reducing reliance on fossil fuels and lowering carbon emissions. However, challenges remain, including reduced low-temperature flexibility, compatibility issues with bitumen, and a lack of long-term mechanical and environmental data under varied stress conditions. Additional barriers to scalability include supply chain constraints, energy-intensive lignin refining processes, and uncertain life-cycle costs. To realise lignin's full potential in eco-friendly infrastructure, future research should prioritise fundamental mechanistic studies, standardised testing methods, and feasibility assessments for full-scale implementation.

A prevailing concern in higher education, especially within the fields of Science, Technology, Engineering, and Mathematics (STEM), often refers to underrepresentation of certain social groups. While the public attention is drawn to the aggregated statistics reflecting participation issues at a macro societal level, the essence of the debate is the real underrepresented individuals behind each number that have been hindered by any tangible or impalpable reasons. Thus, how to address existing disparities in education systems by looking beyond the aggregate number to the nuanced barriers faced by different groups becomes vital. Based on a systematic literature review, this research aims to explore the complex barriers and opportunities regarding the expansion of participation in STEM education. By analyzing global examples, the study identifies socioeconomic disadvantages, exclusionary institutional practices, and internal psychological barriers such as low confidence, lack of belonging, and stereotype threat as key factors that hinder the engagement of marginalized communities in STEM fields. Drawn on a meta-analysis, the research also evaluates successful intervention practices, such as role model-based initiatives and inclusive educational environments, and values-affirmation exercises, which have been shown to improve motivation, strengthen self-efficacy, and increase retention in STEM. Additionally, the study synthesizes these findings to propose systemic reforms at individual, institutional, and governmental levels. In summary, this research offers evidence-based and actionable strategies, leading to a more inclusive STEM landscape for sustainable development.

Given the significant role of asphaltic pavement in surface transportation systems, even minor enhancements in asphalt materials hold the potential for cost savings and reduced environmental impacts. The healing properties of asphalt have drawn interest for sustainability, yet much remains unknown about the causes and influencing factors. To leverage self-healing for extending pavement life, understanding the mechanisms and conditions that stimulate microcrack healing is essential. This study aims to investigate the dynamic progress of microcrack closure in asphalt mastics. The time-series evolution of crack closure led by self-healing is tracked by neutron computed tomography, with image processing facilitating volumetric analysis over a 7 h period. The study examines the healing process in mastic samples with three different sand filler contents (10, 20, and 30%). Results show that for all the investigated samples, the healing rate declines exponentially over time, with 100% recovery not achieved after 7 h at room temperature. Filler content-influenced healing speed and 20% sand demonstrate the best performance. Meanwhile, the healing performance varies within the 10% and 30% groups, depending on initial crack size. Additionally, the study finds that initial crack size influences healing behavior in the samples.

Modified bitumen is a critical material to ensure the durability of asphalt pavements. Traditional polymer-modified bitumen (PMB) has been widely researched and applied in the past two to three decades. Recently, a high-content SBS (Styrene-Butadiene-Styrene) polymer-modified bitumen (HSBSMB) with a higher SBS content of up to 7–9% by weight has started attracting interest from researchers. There are, however, still few specifications or technical guidelines for HSBSMB. To gain a better understanding of HSBSMB, the composition and structure of typical polymer SBS and base bitumen, the micromorphology and micromechanics of HSBSMB, its rheological and aging characteristics, as well as its asphalt mixture and field pavement performance were reviewed comprehensively in this paper. The content covered in this paper is primarily derived from 210 pertinent papers published between 1990 and 2023 in two databases, Web of Science and Google Scholar. It appears from our review that HSBSMB has a stronger internal polymer network than conventional SBSMB and thus exhibits better resistance to rutting, fatigue, and cracking as well as better aging resistance. Furthermore, findings from both laboratory scale and field pavement scale indicate that HSBSMB not only offers higher performance and durability but also leads to reduced pavement structural layer thicknesses in ensuring performance. However, many issues and challenges still remain before HSBSMB will become a viable option for large-scale application in road infrastructure, aspects such as the mechanism of its internal structural changes, the optimization of methods for evaluating its rheological properties, the life cycle assessment of its long-term benefits, as well as the storage stability and workability of HSBSMB. It is hoped that this review will contribute to a better understanding of HSBSMB and promote its application.

The primary objective of this investigation is to evaluate how the incorporation of lignin and high-viscosity modifiers impacts the performance of asphalt binders. Lignin-modified asphalt binder (LBA) and lignin-high viscosity modifier composite-modified asphalt binder (LHA) were created by blending 5 % and 15 % lignin, respectively. To understand the physicochemical interactions, Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), and differential scanning calorimetry (DSC) were employed to analyze functional groups, thermal properties, and phase changes. Additionally, the linear rheological behavior and nonlinear rheological behavior were evaluated through frequency sweep and multiple stress creep recovery tests. The findings suggest that lignin blends physically with the asphalt binder and high-viscosity modifier without a chemical reaction. Although the onset pyrolysis temperature of lignin is significantly lower than that of asphalt binders, due to its relatively low content, the thermal decomposition of lignin-modified asphalt binders is primarily controlled by the asphalt binder itself and still exceeds the construction temperature. However, lignin incorporation increases the asphalt binder's glass transition temperature, potentially affecting low-temperature performance. Lignin significantly enhances the modulus in the high-frequency region of both unmodified and high-viscosity modified asphalt binder. However, it has a negative effect on the modulus in the low-frequency region of high-viscosity modified asphalt binder. Furthermore, nonlinear creep recovery test results demonstrate that lignin positively contributes to the deformation resistance of unmodified asphalt binder in a content-dependent manner, whereas it reduces the elastic behavior and deformation resistance of high-viscosity modified asphalt binder. In addition, low levels of lignin increase the stress sensitivity of binders, while high levels of lignin decrease it. Despite these effects, the performance of lignin and high-viscosity additive composite-modified asphalt binder remains superior to that of unmodified asphalt binder. These findings offer valuable insights into the combined use of lignin and polymers in asphalt binder modification.

Navigating the complex pavement system to the circular economy is a multi-dimensional and time-consuming endeavour. Obstructed by lock-in mechanisms of the prevailing “take-make-dispose” linear mode, the current circular economy studies in pavement infrastructure often focus only on one certain type of practice, featured by fragmentation from a system perspective. This study presents the first systematic literature review on the historical development trend of the circular economy concept in the pavement sector based on the collected 59 studies from 2006 to 2022. This review also identifies the soft (regulatory, social/environmental) and hard (technical, market/economic) drivers of- and barriers to the paradigm shift, aiming to coordinate the existing fragmented findings and facilitate the future systemic implementation of the circular economy. The synthesis of the results indicates that the underdeveloped technical guidance and legal system are inhibiting the paradigm shift to the circular economy. Furthermore, the authors argue that the importance of transparent and standardized data along the whole supply chain should be highlighted. Ultimately, this paper suggests that a welcoming environment set by the road authorities is crucial for innovation and entrepreneurship, as well as for constructing a system where stakeholders can confidently take responsibility and initiative.

As a type of intermodal terminal, pure Ro-Ro terminals are one of the most important logistic hubs in the supply chain for rolling freight stored in containerized and wheeled steel boxes. These large-scale systems are highly complex, with nonlinear and hard-to-predict behavior evolving in a stochastic environment. Consequently, making decisions about any problem thereof is no mean feat, particularly for terminal planners. To assist them in decision-making, a pool of relevant models and tools have been developed over the years in the literature. Nevertheless, models that are oriented toward specific objectives dominate, and generic ones are rare. This paper tries to fill this gap and proposes a generic framework to be used as a factory to create specific decision support models based on simulation for pure Ro-Ro terminals. This framework is formulated following two artifacts: (1) the known classification of key performance indicators combined with the typical functional and physical organization of pure Ro-Ro terminals; (2) the three main arteries of harbor systems, namely flows, decisions and operations. Then a scalable way of making decisions based on a flexible form of the cost function weighted according to a set of coefficients is integrated. These designed coefficients allow decision-makers a wide flexibly in choosing how the best solutions are determined. An application of this framework is illustrated through a real case study, where the weights are estimated using an expert-profiling based approach then pushed into the OptQuest optimizer to be calibrated before analyzing the results. These results are aggregated, then expressed as scores on a scale of 0 to 1. This is to help terminal planners to easily identify the worst and best planning scenarios as well as the relationships and compatibilities between the involved handling rules to suggest different alternatives for managing operations.

Container terminals are complex systems where containerized cargo undergoes a set of processing and handling operations to be delivered to their outgoing modes. A pool of decision support methods and simulation models has been developed to assist planners and managers in making decisions about daily operations. Nevertheless, most are designed for a particular terminal and not generic types. Indeed, a generic model serves as a conceptual factory to create specific models which greatly reduces the time and efforts of development; however, building such a model is no mean feat. To this aim, the paper on hand discusses the complexity of applying genericity, flexibility, and modularity in system modeling and proposes a generic architecture to build modular and flexible simulation models for container terminals. This architecture is split into a set of smaller, manageable, well-connected, and generic modules that facilitate the creation of highly parametrized specific models. An illustrative example of the architecture usage is presented in a case study, the new container terminal of Stockholm, and the resulting models were validated by subject matter experts. Finally, to prove its efficiency, a numerical study fed with real data is conducted to investigate the handling capacity of the studied system under different handling and flow scenarios. The obtained results show that the terminal handling capacity can be increased by around 50% if three to four more straddle carriers are added to the existing fleet.