The research, conducted by Jaya Rajkumar Ramchandani and Suddhasheel Ghosh of Jawaharlal Nehru Engineering College at MGM University in Chhatrapati Sambhaji Nagar, India, formulates flyover design as a three-objective minimization problem. The objectives are flyover length, construction cost expressed in Indian rupees at 2023 base-year prices, and construction-related carbon emissions measured in tonnes of carbon dioxide equivalent. Rather than treating environmental impact as an afterthought to be assessed once a design is complete, the framework builds emissions directly into the optimization loop, drawing emission factors from the IPCC 2019 greenhouse gas inventories, Indian Standards for steel, and Maharashtra state road development project reports.

The case study is grounded in a real infrastructure context: the announced 25-kilometre Shendra–Waluj corridor in Maharashtra, which includes an 8.5-kilometre double-decker metro section. Megaprojects of this scale involve substantial public investment and long-term environmental consequences, which makes the choice of optimization algorithm a strategic decision rather than a technical footnote. The researchers modeled a prestressed concrete box-girder flyover with piers and abutments, loaded according to Indian Roads Congress Class A and 70R live load classes in seismic Zone III, with traffic assumptions of 45,000 vehicles per day growing at six percent annually.

At the heart of the framework are 29 design variables, ranging from clear span lengths of 20 to 45 metres and roadway widths of 7.5 to 15 metres, to deck slab thicknesses, girder depths, bearing types, skew angles, and load distribution factors. The bounds for each variable were established from Indian Road Congress codes, AASHTO specifications, and analysis of existing flyovers in Aurangabad. A variable-importance ranking revealed that clear span length, roadway width, pier height, and slab thickness exert the greatest influence on cost and environmental outcomes, while reinforcement diameter and foundation depth play more moderate roles.

Evaluating thousands of candidate designs with full finite element analysis would be computationally prohibitive, so the team built Radial Basis Function surrogate models for each objective. These models interpolate exactly at training points and approximate smoothly between them, allowing the optimizers to explore the design space at a fraction of the cost. Validation using 500 designs generated by Latin Hypercube Sampling, with ten-fold cross-validation, yielded mean absolute errors of 2.1 percent for length, 3.4 percent for cost, and 4.0 percent for carbon emissions, with coefficients of determination above 0.95. The surrogates achieved efficiency ratios of 95 to 98 percent relative to full finite element evaluation, meaning the entire optimization could run on a standard engineering office computer in under an hour.

Nine algorithms were compared under identical conditions: NSGA-II, NSGA-III, a genetic algorithm, differential evolution, CMA-ES, a classical evolution strategy, a stochastic ranking evolution strategy, Nelder-Mead, and pattern search. Each ran ten times with different random seeds, a population of 100 where applicable, up to 500 generations, and a budget of 50,000 function evaluations. Performance was judged on the hypervolume indicator, which measures the volume of objective space dominated by a Pareto front; the inverted generational distance, which measures closeness to a reference front; spacing, which measures how evenly solutions are distributed; computational time; and the fraction of solutions satisfying IRC and AASHTO constraints.

The results were decisive for the evolutionary multi-objective algorithms. NSGA-III achieved the highest hypervolume at 0.847, narrowly ahead of NSGA-II at 0.839, and both substantially outperformed every single-objective method adapted through weighted-sum scalarization. NSGA-III also produced the most evenly spread front, with a spacing metric of 0.0127 versus 0.0156 for NSGA-II, and generated 134 non-dominated solutions against NSGA-II’s 127. Statistical tests, including Wilcoxon signed-rank and Friedman tests with p-values below 0.05 and Cliff’s delta effect sizes, confirmed that the superiority of the two algorithms was not a product of random variation. Notably, the stochastic ranking evolution strategy was withdrawn from the final comparison due to constraint-handling inconsistencies.

The trade-off structure of the Pareto front itself tells a compelling story. Designs in the 800 to 1000 metre range can be built for 45 to 55 crore rupees with moderate emissions of 35 to 42 tonnes of CO2 equivalent, but they require more piers and denser construction. Designs longer than 1400 metres cost less per kilometre, between 32 and 42 crore rupees, yet emissions climb to 48 to 58 tonnes because of greater land take and material consumption. The balanced region between 1100 and 1400 metres forms the knee of the front, where all three objectives reach reasonable values. For the Aurangabad case, a compromise solution of roughly 1250 metres, 42 crore rupees, and about 40 tonnes of CO2 equivalent was selected using knee-point detection combined with expert weighting. Compared with standard IRC-compliant baseline designs, optimized solutions promise cost reductions of 8 to 12 percent, material savings of 10 to 15 percent, construction schedules shortened by 5 to 7 months, and carbon emission reductions of 18 to 22 percent.

Sensitivity analysis added an important practical dimension. When parameter bounds were varied by plus or minus 20 percent, the multi-objective evolutionary algorithms kept hypervolume variations under 5 percent, while Nelder-Mead’s final solutions shifted by up to 18 percent when span length bounds changed. This robustness matters because real projects rarely have perfectly certain boundary conditions. The study also offers scenario-based guidance: NSGA-II or NSGA-III for comprehensive trade-off exploration, CMA-ES with weighted sums when objective priorities are clear, Nelder-Mead or pattern search for rapid refinement of existing designs, and differential evolution for large infrastructure programs where many structures must be optimized and simplicity aids deployment. For the full 25-kilometre corridor, the authors recommend a hybrid strategy: explore the design space with NSGA-II, present the Pareto front to stakeholders, then refine the preferred design with CMA-ES using stakeholder-derived weights.

The authors acknowledge limitations, including the focus on bound-constrained optimization rather than the full complexity of geometric compatibility and safety-factor constraints, and they point toward future work on uncertainty quantification, hybrid algorithms, integration with multi-criteria decision-making methods such as TOPSIS and AHP, and transfer learning from previous flyover designs across cities. They also note practical barriers to adoption, including stakeholder resistance to non-traditional design parameters, procurement limitations, and regulatory approvals. All data and code are deposited in a DOI-bearing Zenodo repository to support reproducibility. As cities worldwide grapple with the twin demands of mobility and climate responsibility, the message of this study is clear: no single algorithm dominates every scenario, but with the right tool matched to the right project context, flyover design can become measurably cheaper, faster to build, and significantly greener.

Subject of Research: Multi-objective optimization algorithms for sustainable flyover design

Article Title: Comparative analysis of multi-objective optimization algorithms for sustainable flyover design framework

Article References: Ramchandani, J. R., & Ghosh, S. (2026). Comparative analysis of multi-objective optimization algorithms for sustainable flyover design framework. Frontiers in Built Environment, 12, Article 1915058. https://doi.org/10.3389/fbuil.2026.1915058

Image Credits: AI Generated

DOI: 10.3389/fbuil.2026.1915058

Keywords: multi-objective optimization, NSGA-II, NSGA-III, flyover design, radial basis function surrogate models, carbon emissions, Pareto front, sustainable infrastructure, structural engineering, differential evolution, CMA-ES, Aurangabad

Grape and olive pomaces constitute significant volumes of waste, presenting a dual problem of environmental disposal and underutilization of resources. Traditionally discarded, these pomaces are rich in phenolic compounds known for their antioxidant properties. The study meticulously explores how these natural antioxidants can be harnessed to improve the durability and performance of asphalt. By effectively transforming waste into a valuable resource, this research not only addresses environmental concerns but also contributes to innovative solutions for sustainable construction.

The unique properties of phenolic compounds in the pomaces make them ideal candidates for enhancing asphalt’s resistance to oxidative aging and environmental stressors. Asphalt, being a petroleum-based product, is inherently susceptible to degradation from UV radiation and thermal cycling. The introduction of grape and olive pomaces into asphalt formulations could lead to a significant reduction in the rate of deterioration, enhancing the longevity of roads and pavements and reducing the frequency of repairs—a substantial financial saving for municipalities and governments.

Through a series of rigorous experimental analyses, the researchers established a correlation between the concentration of pomaces used and the resulting performance metrics of the modified asphalt. The study utilized advanced characterization techniques to assess the mechanical and compositional properties of the asphalt blends. The findings showed that even modest amounts of grape and olive pomaces significantly improved the physical properties of the asphalt, leading to superior performance in terms of elasticity, ductility, and resistance to thermal cracking.

In addition to enhancing asphalt durability, the study also delves into the potential economic advantages of incorporating agricultural waste into asphalt production. By tapping into the abundant supply of grape and olive pomaces, which are often viewed as a burden by producers in the food industry, the construction sector could benefit from lower material costs. Moreover, using these waste materials aligns with the principles of a circular economy, which promotes minimizing waste and maximizing resource efficiency.

As infrastructure projects around the globe face increasing scrutiny over sustainability practices, integrating bio-renewable antioxidants into asphalt mixtures presents an attractive solution. The research emphasizes not just the technical feasibility but also the societal advantages of such innovations. By adopting alternative materials, the lifespan of road infrastructure could be extended, potentially leading to less frequent and less resource-intensive maintenance, thus alleviating pressure on environmental resources.

The implementation of these findings could have far-reaching implications in regions where grape and olive production is prevalent. Countries with significant wine and olive oil production—such as Italy, Spain, and Greece—could witness a transformative shift in waste management practices, converting a problematic by-product into a valuable material for construction. In this light, the authors of the study emphasize the importance of interdisciplinary partnerships between agriculture and civil engineering, signaling a new era in sustainable practices.

Beyond just economic and environmental benefits, the research also opens the door for enhanced public understanding and engagement with sustainable materials. The shift towards greener construction practices has the potential to change perceptions of infrastructure development, making it more palatable to communities concerned about ecological impacts. By promoting transparency and engagement, stakeholders can foster a greater appreciation for innovative practices that prioritize the health of the planet.

However, while the results are promising, the researchers caution against prematurely adopting the technology without thorough field testing and regulatory assessments. Such considerations are crucial for ensuring that the long-term performance of asphalt incorporated with bio-renewable antioxidants meets industry standards. Future research will undoubtedly be needed to refine processing techniques and assess the scalability of using grape and olive pomaces within commercial asphalt production.

In the context of ongoing climate change challenges, this study is a timely reminder of the potential locked within agricultural waste. It serves as a model for other sectors looking to innovate using valuable by-products that are often overlooked. As we globally face the dual challenges of waste management and sustainable development, research like this one led by Zhang and colleagues could catalyze similar initiatives aimed at turning waste into wealth.

In conclusion, the repurposing of grape and olive pomaces into bio-renewable antioxidants for asphalt paving materials represents a significant advance in sustainable construction practices. This research not only showcases the feasibility of integrating waste into material science but also offers a blueprint for future innovations in the field. As the drive for sustainability intensifies, the lessons gleaned from this study could inspire a broader movement toward the incorporation of renewable resources across various industries.

In summary, the study presents a unique intersection of food waste management and construction materials science, advocating for a holistic approach to fostering ecological balance within infrastructure development. With continued exploration and collaboration across disciplines, there is great potential for cultivating a more sustainable future through the innovative use of bio-renewable materials.

Subject of Research: Repurposing agricultural waste as antioxidants in asphalt paving.

Article Title: Repurpose Grape and Olive Pomaces as Bio-Renewable Antioxidants for Asphalt Paving Materials.

Article References:

Zhang, K., Zhu, Y., Lowenhar, S.P. et al. Repurpose Grape and Olive Pomaces as Bio-Renewable Antioxidants for Asphalt Paving Materials. Waste Biomass Valor (2025). https://doi.org/10.1007/s12649-025-03312-1

Image Credits: AI Generated

DOI: 10.1007/s12649-025-03312-1

Keywords: Sustainable construction, agricultural waste, asphalt, bio-renewable materials, antioxidants.