Caterina Frettoloso

The development of innovative and environmentally sustainable construction materials is a strategic priority in the context of the ecological transition and circular economy. Geopolymers and alkali-activated materials, derived from industrial and construction waste rich in aluminosilicates, are gaining increasing attention as low-carbon alternatives to ordinary Portland cement (OPC), which remains one of the main contributors to anthropogenic CO₂ emissions and landfill-bound construction waste. This review provides a comprehensive analysis of geopolymer-based solutions for building and architectural applications, with a particular focus on modular multilayer panels. Key aspects, such as chemical formulation, mechanical and thermal performance, durability, technological compatibility, and architectural flexibility, are critically examined. The discussion integrates considerations of disassemblability, reusability, and end-of-life scenarios, adopting a life cycle perspective to assess the circular potential of geopolymer building systems. Advanced fabrication strategies, including 3D printing and fibre reinforcement, are evaluated for their contribution to performance enhancement and material customisation. In parallel, the use of parametric modelling and digital tools such as building information modelling (BIM) coupled with life cycle assessment (LCA) enables holistic performance monitoring and optimisation throughout the design and construction process. The review also explores the emerging application of artificial intelligence (AI) and machine learning for predictive mix design and material property forecasting, identifying key trends and limitations in current research. Representative quantitative indicators demonstrate the performance and environmental potential of geopolymer systems: compressive strengths typically range from 30 to 80 MPa, with thermal conductivity values as low as 0.08–0.18 W/m·K for insulating panels. Life cycle assessments report 40–60% reductions in CO₂ emissions compared with OPC-based systems, underscoring their contribution to climate-neutral construction. Although significant progress has been made, challenges remain in terms of long-term durability, standardisation, data availability, and regulatory acceptance. Future perspectives are outlined, emphasising the need for interdisciplinary collaboration, digital integration, and performance-based codes to support the full deployment of geopolymer technologies in sustainable building and architecture.

This paper demonstrates, through the narration of a direct experience in the field, the potential impact generated by the intervention proposed as a case study, as a driver for the development of the territory in a ‘Healthy City’ perspective, expressing a strong potential for social inclusion and functional and spatial qualification. The research, from which it originated, highlighted the role of the University in supporting the PA in proposing strategic governance actions for the development of the territory. This is achieved through its multidisciplinary competences and its ability to draw on the exchange of visions and contributions provided by the actors involved in order to enhance the available local resources and specificities, and to foster the socio-economic well-being of the community.

The theme of connectedness, as a keyword in the revitalization processes of anthropized contexts, constitutes the focus of the paper which investigates its thematic areas related to the environmental, technological, and social dimensions. Sharing the importance of a strongly systemic approach in urban open space transformation interventions, the authors transfer the concept of connectedness, usually applied at vast territorial scales, from the ecological sphere to the urban one. The proposed approach highlights the need to decline the concept of connectedness into multiple dimensions capable of covering the various aspects that characterize the complexity of sustainable transformation processes of the open space-built system. The methodology, through the integration of connectedness in its various declinations, is an attempt to create new relationships of a different grade among and between single design spots (open spaces as an urban infrastructure) to emphasize relations that are not immediately recognizable, but which are at the basis of a regenerative design strongly oriented to providing social and technological-environmental services (inclusiveness and ecosystem services).

Currently, there is an increasing need to use ecological-environmental strategies that can contribute to human well-being and biodiversity in urban contexts that are complex systems with an increasingly diverse demand for ecosystem services. This becomes important especially for areas with high urban density which are those that determine the greatest impacts. Recent studies have related the increase of the COVID-19 pandemic to urban density, and the results seem to converge on the hypothesis that the lack of availability of urban space and high population concentration are factors contributing to the spread of disease. However, density constitutes both a problem and an opportunity to creating open spaces on a human scale, favoring the development and articulation of spaces that can more easily creep in and create the necessary conditions both for functional and environmental improvement and for mending the built environment. A dense environment suggests to work according to new logics that, starting from the optimization of existing spaces able to provide ecosystem services, experiment especially the “micro” and “interconnected” formula. The issue of interconnection in cities is complex as the continuity of connections, necessary to ensure the reticularity of spaces, is often inhibited by urban density. The idea is to replace the “structural continuity” with a “functional continuity” according to the “stepping stones” approach, borrowed from the ecology of the landscape. In analogy to the ecological networks approach, therefore, it is proposed to use this logic to enhance existing open spaces and create new ones with the aim of implementing overall urban quality.