Publications

Authors
Carlos Rodriguez, Fernando Fernandez, Roberto Rodriguez, Marina Sanchez, Pablo Gómez, Felipe Martí, Miriam Hernández and Irene Beleña

Abstract
This research investigates the use of recycled diatomaceous earth (diatomite) from the wine, beer, and oil industries as supplementary cementitious materials in cement-based mixtures. This study aims to reduce embodied energy and promote circular economy practices by incorporating these industrial by-products. The research evaluates the compressive strength, durability, and pozzolanic activity of the mixtures over 7, 28, and 90 days of hydration. The results demonstrate that uncalcined diatoms from wine and oil showed lower compressive strength than natural diatomite, whereas calcination at 500 °C significantly improved performance. Beer diatoms exhibited the lowest mechanical strength because of the organic matter content in their composition. The incorporation of quicklime failed to induce pozzolanic activity in uncalcined diatoms; however, calcination at 500 °C led to improved long-term performance, highlighting the importance of heat treatment for activating diatoms’ pozzolanic properties. This study concludes that recycled diatoms, particularly when calcined, have potential as sustainable cementitious materials.

Type of publication
Journal paper

Publisher
Crystals

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Authors
Carlos Rodriguez, Pablo Gómez, Felipe Martí, Sumit Srivastava, Marina Sanchez, Fernando Fernandez, Irene Beleña and Miriam Hernández

Abstract
The environmental impact of traditional construction materials has led to increasing interest in developing more sustainable alternatives. This study addresses the development of low-carbon autoclaved aerated concrete (AAC) through the complete replacement of ordinary Portland cement (OPC) with ground granulated blast furnace slag (BFS), activated with lime and, in some formulations, supplemented with calcium carbide slag (CCS). Five different AAC mixtures were prepared and evaluated in terms of workability, foaming behavior, compressive strength, phase composition, density, thermal conductivity, and life cycle assessment (LCA). The BFS-based mixtures activated with lime exhibited good workability and foaming stability. After pre-curing, the addition of CCS significantly improved the formation of tobermorite during autoclaving. As a result, the BFS–CCS formulations achieved compressive strengths comparable to the reference OPC-based mix while maintaining low densities (420–441 kg/m3) and thermal conductivities in the range of 0.111–0.119 W/(m·K). These results confirm the technical feasibility of producing structural-grade AAC with a lower environmental footprint.

Type of publication
Journal paper

Publisher
Applied Sciences

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Authors
Stefanie Prenner, Thomas W. Bruchmann, Sabine Jung-Waclik

Abstract
The European Green Deal positions the Circular Economy Action Plan as a key strategy for increasing resource efficiency and sustainability. In this regard, circular business models form an operational basis by integrating various value retention options (R-strategies) and thereby narrowing, slowing down and closing resource loops. In early development phases, the application of the Safe-and-Sustainable-by-Design framework can help to embed safety and sustainability aspects in circular business models from the outset. Despite growing political support, however, circular business models have so far only been implemented to a limited extent. This article therefore examines the challenges and barriers to widespread implementation. The research design, applied by Brimatech in several research and innovation projects, combines literature reviews, qualitative interviews, moderated workshops and content analysis. The results show that limited skills, inadequate policy frameworks, poor cooperation in value networks, cost issues, data problems and low market acceptance are hindering implementation. Overcoming these barriers through coherent frameworks, the use of digital technologies and targeted skills development is crucial to driving a systemic transition to a comprehensive circular economy.

Type of publication
Journal paper

Publisher
Springer Nature – Österreichische Wasser- und Abfallwirtschaft

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Authors
Carlos Rodriguez, Pablo Gómez, Felipe Martí, Sumit Srivastava, Marina Sanchez, Fernando Fernandez, Irene Beleña, Miriam Hernández and Anna Arizzi

Abstract
This paper presents a microstructural, mineralogical, and mechanical study of low-carbon autoclaved concrete (AC), achieved by partially or fully replacing ordinary Portland cement (OPC) with ground-granulated blast furnace slag (BFS) and substituting lime with calcium carbide slag (CCS). Fourteen mixes were produced and evaluated in the green state and after autoclaving. Quantitative X-ray diffraction (XRD) using the Rietveld method, density, compressive strength, and life cycle assessment (LCA) were conducted. Results show that mixes containing BFS achieve green strengths equal to or higher than the OPC reference, ensuring integrity during autoclaving. Using BFS with an adequate calcium supply promotes the formation of pre-autoclave portlandite, which in turn favors tobermorite development and yields post-autoclave strengths comparable to the OPC reference. Partial lime replacement with CCS (50%) maintains mineralogy and strength, whereas excessive CCS may reduce available portlandite and lower strength. Life-cycle assessment indicates that raw material supply dominates emissions and that removing OPC cuts total CO2 by 44% without compromising mechanical performance. These findings demonstrate the feasibility of OPC-lean/OPC-free, lime-optimized autoclaved concretes with substantially lower embodied impacts.

Type of publication
Journal paper

Publisher
Applied Sciences

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Authors

Carlos Rodríguez, Fernando Fernández, Marina Sánchez, Pablo Gómez, Miriam Hernández, and Isidro Sánchez.

Abstract
The valorisation of industrial by-products as supplementary cementitious materials is a promising strategy to reduce clinker consumption and improve the sustainability of cement-based materials. In this study, the influence of submerged arc welding (SAW) slag on the hydration behaviour and microstructural evolution of cement pastes was investigated. Two SAW slags from different industrial sources were incorporated as partial replacements of ordinary Portland cement at 5%, 15%, and 30% by mass. Cement pastes were prepared with water-to-binder ratios of 0.3 and 0.4 and characterised through setting time, water demand, mercury intrusion porosimetry (MIP), differential scanning calorimetry (DSC), and X-ray diffraction (XRD). The results showed that SAW slag systematically delayed both initial and final setting times, while having only a negligible effect on water demand. Under the fixed mix conditions adopted in this study, this retardation is interpreted as the combined effect of clinker dilution and modified fresh-state conditions. MIP analysis revealed higher early-age porosity in SAW-containing pastes, particularly at high replacement levels and higher water-to-binder ratios, although mixtures with up to 15% slag approached the reference pore structure at later ages. Thermal analysis indicated lower bound water and portlandite contents at early ages, mainly due to clinker dilution, while long-term hydration development remained comparable at moderate replacement levels. At higher slag contents, some mixtures showed higher calcium carbonate contents, suggesting a tendency toward increased carbonate formation under the investigated conditions. Overall, the results indicate that SAW slag primarily affected early paste behaviour and pore structure development, with clinker dilution appearing to be the main mechanism, although weak secondary physical or chemical contributions cannot be completely excluded.

Type of publication
Journal paper

Publisher
infrastructures

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Authors: Dimitrios Mendrinos, Spyridon Karytsas, Theoni I. Oikonomou, Constantine Karytsas, Maria Bololia, Elpida Polychroni and Irene Beleña Pozo

Abstract: The objective of this study is to analyse and integrate the gender dimension into the research activities of the SNUG Horizon Europe project, which focuses on circular economy-based material development for sustainable, high-energy performance buildings. The study addresses two research questions: which building component characteristics promote equitable workforce participation and which indoor environment attributes are disproportionately prioritised by women as occupants. A narrative literature review was conducted across ergonomics, gender studies in construction, and indoor environmental quality, followed by an analytical review of SNUG project deliverables and activities. Results reveal that lightweight materials, modular systems, and technically sophisticated installation processes reduce physical barriers to workforce participation, while superior thermal performance and indoor air quality directly address women’s documented sensitivity to thermal comfort and air quality as occupants. A three-tier framework for gender integration across the SNUG research lifecycle is proposed, encompassing structural, analytical, and translational dimensions. The study concludes that the SNUG project’s technical achievements position it as a reference for gender-responsive sustainable construction innovation, contingent on systematic implementation of the proposed recommendations across data management, digital tools, demonstration actions, and communication strategies.

Type of publication
Conference Paper – Open Access
ReShaping the Built Environment through Sustainability and Circularity (ReSBE 2026) International Conference

Publisher
Springer – Lecture Notes in Civil Engineering ReSBE 2026 – Volume 2

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Authors: Dimitrios Mendrinos, Mehmet Eren Sahin and Irene Beleña Pozo

Abstract: This paper examines the theoretical relationships between sustainable lightweight construction materials developed within the SNUG project “Circular Economy Based Materials Development to Foster The Transition to Sustainable and High-Energy Performance Buildings at Optimal Costs” and workforce accessibility in the building sector, with particular attention to ergonomic and gender inclusion dimensions. The study analyses four material innovations evaluating how their physical and installation characteristics may influence the demands placed on construction workers: aerated eco-concrete blocks, self-levelling mortars incorporating phase change materials, aerogel-based insulation and plasters, and bio-based hemp fibre panels. The methodology is literature-based and analytical, drawing on established ergonomics principles, material performance data, and workforce research to identify plausible pathways through which reduced material weight and technically sophisticated installation processes could lower physical barriers and broaden workforce participation. Results indicate that SNUG materials collectively shift installation emphasis from physical strength toward technical knowledge, precision, and equipment operation, though empirical validation remains absent. The paper concludes that the transition to sustainable construction presents an opportunity to intentionally integrate social and environmental goals, while cautioning against premature claims.

Type of publication
Conference Paper – Open Access
ReShaping the Built Environment through Sustainability and Circularity (ReSBE 2026) International Conference

Publisher
Springer – Lecture Notes in Civil Engineering ReSBE 2026 – Volume 2

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Authors: Elpida Polychroni, Maria Bololia, Andreas Androutsopoulos, Irene Beleña Pozo and Jose Maria Peña

Abstract: As climate change and environmental degradation intensify, the Euro-pean Union’s ambitious targets of reducing greenhouse gas emissions (GHG) and reaching climate neutrality by 2050 have become more urgent. Buildings account for approximately 40% of the total energy consumption and GHGs in the European Union. Additionally, throughout their construction, operation, use, renovation and demolition, buildings contribute to about 50% of extracted materials and over 35% of the EU’s total waste generation. The development of sustainable thermal insulation solutions which reduce energy consumption across the buildings’ lifespan while embracing circular econ-omy principles is essential to achieving a climate-neutral future and meeting Zero-Emission Building (ZEB) targets. The objective of this paper is to present a methodology for the performance assessment of selected insulation solutions taking into account their energy and environmental characteristics. The assessment is carried out in a real case build-ing located in central Europe, through virtual energy simulation. The main features evaluated for the selected building solution relate to the improvement of energy-efficiency performance, reduction of energy consumption, CO2 emissions reduction as well as the potential improvement of the indoor comfort conditions.

Type of publication
Conference Paper – Open Access
ReShaping the Built Environment through Sustainability and Circularity (ReSBE 2026) International Conference

Publisher
Springer – Lecture Notes in Civil Engineering ReSBE 2026 – Volume 2

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Authors: Spyridon Karytsas, Dimitrios Mendrinos, Theoni I. Oikonomou, Constantine Karytsas, Carlos L. Rodríguez López, Miriam Hernández Pérez and Irene Beleña Pozo.

Abstract: This paper investigates end-user expectations regarding building thermal insulation materials through a multi-stakeholder survey of 115 respondents across 12 European countries, complemented by statistical analysis and validation with industry manufacturers. The research methodology comprised a literature review of end-user preferences, conceptual model development, survey design, statistical analysis using the Kruskal-Wallis nonparametric test, and a two-phase manufacturer validation. Survey results demonstrate that end-users maintain a functional approach to insulation material selection, prioritizing specifications that deliver tangible, measurable benefits, with a strong emphasis on health and safety considerations, thermal performance, durability, moisture resistance and energy efficiency and relatively low importance assigned to aesthetics and sus-tainability credentials. The end-user behavior hierarchy ranks technical factors as the most important, followed by economic, environmental, and, lastly, social considerations, a ranking confirmed independently by industry manufacturers. Critically, a sustainability gap is identified: current preferences for environmental specifications remain substantially below levels implied by EU policy goals, yet higher-knowledge respondents show significantly greater appreciation for sustain-ability criteria, suggesting that education and regulation will progressively reshape market priorities. The manufacturers’ validation identified durability demonstration, moisture resistance, cost competitiveness, and communication as critical development challenges for innovative materials, defining the frontier where material innovation must meet market requirements to enable widespread adoption of sustainable construction solutions.

Type of publication
Conference Paper – Open Access
ReShaping the Built Environment through Sustainability and Circularity (ReSBE 2026) International Conference

Publisher
Springer – Lecture Notes in Civil Engineering ReSBE 2026 – Volume 2

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Authors: Mehmet Eren Şahin, Hülya Kalaycıoğlu and Uğur Aras

Abstract: Wood-based panels (WBPs) are increasingly important in sustainable and circular construction due to their renewable origin, efficient use of wood residues, and recycling potential. With global WBP production reaching approximately 366 million m3 annually, evaluating the environmental impacts associated with their production has become increasingly important. This study presents a systematic literature review of life cycle assessment research on particleboard, medium-density fiberboard (MDF), oriented strand board (OSB), and plywood using a PRISMA-based methodology and the Web of Science database. A total of 22 peer-reviewed studies published between 2015 and 2025 were comparatively analyzed in terms of system boundaries, environmental indicators, recycling approaches, and production hotspots.
The reviewed studies showed that MDF generally exhibits the highest environmental impacts, with reported carbon footprint values of approximately 500–600 kg CO2e/m3 due to energy-intensive fiber refining and drying processes. In contrast, OSB and plywood demonstrated comparatively lower carbon footprints ranging between 190–220 kg CO2e/m3 and 100–150 kg CO2e/m3, respectively, while particleboard typically ranged between 300–400 kg CO2e/m3 owing to more efficient raw material utilization and lower processing energy requirements. Adhesive production and thermal drying were consistently identified as the dominant environmental hotspots across panel types. These variations are also influenced by regional energy mixes, resin systems, and methodological assumptions.
Overall, the review highlights the importance of recycling pathways, cascading utilization, and methodological consistency in supporting circular wood-based panel production systems with lower environmental impacts.

Type of publication
Conference Paper – Open Access
ReShaping the Built Environment through Sustainability and Circularity (ReSBE 2026) International Conference

Publisher
Springer – Lecture Notes in Civil Engineering ReSBE 2026 – Volume 2

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