Publicaciones científicas CTCON

Abstract The study assesses recycled diatomaceous earth (from wine, beer, and oil filtration) as a supplementary cementitious material in mortars. Mechanical strength, durability, and pozzolanic activity were evaluated at 7, 28, and 90 days. Uncalcined diatoms from wine/oil yielded lower strength than natural diatomite, while calcination at 500 °C markedly improved performance; beer diatoms showed the weakest behavior due to organic matter. Quicklime did not activate uncalcined diatoms, but 500 °C calcination enabled long-term pozzolanic reactivity, indicating that calcined recycled diatoms can function as sustainable cementitious additions.

Abstract Study on valorizing diatomaceous earth wastes from food-industry filtration (wine, oil, beer) as supplementary cementitious material in conventional concrete. Five mixes were produced with 5% cement replacement (CEM I 42.5 R) using natural and recycled diatomite. Tests (compressive strength, capillary absorption, chloride permeability, carbonation) show that concrete with recycled diatoms (wine/beer) achieved up to ~16% higher compressive strength than the reference and exhibited lower capillary absorption, indicating a denser, less permeable matrix. The approach simultaneously diverts a problematic waste from landfill and reduces clinker use and associated CO₂.

Abstract The paper develops low-carbon autoclaved aerated concrete (AAC) by fully replacing OPC with lime-activated GGBFS and, in some mixes, adding calcium carbide slag (CCS). Five AAC formulations were tested (workability, foaming, strength, density, thermal conductivity, phase composition, and LCA). CCS boosted tobermorite formation during autoclaving, enabling BFS+CCS mixes to reach compressive strengths comparable to the OPC reference while keeping very low densities (≈420–441 kg/m³) and thermal conductivities of 0.111–0.119 W/(m·K). LCA (EF 3.1, cradle-to-gate) showed up to ~48% CO₂-equivalent reduction versus OPC-AAC, with BFS+CCS mixes meeting UNE-EN 771-4 strength requirements for load-bearing AAC blocks.

Abstract Book of Abstracts from the 2nd Open-Air Cities International Conference held at Harokopio University of Athens, 14–16 February 2025. The volume compiles abstracts across the four pillars of sustainable development—Environment, Economy, Society, and Culture—mapped to the UN SDGs. Contents include keynote talks (e.g., circular economy, climate-neutral cities, urban forests), special sessions (e.g., forestry & wood products, cultural sustainability and digital transformation), and a full conference schedule. Selected full papers are slated for peer review and potential publication in the Sustainable Development, Culture, Traditions Journal (ISSN 2241-4010).

Abstract The chapter explores replacing natural aggregates with reclaimed asphalt pavement (RAP) in soil-cement base layers to increase ductility and mitigate shrinkage-induced cracking that can reflect to upper asphalt layers. A laboratory program—modulus (tension/compression), strength (tension/compression), and fatigue tests—was performed with varying RAP and cement dosages. Results support RAP soil-cement as a more sustainable, high-performance base option that reduces raw-material use while targeting better cracking resistance.

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.