1. Utilisation of reused steel and slag : analysing the circular economy benefits through three case studiesGenesis Camila Cervantes Puma, Adriana Salles, Janez Turk, Viorel Ungureanu, Luís Bragança, 2024, review article Abstract: This research explores sustainable construction practices focusing on material reuse, specifically reclaimed structural steel and slag. In general, the building stock is not designed for deconstruction, and material recovery for reuse at the end of life of buildings is complex and challenging. The study evaluates the benefits of content reuse through a thorough analysis of three case studies— BedZED eco-friendly housing, Angus Technopôle building, and the use of steel slag aggregate in road construction. It highlights the value of reclaimed structural steel and by-products like steel slag in waste reduction, energy conservation, and resource preservation. The BedZED case study showcases recycled steel’s cost-effectiveness and economic viability in construction, while the Angus Technopôle building exemplifies the adaptive reuse of an old steel frame building. Additionally, the third case study showcases the benefits of using Electric Arc Furnace C slag in asphalt-wearing courses, highlighting the reduction in greenhouse gas emissions and environmental impact. The versatility of reclaimed structural steel and slag is evident in integrating material reuse in building construction and road infrastructure. These case studies illustrate the potential for reusing steel and its by-products in various construction contexts, from eco-friendly housing to road development. Therefore, the study aims to demonstrate the feasibility and benefits of sustainable practices within the construction industry by showcasing the successful incorporation of reclaimed steel and slag in these projects. Considering the significant contributions of building construction to global greenhouse gas emissions, raw material extraction, and waste production, the study advocates for adopting circular economy (CE) principles within the construction industry. Finally, the analysis of case studies underscores the advantages of reclaimed structural steel and the valorisation of steel slag through the lens of CE and their contribution to sustainable development. Keywords: circular economy, reused steel, steel slag aggregate, reclaimed steel, steel members Published in DiRROS: 12.04.2024; Views: 309; Downloads: 144
Full text (1,17 MB) This document has many files! More... |
2. Quantifying the environmental implication of cotton-fiber-based nanocrystalline cellulose : a life-cycle assessmentKatja Malovrh Rebec, Janez Turk, Matjaž Kunaver, 2024, original scientific article Abstract: Considering the increasing demand for nanocrystalline-cellulose in the industry, due to its exceptional physical and biological properties, cheaper and more efficient production processes are sought. Addressing environmental concerns, especially within the framework of EU policies, this study employs Life Cycle Assessment (LCA) to evaluate the environmental performance of a novel nanocrystalline-cellulose production procedure, encompassing biomass depolymerization, rinsing, and bleaching. The LCA aims to identify environmental hotspots, explore mitigation measures, and enables comparisons with other LCA studies on nanocrystalline-cellulose. The results are calculated and reported for 19 environmental impact categories, using the ReCiPe 2016 impact assessment method. The production of 1 kg of dry nanocrystalline-cellulose using the novel process emits 63.7 kg CO2 equivalent, which is lower than the literature average (68 kg CO2 equivalent). The solvent (e.g. diethylene glycol) is the major contributor to the global warming potential and fossil-fuel depletion potential in the product stage of the nanocellulose, while the electricity requirements and glycerin represent environmental hotspots regarding 15 of the 19 impact categories assessed. In terms of the water-consumption potential, the environmental hotspot is production of raw materials (e.g. cotton fibers). Electricity contributes more than 50 % of the burden to the impact categories associated with ionizing radiation, the pollution of aquatic ecosystems and human toxicity related to cancer. It also holds a significant share of the burdens for terrestrial acidification (48 % of the impact), the formation of fine particulate matter (46 % of the impact), and human toxicity related to non-cancer diseases (37 % of the impact). This underscores the importance of optimizing the production process, possibly through upscaling. Additionally, incorporating on-site renewable energy sources and utilizing biomass-derived diethylene glycol can enhance the environmental performance of nanocrystalline-cellulose. Keywords: LCA, cascade use, cellulose nanocrystals, pilot production, environmental performance Published in DiRROS: 06.02.2024; Views: 385; Downloads: 187
Full text (5,07 MB) This document has many files! More... |
3. Pathway toward sustainable winter road maintenance (case study)Katja Malovrh Rebec, Janez Turk, 2023, independent scientific component part or a chapter in a monograph Abstract: Life Cycle Assessment (LCA) method was applied to evaluate the environmental impacts of winter road maintenance managed by an innovative road-weather information system and the impacts of vehicles passing the road during the snowstorm event. A case study refers to 10-hour lasting snowstorm event, considering a specific road section and application of a road-weather information management system to help winter road maintenance agency optimizing activities (salt gritting and/or plowing). Reliable information on the timing of the beginning of the snowstorm event affects (1) the activities of winter road maintenance, (2) the mobility of all vehicles passing the road, and (3) the fuel consumption of the vehicles. Since activities are optimized in case of preventive operation of winter road maintenance, less salt is needed overall. The road remains free of snow cover in case of preventive winter road maintenance operation, meaning that passenger cars and trucks pass the road at normal speed, without undesirable acceleration and braking caused by wheels slipping if snow accumulates on the road. Fuel consumption of vehicles passing salted and snow-free road remains unchanged, while fuel consumption increases in case of snow cover. Reduction of environmental burdens in case of such optimized winter road maintenance operation, is shown in this case study. The overall results of the comparative LCA analysis showed that the use of the road-weather information system in road traffic allows for as much as 25% reduction of environmental footprints. In the scenario where the winter service does not use information system the winter service also uses 40% more salt, which is also related with additional environmental impacts. Keywords: LCA, okoljski odtisi, cesta, snežne razmere, preventivno delovanje, promet, poraba goriva, varnost, LCA, environmental impacts, road, snow cover, preventive operation, traffic, fuel consumption, safety Published in DiRROS: 11.12.2023; Views: 347; Downloads: 219
Full text (19,01 MB) This document has many files! More... |
4. Izgradnja lizimetrov za preučevanje izpiranja potencionalno nevarnih snovi iz gradbenih proizvodovJanez Turk, Janko Urbanc, Ana Mladenovič, Alenka Sešek Pavlin, Primož Oprčkal, Karmen Fifer Bizjak, Barbara Likar, Marko Brodnik, Nina Mali, 2020, original scientific article Abstract: Z uporabo recikliranih odpadkov v gradbeništvu nadomeščamo naravne materiale in s tem vzpostavljamo krožno gospodarstvo na lokalnem nivoju. Pomemben vidik je tudi ohranjanje naravnih virov. To je še posebno pereče pri zemeljskih delih (npr. zasipih in nasipih), kjer prihaja do velike porabe materialov. Geotehnični kompoziti iz recikliranih materialov, v primerjavi z naravnimi agregati ali zemljinami, lahko vsebujejo višje celotne koncentracije potencialno nevarnih snovi (težke kovine, klorid, sulfat, fluorid, organska onesnaževala itd.). Pogoj za uporabo takšnih kompozitov je, da so v njih potencialno nevarne snovi imobilizirane in da so zato iz kemijskega vidika trajno inertni. Možni vplivi na okolje, predvsem prenos različnih potencialno nevarnih snovi iz kompozitov v tla oziroma vodonosnik, so običajno ovrednoteni na laboratorijski ravni, medtem ko je njihovo obnašanje v dejanskem okolju slabo proučeno. Zato se pojavljajo zahteve po razvoju občutljivih, zanesljivih in cenovno ter časovno učinkovitih orodij za določitev masnih tokov potencialno nevarnih snovi iz gradbenih proizvodov, na primer geotehničnih kompozitov, pod vplivi različnih okoljskih dejavnikov. V članku predstavljamo postopek vzpostavitve terenskega laboratorija na osnovi sistema "pan" lizimetrov, za zbiranje izcednih voda iz zasipov, ki so bili izdelani iz geotehničnih kompozitov iz recikliranih materialov. Lizimetre smo konstruirali in izvedli tako, da je njihova izgradnja cenovno ugodna, hkrati pa so po svojih dimenzijah dovolj veliki, da reprezentativno odražajo procese v zgrajenih geotehničnih zasipih. Pridobljeni podatki o količini in parametrih izcedne vode bodo služili kot osnova za določanje vodne bilance in za študij imobilizacije potencialno nevarnih snovi v kompozitih. Hkrati bodo uporabljeni kot vhodni podatki za geokemijski numerični model, s katerim bomo simulirali transport potencialno nevarnih snovi, sproščenih iz preučevanih kompozitov, v različnih tipih vodonosnikov (npr. medzrnski in razpoklinski). Keywords: lizimeter, izlužek, okoljski monitoring, geotehnični zasip, odpadki Published in DiRROS: 12.09.2023; Views: 492; Downloads: 237
Full text (2,46 MB) This document has many files! More... |
5. Environmental and biological impact of fly ash and metakaolin-based alkali-activated foams obtained at 70°C and Fired at 1,000°CCristina Leonelli, Janez Turk, Giovanni Dal Poggetto, Michelina Catauro, Katja Traven, Alenka Mauko Pranjić, Vilma Ducman, 2022, original scientific article Abstract: Alkali-activated foams (AAFs) are inorganic porous materials that can be obtained at temperatures well below 100° C with the use of inorganic wastes as aluminosilicate precursors. In this case, fly ash derived from a Slovenian power plant has been investigated. Despite the environmental benefits per se, due to saving of energy and virgin materials, when using waste materials, it is of extreme importance to also evaluate the potential leaching of heavy metal cations from the alkali-activated foams. This article presents an environmental study of a porous geopolymer derived from this particular fly ash, with respect to the leachability of potentially hazardous elements, its environmental toxicity as determined by biological testing, and the environmental impact of its production. In particular, attention was focused to investigate whether or not 1,000 °C-fired alkali- activated fly ash and metakaolin-based foams, cured at 70 °C, are environmentally friendlier options compared to unfired ones, and attempts to explain the rationale of the results were done. Eventually, the firing process at 1,000 ° C, apart from improving technical performance, could reinforce heavy metal cation entrapment within the aluminosilicate matrix. Since technical performance was also modified by addition of different types of activators (K-based or Na-based), as well as by partial replacement of fly ash with metakaolin, a life cycle assessment (LCA) analysis was performed to quantify the effect of these additions and processes (curing at 70 ° C and firing at 1,000 °C) in terms of global warming potential. Selected samples were also evaluated in terms of leaching of potentially deleterious elements as well as for the immobilization effect of firing. The leaching test indicated that none of the alkali-activated material is classified as hazardous, not even the as-received fly ash as component of new AAF. All of the alkali-activated foams do meet the requirements for an inertness. The highest impact on bacterial colonies was found in samples that did not undergo firing procedures, i.e., those that were cured at 70 °C, which induced the reduction of bacterial Enterococcus faecalis viability. The second family of bacteria tested, Escherichia coli, appeared more resistant to the alkaline environment (pH = 10–12) generated by the unfired AAMs. Cell viability recorded the lowest value for unfired alkali-activated materials produced from fly ash and K-based activators. Its reticulation is only partial, with the leachate solution appearing to be characterized with the most alkaline pH and with the highest ionic conductivity, i.e., highest number of soluble ions. By LCA, it has been shown that 1) changing K-based activators to Na-based activators increases environmental impact of the alkali-activated foams by 1%–4% in terms of most of the impact categories (taking into account the production stage). However, in terms of impact on abiotic depletion of elements and impact on ozone layer depletion, the increase is relatively more significant (11% and 18%, respectively); 2) replacing some parts of fly ash with metakaolin also results in relatively higher environmental footprint (increase of around 1%–4%, while the impact on abiotic depletion of elements increases by 14%); and finally, 3) firing at 1,000°C contributes significantly to the environmental footprint of alkali- activated foams. In such a case, the footprint increases by around one third, compared to the footprint of alkali-activated foams produced at 70 ° C. A combination of LCA and leaching/toxicity behavior analysis presents relevant combinations, which can provide information about long-term environmental impact of newly developed waste-based materials. Keywords: alkali activated materials, geopolimers, leaching, LCA Published in DiRROS: 20.06.2023; Views: 472; Downloads: 250
Full text (3,42 MB) This document has many files! More... |
6. Environmental acceptability of geotechnical composites from recycled materials : comparative study of laboratory and field investigationsMarija Đurić, Vesna Zalar Serjun, Ana Mladenovič, Alenka Mauko Pranjić, Radmila Milačič, Janez Ščančar, Janko Urbanc, Nina Mali, Alenka Sešek Pavlin, Janez Turk, Primož Oprčkal, 2023, original scientific article Abstract: The environmental properties of three geotechnical composites made by recycling wastes were investigated on a laboratory scale and in the field with the use of lysimeters designated for the revitalization of degraded mining sites. Composites were prepared by combining the mine waste with paper-mill sludge and foundry sand (Composite 1), with digestate from municipal waste and paper ash (Composite 2), and with coal ash, foundry slag and waste incineration bottom ash (Composite 3). The results of laboratory leaching tests proved that Composites 1 and 3 are envi- ronmentally acceptable, according to the legislative limits, as the potentially hazardous substances were immobilized, while in Composite 2, the legislative limits were exceeded. In the field lysimeters, the lowest rate of leaching was determined for optimally compacted Composites 1 and 3, while for Composite 2 the leaching of Cu was high. This study proved that optimally installed Composites 1 and 3 are environmentally acceptable for use in construction as an alternative to virgin materials, for the revitalization of degraded mining sites or, along with Composite 2, for closure operations with landfills. In this way, locally available waste streams are valorised and channelized into a beneficial and sustainable recycling practice. Keywords: waste, recycling, lysimeter, potentiali hazardous substances, immobilization, revitalisation, environmental, open access Published in DiRROS: 29.05.2023; Views: 504; Downloads: 368
Full text (3,42 MB) This document has many files! More... |