1. Rapid immobilisation of chemical reactions in alkali-activated materials using solely microwave irradiationAnže Tesovnik, Barbara Horvat, 2024, izvirni znanstveni članek Povzetek: Efflorescence, a time-dependent and water-driven phenomenon, is a major concern inalkali-activated materials (AAMs), impacting their practical use and preservation in a time-frozen state for post-characterisation. Although a method for stopping chemical reactions in conventional cements exists, it is time-consuming and not chemical-free. Therefore, this study explored the effects of low-power microwave-induced dehydration on efflorescence, mechanical performance, and structural integrity in AAMs, to create an alternative and more “user-friendly” dehydration method. For this purpose, several mixtures based on secondary raw (slag, fly ash, glass wool, and rock wool) and non-waste (metakaolin) materials were activated with a commercial Na-silicate solution in ratios that promoted or prevented efflorescence. Characterisation techniques, including Fourier-transform infrared spectroscopy and X-ray diffraction, showed that microwave dehydration effectively removed water without altering crystallinity, while mercury intrusion porosimetry and compressive strength tests confirmed increased porosity. In addition to being an efficient, time-saving, and solvent-free manner of stopping the reactions in AAMs, microwave irradiation emerged as an innovative, chemical-free method for evaluating curing finalisation and engineering foams in a stage when all other existing methods fail. However, the artificially provoked efflorescence in aged dehydrated AAMs connected the slipperiness of AAM with the instant extraction of Na, which raised the need for further research into alternative alkali replacements to evaluate the practical use of AAM.
Ključne besede: materials chemistry, alkali-activated materials, geopolymers, slag, fly ash, rock wool, glass wool, metakaolin, microwave irradiation, dehydration, stopping chemical reactions, efflorescence
Objavljeno v DiRROS: 23.12.2024; Ogledov: 165; Prenosov: 75
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2. Dehydration with microwave irradiationAnže Tesovnik, Barbara Horvat, 2024, zaključena znanstvena zbirka raziskovalnih podatkov Povzetek: The dataset supports the results shown in the tables and figures in the article entitled “Rapid immobilisation of chemical reactions in alkali-activated materials using solely microwave irradiation” (doi: https://doi.org/10.3390/min14121219). It contains measurements of mechanical and structural evaluation, as well as chemical and mineralogical analysis.
Ključne besede: measurments, alkali-activated materials, geopolymers, slag, fly ash, rock wool, glass wool, metakaolin, microwave irradiation, dehydration, stopping of chemical reactions, efflorescence
Objavljeno v DiRROS: 12.08.2024; Ogledov: 197; Prenosov: 11422
 Raziskovalni podatki (4,87 MB) |
3. Why geopolymers and alkali-activated materials are key components of a sustainable world : a perspective contributionWaltraud M. Kriven, Cristina Leonelli, John L. Provis, Aldo R. Boccaccini, Cyril Attwell, Vilma Ducman, Claudio Ferone, Sylvie Rossignol, Tero Luukkonen, Jannie S. J. Van Deventer, José V. Emiliano, Jérôme E. Lombardi, 2024, izvirni znanstveni članek Povzetek: This perspective article delves into the transformative potential of alkali-activated materials, acid-activated materials, and geopolymers in mitigating climate change and market challenges. To harness the benefits of these materials, a comprehensive strategy is proposed. This strategy aims to integrate these materials into existing construction regulations, facilitate certification, and promote market access. Emphasizing research and innovation, the article advocates for, increased funding to refine the chemistry and production of these materials, prioritizing low-cost alternatives and local waste materials. Collaboration between academia and industry is encouraged to expedite technological advances and broaden applications. This article also underscores the need to develop economic and business models emphasizing the long-term benefits of these materials, including lower life-cycle costs and reduced environmental impact. Incentivizing adoption through financial mechanisms like tax credits and subsidies is suggested. The strategy also includes scaling up production technology, fostering industrial collaboration for commercial viability, and developing global supply chains. Educational programs for professionals and regulators are recommended to enhance awareness and adoption. Additionally, comprehensive life-cycle assessments are proposed to demonstrate environmental benefits. The strategy culminates in expanding the applications of these materials beyond construction, fostering international collaboration for knowledge sharing, and thus positioning these materials as essential for sustainable construction and climate change mitigation.
Ključne besede: geopolymers, alkali activated materials, perspective
Objavljeno v DiRROS: 15.04.2024; Ogledov: 570; Prenosov: 535
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4. Innovative pre-fabricated components including different waste construction materials reducing building energy and minimising environmental impacts (InnoWEE)Elena Loredana Fodor, Vilma Ducman, Giovanni Ferrarini, Sergio Tamburini, Constantinos Tsoutis, Francesca Becherini, Antonio Garrido-Marijuán,, Giulia Mezzasalma, Leonardo Rossi, Emil Lezak, Adriana Bernardi, 2019, objavljeni znanstveni prispevek na konferenci Povzetek: InnoWEE is a four-year project (from 2016 to 2020) financed by the European Community that involves ten partners from different European countries, as Greece, Italy, Belgium, Romania, Slovenia, Spain and Poland. The aim is to use the waste materials coming from construction and demolition processes of buildings and include them into a geopolymeric matrix with the purpose of producing prefabricated panels for different applications. Construction and demolition waste (CDW) materials with suitable characteristics have been selected to develop high performance geopolymeric panels for building walls envelopes and radiant panels for indoor walls and ceilings with low environmental impact. Field tests will be carried out in different sites in Europe characterized by different climatic conditions to check the simplicity of the installation procedure and the performance of the panels in terms of energy efficiency and environmental impact.
Ključne besede: prefabriced elements, geopolymers, CDW
Objavljeno v DiRROS: 08.03.2024; Ogledov: 552; Prenosov: 255
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5. Life cycle assessment of prefabricated geopolymeric façade cladding panels made from large fractions of recycled construction and demolition wasteDavor Kvočka, Anja Lešek, Friderik Knez, Vilma Ducman, Matteo Panizza, Constantinos Tsoutis, Adriana Bernardi, 2020, izvirni znanstveni članek Povzetek: The construction and demolition sector is one of the biggest consumers of natural resources in the world and consequently, one of the biggest waste producers worldwide. The proper management of construction and demolition waste (CDW) can provide major benefits for the construction and recycling industry. However, the recycling rate of CDW is relatively low, as there is still a lack of confidence in the quality of recycled CDW materials. Therefore, new research projects are looking for innovative solutions within recycling of CDW in order to overcome uncertainties currently associated with the use of construction products made from recycled or re-used CDW. In this paper, a “cradle-to-cradle” life cycle assessment (LCA) study has been conducted to investigate the environmental performance of the prefabricated geopolymeric façade cladding panels made from large fractions of CDW. The LCA results indicate that the majority of the environmental burden arises within the manufacturing stage; however, the environmental burden can be reduced with simple optimisation of the manufacturing process. Furthermore, the environmental impact of the prefabricated geopolymeric façade cladding panels is generally lower than the environmental burden associated with the façade cladding panels made from virgin materials.
Ključne besede: construction and demolition waste, alkali activated materials, geopolymers, LCA
Objavljeno v DiRROS: 24.08.2023; Ogledov: 718; Prenosov: 358
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6. Characterization of fly ash alkali activated foams obtained using sodium perborate monohydrate as a foaming agent at room and elevated temperaturesLidija Korat, Vilma Ducman, 2020, izvirni znanstveni članek Povzetek: Alkali activated foams have been extensively studied in recent years, due to their high performance and low environmental footprint compared to foams produced via other methods. Three types of fly ash differing in chemical and mineralogical composition and specific surface were used to synthesize alkali activated foams. Sodium perborate monohydrate was added as a foaming agent and sodium dodecyl sulphate as a stabilizing agent. Foams were characterized at room temperature and after exposure to an elevated temperature (1,000 °C). Densities from 1.2 down to 0.3 g/cm 3 were obtained, depending on the type of fly ash and quantity of foaming agent added. Correspondingly, compressive strength ranged from 1 to 6 MPa. Comparing all three fly ashes the most favorable results, in terms of density and corresponding compressive strength, were achieved from the fly ash with the highest amounts of SiO 2 and Al2 O 3 , as well as the highest amorphous phase content i.e., RI fly ash. Furthermore, after firing to 1,000 °C, the density of samples prepared using fly ash RI remained approximately the same, while the compressive strength increased on average by 50%. In the other two types of fly ash the density increased slightly after firing, due to significant shrinkage, and compressive strength increased by as much as 800%. X-ray powder diffraction analysis confirmed the occurrence of a crystallization process after firing to 1,000 ° C, which resulted in newly formed crystal phases, including nepheline, sodalite, tridymite, and gehlenite.
Ključne besede: foamed alkali activated materials, geopolymers, properties, micro-CT
Objavljeno v DiRROS: 22.08.2023; Ogledov: 688; Prenosov: 412
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7. Up-scaling and performance assessment of façade panels produced from construction and demolition waste using alkali activation technologyAna Frankovič, Vilma Ducman, Sabina Dolenec, Matteo Panizza, Sergio Tamburini, Marco Natali, Katherine-Maria Pappas, Constantinos Tsoutis, Adriana Bernardi, 2020, izvirni znanstveni članek Povzetek: Novel prefabricated insulating façade panels were developed from construction and demolition waste (CDW) aggregates under the framework of the European H2020 project InnoWEE. These non-structural components, aimed at improving the thermal efficiency of existing buildings, consist of an insulating plate covered by a facing layer made of CDW aggregates bound with metakaolin, furnace slag and class F fly ash activated by a potassium silicate solution. The paper presents the design and assessment of the binder and panels for exterior use, taking into account mechanical performance, behaviour in the presence of water and durability issues. Testing was carried out on both laboratory prototypes and panels from the pilot industrial production.
Ključne besede: construction and demolition waste, alkali activated materials, geopolymers, properties, up-scalimg
Objavljeno v DiRROS: 21.08.2023; Ogledov: 662; Prenosov: 410
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8. Optimization and mechanical-physical characterization of geopolymers with construction and demolition waste (CDW) aggregates for construction productsMatteo Panizza, Marco Natali, Enrico Garbin, Vilma Ducman, Sergio Tamburini, 2020, izvirni znanstveni članek Povzetek: The paper presents the mechanical and physical characterization of a metakaolin-slag-fly ash-potassium silicate geopolymer mortar embedding inorganic recycled aggregates from Construction and Demolition Waste (CDW). The binder was holistically optimized to comply with the pilot plant requirements for producing architectural panels of satisfactory quality, among them: reduced viscosity, minimum open time of 1 h, use of commercial reagents, sufficient strength and limited shrinkage. Size and aspect ratio of small scale cylindrical specimens were investigated in compression, comparing the performance of tested geopolymers to available provisions for natural rocks, cement concrete and mortars. Empirical correlations between compressive and splitting tensile strength were calibrated through the results of about 130 geopolymer mixtures produced in former and current activities. Lastly, the suitability of reusing geopolymers at their end-of-life as recycled aggregates in a new geopolymer production was preliminarily assessed to explore the feasibility of a closed-loop process.
Ključne besede: construction and demolition waste, alkali activated materials, geopolymers, properties
Objavljeno v DiRROS: 17.08.2023; Ogledov: 776; Prenosov: 413
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9. RILEM TC 247-DTA round robin test : sulfate resistance, alkali-silica reaction and freeze-thaw resistance of alkali-activated concretesFrank Winnefeld, Gregor J. G. Gluth, Susan A. Bernal, Maria Chiara Bignozzi, Lorenza Carabba, Sundararaman Chithiraputhiran, Alireza Dehghan, Sabina Dolenec, Katja Dombrowski-Daube, Ashish Dubey, Vilma Ducman, Yu Jin, Karl Peterson, Stephen Dietmar, John L. Provis, 2020, izvirni znanstveni članek Povzetek: The RILEM technical committee TC 247-DTA ‘Durability Testing of Alkali-Activated Materials’ conducted a round robin testing programme to determine the validity of various durability testing methods, originally developed for Portland cement based-concretes, for the assessment of the durability of alkali-activated concretes. The outcomes of the round robin tests evaluating sulfate resistance, alkali-silica reaction (ASR) and freeze–thaw resistance are presented in this contribution. Five different alkali-activated concretes, based on ground granulated blast furnace slag, fly ash, or metakaolin were investigated. The extent of sulfate damage to concretes based on slag or fly ash seems to be limited when exposed to an Na2SO4 solution. The mixture based on metakaolin showed an excessive, very early expansion, followed by a dimensionally stable period, which cannot be explained at present. In the slag-based concretes, MgSO4 caused more expansion and visual damage than Na2SO4; however, the expansion limits defined in the respective standards were not exceeded. Both the ASTM C1293 and RILEM AAR-3.1 test methods for the determination of ASR expansion appear to give essentially reliable identification of expansion caused by highly reactive aggregates. Alkali-activated materials in combination with an unreactive or potentially expansive aggregate were in no case seen to cause larger expansions; only the aggregates of known very high reactivity were seen to be problematic. The results of freeze–thaw testing (with/without deicing salts) of alkali-activated concretes suggest an important influence of the curing conditions and experimental conditions on the test outcomes, which need to be understood before the tests can be reliably applied and interpreted.
Ključne besede: alkali-activated materials/geopolymers, sulphate resistance, alkali silica reactivity, freeze-thaw resistance, Rilem TC
Objavljeno v DiRROS: 17.08.2023; Ogledov: 844; Prenosov: 433
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10. High temperature resistant fly-ash and metakaolin-based alkali-activated foamsKatja Traven, Mark Češnovar, Srečo D. Škapin, Vilma Ducman, 2021, izvirni znanstveni članek Povzetek: Alkali-activated foams (AAFs) present one of the most promising materials for use in the construction sector. Their main advantages lie in their utilization of waste material and their ability to form at temperatures well below 100 °C, while still competing in performance with foamed glass or ceramics. The present body of research has focused on improving the thermal stability of fly-ash foams by i) adding metakaolin, and ii) changing the activator from sodium-based to potassium-based components. It has been confirmed that a certain increase in thermal resistance is achieved through the addition of metakaolin while changing activators played a crucial role. While sodium-based AAFs without metakaolin start to shrink at approximately 600 °C, samples that have had metakaolin added start to shrink at approximately 700 °C. Samples without metakaolin that have used a potassium activator start to shrink at approximately 800 °C, whereas potassium-based samples with the addition of metakaolin start to shrink at approximately 900 °C.
Ključne besede: alkali activated materials, geopolymers, high temperature, resistance, foams
Objavljeno v DiRROS: 01.08.2023; Ogledov: 1035; Prenosov: 619
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