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2. Analysis of alkali-activated mineral wool-slag binders : evaluating the differences between one-part and two-part variationsElijah Adesanya, Rawia Dabbebi, Christine Rößler, Majda Pavlin, Zhenming Li, Tero Luukkonen, Juho Yliniemi, Mirja Illikainen, 2024, izvirni znanstveni članek Povzetek: Two synthesis pathways (one- and two-part) in alkali-activated binders were compared using ground granulated blast furnace slag (GGBFS), mineral wool (MW) activated using dry and liquid alkali activators with similar Na2O/SiO2 modulus. The effect of activator type on reaction kinetics, strength development, setting times, and durability shows that one-part synthesis does not only improve early strength, but also provide better durability properties. While the highest compressive strength (56 MPa, 90 days) was achieved for the one-part mix (DM), the reaction products (presence of Mg–Al layered double hydroxide and C–S–H-like phases) observed for both mortar mixes were similar. The DM mortars showed better resistance to sulfate attack than two-part mix (WM) mortars and sets faster. The results highlight the significance of the one-part pathways in the synthesis of alkali-activated materials. Ključne besede: recycling, alkali activated material, mineral wool Objavljeno v DiRROS: 11.03.2024; Ogledov: 100; Prenosov: 73 Celotno besedilo (1,28 MB) Gradivo ima več datotek! Več... |
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4. Characterisation of a 3D-printed alkali-activated material based on waste mineral wool at room and elevated temperaturesMajda Pavlin, Barbara Horvat, Romana Cerc Korošec, Rok Capuder, Lidija Korat, Vilma Ducman, 2024, izvirni znanstveni članek Ključne besede: recycling, alkalijsko aktivirani materiali, 3D print, mineralna volna Objavljeno v DiRROS: 25.01.2024; Ogledov: 216; Prenosov: 104 Celotno besedilo (17,73 MB) Gradivo ima več datotek! Več... |
5. Fibre reinforced alkali-activated rock woolMajda Pavlin, Barbara Horvat, Vilma Ducman, 2022, objavljeni znanstveni prispevek na konferenci Povzetek: Mineral wool, i.e. rock and glass wool, represents considerable challenge after its functional-time runs out due to its small density leading to large volume consumption during transport and in landfills where it usually ends. Because rock wool is mineralogically and chemically a promising precursor material for alkali-activation, it was milled from few centimetres-decimeters long fibres to micron-sized fibres. Since fibres in alkali-activated materials generally show an increase in mechanical strength, especially the bending strength, 1 m% of additional fibres (basalt, cellulose (2 types), glass, polypropylene, polyvinyl alcohol and steel fibres) was used in the alkali mixture, that was curred at 40 °C for 3 days. Time dependence of the mechanical strengths of alkali- activated materials with and without additional fibres was followed. Maximal increase of compressive and bending strength after 28 days was reached with polypropylene fibres, i.e. it was 20% and 30% higher than compressive and bending strength of alkali- activated material without additional fibres respectively. Ključne besede: secondary raw material, alkali activated material, foaming, homogenization, mechanical strength Objavljeno v DiRROS: 21.12.2023; Ogledov: 215; Prenosov: 71 Celotno besedilo (8,39 MB) Gradivo ima več datotek! Več... |
6. Influence of homogenization of alkali-activated slurry on mechanical strengthBarbara Horvat, Mark Češnovar, Katja Traven, Majda Pavlin, Katja Koenig, Vilma Ducman, 2022, objavljeni znanstveni prispevek na konferenci Povzetek: Alkali-activated materials are promising materials for the construction industry due to the accessibility of the precursors, which are mainly secondary industrial by-products, and their cost- effective and energy-efficient production. Although these materials are not new, some of the parameters in the technological process are not yet fully understood and tested. Therefore, in this paper in the means of mechanical strength, the preparation of alkali-activated pastes by using a three-roll mill homogenization method is discussed. The influence of homogenization of alkali- activated slurry has been evaluated on different waste materials (fly ash, fly ash with metakaolin, slag mixture (electric arc furnace slag and ladle slag), glass wool, waste green ceramics), which are treated with different alkali activators (NaOH, commercial sodium silicate solution, laboratory-produced alkali activators based on waste cathode- ray tube glass) with different curing regimes (60 °C and 70 °C) and different drying methods (drying at room temperature, drying at 105 °C). The viscosity of the slurry before homogenization was higher than after homogenization, the distribution of elements was more uniform and the compressive strength higher in all homogenized alkali activated materials, regardless of other parameters. Ključne besede: secondary raw material, alkali activated material, foaming, homogenization, mechanical strength Objavljeno v DiRROS: 21.12.2023; Ogledov: 233; Prenosov: 76 Celotno besedilo (15,82 MB) Gradivo ima več datotek! Več... |
7. Pilot production of façade panels : variability of mix designMajda Pavlin, Barbara Horvat, Vilma Ducman, 2023, objavljeni znanstveni prispevek na konferenci Povzetek: As part of the WOOL2LOOP project, the Slovenian National Building and Civil Engineering Institute (ZAG), in collaboration with Termit d.d. were responsible for the production of façade panels. An initial mix design was developed at ZAG, where alkali-activated façade panels were produced, primarily from stone wool waste, while production took place at Termit. The mix design was changed twice during the pilot production, before a final product with suitable durability was developed. A compressive strength of up to 60 MPa and bending strength of approximately 20 MPa was achieved. The mechanical properties, however, varied, due to the unevenly milled batches of the milled mineral wool. Milling on a larger scale is very challenging, and it is difficult to obtain consistent quality of the milled material. Once the correct curing process had been found, however, the panels produced showed good performance. Moreover, the results from leaching tests showed that the elevated concentrations of certain elements (Cr, As and Mo) did not exceed the legal limits for non- hazardous waste. Ključne besede: waste mineral wool, alkali activated material, façade panels, pilot production, circular economy Objavljeno v DiRROS: 28.11.2023; Ogledov: 265; Prenosov: 98 Celotno besedilo (1000,34 KB) Gradivo ima več datotek! Več... |
8. Microwave irradiation of alkali - activated metakaolin slurryBarbara Horvat, Branka Mušič, Majda Pavlin, Vilma Ducman, 2023, objavljeni znanstveni prispevek na konferenci Povzetek: The building and civil engineering industry generates more than 40% of man-caused carbon emissions, consumes a lot of energy just to produce building materials, generates a large amount of waste through construction and demolition, and consumes a large amount of natural resources. One of the possible solutions is to use alkali-activated materials, which can use waste instead of raw materials and are produced at lower temperatures, with less energy consumption and in less time than traditional building products. All of this lowers the carbon footprint, which could be further reduced by the timely-short implementation of microwave irradiation in the early stages of alkali-activation synthesis. Therefore, metakaolin activated with Na-water glass in a theoretically optimal ratio was irradiated with microwaves of 2.45 GHz at powers of 100 W and 1000 W for 1 min, and compared to non-irradiated reference cured only at room conditions. Samples prepared at higher power, i.e., 1000 W, solidified completely and foamed. TG-DTA was performed on all samples in the early stages of curing, mechanical strengths were measured on 3 and 28-day- old samples, and leaching tests on aged samples. Ključne besede: metakaolin, alkali activated material, alkali activated foams, microwave irradiation Objavljeno v DiRROS: 28.11.2023; Ogledov: 238; Prenosov: 103 Celotno besedilo (791,17 KB) Gradivo ima več datotek! Več... |
9. Radioimunološko določanje luteinizirajočega hormona (LH), folikel stimulirajočega hormona (FSH) in testosterona v krvi in spermi fertilnih in infertilnih moškihElko Borko, Radovan Breznik, Ksenija Ogrizek-Pelkič, Majda Rižnik, Jurij Šubic, Rudi Turk, 1978, izvirni znanstveni članek Povzetek: Avtorji poročajo o svojih izkušnjah z določanjem LH, FSH in testosterona v krvi in v spermi pri fertilnih in infertilnih moških. Naše dosedanje preiskave so pokazale, da je količina FSH v krvi v primeru okvarjene spermatogeneze povečana. Vrednosti LH so v spermi višje kot statistično signifikantne korelacije glede na spermatogenezo. Avtorji načrtujejo nadaljne raziskave o gibanju teh hormonov v krvi in spermi pri različnih oblikah okvarjene sprematogeneze. Objavljeno v DiRROS: 14.09.2023; Ogledov: 197; Prenosov: 64 Celotno besedilo (350,78 KB) |
10. Evaluation of locally available amorphous waste materials as a source for alternative alkali activatorsKatja Koenig, Katja Traven, Majda Pavlin, Vilma Ducman, 2021, izvirni znanstveni članek Povzetek: The production of alkali-activated materials with excellent mechanical performance requires the use of waterglass, which has a significant carbon footprint. Such materials can have a lower carbon footprint if we replace water glass with alternative activators sourced from waste. In this study, we assessed the suitability of locally available amorphous waste materials (stone wool, glass wool, bottle glass and cathode-ray tube glass) as a source for the preparation of alternative alkali activators. We quantified the amount of silicon and aluminium dissolved in the activator solutions via inductively coupled plasma-optical emission spectrometry. The alternative activators were then used to produce alkali-activated fly ash and slag. The compressive strength values of alkali-activated fly ash specimens upon the addition of NaOH, water glass and the most promising alternative activator were 38.98 MPa, 31.34 MPa and 40.37 MPa, respectively. The compressive strength of slag specimens activated with alternative activators with the highest concentration of dissolved silicon (21 g/L) was, however, 70% higher than the compressive strength of slag specimens activated with only 10 M sodium hydroxide. The compressive strength of slag specimens with the addition of the most promising alternative activator was significantly lower (3.5 MPa) than the compressive strength of those that had been activated by commercial water glass (34.3 MPa). Ključne besede: alkalijsko aktivirani materiali, alternativni aktivatorji, lastnosti, alkali activated materials/geopolimers, alternative activators, properties Objavljeno v DiRROS: 22.08.2023; Ogledov: 218; Prenosov: 147 Celotno besedilo (6,02 MB) Gradivo ima več datotek! Več... |