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Povzetek: This study explores the potential of hydrothermally treated waste glass for producing foamed glass using a carbonaceous foaming agent (glycerol) in an air atmosphere. The objective was to assess the feasibility of this alternative route for producing sustainable, lightweight materials with reduced energy and material inputs by repurposing cathode ray tube panels (CRT), flint glass (FG), and mixed-color container glass (MCG). Investigated glass powders were treated in a saturated steam atmosphere inside a pressure vessel and characterized using Xray diffraction and Fourier-transform spectroscopy to identify structural changes. The foaming behavior of hydrothermally treated waste was analyzed through heating stage microscopy and thermogravimetric analysis coupled with mass spectrometry. The foamed glass samples were further assessed for density and thermal conductivity. The results demonstrate that hydrothermal treatment significantly influences the foaming process. Glass powders with higher content of structurally bonded water exhibit lower sintering temperature and pronounced expansion after the hydrothermal treatment. A higher hydration level reduced the onset foaming temperature and facilitated higher expansion. Additionally, combining hydrothermally treated powders with glycerol as a foaming agent enabled effective expansion, even in an air atmosphere, achieving density as low as 108 kg m-3. The results of this study suggest that hydrothermal treatment of waste glasses enables the implementation of carbonaceous foaming agents in the air atmosphere and could thus offer an alternative route for the foaming of glass.
Ključne besede: foamed glass, waste glass, hydrothermal treatment
Objavljeno v DiRROS: 18.11.2025; Ogledov: 359; Prenosov: 128
Celotno besedilo (5,56 MB)
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Povzetek: This literature review critically examines the incorporation of mineral wool waste (MWW), a byproduct of insulation materials, into new construction materials as a sustainable recycling strategy. Covering research published between 2000 and 2025, the review focuses on the effects of MWW on various material properties and performance, including concrete, mortar, alkali-activated materials (AAMs), geopolymers (GPs), building ceramics, and asphalt. Experimental evidence demonstrates that MWW can enhance or alter the performance of these materials, offering promising opportunities for waste valorization. The review also identifies challenges related to optimizing material compositions and production methods, and highlights the need for further research to facilitate the industrial-scale application of MWW-recycled construction materials. By synthesizing current knowledge, this work aims to inform sustainable development and circular economy practices in the construction sector.
Ključne besede: mineral wool waste, rock wool, glass wool, recycling, sustainability, construction and demolition waste
Objavljeno v DiRROS: 19.09.2025; Ogledov: 464; Prenosov: 200
Celotno besedilo (7,16 MB)
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Povzetek: Alkali-activated binders are an environmentally friendly alternative to Portland cement, particularly when locally-available raw materials are used. It is well known that alkali activation with a sodium silicate activator generates a hardened binder with higher compressive strength than a binder hardened with sodium hydroxide. As the alkali-silicate activators are produced through energy extensive processes, and their use can significantly increase the carbon footprint of the final products, it is of great significance to develop alternative alkaline activators based on locally-available waste materials. This article assesses the potential to apply waste bottle glass and waste cathode-ray tube (CRT) glass to synthesise alternative alkali activators by the hydrothermal method. Inductively coupled plasma-optical emission spectrometry (ICP-OES) was used to determine silicon and aluminium content in the alternative activators. The influence of dissolution process parameters (time, temperature, particle size) on the concentrations of silicon and aluminium in the alternative activators was investigated. The alternative activators with silicon concentration up to 19 g/L and aluminium concentration up to 0.9 g/L were prepared at T = 120 °C and boiling time 24 h. The alternative alkali activators and, for comparison, also commercial sodium silicate were used in the alkali activation of fly ash powder. The formed pastes were cured at 70 °C for 72 h. Mechanical strength measurements indicated that alkali activation of fly ash with the optimal alternative activator yielded hardened paste with compressive strength of 33 MPa. However, the compressive strength of hardened paste prepared from fly ash and commercial sodium silicate reached 70 MPa. Part of this difference can be ascribed to the lower density of hardened pastes prepared with alternative activators.
Ključne besede: alkali -activated materials, alternative alkali activators, waste bottle glass, waste cathode -ray tube glass, fly ash, hydrothermal method
Objavljeno v DiRROS: 25.01.2024; Ogledov: 4167; Prenosov: 908
Celotno besedilo (14,96 MB)
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