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Povzetek: Artificial aggregates offer a sustainable solution to large-scale waste utilization and the increasing demand for limited natural aggregates. This study extends the understanding of the production of artificial lightweight aggregates with a variable rotation speed approach based solely on biomass fly ash (BFA) alkali-activated materials (AAMs). Systematic variation of alkali content and solution density at a constant water-to-solids ratio showed that alkali concentration significantly influences granulation beyond what can be explained by water availability. The interplay between alkali activation and carbonation was investigated using different mix designs and curing conditions, as well as comparing simultaneous curing carbonation with post-cure carbonation. The results were evaluated with regard to the effects on the macro- and microstructural properties as well as on the leaching behavior. Prolonged carbonation initiated after aggregate formation resulted in premature depletion of Ca, limiting the development of C-A-S-H gels and increasing microporosity, leading to a reduction in mechanical properties. In contrast, post-curing carbonation maintained a compressive strength of over 1 MPa while still allowing carbonation benefits, resulting in compressive strengths comparable to lightweight expanded clay aggregates. Carbonation also proved to be an effective leaching mitigation strategy by stabilizing heavy metals through both physical encapsulation and chemical pH regulation. These results underline the importance of carbonation timing in high Ca AAMs and highlight lightweight aggregates as a viable pathway for BFA valorization, CO₂ sequestration and sustainable construction applications. This approach offers an alternative valorization strategy for BFA facing regulatory restrictions for direct use in cement, while contributing to carbon capture and circular economy initiatives.
Ključne besede: artificial aggregates, lightweight aggregates, biomass ash, alkali-activated materials, leaching, carbonation
Objavljeno v DiRROS: 18.07.2025; Ogledov: 472; Prenosov: 487
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Povzetek: Building and civil engineering conventional inorganic binding materials represent a significant burden for the environment, leading to the search for more sustainable materials. One of the potential solutions is alkali-activated materials (AAMs), which can be made solely from waste materials and at lower temperatures. However, reaction rate and solidification time depend on the precursor used. To enhance the speed of solidification, the curing temperature can be increased, but from the inside out not to create the crust on the surface, which would hinder the dehydration. Therefore, three mixtures of alkali-activated glass wool, a slow-in-alkali media solidifying precursor, were irradiated with low- and high-power microwaves in the late curing stage till complete dehydration, to determine the influence of artificial volumetric solidification onto thermomechanical behaviour of the AAM. As the electromagnetic power increased, the damages in the AAM became more severe, resulting in a reduction in mechanical strength.
Ključne besede: microwave irradiation, electromagnetic dehydration, glass wool, alkali-activated materials, mechanical performance
Objavljeno v DiRROS: 07.04.2025; Ogledov: 668; Prenosov: 479
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Povzetek: This research aimed to investigate the potential of using alkali activation technology to valorize steel slag and bauxite residue for the production of high-performance pavement blocks. By utilizing these industrial by-products, the study seeks to reduce their environmental impact and support the development of sustainable construction materials. Lab-scale testing showed that bauxite pavers showed a decrease in mechanical strength with increasing replacement of ordinary Portland cement. Partial replacement up to 20% still exceeded 30 MPa in compressive strength. Steel slag-based pavers achieved the 30 MPa threshold required for the application with selected mix designs. Pilot-scale production-optimized formulations and standards testing, including freeze–thaw resistance, confirmed the technical viability of these products. Life cycle analysis indicated a 25–27% reduction in CO2 emissions for slag-based tiles compared to traditional concrete tiles. Moreover, using industrial residue reduced mineral resource depletion. This study examined the properties of the resulting alkali-activated binders, their ecological benefits, and their performance compared to conventional materials. Through a comprehensive analysis of these applications, our research promotes the circular economy and the advancement of sustainable construction products.
Ključne besede: alkali-activated materials, building materials, bauxite residue, steel slag, pavers
Objavljeno v DiRROS: 20.01.2025; Ogledov: 851; Prenosov: 454
Celotno besedilo (4,04 MB)
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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: 1259; Prenosov: 11675
Raziskovalni podatki (4,87 MB)

Ključne besede: alkalijsko aktivirani materiali, odpadni materiali, mehanske trdnosti
Objavljeno v DiRROS: 11.03.2024; Ogledov: 7573; Prenosov: 0
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