2425 s2 - Biobased Wet Cell: verschil tussen versies

Versie van 22 okt 2025 23:39

About this project

Start date:
Project description:	The construction industry is undergoing a critical transformation as it faces mounting pressure to meet climate targets and material sustainability goals. One of the most urgent challenges lies in reducing the carbon emissions associated with conventional cement-based construction materials, which remain the dominant yet environmentally detrimental option in structural and non-structural applications. Although alkali-activated materials (AAMs) such as granulated blast furnace slag (GBFS)-based geopolymers have emerged as promising low-CO₂ alternatives, their widespread implementation is hindered by key durability and processing limitations—particularly in high-humidity or wet environments. This study seeks to move beyond empirical tweaking and instead focus on uncovering fundamental mechanisms that affect geopolymer stability and functionality in humid conditions. Ultimately, it aims to deliver a modified mixture and curing method capable of producing a geopolymer tile with low porosity, minimal efflorescence, consistent structural performance, and resilience in wet environments. the central research question is: How can the composition and curing conditions of a slag-based geopolymer be optimized to significantly improve water resistance and alkali stability, without compromising mechanical performance, in high-humidity environments?
Outcomes:	The cured material does not exhibit a highly polymerized geopolymeric alumino-silicate structure. XRF analysis revealed a lower-than-expected alumina content (~8% vs. 12%), resulting in a high Si/Al ratio (~4.67), which limits stable geopolymer formation. This leads to weaker silica-rich gels prone to alkali leaching. Efflorescence (sodium carbonate) indicates strong alkali migration, while leachates consist mostly of amorphous silica. Unexpected mass gain after drying is likely due to CO₂ reacting with residual sodium silicates, forming stable gels, making gravimetric analysis unreliable. Recommendations: Adjust mix design by adding aluminosilicates (e.g., metakaolin or kaolinite) to reduce the Si/Al ratio to the optimal range (1.75–2.25). Investigate alternative, low-energy aluminosilicate sources like volcanic ash, pumice, or perlite. Use MAS NMR to better understand the structure and behavior of silicon and aluminum species in both the cured material and the silicate solutions.
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 have emerged as promising low-CO₂ alternatives, their widespread implementation is hindered by key durability and processing limitations—particularly in high-humidity or wet environments. This study seeks to move beyond empirical tweaking and instead focus on uncovering fundamental mechanisms that affect geopolymer stability and functionality in humid conditions. Ultimately, it aims to deliver a modified mixture and curing method capable of producing a geopolymer tile with low porosity, minimal efflorescence, consistent structural performance, and resilience in wet environments. the central research question is: How can the composition and curing conditions of a slag-based geopolymer be optimized to significantly improve water resistance and alkali
 stability, without compromising mechanical performance, in high-humidity environments?
-|Outcomes=The cured material does not exhibit a highly polymerized geopolymeric alumino-silicate structure. XRF analysis revealed a lower-than-expected alumina content (~8% vs. 12%), resulting in a high Si/Al ratio (~4.67), which limits stable geopolymer formation. This leads to weaker silica-rich gels prone to alkali leaching.
+|outcomes=The cured material does not exhibit a highly polymerized geopolymeric alumino-silicate structure. XRF analysis revealed a lower-than-expected alumina content (~8% vs. 12%), resulting in a high Si/Al ratio (~4.67), which limits stable geopolymer formation. This leads to weaker silica-rich gels prone to alkali leaching.
 Efflorescence (sodium carbonate) indicates strong alkali migration, while leachates consist mostly of amorphous silica. Unexpected mass gain after drying is likely due to CO₂ reacting with residual sodium silicates, forming stable gels, making gravimetric analysis unreliable.