In this study, the effect of different types of aluminosilicates on the thermo-mechanical properties of metakaolinite-based geopolymer binders and composites was examined. The metakaolinite-based geopolymer binders and composites were produced from three different types of aluminosilicates (one metakaolin and two calcined claystones) and a potassium alkaline activator. Chamotte was added as a filler, amounting to 65% by volume, to create geopolymer composites. Geopolymer binders were characterized by X-ray diffraction, rotary rheometer and scanning electron microscopy. The mechanical properties, thermal dilatation and thermal conductivity were investigated on geopolymer composites with three different aluminosilicates before and after exposure to high temperatures (up to 1200 °C). The results showed that the geopolymer binders prepared from calcined claystones had a lower dynamic viscosity (787 and 588 mPa·s) compared to the geopolymer binders prepared from metakaolin (1090 mPa·s). Geopolymer composites based on metakaolin had lower shrinkage (0.6%) and higher refractoriness (1520 °C) than geopolymers from calcined claystones (0.9% and 1.5%, 1500 °C and 1470 °C). Geopolymers based on calcined kaolinitic claystones are a promising material with higher compressive (95.2 and 71.5 MPa) and flexural strength (12.4 and 10.7 MPa) compared to geopolymers based on metakaolin (compressive strength 57.7 MPa).
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http://dx.doi.org/10.3390/polym14224838 | DOI Listing |
Nat Commun
January 2025
Chair of Sustainable Construction, Institute of Construction and Infrastructure Management (IBI), ETH Zürich, Stefano-Franscini-Platz 5, 8093, Zurich, Switzerland.
Indoor humidity can significantly impact our comfort and well-being, often leading to the use of mechanical systems for its management. However, these systems can result in substantial carbon emissions and energy precarity. This study offers an alternative: using low-carbon materials that naturally buffer moisture to passively regulate the indoor humidity.
View Article and Find Full Text PDFSci Rep
January 2025
Copernicus Institute of Sustainable Development, Utrecht University, Utrecht, The Netherlands.
This study explores the mechanical properties of geopolymer mortars incorporating ceramic and glass powders sourced from industrial waste. A Box-Behnken design was employed to assess the effects of ceramic waste powder (CWP) content, alkaline activator ratio, solution-to-binder (S: B) ratio, and oven curing duration on the mortar's performance. Compressive strengths were measured at 3 and 28 days, and regression models were developed to predict these outcomes.
View Article and Find Full Text PDFJ Environ Manage
January 2025
Division of Environmental Science and Engineering (DESE), Pohang University of Science and Technology (POSTECH), Pohang, 37673, Republic of Korea; Division of Advanced Nuclear Engineering (DANE), Pohang University of Science and Technology (POSTECH), Pohang, 37673, Republic of Korea. Electronic address:
A geopolymer waste form has become a suitable approach for the immobilization of the volatile technetium (Tc) due to the low curing temperature (<60 °C). However, the low retention and the high mobility of the anionic technetium (TcO) remain challenging due to the charge repulsion stemming from the negative charges of the geopolymer surface and the anionic TcO. Herein, a geopolymer composite containing sulfidized nanoscale zerovalent iron (S-nZVI) was developed to reductively immobilize ReO (used as a non-radioactive surrogate for TcO).
View Article and Find Full Text PDFEnviron Sci Pollut Res Int
December 2024
Department of Civil Engineering, SRM University-AP, Andhra Pradesh, Amaravati, India.
J Environ Manage
January 2025
School of Water Conservancy and Transportation, Zhengzhou University, Zhengzhou, Henan, 450001, China.
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