Park Sol-Moi, Jang Jeong-Gook, Chae Seen-Ae, Lee Haeng-Ki
Department of Civil and Environmental Engineering, Korea Advanced Institute of Science and Technology, 291 Daehak-ro, Yuseong-gu, Daejeon 34141, Korea.
Western Seoul Center, Korea Basic Science Institute, University-Industry Cooperation Building, 150 Bugahyeon-ro, Seodaemun-gu, Seoul 03759, Korea.
Materials (Basel). 2016 Apr 26;9(5):308. doi: 10.3390/ma9050308.
The present study investigated aluminosilicate gel in alkali-activated fly ash exposed to a CO₂-rich environment by means of NMR spectroscopy. The alkali-activated fly ash was exposed to an atmospheric CO₂ concentration of 10% after curing at 80 °C initially for 24 h. Under high concentrations of CO₂, highly reactive components Na and Al, which completely reacted within the first few hours, were unaffected by carbonation, while Si, with relatively slower reactivity, behaved differently. Despite a lower degree of the reaction in the carbonated sample, the monomeric silicates rapidly became of higher polymerization, meaning that exposure to high concentrations of CO₂ caused Si to form a binding gel phase. Consequently, the carbonated sample possessed a higher amount of binding gel. The obtained results may be useful to understand the fundamental chemistry and behavior of aluminosilicate gel under high concentrations of CO₂.
