TY - JOUR
T1 - Alkali-activated materials partially activated using flue gas residues
T2 - An insight into reaction products
AU - Riaz Ahmad, Muhammad
AU - Khan, Mehran
AU - Wang, Aiguo
AU - Zhang, Zuhua
AU - Dai, Jian Guo
N1 - Funding Information:
The authors would like to acknowledge the financial support received from NSFC/RGC Joint Research Scheme (N_PolyU542/20), Hong Kong RGC General Research Fund (No. 15223120), The Hong Kong Polytechnic University through the Post-doctoral Fellowship (1-W16R) the Research Institute for Sustainable Urban Development (No.1-BBWE). We also gratefully acknowledge the support of the University Research Facility on Chemical and Environmental Analysis (UCEA) of PolyU.
Publisher Copyright:
© 2023 Elsevier Ltd
PY - 2023/3/31
Y1 - 2023/3/31
N2 - This study explored the feasibility of using flue gas residues (FGR) and commercial sodium silicate (CSS) as hybrid activators (HA) to prepare alkali-activated materials (AAMs). The CSS was replaced by 8, 16, and 24% FGR for a fixed amount of Na2O. Results from selective dissolution techniques showed that control paste (CP-0F, 0% FGR) contained a slightly higher amount of N-A-S-H gel as compared to pastes prepared by hybrid activators (HAPs), whereas the amount of C-A-S-H gel was higher in HAPs containing 16% and 24% FGR. These findings were further corroborated by SEM-EDS analysis results. TGA, XRF and SEM-EDS analysis on paste residues confirmed the efficacy of HCl and SAM dissolution approaches to selectively dissolve the reaction products (N-A-S-H and C-A-S-H gels). SEM-EDS analysis showed that calcium-rich cross-linked gel (C-(N)-A-S-H) was present in all pastes. The gradual increase in reaction products of alkali-actived fly ash/slag (AAFS) pastes with the increase in curing age was observed by XRD analysis. The 29Si MAS NMR analysis revealed the formation of a higher amount of Q4(0Al) and Q4(1Al) species in HAPs as compared to control paste however a decline in the amount of Q4(3Al) and Q4(4Al) species was observed.
AB - This study explored the feasibility of using flue gas residues (FGR) and commercial sodium silicate (CSS) as hybrid activators (HA) to prepare alkali-activated materials (AAMs). The CSS was replaced by 8, 16, and 24% FGR for a fixed amount of Na2O. Results from selective dissolution techniques showed that control paste (CP-0F, 0% FGR) contained a slightly higher amount of N-A-S-H gel as compared to pastes prepared by hybrid activators (HAPs), whereas the amount of C-A-S-H gel was higher in HAPs containing 16% and 24% FGR. These findings were further corroborated by SEM-EDS analysis results. TGA, XRF and SEM-EDS analysis on paste residues confirmed the efficacy of HCl and SAM dissolution approaches to selectively dissolve the reaction products (N-A-S-H and C-A-S-H gels). SEM-EDS analysis showed that calcium-rich cross-linked gel (C-(N)-A-S-H) was present in all pastes. The gradual increase in reaction products of alkali-actived fly ash/slag (AAFS) pastes with the increase in curing age was observed by XRD analysis. The 29Si MAS NMR analysis revealed the formation of a higher amount of Q4(0Al) and Q4(1Al) species in HAPs as compared to control paste however a decline in the amount of Q4(3Al) and Q4(4Al) species was observed.
KW - Alkali-activated gel
KW - Flue gas residue
KW - Microstructure
KW - Nuclear magnetic resonance
KW - Reaction products
KW - Selective dissolution
UR - https://www.scopus.com/pages/publications/85148542255
U2 - 10.1016/j.conbuildmat.2023.130760
DO - 10.1016/j.conbuildmat.2023.130760
M3 - Journal article
AN - SCOPUS:85148542255
SN - 0950-0618
VL - 371
JO - Construction and Building Materials
JF - Construction and Building Materials
M1 - 130760
ER -