Kinetics of fly ash geopolymerization |
| |
Authors: | Chen Chen Weiliang Gong Werner Lutze Ian L Pegg |
| |
Affiliation: | (1) Vitreous State Laboratory, The Catholic University of America, Washington, DC, USA;(2) State Key Laboratory of Pollution Control and Resources Reuse and School of the Environment, Nanjing University, Nanjing, 210093, People’s Republic of China; |
| |
Abstract: | Based on the wet chemical analysis, we measured and modeled the kinetics of reactions between fly ash and KOH at various temperatures
and water-to-solid mass ratios (W/S). We find that three consecutive rate-limiting processes control reaction progress: (1) dissolution or alteration of the
glass phase in the fly ash, (2) classical Fick diffusion through a surface layer, and (3) diffusive transport through a more
complex gel structure (interstitial gel). This sequence of processes is independent of W/S (0.35–40), temperature (22–75 °C), and KOH concentration (5–10 M). The relative contribution of each process to the overall
reaction progress changes with experimental conditions. Only if and when the third process is rate limiting, a fly ash geopolymer
forms and develops mechanical strength (sufficiently low W/S ratio provided). The rate of reaction progress decreases significantly, due to slow transport of reacting species to the
surface of the glass particles. |
| |
Keywords: | |
本文献已被 SpringerLink 等数据库收录! |
|