Title:
Kinetics of Reaction of Calcium Hydroxide and Fly Ash
Author(s):
Joseph J. Biernacki, P. Jason Williams, and Paul E. Stutzman
Publication:
Materials Journal
Volume:
98
Issue:
4
Appears on pages(s):
340-349
Keywords:
fly ash; hydration; pozzolan.
DOI:
10.14359/10403
Date:
7/1/2001
Abstract:
The alkali activated reaction kinetics of a Type-F fly ash with calcium hydroxide (CH) and water has been investigated at temperatures between 25 and 60 C. Thermogravimetric analysis (TGA) was used to determine CH consumption and production of hydrates (nonevaporable water) as a function of hydration temperature and time for various CH/fly ash ratios. The results indicate that the reaction rate, reaction stoichiometry, and activation energy are dependent on the CH/ash ratio. The reaction rate was also found to be a function of the extent of reaction of both CH and fly ash phases. Various kinetic models were considered including those proposed by Knudsen and Avrami. These, however, were found to have limited applicability. A model is suggested that provides a broader fit to the observed data.