Abstract
Samples of a Class F fly ash and calcium hydroxide (CH) hydrated in pH 13.2 sodium hydroxide solution were analyzed using backscattered electron, scanning Auger, and X-ray microanalysis. The Class F fly ash, composed mainly of aluminosilicate glass and silica, was reacted for 8, 14, and 78 days at various temperatures. These samples represent both long-term and early-age stages of hydration. Results show that a hydrate product with calcium to silica ratio near 1.4 and katoite are formed. X-ray and scanning Auger microanalysis show evidence of the formation of hydrate product on the surface of both fly ash and CH particles at early ages. This finding suggests a new mechanism to explain prior data that shows that the hydration rates increase with increasing CH-ash content in the starting mixture.
| Original language | English |
|---|---|
| Pages (from-to) | 963-972 |
| Number of pages | 10 |
| Journal | Cement and Concrete Research |
| Volume | 32 |
| Issue number | 6 |
| DOIs | |
| State | Published - Jun 2002 |
| Externally published | Yes |
Funding
The authors would like to thank Holnam and the Tennessee Technological University Center for the Management, Utilization, and Conservation of Water Resources for their generous ongoing support. This research was performed in part at the Oak Ridge National Laboratory on beamline X-14A at the National Synchrotron Light Source at Brookhaven National Laboratory and was sponsored by the Assistant Secretary for Energy Efficiency and Renewable Energy, Office of Transportation Technologies, as part of the High Temperature Materials Laboratory User Program, at the Oak Ridge National Laboratory, which is managed by UT-Battelle, LLC, for the US Department of Energy under contract no. DE-AC05-00OR22725.
| Funders | Funder number |
|---|---|
| Office of Transportation Technologies | |
| US Department of Energy | |
| Office of Energy Efficiency and Renewable Energy |
Keywords
- Ca(OH)
- Calcium silicate hydrate (C-S-H)
- Fly ash
- Microstructure
- S.E.M.