Abstract
Effects of curing temperature and NaOH addition on hydration and strength development of cement kiln dust (CKD)-fly ash (FA) binders were investigated. Pastes made with 50% CKD and 50% FA, having 0, 2, and 5% NaOH addition, and cured at temperatures of 24, 38, and 50 °C were evaluated. The hydration products of the binders were examined by thermogravimetric analysis (TGA) and X-ray diffraction (XRD) tests. The results indicate that the major crystalline hydration product of the CKD-FA binders is ettringite, and the ettringite is stable in the CKD-FA system at age over 100 days. Curing at elevated temperature is more effective for CKD-FA binder strength improvement than NaOH addition, the later often depressing ettringite formation in a CKD-FA system. At a proper curing temperature (38 °C), addition of a small amount of NaOH (2%) may increase CKD-FA binder strength; while at a high curing temperature (50 °C), addition of NaOH (2%) may reduce the binder strength.
| Original language | English (US) |
|---|---|
| Pages (from-to) | 299-309 |
| Number of pages | 11 |
| Journal | Cement and Concrete Research |
| Volume | 34 |
| Issue number | 2 |
| DOIs | |
| State | Published - Feb 2004 |
Funding
The authors would like to acknowledge the Cement for Advanced Cement Based Materials (ACBM) and the National Science Foundation (NSF) for providing funding for the present research under Research Grant Number (CMS-0086819). All tests were performed at Iowa State University (ISU). The authors would like to thank the Materials Analysis and Research Laboratory at ISU for providing facilities and assistance on TGA and XRD tests and Lafarge, Cement Group/U.S. Region, for providing raw materials and information.
Keywords
- Cement kiln dust
- Elevated curing temperature
- Fly ash
- NaOH addition
- Thermal analysis
- X-ray diffraction
- XRD
ASJC Scopus subject areas
- Building and Construction
- General Materials Science